The dirtiest part of a vegetable could improve gut health and save the world

It’s incredible tragedy that a third of the world’s food is wasted. To put that into perspective, it would take an area the size of China to grow so much food and if food waste were a country it would be the world’s third largest producer of greenhouse gases.

Reducing the amount of food we discard is imperative – it is a major threat to our climate, food security and the global economy. Everyone can play a role in addressing this problem by eliminating unnecessary food waste. But despite our best efforts, there will always be a few, and it’s really important that we make the best use of them.

One way to approach this goal is to use a food waste management hierarchy. The first priority is to minimize waste (for example by running out of leftovers or buying flaky fruit and vegetables) or redistributing the unavoidable waste to hungry people or animals.

But a large amount of food waste is inedible, because it has exploded, has been contaminated or is an inedible co-product of the food industry such as onion skins or cocoa bean shells. These products are then recycled for relatively low-value purposes (such as making fertilizer or generating energy) or disposed of as landfill.

But a new category is emerging in this hierarchy: recycling which preserves the value of food molecules so that they can still be used for their intended purpose of providing health and nutritional benefits. An example of this is the production of prebiotics.

Food for the intestine

Prebiotics are a group of nutrients (mostly carbohydrates) that are resistant to the acidic conditions found in the human gut and stimulate 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 intestinal microorganisms called bifidobacteria.

Consumption of prebiotics has been shown to improve overall digestive health by improving the absorption of micronutrients such as calcium, changing the rate at which some foods lead to blood sugar spikes, and improving the barrier function of the gut.

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’t stop there: the growth of healthy bacteria that use prebiotics as an energy source leads to the production of small molecules called short-chain fatty acids, which enter the bloodstream and benefit the immune, cardiovascular and central systems. nervous.

Many fruits, vegetables, and whole grains are sources of prebiotics.Shutterstock

Although prebiotics naturally exist in foods, they are usually found in low quantities. That’s why scientists are looking for alternative ways to produce them on a large scale so that they can be used as supplements or to fortify existing food products.

Making prebiotics from food waste

Most prebiotic supplement oligosaccharides are produced commercially using enzymes, which are biological catalysts that accelerate the rate of chemical reactions. Enzymes can work in various ways, from breaking down large carbohydrates into prebiotic oligosaccharides to synthesizing oligosaccharides from simple sugars such as glucose and galactose.

But nowadays several industries are shifting their focus to synthesize nutrients sustainably by using microorganisms or enzymes that grow on food industry waste or by developing more environmentally friendly technologies.

There is some evidence that pectin oligosaccharides, which were produced from carbohydrates extracted from certain food waste such as potato peel, could be used to make a prebiotic, but so far it has only been done on a small scale in a laboratory setting.

These carbohydrates could not be extracted from food waste using existing industrial-scale processes, which means that until now it has not been possible to produce sufficient quantities of pectin oligosaccharides from food waste to test its prebiotic properties in human tests. This has been a major hurdle, so since 2016 we have been working to develop a new process to extract target carbohydrates from potato waste on a large scale.

The process uses microwave technology, and because it is electrically powered, it means they can use renewable energy sources rather than relying on burning fossil fuels.

Unlike similar industrial-scale extraction processes that use acids to extract target molecules, our process uses only water as a solvent. The water diffuses into the plant material, where pectins are released from the plant cell wall and dissolve in the water.

So, we are now able to extract sufficient amounts of pectin oligosaccharides to test their prebiotic activity, and we are using a number of different food waste materials in addition to potato scraps, such as sugar beet pulp and apple pomace, which are important. co-products of the British food industry. And the best part is that we only use electricity and water, no fossil energy and no toxic chemicals.

With this new technology, we hope to produce a new range of new prebiotic products. This will be good for our health and will also help us reduce the impact of food waste on the environment.

This article was originally published on The conversation by Eleanor Binner at the University of Nottingham and Afroditi Chatzifragkou at the University of Reading. Read the original article here.

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