Okara is a by-product of tofu and can be used to make vegetarian ‘nuggets’. | Photo: Manuel Lopez

Switzerland wastes a lot of food. Roughly one third of all foodstuffs is lost, either on its way from the farm to our plate, or afterwards in the form of food waste. It adds up to 310 kilograms per person per year, with Swiss households responsible for just over a quarter of the total.

But even more food is lost during processing – over a third of overall losses – resulting in by-products such as whey, wheat bran, brewers’ grains or oil cake, most of which are fed to animals today. A small proportion of them is also used either as compost or in biogas plants.

“The quality of some of these by-products is at least as high as that of the main products we use for food”, says Nadina Müller, the head of the Food Technology Research Group at the Zurich University of Applied Sciences (ZHAW). She is also the co-author of the interim report ‘Food waste and loss’, commissioned by the Swiss Federal Office for the Environment and published in 2025. Wheat bran is a by-product of the manufacturing process for white flour, for example, though in fact the bran is healthier for us than the flour.

Cocoa shells, soy fibre residues

There are many possibilities for making better use of such edible by-products, says Müller. Her team, for example, has been using ground cocoa bean shells as a partial replacement for cocoa beans themselves in chocolate or chocolate ice cream. “It works really well”, she says. Chocolate containing up to 25 percent bean shells has thus far been received positively.

Another example of how such residue can be refined is provided by the start-up Luya Foods – a spin-off from the Bern University of Applied Sciences, co-founded by Nina Schaller. It is producing plant-based foods using various ingredients that are regarded as by-products, such as okara, or ‘soy pulp’. This is the nutrient-rich fibre residue that is produced when soybeans are turned into soy milk or tofu. “Roughly speaking, producing one kilogram of tofu generates one kilogram of pulp”, says Schaller.

Schaller’s start-up has developed a technology that allows it to ferment soy pulp on an industrial scale. “In culinary terms, it’s not particularly exciting in its conventional form”, says Schaller. “But it has enormous potential when it’s fermented”. In order to refine its taste, Luya mixes it with chickpeas and seasons the resulting products, or coats them in breadcrumbs. They are then sold as plant-based nuggets or mince – in canteens, restaurants and supermarkets such as Coop.

Luya Foods gets its soy pulp from Swiss tofu producers who use Swiss soybeans – not least because it’s an extremely perishable product, making short production distances important. Schaller says that standardisation was a challenge. This is because tofu or soya milk always has to be of a uniform quality, so manufacturers try to transfer any seasonal fluctuations in protein content or other ingredients to the by-product. “This is why we had to cope with different types of soy pulp at the start”, she says, “though we’ve meanwhile standardised the process with our suppliers”.

Fermentation is the key

Other Swiss start-up companies have already started selling foodstuffs made from by-products. For example, Yeastup was founded in Brugg in Canton Aargau in 2020. It extracts proteins and fibre from surplus brewer’s yeast, which can be added to sports bars or dietary supplements. And Eggfield, a company based in Illnau in Canton Zurich, founded in 2022, produces vegan egg substitutes from the water left over from cooking chickpeas for hummus.

There’s no official figure for the number of Swiss start-ups using by-products from foodstuff production. But the reports of the Swiss Startup Association suggest that there are some 150 of them. And this sector has grown by 60 percent since 2021. In reply to our queries, the Association wrote that: “Within this ecosystem, we’re seeing a clear qualitative trend towards sustainability, a circular economy and food upcycling”.

Upcycling the waste from foodstuff production is a big topic in the industry today, says Wolfram Brück, a microbiologist at the University of Applied Sciences Western Switzerland (HES-SO Valais-Wallis). He’s also the president of Swiss Food Research, an association that brings together over 260 members including start-ups, established companies and research institutions.

Fermentation is one of the key techniques used – and in this regard, says Brück, Europe could learn a lot from countries in Africa or Asia. They are home to a wide variety of fermented products, from flatbread made from teff flour (from a type of grass found in Ethiopia) to grain drinks and fermented carob seeds. “But over here, a lot of traditional knowledge has already been lost”, he says.

Brück himself is primarily researching into how by-products can be turned into high-quality substances to serve as foodstuffs that can even be beneficial to our health. Examples include prebiotics and antioxidant substances. It’s products such as these that his research group is extracting from soy pulp, pomegranate peel, cranberry pomace and other sources.

Packaging from carrots

Gustav Nyström works at Empa, the Swiss Federal Laboratories for Materials Science and Technology. He’s busy pursuing another idea for recycling surplus products from the foodstuff industry, using them instead to manufacture environmentally friendly packaging. In a collaboration with Lidl Switzerland, his team has been extracting cellulose fibres from fruit and vegetable scraps – such as carrots – and turning them into a protective film that can be sprayed onto cucumbers, tomatoes, apples, bananas and other foods.

“This wrapping can extend the shelf life of cucumbers, for example, by more than two weeks”, says Nyström, making it better than conventional plastic film. This is probably because the cellulose fibres are slightly permeable, so hardly any condensation can form on the cucumber itself.

The film comprises solely natural materials and can simply be washed off before consumption. In fact, you can also eat it. But there’s still work to be done before this ‘waste packaging’ can be made commercially available. “The product has to get official approval because it’s applied directly to food. And this process is still ongoing”.

In another project, Nyström’s team has developed a cooling, protective cover made from brewer’s grains, again after having extracted cellulose fibres from them. “In this case, however, we used the fibres to produce a foam-like material that has heat-insulating properties”, says Nyström. “We have also combined it with polyethylene glycol, a so-called latent heat storage material”. When this material melts, it absorbs heat, thereby enhancing the cooling effect. Nyström’s group recently published a study showing that cooling packaging such as this can keep meat products below freezing point for roughly four times as long as conventional packaging.

Keeping an eye on the environmental impact

But are all these ideas for using by-products actually ecologically sound? “Sure they are”, says Nadina Müller. She recently led a project to investigate the potential of 15 by-products ranging from wheat bran and buttermilk to apple pomace and apricot kernels. It’s crucial to keep an eye on the environmental impact of each and every one of these processes, says Müller. But she insists that it’s almost always better for the environment when we use by-products for human consumption instead of consigning them to animal feed. “Applications in the foodstuff sector therefore have to be our first choice”.

Müller also notes that protective packaging made from surplus materials could also be more ecologically meaningful than feeding them to animals. This is far from negligible because the quantity of residual products we create is enormous. Switzerland, for example, produces 17,000 tonnes of brewer’s grains each year – and over 130,000 tonnes of coffee grounds. Müller’s group has started using these to replace some of the oat flakes in crunchy muesli for example. “But even if you wanted to”, says Müller, “you couldn’t put all foodstuff by-products back into food”.