The physics of ice cream: food scientist Douglas Goff talks about this remarkable material

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Hello, and welcome to this festive edition of

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the Physics World Weekly podcast.

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I'm Hamish Johnston.

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December might be dark and chilly

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here in the northern hemisphere,

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but it's summer south of the equator.

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And for many people, that means eating ice

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cream.

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And it turns out that the physics of

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ice cream is rather remarkable.

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As I discovered when I traveled to Canada's

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University of Guelph, and met a leading expert

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on the science of frozen desserts.

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Here is that conversation

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with the food scientist,

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Douglas Gough.

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Hi, Doug. Welcome to the podcast.

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Hi, Hamish. It's a pleasure to be here.

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And, yeah, I'm really looking forward to, to

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talking about ice cream with you. And, I

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have to say for the benefit of our

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listeners, it is October

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in Ontario but it is an ice cream

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day out there. It's absolutely beautiful

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outside, and I'm so pleased that I've come

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up to the University of Guelph.

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So

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the first question, and I suppose Doug this

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is a question for all our listeners who

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are physicists,

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how would you describe the material properties of

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ice cream to a physicist?

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Is it a solid for example? Is it

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crystalline?

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Is it amorphous or maybe a bit of

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both?

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Is its melting point

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0 degrees celsius? What what what is ice

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cream from a materials point of view? Well

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the

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the the first

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part of the response would have to be

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to say that it's a very complicated system.

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It's really all about surfaces.

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And so I think when we talk about

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the physics,

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we're talking about mostly the particles

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that would be present in it. And believe

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me, there's lots of particles there. So it's

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a multiphase

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system.

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It starts off being an emulsion. So we

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have the fat, which is emulsified

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into the water phase, the aqueous phase.

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So we start off with an emulsion

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and then

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in the manufacturing

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of ice cream, we whip the emulsion

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to incorporate an air phase into it. So

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in a frozen tub of ice cream, about

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half of the volume is air,

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but that air is present in the form

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of of tiny bubbles that are distributed through

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the the product.

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And then we partially freeze the aqueous phase

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and turn

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at least half or 3 quarters of the

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water into ice crystals.

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And we do that in such a way

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that, again, we end up with microscopically

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small ice crystals

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distributed

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it in that unfrozen phase.

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And the unfrozen phase is the part that

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makes it soft and scoopable and chewable,

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and it remains

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unfrozen as a solvent because of all the

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sugar that's dissolved in it, which acts as

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a solute,

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depresses the freezing point according to Raoult's law.

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So you end up with this multi phase

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system that is,

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fat droplets in the form of an emulsion,

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air bubbles in the form of a foam,

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and a partially

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crystalline

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solvent in the form of ice crystals

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and a freeze concentrated

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sugar solution

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that remains unfrozen because of Raoult's law. So

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it really becomes a very complicated system.

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Right.

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And and so if you were to do

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some sort of, I don't know, let's say

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neutron scattering

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study of ice cream,

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would you, would there be a characteristic

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length

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in there? You know, the separation

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between

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areas of of different phases? Or is it

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all sort

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of I'm just trying to get an idea

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of the microscopic.

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Right. So

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we've done a lot of

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electron microscopy research in my lab. In fact,

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I have to go back to my early

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days and say, you know, our research was

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some of the very first that was, that

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utilized electron microscopy techniques for looking at the

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structure of ice cream.

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So our fat droplets would be in the

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order of about 1 micrometre in size after

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homogenization.

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Air bubbles, again, depending on the equipment that's

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used, would be in the order of 20

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to 30 microns in size.

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And

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ice crystals start off in that

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10 to 20 micrometre

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in size range.

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But

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one of the things that happens to both

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the air phase and the ice phase over

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time is is some recrystallization,

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austral ripening and so on.

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So it's not uncommon to find ice crystals

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up into the 30, 40 micron size.

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And

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then, you know, when you think about all

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that surface area, of course, that

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that unfrozen phase remains, you know, distributed around

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all of that and so we end up

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with these lamellae kind of plateau borders that

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can be on the order of again

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microns in size.

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So it's a it really is a beautiful

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thing to look at under an electron microscope

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depending on the technique that you use

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And we might chat about our techniques a

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little later.

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But that's typically where we're going to see

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all 4 phases: the ice, the air, the

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fat, and the unfrozen phase. Right, I see.

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So it sounds like ice cream is a

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really complex and and beautiful

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material.

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Is it very difficult to make?

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Is it hard to make ice cream when

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if I were to set it in my

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kitchen to make it, would I be hopeless

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at it? Or is it a fairly simple

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process? Well,

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it it can be a very simple process

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right through to being at the commercial scale,

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of course, a very

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large industrial process

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that does become very complicated when you think

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about all the equipment involved.

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So if I just break it down, we

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have the mix making

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step, which would be the combination of our

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liquid ingredients and dry sugars and stabilizer and

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so on to make a liquid mix.

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Commercially, that would be pasteurized

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to heat it for food safety reasons and

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then homogenized

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to distribute the fat.

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If you were making it at home in

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the kitchen, you'd combine your milk and cream

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and sugar and and, you know, whisk that

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probably heat it

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on the stove.

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But it wouldn't be homogenized

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because you would typically be using homogenized cream

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to make it with and so that would

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be the homogenization

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step.

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So we make our mix

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and then the mix is whipped and frozen

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in that

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concomitant

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process that becomes the ice cream maker.

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So again you can buy kitchen gadgets that

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will make ice cream. You can do it

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quite simply by just shaking and stirring. We

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have some things that we do with kids

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where they,

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put a small amount of mix in a

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ziplock bag and put that in a bigger

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ziplock bag with salt and ice and just

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shake the heck out of it for for

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10, 15 minutes

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and you can start freezing it up. So

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it can be as simple as that, but

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if you were to walk into a big

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commercial factory, you'd see equipment that you know

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is running at 1,000 of liters per hour

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And,

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yeah, a lot of engineering that goes into

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to to designing that structure.

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Making sure the ice crystals are small and

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the air bubbles are small and well distributed.

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So,

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I would say, you know, at the kitchen

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level it could be quite simple.

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But if you try to extrapolate

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that to a commercial scale, then yeah, that

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scale up becomes very complicated. I suppose the

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mixing bit is the thing, you know, when

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people think of my of making ice cream

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they think of you have to keep mixing

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it. So is that to make sure that

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the ice crystals don't get too big? Yes.

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Is that the key there?

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And the incorporation of the air phase.

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So in that,

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in that

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freezing and whipping that happens at the same

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time, whether it be in your ice cream

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maker in the kitchen or commercially,

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air is being injected.

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So air is being whipped from the headspace

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or air is being injected into it And

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the

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the dasher, the whipping action is incorporating the

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air to make that small. So that's our

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foaming step. But at the same time,

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the ice is freezing and you want to

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do that under that very rapid dynamic condition

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so you keep the ice crystals very small.

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I see. So again, your big commercial equipment

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would be designed, it would be a scrape

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surface type freezer

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designed with high high rate of shear in

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the barrel

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and a high rate of heat transfer in

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order

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to to to pull the heat out, create

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those ice crystals, but under that dynamic condition

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to keep them really small. I see. And

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the biggest difference between what you do in

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the kitchen and what they're going to do

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in the factory

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is the structure of what you create.

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Homemade ice cream is fine for maybe a

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day or 2, but it's gonna get start

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getting pretty icy pretty quick.

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Whereas we want shelf life of

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months to a year when ice cream is

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made commercially.

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And I wanted to ask you about that

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sort of degradation process. I mean we all

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sort of we defrost our freezers and we

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find that ice cream that we bought last

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summer, they go, I'm gonna have some, open

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up the the container and it's

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it's all ice. How

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how does that happen?

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Is it a very slow phase transition that

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occurs within the the ice cream?

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It's totally dependent on temperature

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and so I just have to describe what

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happens when you warm ice cream up a

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little bit. Again, go back to Raoult's law

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and that freeze concentration of that unfrozen phase.

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So if ice cream warms up during its

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storage time,

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ice is melting in order to maintain that

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equilibrium

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freezing curve, that balance between solvent and and,

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solution.

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So that

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when the temperature would be lowered again, now

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you are freezing more water back into the

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ice phase,

278
00:10:42,884 --> 00:10:44,965
but it doesn't create new ice crystals. It

279
00:10:44,965 --> 00:10:47,304
just grows onto existing ice crystals.

