An interview with Prof. David Julian McClements/
Getting into detail about plant-based protein

Your work is really revolutionary; how did you get into doing what you’re doing now?

I trained in Leeds, UK as a food scientist, and then I did postdoctoral research in California and Ireland, mainly on things like dairy proteins. I learned a lot about biopolymers and colloids: like proteins, and polysaccharides, and tiny particles in foods. Most foods are made up of these biopolymers and colloids, so the research I did is applicable to almost everything, which is nice. I can really change my research area in response to current trends in the food industry. We’ve done a lot of work on making foods healthier as there's a big health and wellness trend. It’s a case of trying to design things to increase bioavailability or to fortify foods with vitamins and minerals. The  plant-based food thing has really, really taken off in America. Every week I get a company contacting me for a report; tomorrow, we've got a TV company from Boston coming in to do a film about the plant-based food work. The students are really excited about it, and I get so many more students when I work in the lab now! So for me, it’s a no-brainer to do the plant-based foods stuff.

So, you didn’t start off plant-based but rather, you’ve gone down that avenue as life and trends have pushed you in that direction?

My daughter became a vegetarian when she was something like thirteen; that was about eight years ago. And when she turned vegetarian, we all did. I think I tried it before when I was at university, but it was really hard to keep it up then because there just weren’t many good plant-based foods. And I was a terrible cook! But now, it’s much, much easier to do it, especially where we live.

What is your main goal with your research? Is it specifically health and wellness and augmenting the nutrition of foods, or are you aiming to create more plant-based food options?

All of those things. I think the fundamental thing is to understand the science behind plant-based foods. They're often made in quite an empirical way: people just mix things together, do some kind of cooking or processing, and then see what comes out the other end. But we're really trying to understand what's happening to the molecules. How do they interact with each other, and then how does that influence things like the appearance and the texture and the way they behave in your body? Ultimately, we want to use that knowledge to make things more healthy, sustainable, and high-quality. And then to focus on making plant-based seafood, or whole-tissue chicken, or beef steak, or lamb chop or something like that. So we’re trying to understand the science behind those more complicated micro-structures.

You mentioned sustainability: how do the manufacturing processes factor into the sustainability of, say, a plant-based chicken-breast substitute?

In some plant-based foods, you can get quite a long list of ingredients, and they come from all over the world. There are things like the manufacturing cost of each ingredient, distribution costs, factory costs, etc. There are a lot of potential costs associated with that but I read an article yesterday that showed that, even with all of that taken into account, plant-based foods are still much, much more sustainable than animal-based foods. Again, the thing is that once we understand the science better, we can bring in the supply chain so we can do much more local production. We can have it localized near big urban centers, we can have the factories there and everything to reduce the supply chain and the petroleum costs.

Are you seeing these new plant-based foods as ultimately being available to everyone in terms of price and distribution? There’s currently a lot of vegan convenience food available, but much of it is heavily processed and very expensive. How do you see these foods fitting into the market?

I think it should be food for the masses really, so that everybody can have a sustainable diet. A lot of these things are highly processed foods. Just to make something out of plant-based ingredients that looks exactly like meat, cheese, or milk, you have to do a lot of processing and include lots of different ingredients in. But my argument is that it doesn't necessarily have to be bad because it's highly processed. The bottom line is: does it taste good? Is it good for your health? And is it good for the environment? I think we have to use those as criteria rather than how much processing goes into it. If we're going to make this huge transition from an animal-based diet to a plant-based diet, it's really important that we design health and wellness into it at the beginning, because otherwise these could end up as just being another highly processed food that's really bad for your health, even though they might be better for the environment.

Frank Hu at Harvard University has written on the dietary implications of plant-based diets, and I think he mentions that there are two types: healthy plant-based diets and unhealthy plant-based diets. The healthy ones are whole legumes and whole grain cereals and stuff like that, and the unhealthy ones are all of the highly processed foods, cookies, biscuits, and snacks. 

In terms of the plant proteins, and pulses in general, which ones work best for you?

To be honest, we’ve found it really difficult to find high-quality ingredients to work with, because with the methods we use — soft matter physics principles — we need to have almost individual, native proteins. But most of the post proteins we get from industry have already been damaged considerably during the process, because they haven't been isolated for their functionality, they've been isolated to extract the oil out or extract the starch out. So the protein is like the side stream, and often it doesn't have the functional requirements that we need. We're doing some work with peas now, and we have to take the peas and extract the proteins ourselves. Sometimes, when we buy soy proteins, they’re already completely denatured, and they just don't function properly. So now, we’re often working with innovative startup companies who are trying to look at new sources of protein. They can isolate them and give us some, but usually only small amounts, so we can only do a limited amount of research.

