Prebiotics from Food Waste

Prebiotics are defined as “substrates that are selectively utilised by host microorganisms conferring a health benefit”². Prebiotics can be found naturally in food, such as Jerusalem artichoke, chicory, leeks, bananas, legumes and beans, but are also becoming more widely available in supplement form or as added ingredients in food. The dietary prebiotics most widely studied are non-digestible oligosaccharides such as fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), as well as inulin, lactulose and resistant starch. 

Since fruit and vegetable wastes contain microbe-accessible nutrients like dietary fibre, prebiotics and phenolic compounds, researchers are exploring ways to utilise these by-products to improve organoleptic properties and nutritional value of foods. For example, fruit pomace (rich in dietary fibre and bioactive compounds), a by-product of fruit juice production, can be processed into a powder and used in baked goods to improve  texture, colour (natural pigments) and nutritional value.  Moreover, some evidence shows that pectin oligosaccharides (POS) derived from pectin-containing food wastes such as potato skins, orange peels, apple pulp etc., may have a prebiotic effect³. 

However, the extraction of POS by the conventional hydrothermal treatment process is often neither very environmentally friendly nor efficient, hence newer methods are being are being tested. Currently, researchers in the UK are studying the use of microwave technology to extract POS from fruit and vegetable waste – so far this method has proven to be more energy efficient, less reagent intensive and produces a higher yield of POS⁴. 

Thus, innovative technologies such as these could help our planet by reducing the environmental impact of food waste and at the same time help keep our gut microbes happy and healthy! In the meantime, let’s do our part in minimising food waste and environmental footprint within our own households and local communities.