280
00:10:47,899 --> 00:10:50,620
So if during the storage time of ice

281
00:10:50,620 --> 00:10:53,360
cream, it's subject to temperature fluctuation,

282
00:10:53,820 --> 00:10:55,919
it's gonna degrade much quicker

283
00:10:56,299 --> 00:10:58,480
than if it was stored at constant temperature.

284
00:10:58,860 --> 00:11:00,960
And likewise, the warmer the temperature,

285
00:11:01,315 --> 00:11:03,014
the faster that rate of recrystallization

286
00:11:03,555 --> 00:11:04,695
process is gonna

287
00:11:05,154 --> 00:11:07,495
be. So we talk about recrystallization.

288
00:11:08,514 --> 00:11:10,835
It can happen at constant temperature, a bit

289
00:11:10,835 --> 00:11:13,654
of Ostwald ripening, but it's very, very slow.

290
00:11:14,129 --> 00:11:17,509
The biggest thing that that exacerbates recrystallization

291
00:11:17,970 --> 00:11:20,129
or the growth of ice crystals is temperature

292
00:11:20,129 --> 00:11:20,629
abuse.

293
00:11:21,250 --> 00:11:23,889
I see. And so you you mentioned that

294
00:11:23,889 --> 00:11:25,889
commercial ice creams can be stored for a

295
00:11:25,889 --> 00:11:28,129
very long time. Is that just because they've

296
00:11:28,129 --> 00:11:30,795
got very very good freezers that maintain

297
00:11:31,975 --> 00:11:34,215
an exact temperature or is there something else

298
00:11:34,215 --> 00:11:35,975
that they can do to the to the

299
00:11:35,975 --> 00:11:38,615
ice cream to stop it? So I'd have

300
00:11:38,615 --> 00:11:41,254
to say there's maybe again 3 different things

301
00:11:41,254 --> 00:11:43,920
I want to comment on there. That yes,

302
00:11:43,980 --> 00:11:45,120
low and constant

303
00:11:45,500 --> 00:11:49,500
temperature storage is what everybody strives for. And

304
00:11:49,500 --> 00:11:53,040
so the lower the temperature and the more

305
00:11:53,100 --> 00:11:56,460
constant it is, then the longer your shelf

306
00:11:56,460 --> 00:11:58,720
life before changes start occurring.

307
00:11:59,914 --> 00:12:00,735
There's another

308
00:12:01,115 --> 00:12:03,855
element that comes into that and that's that

309
00:12:04,394 --> 00:12:06,575
as part of the structure of ice cream,

310
00:12:06,794 --> 00:12:07,615
when that

311
00:12:09,835 --> 00:12:11,134
unfrozen phase

312
00:12:11,595 --> 00:12:12,654
gets concentrated

313
00:12:13,034 --> 00:12:13,534
enough

314
00:12:14,169 --> 00:12:15,710
it goes through a glass transition.

315
00:12:16,330 --> 00:12:19,049
And so that that what we consider that

316
00:12:19,049 --> 00:12:21,790
unfrozen phase that makes it soft and scoopable

317
00:12:22,330 --> 00:12:23,549
when it's warm enough,

318
00:12:24,009 --> 00:12:26,730
if it undergoes a glass transition and itself

319
00:12:26,730 --> 00:12:28,429
becomes an amorphous solid,

320
00:12:28,815 --> 00:12:31,235
then there will be no movement of water,

321
00:12:31,294 --> 00:12:34,595
no movement of of solute within the system,

322
00:12:34,735 --> 00:12:36,595
and it can be it can remain,

323
00:12:37,375 --> 00:12:38,035
you know,

324
00:12:38,575 --> 00:12:40,115
unchanged for years.

325
00:12:40,830 --> 00:12:43,649
And that glass transition temperature is around

326
00:12:44,029 --> 00:12:46,850
-twenty 8 to -thirty 2 degrees C.

327
00:12:47,470 --> 00:12:49,970
So if you want long term storage

328
00:12:50,670 --> 00:12:52,610
you have to get down below that

329
00:12:52,934 --> 00:12:55,654
that tg that glass transition. Is that reasonable

330
00:12:55,654 --> 00:12:58,134
from a cost point of view? Well, it's

331
00:12:58,134 --> 00:13:01,975
expensive. You're right. We maintain a storage freezer

332
00:13:01,975 --> 00:13:02,955
here at the university,

333
00:13:03,894 --> 00:13:05,754
about minus 32 degrees.

334
00:13:06,279 --> 00:13:06,779
And

335
00:13:07,879 --> 00:13:09,820
we had ice cream that went in there

336
00:13:09,960 --> 00:13:12,779
just before the pandemic and then,

337
00:13:13,960 --> 00:13:15,559
of course it was 2 or 3 years

338
00:13:15,559 --> 00:13:17,659
before we got back to it again.

339
00:13:18,039 --> 00:13:19,879
And it was it was just as good

340
00:13:19,879 --> 00:13:21,259
as the day it was manufactured.

341
00:13:22,054 --> 00:13:23,735
So you know when people say to me,

342
00:13:23,735 --> 00:13:25,414
what's the shelf life of ice cream? I

343
00:13:25,414 --> 00:13:27,595
say, well what's the temperature? Because

344
00:13:27,975 --> 00:13:29,514
it can be 2 or 3

345
00:13:29,894 --> 00:13:31,735
years or it can be 2 or 3

346
00:13:31,735 --> 00:13:34,534
days if you start getting up into those

347
00:13:34,534 --> 00:13:37,809
abusive temperature conditions. Right. And and what about

348
00:13:37,809 --> 00:13:40,450
the opposite? I mean I would imagine for

349
00:13:40,450 --> 00:13:41,190
ice cream

350
00:13:41,809 --> 00:13:42,309
manufacturers

351
00:13:42,929 --> 00:13:43,750
there's always

352
00:13:44,370 --> 00:13:47,110
a danger that somewhere in their supply

353
00:13:47,490 --> 00:13:50,485
chain the temperature will go up Yes. And

354
00:13:50,485 --> 00:13:52,324
that could cause them a problem. Is there

355
00:13:52,324 --> 00:13:54,745
anything that that they can do to

356
00:13:55,284 --> 00:13:58,084
ensure stability of their ice cream at high

357
00:13:58,084 --> 00:14:00,264
temperatures, you know, just to guarantee?

358
00:14:00,725 --> 00:14:02,485
Right. And that so that brings me to

359
00:14:02,485 --> 00:14:03,544
point number 3,

360
00:14:03,850 --> 00:14:04,889
And that's that,

361
00:14:05,610 --> 00:14:07,309
the addition of stabilizers

362
00:14:07,690 --> 00:14:09,309
to to an ice cream formulation.

363
00:14:09,850 --> 00:14:12,570
Those are things like locust bean gum, guar

364
00:14:12,570 --> 00:14:13,070
gum,

365
00:14:13,929 --> 00:14:15,070
cellulose gum,

366
00:14:15,769 --> 00:14:17,595
and there are some novel ones as well.

367
00:14:17,674 --> 00:14:20,095
Well. And what those do is to increase

368
00:14:20,154 --> 00:14:23,914
the viscosity in that unfrozen phase. And so

369
00:14:23,914 --> 00:14:26,574
it slows down the rate of ice recrystallization

370
00:14:27,434 --> 00:14:30,334
just because of a very viscous system

371
00:14:30,860 --> 00:14:31,519
that then,

372
00:14:31,820 --> 00:14:33,839
has an impact on on diffusion,

373
00:14:34,699 --> 00:14:36,000
of of water

374
00:14:36,539 --> 00:14:38,240
and, growth of ice.

375
00:14:38,699 --> 00:14:39,199
So,

376
00:14:39,740 --> 00:14:41,519
if you compare an unstabilized

377
00:14:42,059 --> 00:14:44,459
ice cream to one that would contain guar

378
00:14:44,459 --> 00:14:45,679
gum, for example,

379
00:14:46,074 --> 00:14:47,534
the guar would give you

380
00:14:48,074 --> 00:14:48,654
a much

381
00:14:49,355 --> 00:14:50,654
slower rate of recrystallization

382
00:14:51,115 --> 00:14:52,574
and longer shelf life.

383
00:14:53,274 --> 00:14:54,975
There are some other novel

384
00:14:55,514 --> 00:14:56,414
ice recrystallization

385
00:14:57,274 --> 00:14:58,414
inhibition agents.