We'd love to be able to just buy the ingredients — really high quality ingredients — and use them to formulate these plant-based foods. But at the moment, getting those high-quality, reliable ingredients is one of the bottlenecks in this area.

I’ve read about your plant-based scallops and also the chicken-breast gel made from plant proteins; what is your main area of focus? Are you aiming at specific foods or just trying to create a material that can be used to make a wide range of foods?

Both of those areas. One of the main things is that we’re trying to understand what kind of textures, appearances and behaviours you get when you take plant-based proteins and polysaccharides and combine them in different ways. Hopefully then you can say “Well, that goes to chicken, this goes to fish, this goes to beef.” We’re partly doing that, and we also have a lot of individual students. Some are doing plant-based milks, some are doing plant-based eggs, plant-based cheese, plant-based fish; it depends on what their particular thesis is about. 

What is the biggest difficulty given that you’re essentially trying to create flesh from plants?

Getting good quality ingredients first of all! But then the fact that meat has such a complicated structural hierarchy. There are all these fibers that are in bundles that are in other bundles, and then you've got connective tissue around it, then you've got adipose tissue around that. It's an incredibly complicated structure. We're trying to use structural-design approaches or food-architecture approaches to assemble plant proteins and polysaccharides into structures that resemble those you find in meat. This idea is that if we can simulate what's going on at the nanostructure and microstructure level, then we can simulate what's going on with the texture, cook-ability, and mouthfeel. And with how it breaks down in your teeth.

So to make the different layers of meat, are you layering different types of protein onto each other, or are you manipulating single proteins differently to get some into strands and others into support structures, etc.?

We're trying to make some form strands; we do this controlled denaturation where we get the proteins to unfold and form these long strings which are trying to be like the filaments in meat. And then we use thermodynamic incompatibility, where you mix some polysaccharides, and they spontaneously separate into different phases. Then you can stir them, and they form these microstructure fibers, so you can almost get like the bundles of fibers that you find in meat. And then we're using these other methods to make adipose tissue: we’re using a motion technology to create fat droplets and turn them into something that looks like the adipose tissue that you’d get in beef or something similar. Then we’re trying to put those together to get the final structure.

If you’re working with plant proteins, then presumably you would have the nutritional characteristics of the plant protein rather than whatever it is that you’re trying to replace. Are you trying to create nutritional profiles similar to those of the foods that you’re trying to replicate, or are you going to something entirely new?

I think we usually start trying to have something that's got approximately the same sort of nutrient composition: so maybe the same fat, protein, mineral content, and things like that. You want at least to mimic it, but ideally, make it more healthy if you can. That might be reducing saturated fat, but then there's some controversy over whether saturated fats are good or bad. That's one of the problems of being a food scientist: you're always responding to nutritional recommendations and they're often based on shaky science, and they change over time. Trans fats are a good example. Really, we’d be trying to fortify with vitamins and minerals and trying to design the food structure to make sure that everything is bioavailable.

It’s like with Omega-3s; we’ve done a lot of work on Omega-3s, as they’re often lacking in plant-based foods. They’re also very highly susceptible to oxidation, so when you put them into plant-based foods, they can break down very quickly. We’re trying to develop strategies so that we can put them into foods and they’ll stay stable. That way, you won’t get rancid flavors and toxic reaction products formed.

How do you see current food technology sitting alongside the impetus to reduce reliance on technology in general and to simplify our lives?

Even if you only eat whole foods, you’re still relying on technology to plant it, harvest it, ship it, etc. So this is just a different level of processing. But I think, ideally, you want to keep things intact — like fruits and vegetables — because it’s more difficult for your body to break it down. Things get released more slowly; you don’t get the spikes of glucose or lipids in your bloodstream which can cause thing like dysregulation of your hormonal system and cause you to overeat because you don’t get satiety impulses. But I think that once we understand the science, we can redesign that back into processed foods. That’s why I think that just because it’s processed doesn’t necessarily mean it’s bad. A lot of processed foods available now are bad, but potentially, we can overcome that. I personally just haven’t got the time or motivation to cook a lot, so I’m happy to have processed food if I can. If it were up to me, I’d be having microwave meals and everything!

Ultimately, it would be nice if we could actually prove that these new foods are healthy and healthier. I think that if consumers are demanding healthier food, if the demand for healthy and sustainable food increases, then maybe there could be some mandate for labels that actually explain the real health aspects and sustainability of a product. That might drive consumer choice as well, not for everyone, but maybe for some people.

Finally, I’d love to know if you eat pulses and legumes at home. Can you eat them and enjoy them, or do you look at them and see how they can be changed? Does work stay in the lab?

We eat a lot of beans, peas, and lentils, so yeah, we eat a lot. I usually leave work at work; I’m very good at disassociating from that side of things!