{"id":23664,"date":"2022-03-09T08:57:14","date_gmt":"2022-03-09T08:57:14","guid":{"rendered":"https:\/\/research.reading.ac.uk\/research-blog\/?p=23664"},"modified":"2023-02-23T11:20:10","modified_gmt":"2023-02-23T11:20:10","slug":"were-recycling-potato-skins-to-make-prebiotics-heres-why-thats-good-for-your-gut-and-the-planet","status":"publish","type":"post","link":"https:\/\/research.reading.ac.uk\/research-blog\/2022\/03\/09\/were-recycling-potato-skins-to-make-prebiotics-heres-why-thats-good-for-your-gut-and-the-planet\/","title":{"rendered":"We\u2019re recycling potato skins to make prebiotics: here\u2019s why that\u2019s good for your gut \u2013 and the planet"},"content":{"rendered":"

It\u2019s an unbelievable tragedy that\u00a0a third<\/a>\u00a0of the world\u2019s\u00a0food is wasted<\/a>. To put that in perspective, it would take an area the size of China to grow that much food \u2013 and if food waste were a country it would be the world\u2019s third-largest greenhouse gas emitter.<\/p>\n

\"\"<\/p>\n

<\/p>\n

Reducing the amount of food we discard is imperative \u2013 it\u2019s a major threat to our climate, food security and the global economy. Everyone can play a role in addressing this problem by\u00a0eliminating unnecessary food wastage<\/a>. But despite our best efforts there will always be some, and it\u2019s really important that we make the best use of it.<\/p>\n

One way to approach this goal is to use a food waste management\u00a0hierarchy<\/a>. The first priority is to minimise waste (for example by using up leftovers or buying wonky fruit and veg) or to redistribute unavoidable waste to hungry people or animals.<\/p>\n

But a large amount of food waste is inedible \u2013 either because it has gone off, become contaminated, or is an inedible co-product of the food industry such as onion skins or cocoa bean shells. These products are then either recycled for relatively low value purposes (such as to make fertiliser or generate energy) or disposed of as landfill.<\/p>\n

\n
\"\"<\/div>\n
Author provided (no reuse)<\/span><\/div>\n<\/figure>\n

 <\/p>\n

But a new category is emerging in this hierarchy \u2013 recycling that retains the value of the food molecules so that they can still be used for their intended purpose of providing health and nutritional benefits. One example of this is the production of prebiotics.<\/p>\n

Food for the gut<\/h3>\n

Prebiotics are a group of nutrients (mostly carbohydrates) that are resistant to the acidic conditions found in the human gut and boost the growth of beneficial bacteria. Various types of these non-digestible carbohydrates are found naturally in fruits and vegetables such as asparagus, chicory, jerusalem artichoke, beans, chickpeas, bananas and apples. Human milk is also known to be rich in prebiotic oligosaccharides (a simple sugar), which have been shown to promote a specific group of beneficial gut microorganisms called bifidobacteria.<\/p>\n

It has been shown that consuming prebiotics\u00a0boosts overall digestive health<\/a>\u00a0by improving the absorption of micronutrients such as calcium, changing the rate at which certain foods lead to spikes in blood sugar, and improving the barrier function of the gut.<\/p>\n

Most importantly, prebiotics support the immune system by increasing the number of protective microorganisms in the gut and decreasing harmful bacteria. And the benefits don\u2019t stop there \u2013 the growth of healthy bacteria that use prebiotics as their source of energy leads to the production of small molecules called short-chain fatty acids, which enter blood circulation\u00a0and benefit<\/a>\u00a0the immune, cardiovascular and central nervous system.<\/p>\n

Although prebiotics naturally exist in foods, they are usually found in low quantities. That\u2019s why scientists are looking into alternative ways to make them on a large scale so that they can be used as supplements or to fortify existing food products.<\/p>\n

Making prebiotics from food waste<\/h3>\n

Most prebiotic oligosaccharides for supplements are produced commercially using enzymes, which are biological catalysts that speed up the rate of chemical reactions. Enzymes may work in various ways, from breaking down large carbohydrates into prebiotic oligosaccharides, to synthesising oligosaccharides from simple sugars such as glucose and galactose.<\/p>\n

But nowadays several industries are shifting their focus to synthesise nutrients in a sustainable way by using microorganisms or enzymes that grow on food industry waste \u2013 or by developing technologies that are more environmentally friendly.<\/p>\n

There is some evidence that pectin oligosaccharides, which have been produced from carbohydrates extracted from certain food waste such as potato peel, could be used to make a prebiotic \u2013 but so far it has only been done on a\u00a0small scale<\/a>\u00a0within a lab setting.<\/p>\n

These carbohydrates couldn\u2019t be extracted from food waste using existing industrial-scale processes, meaning that until now it hasn\u2019t been possible to produce large enough quantities of pectin oligosaccharides from food waste to test their prebiotic properties in human trials. This was a major stumbling block, so since 2016 we have been working to develop a new process to extract the target carbohydrates\u00a0from potato waste<\/a>\u00a0on a large scale.<\/p>\n