386
00:14:59,620 --> 00:15:01,480
One of them is propylene glycolmonosteriate,

387
00:15:02,580 --> 00:15:04,820
and it is really unique in that it

388
00:15:04,820 --> 00:15:07,299
can adsorb onto the surface of an ice

389
00:15:07,299 --> 00:15:10,039
crystal very much the same way that these

390
00:15:10,259 --> 00:15:13,240
ice structuring proteins do, or the antifreeze proteins

391
00:15:13,299 --> 00:15:15,485
in nature. And and,

392
00:15:15,965 --> 00:15:18,285
really block the growth of of ice crystals

393
00:15:18,285 --> 00:15:19,825
and keep them very very small.

394
00:15:20,365 --> 00:15:22,065
So for commercial

395
00:15:22,524 --> 00:15:24,065
recipes that need

396
00:15:25,725 --> 00:15:28,524
long shelf life in the presence of potential

397
00:15:28,524 --> 00:15:29,665
temperature abuse,

398
00:15:30,110 --> 00:15:32,350
there are some special agents that they can

399
00:15:32,350 --> 00:15:34,029
add to the to the recipe to try

400
00:15:34,029 --> 00:15:36,429
to give them that longer shelf life. Right.

401
00:15:36,429 --> 00:15:37,490
So so these

402
00:15:38,029 --> 00:15:41,149
those would be natural antifreezes. I mean, try

403
00:15:41,149 --> 00:15:43,149
imagining a fish that lives in very cold

404
00:15:43,149 --> 00:15:43,649
water.

405
00:15:43,995 --> 00:15:45,835
It might have something in its body that

406
00:15:45,835 --> 00:15:49,115
prevents it from freezing. Yeah, and that's again

407
00:15:49,115 --> 00:15:51,695
a very very interesting subject. And

408
00:15:52,394 --> 00:15:55,615
and both both insects and fish and plants,

409
00:15:56,940 --> 00:15:59,600
they all have means of controlling,

410
00:16:00,779 --> 00:16:02,940
the the development of ice that could be

411
00:16:02,940 --> 00:16:04,559
harmful to tissue structures.

412
00:16:05,019 --> 00:16:07,519
And and what we typically say is antifreeze,

413
00:16:09,134 --> 00:16:09,855
there are,

414
00:16:10,414 --> 00:16:13,235
agents certainly that prevent the formation of ice.

415
00:16:13,294 --> 00:16:16,355
But in many cases it's actually anti growth

416
00:16:16,894 --> 00:16:18,815
that a lot of fish swim around with

417
00:16:18,815 --> 00:16:20,995
minute ice crystals in their,

418
00:16:21,454 --> 00:16:22,834
in their body tissues.

419
00:16:23,190 --> 00:16:23,929
But these

420
00:16:24,710 --> 00:16:27,750
these, types of of ice structuring proteins prevent

421
00:16:27,750 --> 00:16:29,830
those ice crystals from getting big enough to

422
00:16:29,830 --> 00:16:30,570
cause harm.

423
00:16:31,029 --> 00:16:33,029
So it could be antifreeze or it could

424
00:16:33,029 --> 00:16:34,169
be antigrowth.

425
00:16:34,790 --> 00:16:35,850
Right. And it's really,

426
00:16:36,309 --> 00:16:38,490
what we want in ice cream is the

427
00:16:38,615 --> 00:16:41,174
is to prevent the growth. You don't want

428
00:16:41,174 --> 00:16:44,214
to prevent the formation of ice because that's

429
00:16:44,214 --> 00:16:45,434
a given. What

430
00:16:45,975 --> 00:16:47,975
we want is to prevent those ice crystals

431
00:16:47,975 --> 00:16:51,834
from growing. I see. And what you

432
00:16:52,214 --> 00:16:54,690
talked about sort of the basic ingredients of

433
00:16:54,690 --> 00:16:56,850
ice cream, but of course today you can

434
00:16:56,850 --> 00:16:59,169
get lots of different flavours. I mean when

435
00:16:59,169 --> 00:17:00,149
you start putting

436
00:17:00,610 --> 00:17:03,590
chocolate or coffee or maybe fruit juice

437
00:17:04,049 --> 00:17:06,309
into your ice cream, do those

438
00:17:06,974 --> 00:17:08,194
additions change

439
00:17:08,815 --> 00:17:10,575
the nature of how you, so would you

440
00:17:10,575 --> 00:17:12,494
have to make a strawberry ice cream in

441
00:17:12,494 --> 00:17:14,255
a different way to a chocolate ice cream

442
00:17:14,255 --> 00:17:14,914
to accommodate

443
00:17:15,535 --> 00:17:17,934
the the chemical and physical properties of the

444
00:17:17,934 --> 00:17:20,674
flavouring? Again, very good question. And

445
00:17:21,230 --> 00:17:22,990
because when you think about ice cream around

446
00:17:22,990 --> 00:17:25,710
the world, there are literally 100 and 100

447
00:17:25,710 --> 00:17:26,849
of different flavors.

448
00:17:27,309 --> 00:17:29,890
And so the biggest question is

449
00:17:30,910 --> 00:17:31,970
is that flavoring

450
00:17:33,070 --> 00:17:33,970
either material

451
00:17:34,269 --> 00:17:35,009
or or

452
00:17:36,325 --> 00:17:37,625
flavor addition itself,

453
00:17:37,924 --> 00:17:39,065
is that impacting

454
00:17:39,445 --> 00:17:40,345
on the

455
00:17:41,125 --> 00:17:43,065
the nature of the solution

456
00:17:43,445 --> 00:17:46,325
or emulsion that's in there? For example, a

457
00:17:46,325 --> 00:17:48,965
chocolate chip. It's going to be totally inert.

458
00:17:48,965 --> 00:17:50,424
It's not going to interact

459
00:17:50,849 --> 00:17:53,029
at all with the rest of the matrix.

460
00:17:53,410 --> 00:17:55,809
So no problem to throw something like chocolate

461
00:17:55,809 --> 00:17:57,970
chips or nuts or something that would be

462
00:17:57,970 --> 00:17:58,869
totally inert.

463
00:17:59,329 --> 00:18:01,970
Nuts might be a little difficult because if

464
00:18:01,970 --> 00:18:03,589
they start absorbing water,

465
00:18:04,224 --> 00:18:06,065
changes the balance of the things that are

466
00:18:06,065 --> 00:18:07,924
in that unfrozen phase.

467
00:18:09,264 --> 00:18:09,764
Strawberries

468
00:18:10,065 --> 00:18:13,444
would be a good example of really impacting

469
00:18:13,504 --> 00:18:14,404
on the system

470
00:18:14,704 --> 00:18:17,024
because of the high sugar content that's in

471
00:18:17,024 --> 00:18:18,085
the fruit preparation.

472
00:18:18,759 --> 00:18:20,440
We need to add sugar to the fruit

473
00:18:20,440 --> 00:18:22,200
to make sure the fruit is softer than

474
00:18:22,200 --> 00:18:24,119
the ice cream itself. You don't wanna bite

475
00:18:24,119 --> 00:18:26,039
into ice cream and have a hard frozen

476
00:18:26,039 --> 00:18:27,099
berry in there.

477
00:18:27,480 --> 00:18:29,500
So most of the fruit would be sugared.

478
00:18:30,119 --> 00:18:31,799
Now the problem is that some of that

479
00:18:31,799 --> 00:18:33,179
sugar is gonna diffuse

480
00:18:33,480 --> 00:18:33,980
into

481
00:18:34,714 --> 00:18:36,494
the unfrozen phase

482
00:18:36,955 --> 00:18:40,095
and lower the freezing point of it. So

483
00:18:40,234 --> 00:18:42,815
if you don't do anything to the formulation,

484
00:18:43,515 --> 00:18:45,695
then strawberry ice cream would be softer

485
00:18:46,234 --> 00:18:48,335
overall than something like vanilla,

486
00:18:49,190 --> 00:18:50,009
because of

487
00:18:50,390 --> 00:18:51,609
the the addition of sugar,

488
00:18:52,630 --> 00:18:53,930
that comes with the fruit.

489
00:18:54,630 --> 00:18:55,769
So if scooping,

490
00:18:56,150 --> 00:18:58,150
for example, is one of the things that's

491
00:18:58,150 --> 00:18:59,690
critical for your operation,

492
00:19:00,069 --> 00:19:01,670
as it would be for, you know, people

493
00:19:01,670 --> 00:19:03,984
running the scoop shop, then they might have

494
00:19:03,984 --> 00:19:06,065
to make a base mix for their fruit

495
00:19:06,065 --> 00:19:08,164
flavors that had less sugar in it

496
00:19:08,545 --> 00:19:10,464
to offset the sugar that would come from

497
00:19:10,464 --> 00:19:12,545
the fruit and give you the same level

498
00:19:12,545 --> 00:19:15,125
of scoopability once it went into the freezer

499
00:19:15,585 --> 00:19:16,085
cabinet.

