Leftover bread crusts can be turned into new food – research

Dr David Bryant

If you are concerned about the crusts of your bread going to waste, then new research that promises to turn it into new kinds of food could be the answer.

In a paper published in the journal ‘NPJ Science of Food’, academics at Aberystwyth University have shown that waste bread can be fermented into highly nutritious foods.

Wheat is one of the most consumed crops worldwide, contributing to 20% of the calories and proteins in human diets.

It is a key ingredient for many staple foods, such as breads, cakes, biscuits, cookies and crackers.

Bakery waste, particularly from bread, is a major global concern. Currently around 10% of the 185 million tons of bread baked each year is wasted, mostly at supermarkets and commercial bakers.

While most of this surplus is safe to eat, with some of it distributed by charities, it cannot be sold more generally.

The new study is the first time academics have shown grass traditionally used for livestock production can be successfully fermented along with bread by fungi to make alternative proteins.

The new process combines surplus bread with juice from pressed grass which is full of nutrients and protein for fungal growth.

The alternative protein that can be produced from it could end up on the plates of millions, including in fortified bread, pork pies or sausages.

Dr David Bryant from the Institute of Biological, Environmental and Rural Sciences at Aberystwyth University said:

“This is a real breakthrough that will hopefully tackle the growing global problem of wasted food. Most of us know only too well how much of a problem bread waste is - from the toast thrown away at breakfast or our uneaten sandwiches. But that is not the whole issue – much is wasted commercially in manufacture and retail as well.

“This research gives us a way of tackling that problem through fermentation.  It is the use of grass that makes these findings a genuine first. The beauty of this method is that it can use that everyday plant to turn waste into new types of food for the growing world population.”

The type of fungi used in the scientists’ new fermentation is already widely used to produce tempeh, a vegetarian alternative to meat made from fermented cooked soya beans and which is widely eaten in parts of Asia.

Using the pilot-scale biorefining facility at AberInnovation, which is based on Aberystwyth University’s Gogerddan Campus, the scientific breakthrough takes advantage of solid-state fermentation, which is more environmentally friendly and produces less wastewater than other methods.

A spokesperson for Samworth Brothers added:

“Samworth Brothers is a food business with significant influence – our activities impact the environment and climate change, nutrition, employment, supply chains and the communities in which we operate. We’re determined that our influence is for the good.

Supporting this project is a great example of what we can do in addition to our food redistribution activities to find alternative uses for bread crusts.”

The four-year research project is funded by the UKRI Biotechnology and Biological Sciences Research Council (BBSRC).

Professor Anne Ferguson-Smith, BBSRC Executive Chair, said:

"Embracing innovative approaches like this not only helps to combat food waste but also pioneers new ways to sustain our growing population with nutritious alternatives. This latest research from IBERS, one of BBSRC's strategically supported research institutes, epitomises the type of transformative science BBSRC invests in to foster sustainable and resilient food systems across the UK and around the world. The potential of turning everyday waste into valuable food resources is an opportunity we must capitalise on if we are to successfully secure our global food supply both now and in the future."

As the study continues, researchers will consider how they can change the flavours and improve the taste of the alternative proteins produced by the fermentation.

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