500
00:19:16,390 --> 00:19:18,970
I see. And are there any additives,

501
00:19:19,669 --> 00:19:21,509
well additives that's a sort of a harsh

502
00:19:21,509 --> 00:19:24,329
word, any you know sort of flavors

503
00:19:24,789 --> 00:19:25,289
or

504
00:19:25,910 --> 00:19:28,069
stuff I suppose that you can that you

505
00:19:28,069 --> 00:19:29,910
that people have tried to put into ice

506
00:19:29,910 --> 00:19:30,730
cream but

507
00:19:31,125 --> 00:19:33,924
it just doesn't work for whatever reason. You

508
00:19:33,924 --> 00:19:36,404
can't make a, I don't know, pineapple ice

509
00:19:36,404 --> 00:19:39,445
cream for you know various reasons. Or can

510
00:19:39,445 --> 00:19:42,025
you make ice cream with any flavour? Well

511
00:19:42,484 --> 00:19:44,009
I think you can try to make ice

512
00:19:44,009 --> 00:19:46,009
cream with just about anything. The question is

513
00:19:46,009 --> 00:19:47,309
whether anybody's gonna

514
00:19:47,930 --> 00:19:50,089
either buy it once or more importantly buy

515
00:19:50,089 --> 00:19:52,250
it twice. You know, they might buy it

516
00:19:52,250 --> 00:19:53,470
once to try it.

517
00:19:54,009 --> 00:19:56,430
So gosh, we've seen everything from, you know,

518
00:19:56,554 --> 00:19:59,515
hot jalapeno peppers and, you know, that kind

519
00:19:59,515 --> 00:20:01,694
of a thing to to the

520
00:20:02,154 --> 00:20:05,674
the floral fragrant flavors and, you know, the

521
00:20:05,674 --> 00:20:08,394
alcohol based flavors. So that would be a

522
00:20:08,394 --> 00:20:11,035
good example. You think of anything from rum

523
00:20:11,035 --> 00:20:11,535
to

524
00:20:11,910 --> 00:20:12,410
to,

525
00:20:13,109 --> 00:20:15,609
Bailey's Irish cream or or Frangelico

526
00:20:15,990 --> 00:20:18,410
or any of those. They're very very popular.

527
00:20:18,549 --> 00:20:20,730
Wine based and beer based flavors.

528
00:20:21,109 --> 00:20:23,430
Very popular. But the alcohol is going to

529
00:20:23,430 --> 00:20:25,454
depress the freezing point. And you're going to

530
00:20:25,454 --> 00:20:26,914
get to the point where,

531
00:20:27,375 --> 00:20:29,855
you know, if you added enough alcohol to

532
00:20:29,855 --> 00:20:32,414
give you the flavor intensity that you want,

533
00:20:32,414 --> 00:20:33,954
then your product wouldn't freeze.

534
00:20:35,054 --> 00:20:37,134
So in that case, you might need to

535
00:20:37,134 --> 00:20:39,630
add less of the alcohol and a little

536
00:20:39,630 --> 00:20:42,049
bit more of like a flavouring, a dealkalized

537
00:20:42,990 --> 00:20:43,490
flavouring

538
00:20:43,950 --> 00:20:45,730
to get both the flavour combination

539
00:20:46,109 --> 00:20:46,589
and,

540
00:20:47,230 --> 00:20:48,529
and having some real,

541
00:20:48,909 --> 00:20:51,470
you know, bourbon in there or whatever the

542
00:20:51,470 --> 00:20:52,529
the case is.

543
00:20:52,829 --> 00:20:53,329
So

544
00:20:53,785 --> 00:20:55,224
I would say you can try to make

545
00:20:55,224 --> 00:20:57,144
ice cream with just about any flavor but

546
00:20:57,144 --> 00:20:59,384
you you certainly have to look at what

547
00:20:59,384 --> 00:21:01,884
that flavouring is going to do to the

548
00:21:02,265 --> 00:21:03,404
structure and

549
00:21:05,224 --> 00:21:07,144
the things like shelf life and balance and

550
00:21:07,144 --> 00:21:08,744
so on that that would be present in

551
00:21:08,744 --> 00:21:12,289
there. Right. And I suppose in in standard

552
00:21:12,430 --> 00:21:14,369
ice cream it is made for milk,

553
00:21:15,150 --> 00:21:17,250
but I'm guessing that you can buy vegan

554
00:21:17,630 --> 00:21:20,269
ice cream these days. Was was that very

555
00:21:20,269 --> 00:21:23,070
difficult to do to make an ice cream

556
00:21:23,070 --> 00:21:25,184
that didn't have any cream in it. Right,

557
00:21:25,184 --> 00:21:26,144
is that hard?

558
00:21:27,825 --> 00:21:29,025
So a lot of it is going to

559
00:21:29,025 --> 00:21:31,664
be pretty similar because we're going to have

560
00:21:31,664 --> 00:21:34,484
an emulsified fat source. Typically it,

561
00:21:35,345 --> 00:21:37,664
would be something like coconut oil or palm

562
00:21:37,664 --> 00:21:38,565
kernel oil.

563
00:21:39,410 --> 00:21:41,329
I didn't really mention that when I talked

564
00:21:41,329 --> 00:21:43,490
about the structure of ice cream, but that

565
00:21:43,490 --> 00:21:43,990
fat

566
00:21:44,690 --> 00:21:46,230
itself has to be crystalline.

567
00:21:47,410 --> 00:21:49,890
If it was liquid oil at the time

568
00:21:49,890 --> 00:21:50,950
of of the

569
00:21:51,250 --> 00:21:52,230
whipping process,

570
00:21:52,534 --> 00:21:54,954
then the oil would coalesce and separate out.

571
00:21:55,255 --> 00:21:58,075
And so our fat phase is also crystalline.

572
00:21:58,934 --> 00:22:00,694
I failed to mention that when I was

573
00:22:00,694 --> 00:22:01,835
talking about structure.

574
00:22:02,134 --> 00:22:04,214
So that means that you're limited to the

575
00:22:04,214 --> 00:22:05,974
type of fat that can go in there.

576
00:22:05,974 --> 00:22:07,994
It really has to be a solid crystalline

577
00:22:08,054 --> 00:22:10,830
fat. So you've got, you know, your fat

578
00:22:10,830 --> 00:22:13,309
phase. You've got of course all the sugar

579
00:22:13,309 --> 00:22:15,070
and stabilizer and so on that you would

580
00:22:15,070 --> 00:22:16,930
have in a normal ice cream.

581
00:22:17,390 --> 00:22:18,930
The difference is the protein.

582
00:22:19,309 --> 00:22:22,350
So if we take away milk protein, milk

583
00:22:22,350 --> 00:22:24,284
protein by the way is both a very

584
00:22:24,284 --> 00:22:26,784
good foaming agent and a very good emulsifying

585
00:22:27,085 --> 00:22:30,065
agent, then we need to replace the functionality

586
00:22:30,204 --> 00:22:31,024
of the protein.

587
00:22:31,325 --> 00:22:33,664
And plant proteins aren't very good

588
00:22:33,964 --> 00:22:34,865
foaming agents,

589
00:22:35,404 --> 00:22:37,024
or emulsifying agents.

590
00:22:37,460 --> 00:22:39,720
Eggs are, but again they are not

591
00:22:40,099 --> 00:22:43,059
vegan. So if you start looking at these

592
00:22:43,059 --> 00:22:46,420
cashew or almond or soy based products, you'll

593
00:22:46,420 --> 00:22:49,000
often find on the ingredient list some ingredients

594
00:22:49,059 --> 00:22:51,785
that are in there to deliver that functionality

595
00:22:51,924 --> 00:22:53,605
that we would have gotten from the milk

596
00:22:53,605 --> 00:22:54,105
protein.

597
00:22:54,725 --> 00:22:56,505
So I think that the big considerations

598
00:22:56,884 --> 00:22:58,965
are going to be flavour and texture that

599
00:22:58,965 --> 00:23:01,144
are coming from the plant source itself,

600
00:23:01,765 --> 00:23:02,505
but then

601
00:23:04,100 --> 00:23:06,039
the delivery of the functionality that you need

602
00:23:06,039 --> 00:23:08,033
to make a you know a good product.

603
00:23:08,033 --> 00:23:09,640
I see. And

604
00:23:10,180 --> 00:23:10,840
what about

605
00:23:11,299 --> 00:23:12,279
desserts like

606
00:23:12,820 --> 00:23:13,320
gelato

607
00:23:13,940 --> 00:23:14,680
and sorbet?

608
00:23:15,140 --> 00:23:17,355
Are they ice creams or are they

609
00:23:17,994 --> 00:23:19,914
similar to ice creams? Are they made in

610
00:23:19,914 --> 00:23:22,654
roughly the same way? Are they completely different?

611
00:23:23,275 --> 00:23:25,355
More similar than different I would have to

612
00:23:25,355 --> 00:23:25,855
say.

613
00:23:26,714 --> 00:23:28,575
Gelato doesn't really have

614
00:23:29,559 --> 00:23:32,119
a standard of identity as such. It's really

615
00:23:32,119 --> 00:23:34,680
just Italian style ice cream. So there's some

616
00:23:34,680 --> 00:23:35,180
unique

617
00:23:35,559 --> 00:23:37,160
things about it that make it a little

618
00:23:37,160 --> 00:23:39,880
bit different. Typically lower in fat and higher

619
00:23:39,880 --> 00:23:42,119
in sugar compared to a standard ice cream

620
00:23:42,119 --> 00:23:44,619
recipe. And that gives it more of that

621
00:23:45,184 --> 00:23:47,825
soft sticky texture that you typically get from

622
00:23:47,825 --> 00:23:48,565
a gelato.

623
00:23:49,265 --> 00:23:50,724
Typically, it's not hard,

624
00:23:51,664 --> 00:23:53,984
hardened or hard frozen the way an ice

625
00:23:53,984 --> 00:23:56,464
cream would be. And so it can be,

626
00:23:56,464 --> 00:23:59,105
you know, paddled rather than scooped kind of

627
00:23:59,105 --> 00:23:59,605
thing.

628
00:24:00,390 --> 00:24:01,609
Sorbet is,

629
00:24:02,470 --> 00:24:04,490
has no dairy in it at all.

630
00:24:05,509 --> 00:24:07,930
Typically just fruit juice, sugar,

631
00:24:08,630 --> 00:24:09,990
and water. And,

632
00:24:10,470 --> 00:24:12,965
it's so it's it's whipped and frozen. So

633
00:24:12,965 --> 00:24:14,805
you have the ice phase and you have

634
00:24:14,805 --> 00:24:15,305
the

635
00:24:15,924 --> 00:24:18,585
ice crystal, ice crystals in the air phase,

636
00:24:18,805 --> 00:24:20,725
but you don't typically have any fat in

637
00:24:20,725 --> 00:24:21,225
there.

638
00:24:21,684 --> 00:24:24,585
And because you don't have any protein neither,

639
00:24:24,950 --> 00:24:26,789
it makes it very hard to get much

640
00:24:26,789 --> 00:24:29,990
air incorporated into it. So sorbets can be

641
00:24:29,990 --> 00:24:32,230
really good but they're they're tricky to make

642
00:24:32,230 --> 00:24:34,470
on a commercial scale just because the overrun

643
00:24:34,470 --> 00:24:36,230
needs to be or the air content needs

644
00:24:36,230 --> 00:24:39,345
to be quite low. I see. And Doug

645
00:24:39,345 --> 00:24:40,484
you mentioned earlier

646
00:24:41,345 --> 00:24:42,325
electron microscopy.

647
00:24:44,945 --> 00:24:46,805
Can you talk a bit about the techniques

648
00:24:46,945 --> 00:24:49,765
that you use to study ice creams?

649
00:24:50,305 --> 00:24:52,859
I mean is it I would have naively

650
00:24:52,920 --> 00:24:55,019
thought that your electron beam would melt

651
00:24:55,400 --> 00:24:56,380
your ice cream,

652
00:24:56,920 --> 00:24:59,400
but maybe that isn't the case. How do

653
00:24:59,400 --> 00:25:01,559
you so maybe if you could first talk

654
00:25:01,559 --> 00:25:02,539
about electron?

655
00:25:02,920 --> 00:25:05,035
So I would say the work courses of

656
00:25:05,035 --> 00:25:08,075
of instrumentation for research, not necessarily at the

657
00:25:08,075 --> 00:25:09,695
factory level, but for research

658
00:25:10,154 --> 00:25:11,934
would be particle size analysis.

659
00:25:12,555 --> 00:25:15,434
So laser light scattering, and that's gonna tell

660
00:25:15,434 --> 00:25:17,835
you everything you need to know about your

661
00:25:17,835 --> 00:25:19,775
your fat globules and fat structure.

662
00:25:21,410 --> 00:25:23,430
Then we do use a lot of microscopy

663
00:25:23,650 --> 00:25:24,950
techniques. Light microscopy,

664
00:25:27,170 --> 00:25:29,349
with a cold stage. That's the critical

665
00:25:29,650 --> 00:25:31,809
part there. So you either need to put

666
00:25:31,809 --> 00:25:33,349
your microscope in a freezer

667
00:25:34,515 --> 00:25:37,555
or in a cold box with a with,

668
00:25:37,555 --> 00:25:39,875
you know, gloves to to use it, or

669
00:25:39,875 --> 00:25:41,875
have a cold stage where you mount your

670
00:25:41,875 --> 00:25:43,894
your ice cream on a slide

671
00:25:44,275 --> 00:25:46,674
inside of a chamber with with that's cooled

672
00:25:46,674 --> 00:25:48,055
with with liquid nitrogen.

673
00:25:48,660 --> 00:25:49,059
So,

674
00:25:49,460 --> 00:25:50,119
on the

675
00:25:50,500 --> 00:25:53,700
electron microscopy side we've done we've done a

676
00:25:53,700 --> 00:25:54,600
lot of cryo

677
00:25:55,059 --> 00:25:56,519
scanning electron microscopy.

678
00:25:57,059 --> 00:25:58,200
So having a

679
00:25:58,980 --> 00:26:01,320
a low temperature unit on the SEM.

680
00:26:02,325 --> 00:26:04,244
And we've also done a lot of transmission

681
00:26:04,244 --> 00:26:05,304
electron microscopy.

682
00:26:05,924 --> 00:26:08,325
And there the technique is to fix the

683
00:26:08,325 --> 00:26:10,404
sample with some sort of a of a

684
00:26:10,404 --> 00:26:10,904
fixative

685
00:26:11,924 --> 00:26:13,384
and then dry it.

686
00:26:14,244 --> 00:26:15,865
Critical point drying typically.

687
00:26:16,269 --> 00:26:18,269
Then you can thin section it and and

688
00:26:18,269 --> 00:26:20,769
look at it with a transmission electron microscope.

689
00:26:21,470 --> 00:26:25,150
Now there are some cryo TEM instruments available

690
00:26:25,150 --> 00:26:27,630
as well, but we're talking, you know, the

691
00:26:27,630 --> 00:26:29,730
real high end of technology.

692
00:26:30,724 --> 00:26:32,664
But cryo SEM and

693
00:26:33,205 --> 00:26:34,984
then TEM with cryo fixation,

694
00:26:35,765 --> 00:26:38,744
would both be excellent techniques. Or light microscopy

695
00:26:38,884 --> 00:26:41,545
with the cold stage for examining the structural

696
00:26:41,605 --> 00:26:42,825
elements that are there.

697
00:26:43,190 --> 00:26:44,869
And then rheology. Of course, we do a

698
00:26:44,869 --> 00:26:46,170
tremendous amount of rheology.

699
00:26:47,589 --> 00:26:48,089
Both

700
00:26:48,869 --> 00:26:52,329
small deformation rheology. Looking at things like mix

701
00:26:53,349 --> 00:26:53,849
viscoelasticity,

702
00:26:54,630 --> 00:26:56,890
G prime, G double prime and so on.

703
00:26:57,335 --> 00:26:57,994
And then,

704
00:26:58,934 --> 00:27:00,875
large deformation rheology.

705
00:27:01,174 --> 00:27:03,815
Things like a instrailing machine where you're going

706
00:27:03,815 --> 00:27:05,195
to measure force deformation

707
00:27:05,894 --> 00:27:07,575
sorts of and that's going to give you

708
00:27:07,575 --> 00:27:08,714
an idea of hardness

709
00:27:09,095 --> 00:27:11,035
measurements on on the ice cream.

710
00:27:11,460 --> 00:27:13,539
So I would that would be the the

711
00:27:13,539 --> 00:27:17,140
toolkit would be particle size analysis, rheology, and

712
00:27:17,140 --> 00:27:20,419
microscopy. I see. And what about computational techniques?

713
00:27:20,419 --> 00:27:21,559
Are there some sophisticated

714
00:27:21,859 --> 00:27:24,764
computer models of ice cream out there? There

715
00:27:24,764 --> 00:27:26,384
have been some papers published.

716
00:27:27,085 --> 00:27:29,404
It's not really an area that,

717
00:27:30,365 --> 00:27:33,804
I don't think is going to really get

718
00:27:33,804 --> 00:27:35,504
us very far, to be honest.

719
00:27:36,070 --> 00:27:37,670
Is it just too complicated of a system?

720
00:27:37,670 --> 00:27:39,590
Yeah. It is. Just too complicated of a

721
00:27:39,590 --> 00:27:41,690
system to to try to model it.

722
00:27:42,070 --> 00:27:44,730
And then and then to get anything meaningful

723
00:27:44,869 --> 00:27:46,630
out of your model that you could relate

724
00:27:46,630 --> 00:27:48,950
back to, you know, to something that would

725
00:27:48,950 --> 00:27:50,009
happen in the factory.

726
00:27:51,134 --> 00:27:52,434
There might be computational

727
00:27:52,735 --> 00:27:53,235
design,

728
00:27:54,414 --> 00:27:56,894
utilized in the engineering of some of the

729
00:27:56,894 --> 00:27:57,875
equipment particularly,

730
00:27:58,735 --> 00:28:01,934
looking at the barrel freezers, the scrape surface

731
00:28:01,934 --> 00:28:02,595
heat exchangers.

732
00:28:03,529 --> 00:28:05,769
So if you went to some of the

733
00:28:05,769 --> 00:28:08,409
big global suppliers of equipment, you might find

734
00:28:08,409 --> 00:28:08,909
them

735
00:28:09,210 --> 00:28:10,909
trying to do design work

736
00:28:11,210 --> 00:28:11,710
of,

737
00:28:12,329 --> 00:28:14,730
you know, things like residence time and residence

738
00:28:14,730 --> 00:28:15,230
distribution

739
00:28:16,565 --> 00:28:17,785
inside their equipment,

740
00:28:18,565 --> 00:28:20,325
that would be an example I think where

741
00:28:20,325 --> 00:28:22,345
you'd find some some more

742
00:28:23,365 --> 00:28:26,085
design work happening. Right. And so what are

743
00:28:26,085 --> 00:28:28,345
the the hot topics at the moment,

744
00:28:28,644 --> 00:28:30,184
you know in in the academic

745
00:28:30,690 --> 00:28:32,149
study of ice cream? What

746
00:28:32,450 --> 00:28:34,049
what are you interested in, you and your

747
00:28:34,049 --> 00:28:34,549
colleagues?

748
00:28:35,569 --> 00:28:38,210
For a long time we focused on ice

749
00:28:38,210 --> 00:28:39,829
cream structure and understanding,

750
00:28:41,409 --> 00:28:42,470
ingredient functionality.

751
00:28:43,244 --> 00:28:44,545
And so both

752
00:28:45,164 --> 00:28:47,265
things like like emulsifier functionality,

753
00:28:47,805 --> 00:28:49,025
stabilizer functionality,

754
00:28:49,404 --> 00:28:50,384
protein functionality,

755
00:28:51,005 --> 00:28:52,144
to try to understand,

756
00:28:52,845 --> 00:28:55,345
you know, if changes were made in formulations,

757
00:28:55,565 --> 00:28:57,825
what impact were they gonna have on structure.

758
00:28:58,509 --> 00:28:59,250
And then

759
00:28:59,710 --> 00:29:02,349
shelf life is kind of the extension of

760
00:29:02,349 --> 00:29:02,849
structure.

761
00:29:05,630 --> 00:29:07,630
So but I would have to say if

762
00:29:07,630 --> 00:29:10,289
you look at it from an industrial perspective,

763
00:29:12,275 --> 00:29:15,634
the biggest concern of of manufacturers is food

764
00:29:15,634 --> 00:29:18,134
safety and and eliminating pathogenic

765
00:29:19,394 --> 00:29:20,454
presence. So

766
00:29:20,994 --> 00:29:22,214
so pathogen control.

767
00:29:23,315 --> 00:29:25,335
Gosh that that field has evolved

768
00:29:26,250 --> 00:29:28,009
so much in the last few years in

769
00:29:28,009 --> 00:29:29,230
terms of our ability

770
00:29:29,930 --> 00:29:33,070
to understand sanitation and hygiene and prevent contamination.

771
00:29:34,330 --> 00:29:36,109
So I would say that probably

772
00:29:36,490 --> 00:29:38,650
keeps people awake at night more than anything

773
00:29:38,650 --> 00:29:39,150
else.

774
00:29:40,684 --> 00:29:41,825
Besides that,

775
00:29:42,765 --> 00:29:44,444
we talked a little bit about the health

776
00:29:44,444 --> 00:29:47,884
conscious formulations. So sugar reduction is a is

777
00:29:47,884 --> 00:29:49,265
a big one right now,

778
00:29:50,605 --> 00:29:52,785
more so than fat reduction, I think.

779
00:29:53,210 --> 00:29:55,049
But it's interesting, I would say, when I

780
00:29:55,049 --> 00:29:57,529
look at those sort of healthier for you

781
00:29:57,529 --> 00:29:58,029
formulations,

782
00:29:59,450 --> 00:30:01,529
there's a lot of them out there. They

783
00:30:01,529 --> 00:30:03,529
don't have a lot of market share, to

784
00:30:03,529 --> 00:30:04,670
be honest, because

785
00:30:05,049 --> 00:30:05,869
most consumers

786
00:30:06,170 --> 00:30:08,404
really say, you know, don't mess with my

787
00:30:08,404 --> 00:30:10,644
ice cream. I'll eat a good diet all

788
00:30:10,644 --> 00:30:12,085
week long, but at the end of the

789
00:30:12,085 --> 00:30:14,484
week, I just want a nice bowl of

790
00:30:14,484 --> 00:30:17,545
ice cream. So I'm not gonna worry about

791
00:30:17,605 --> 00:30:19,605
the fat or the sugar content. I'm just

792
00:30:19,605 --> 00:30:21,880
going to enjoy it. So we really have

793
00:30:21,880 --> 00:30:24,460
to remember that for many people it is

794
00:30:24,759 --> 00:30:27,500
an indulgent treat. That's that's where it exists

795
00:30:27,559 --> 00:30:29,880
in in the whole scheme of their food

796
00:30:29,880 --> 00:30:30,380
diet.

797
00:30:30,759 --> 00:30:31,259
And

798
00:30:32,119 --> 00:30:35,420
so I think just maintaining that that positioning.

799
00:30:36,365 --> 00:30:38,845
And in terms of health, I would I

800
00:30:38,845 --> 00:30:41,164
would rather suggest to people that they eat

801
00:30:41,164 --> 00:30:42,305
a smaller portion

802
00:30:42,684 --> 00:30:44,065
of a really good product

803
00:30:44,365 --> 00:30:46,525
than a bigger portion of something in which

804
00:30:46,525 --> 00:30:48,605
that would have lower fat. You know, just

805
00:30:48,605 --> 00:30:49,585
portion control.

806
00:30:50,200 --> 00:30:51,799
And again, you see a lot of that

807
00:30:51,799 --> 00:30:53,340
in some of the new novelty,

808
00:30:53,880 --> 00:30:56,539
ice cream products. For example, ice cream bars.

809
00:30:56,840 --> 00:30:58,700
They're a little bit smaller in size.

810
00:30:59,320 --> 00:31:02,619
And so again, really good gourmet bar,

811
00:31:03,160 --> 00:31:04,460
real good ice cream,

812
00:31:05,035 --> 00:31:07,275
a real good chocolate on it, but just

813
00:31:07,275 --> 00:31:09,994
a smaller size. And that way, you're you're

814
00:31:09,994 --> 00:31:13,115
watching your fat and sugar intake. Right. Yeah.

815
00:31:13,115 --> 00:31:15,914
I'm thinking of, the Magnum Mini in the

816
00:31:15,914 --> 00:31:16,414
UK,

817
00:31:16,840 --> 00:31:18,600
which is what we like right because I

818
00:31:18,600 --> 00:31:19,420
mean the magnums

819
00:31:20,039 --> 00:31:22,600
themselves are just over the top but yeah

820
00:31:22,600 --> 00:31:23,740
the Mini is nice.

821
00:31:24,119 --> 00:31:26,279
So Doug we're here at the University of

822
00:31:26,279 --> 00:31:27,340
Guelph which

823
00:31:28,119 --> 00:31:29,240
started out as

824
00:31:29,559 --> 00:31:31,500
the Ontario Veterinary College

825
00:31:31,904 --> 00:31:34,164
and the Ontario Agricultural College.

826
00:31:34,865 --> 00:31:37,285
And I think at the OAC,

827
00:31:38,545 --> 00:31:40,244
there has been a course

828
00:31:40,785 --> 00:31:41,285
running

829
00:31:41,744 --> 00:31:42,884
in ice cream

830
00:31:44,309 --> 00:31:46,869
studies or technology for over a 100 years?

831
00:31:46,869 --> 00:31:48,630
Yes. Is that right? Can you can you

832
00:31:48,630 --> 00:31:51,109
tell us something about that course? Our so

833
00:31:51,109 --> 00:31:52,329
we teach an,

834
00:31:52,789 --> 00:31:53,609
an annual

835
00:31:54,309 --> 00:31:55,529
1 week course

836
00:31:57,295 --> 00:32:00,674
for industry people. This ice cream technology course.

837
00:32:01,215 --> 00:32:05,055
And we started teaching that in that's the

838
00:32:05,055 --> 00:32:07,475
collective we, not me, in 1914.

839
00:32:10,190 --> 00:32:12,049
Here's an interesting fun fact.

840
00:32:12,589 --> 00:32:13,490
In a 110

841
00:32:13,869 --> 00:32:14,369
years,

842
00:32:14,670 --> 00:32:17,329
there's only been 4 instructors of the course.

843
00:32:17,710 --> 00:32:19,809
I've taught the course now for,

844
00:32:20,589 --> 00:32:21,650
36 years,

845
00:32:22,005 --> 00:32:22,664
And my predecessor

846
00:32:23,765 --> 00:32:25,545
taught it for 34 years.

847
00:32:26,565 --> 00:32:28,964
And the gentleman before him taught it for

848
00:32:28,964 --> 00:32:29,785
30 years.

849
00:32:30,164 --> 00:32:30,565
So,

850
00:32:31,204 --> 00:32:32,025
it's amazing

851
00:32:32,325 --> 00:32:34,265
that that sense of of longevity

852
00:32:34,565 --> 00:32:35,785
of of the instructors.

853
00:32:36,390 --> 00:32:38,470
So we get on average about 50 people

854
00:32:38,470 --> 00:32:40,630
a year that come from around the world,

855
00:32:42,150 --> 00:32:44,630
to the University of Guelph. And so it's

856
00:32:44,630 --> 00:32:46,330
very much a science and technology

857
00:32:46,950 --> 00:32:48,170
focused course

858
00:32:48,894 --> 00:32:49,394
on

859
00:32:50,494 --> 00:32:50,994
formulations,

860
00:32:51,454 --> 00:32:51,954
ingredients,

861
00:32:53,214 --> 00:32:53,714
processing

862
00:32:54,174 --> 00:32:56,894
and quality issues. So that would be how

863
00:32:56,894 --> 00:32:58,434
I would divide up the curriculum.

864
00:32:59,535 --> 00:33:01,714
Some people arrive and they think, you know,

865
00:33:02,250 --> 00:33:04,830
wow, can we fill 5 days? And then

866
00:33:05,210 --> 00:33:06,650
at the end of it, they go, wow,

867
00:33:06,650 --> 00:33:09,150
I think we need another 5 days. Because,

868
00:33:10,089 --> 00:33:12,410
it it really at that when you start

869
00:33:12,410 --> 00:33:15,609
moving from the kitchen or the artisanal shop

870
00:33:15,609 --> 00:33:18,315
level to to scale up, you realize, well

871
00:33:18,454 --> 00:33:20,934
it's a very complicated product to make and

872
00:33:20,934 --> 00:33:23,494
we've got lots of potential things that can

873
00:33:23,494 --> 00:33:24,154
go wrong.

874
00:33:25,414 --> 00:33:27,595
And when things go wrong, it can cost,

875
00:33:27,734 --> 00:33:29,434
you know, 1,000,000 of dollars.

876
00:33:30,690 --> 00:33:33,970
So there certainly needs to be great attention

877
00:33:33,970 --> 00:33:34,630
to quality.

878
00:33:35,089 --> 00:33:37,730
And and the people that, that come to

879
00:33:37,730 --> 00:33:39,490
to take the course, are these people who

880
00:33:39,490 --> 00:33:40,630
are developing new

881
00:33:41,169 --> 00:33:43,569
ice cream products? Or are they the people

882
00:33:43,569 --> 00:33:44,309
who run

883
00:33:44,714 --> 00:33:46,714
the factories where the ice cream is made

884
00:33:46,714 --> 00:33:48,095
or is it sort of a mix?

885
00:33:48,554 --> 00:33:50,794
It's a mix. So we get,

886
00:33:52,554 --> 00:33:54,095
from the from the

887
00:33:54,394 --> 00:33:58,815
processing side we get, both processing operations people

888
00:33:59,480 --> 00:34:01,500
and research and development people

889
00:34:01,880 --> 00:34:04,140
and quality assurance people. So

890
00:34:04,440 --> 00:34:07,820
so that quality processing and and product development

891
00:34:07,880 --> 00:34:09,420
side is is all covered.

892
00:34:09,880 --> 00:34:11,179
We get some

893
00:34:14,704 --> 00:34:17,824
inspectors, for example, government agency people that would

894
00:34:17,824 --> 00:34:20,565
come that that need to know more about,

895
00:34:21,184 --> 00:34:23,025
how ice cream is made so that they

896
00:34:23,025 --> 00:34:26,085
can, you know, effectively do inspections and certifications.

897
00:34:27,900 --> 00:34:30,000
We get people from the supplier industries.

898
00:34:31,019 --> 00:34:33,659
For example, people that process strawberries that need

899
00:34:33,659 --> 00:34:35,739
to know, well, how is it going to

900
00:34:35,739 --> 00:34:37,679
behave when it goes into ice cream?

901
00:34:38,059 --> 00:34:40,239
So the the ingredient suppliers

902
00:34:40,755 --> 00:34:43,014
would be flavoring people or stabilizer

903
00:34:43,635 --> 00:34:44,135
suppliers

904
00:34:44,514 --> 00:34:45,014
or

905
00:34:45,315 --> 00:34:47,414
milk protein companies, for example.

906
00:34:47,795 --> 00:34:50,755
So the supplier people, the inspector people, but

907
00:34:50,755 --> 00:34:53,559
largely people from the industry. I see and

908
00:34:53,559 --> 00:34:55,159
is it hands on? Do you have a

909
00:34:55,159 --> 00:34:57,179
kitchen and do you have facilities

910
00:34:57,719 --> 00:35:00,119
similar to that in industry where people can

911
00:35:00,119 --> 00:35:02,039
can actually have a go themselves? Yes we

912
00:35:02,039 --> 00:35:04,039
have a full scale pilot plant here at

913
00:35:04,039 --> 00:35:04,699
the University,

914
00:35:05,960 --> 00:35:06,539
with with

915
00:35:07,275 --> 00:35:09,454
the kind of equipment that you'd find commercially,

916
00:35:09,994 --> 00:35:11,775
a little bit smaller in scale.

917
00:35:12,155 --> 00:35:13,454
But our commercial

918
00:35:13,835 --> 00:35:15,994
our ice cream freezer in the pilot plant

919
00:35:15,994 --> 00:35:18,174
can run at 700 liters an hour.

920
00:35:18,635 --> 00:35:20,094
So it's certainly

921
00:35:20,719 --> 00:35:23,699
scalable to to an industry setting.

922
00:35:24,400 --> 00:35:25,599
And we do spend,

923
00:35:27,039 --> 00:35:29,219
a couple of days in the pilot plan.

924
00:35:29,519 --> 00:35:30,260
We also,

925
00:35:31,679 --> 00:35:34,215
do a lot of tasting and evaluations.

926
00:35:34,594 --> 00:35:37,234
We we before the course begins, we make

927
00:35:37,234 --> 00:35:39,715
a lot of products with different levels of

928
00:35:39,715 --> 00:35:42,675
fat, for example, different levels of sugar, different

929
00:35:42,675 --> 00:35:45,394
types of sugar so that people can not

930
00:35:45,394 --> 00:35:47,519
only hear about it in the classroom, but

931
00:35:47,519 --> 00:35:49,519
but we can show them this is what

932
00:35:49,519 --> 00:35:52,000
happens when you modify the formulation in in

933
00:35:52,000 --> 00:35:55,519
these particular ways. I see. And final question

934
00:35:55,519 --> 00:35:57,039
Doug, I'm sure you get this all the

935
00:35:57,039 --> 00:35:58,800
time but I'm I don't think they'd let

936
00:35:58,800 --> 00:36:00,800
me back to physics world if I didn't

937
00:36:00,800 --> 00:36:03,464
ask you: what's your favourite flavor of ice

938
00:36:03,464 --> 00:36:04,444
cream and why?

939
00:36:06,424 --> 00:36:08,904
Well again I have two answers to that.

940
00:36:08,904 --> 00:36:11,384
If if, if I put my professional hat

941
00:36:11,384 --> 00:36:12,605
on it's it's vanilla

942
00:36:13,224 --> 00:36:16,444
and the and the reason why is that

943
00:36:16,664 --> 00:36:19,750
it gives you the the best opportunity to

944
00:36:19,750 --> 00:36:21,829
really evaluate the quality of the ice cream

945
00:36:21,829 --> 00:36:24,569
itself. It's not masked by anything else.

946
00:36:25,030 --> 00:36:27,349
So the flavour that's gonna be there other

947
00:36:27,349 --> 00:36:29,829
than the little hint of vanilla flavouring, but

948
00:36:29,829 --> 00:36:32,010
the flavour is really going to show

949
00:36:32,335 --> 00:36:34,035
how the mix itself,

950
00:36:34,494 --> 00:36:36,815
the ingredients of the mix. So if there's

951
00:36:36,815 --> 00:36:37,635
any particular

952
00:36:37,934 --> 00:36:40,655
off note, you're going to detect that. As

953
00:36:40,655 --> 00:36:42,974
soon as you throw Smarties into it or

954
00:36:42,974 --> 00:36:45,295
chocolate or, you know, butterscotch, it's going to

955
00:36:45,295 --> 00:36:49,039
cover that up. So we always evaluate vanilla

956
00:36:49,039 --> 00:36:51,840
ice creams because it's it's the closest to

957
00:36:51,840 --> 00:36:53,760
the flavor and structure of the ice cream

958
00:36:53,760 --> 00:36:56,500
itself without being masked by anything else.

959
00:36:57,119 --> 00:36:59,039
If I take my professional hat off and

960
00:36:59,039 --> 00:37:00,079
put my my,

961
00:37:00,400 --> 00:37:01,539
fun hat on,

962
00:37:01,875 --> 00:37:03,394
then when I go to an ice cream

963
00:37:03,394 --> 00:37:05,954
shop, I I look for something that I've

964
00:37:05,954 --> 00:37:08,275
never had before, and I would buy that

965
00:37:08,275 --> 00:37:10,275
just to try it to add to my,

966
00:37:10,275 --> 00:37:11,974
you know, collection of stories.

967
00:37:13,554 --> 00:37:14,454
And for example,

968
00:37:17,269 --> 00:37:19,530
my last trip over to Ireland, I found

969
00:37:20,550 --> 00:37:23,030
a fig and blue cheese ice cream. And

970
00:37:23,030 --> 00:37:24,090
I thought to myself,

971
00:37:24,469 --> 00:37:26,869
I don't think I've ever had blue cheese

972
00:37:26,869 --> 00:37:28,789
in an ice cream before, so that's what

973
00:37:28,789 --> 00:37:29,769
I wanna try.

974
00:37:30,215 --> 00:37:32,375
We've had lots of rancid flavors in ice

975
00:37:32,375 --> 00:37:34,295
cream that didn't belong there. But when you

976
00:37:34,295 --> 00:37:37,335
think about actually trying to add blue cheese

977
00:37:37,335 --> 00:37:39,255
to ice cream, you've got wow. That's a

978
00:37:39,255 --> 00:37:40,715
flavor. Did it work?

979
00:37:42,650 --> 00:37:44,969
Well you have to like blue cheese, but

980
00:37:45,369 --> 00:37:48,110
it it did if you're given that caveat.

981
00:37:48,489 --> 00:37:48,989
Right.

982
00:37:49,289 --> 00:37:51,130
And and all this, you know, decades of

983
00:37:51,130 --> 00:37:52,910
work that you've done on ice cream,

984
00:37:53,849 --> 00:37:55,530
do your eyes still light up when you

985
00:37:55,530 --> 00:37:56,269
go into

986
00:37:56,744 --> 00:37:59,224
an ice cream parlor that you've never been

987
00:37:59,224 --> 00:38:01,545
to before? Are you still excited about it?

988
00:38:01,545 --> 00:38:02,284
Oh absolutely.

989
00:38:02,664 --> 00:38:05,464
I've, you know, I've been fortunate enough to

990
00:38:05,464 --> 00:38:08,844
have traveled to many many interesting countries and

991
00:38:09,279 --> 00:38:11,599
and always see what the ice cream market

992
00:38:11,599 --> 00:38:12,900
looks like when I'm there,

993
00:38:13,519 --> 00:38:15,759
either in the grocery store or visit to

994
00:38:15,759 --> 00:38:17,920
an ice cream parlor or a scoop shop

995
00:38:17,920 --> 00:38:18,420
somewhere.

996
00:38:20,960 --> 00:38:23,039
I I enjoy it. I mean, it's not

997
00:38:23,039 --> 00:38:25,484
just a professional thing. I I also like

998
00:38:25,484 --> 00:38:27,324
to know what's going on around the world

999
00:38:27,324 --> 00:38:29,424
so I can share that with with people.

1000
00:38:30,525 --> 00:38:32,125
But of course, it's how can you go

1001
00:38:32,125 --> 00:38:33,724
wrong with ice cream? It's such a fun

1002
00:38:33,724 --> 00:38:35,505
product to be associated with.

1003
00:38:36,684 --> 00:38:38,284
That's a great way to end the interview,

1004
00:38:38,284 --> 00:38:40,630
Doug. Thanks a lot. Oh, you're most welcome.

1005
00:38:40,630 --> 00:38:41,449
It's been fun.

1006
00:38:48,070 --> 00:38:49,989
I'm afraid that's all the time we have

1007
00:38:49,989 --> 00:38:51,210
for this week's podcast.

1008
00:38:51,605 --> 00:38:54,984
Thanks to Douglas Gough for joining me today.

1009
00:38:55,204 --> 00:38:57,844
And a special thanks to our producer, Fred

1010
00:38:57,844 --> 00:38:58,344
Ailes.

1011
00:38:58,885 --> 00:39:01,944
This is the last Physics World Weekly podcast

1012
00:39:02,005 --> 00:39:02,984
of 2024.

1013
00:39:03,764 --> 00:39:05,844
And I would like to thank all of

1014
00:39:05,844 --> 00:39:09,619
the fascinating guests who shared their passions for

1015
00:39:09,619 --> 00:39:11,800
physics with us this year

1016
00:39:12,260 --> 00:39:13,960
and to our many listeners

1017
00:39:14,260 --> 00:39:16,760
for tuning in throughout the year.

1018
00:39:17,619 --> 00:39:18,839
Looking to the future,

1019
00:39:19,300 --> 00:39:19,800
2025

1020
00:39:20,744 --> 00:39:21,484
is the international

1021
00:39:22,025 --> 00:39:24,844
year of quantum science and technology

1022
00:39:25,464 --> 00:39:26,284
as proclaimed

1023
00:39:26,664 --> 00:39:28,364
by the United Nations.

1024
00:39:29,065 --> 00:39:31,545
So you can look forward to lots of

1025
00:39:31,545 --> 00:39:33,804
quantum coverage in the podcast

1026
00:39:34,105 --> 00:39:34,924
next year.

1027
00:39:35,224 --> 00:39:37,460
And that kicks off with a conversation

1028
00:39:38,159 --> 00:39:39,139
with a physicist

1029
00:39:39,519 --> 00:39:40,420
who's developing

1030
00:39:41,119 --> 00:39:41,940
new platforms

1031
00:39:42,400 --> 00:39:43,300
for quantum

1032
00:39:43,679 --> 00:39:44,179
communications.

1033
00:39:45,199 --> 00:39:46,980
That's coming up in January.

1034
00:39:47,440 --> 00:39:48,420
Until then,

1035
00:39:48,800 --> 00:39:51,780
goodbye from the Physics World Weekly podcast.