Andrew Plunkett, research associate at Manchester Metropolitan University, is working with a number of PHD students to investigate the uses of extrusion, beyond simple snack manufacturing.
His team is working with a range of raw materials from rice bran to brewer’s spent grain, looking to break down tight matrixes and extract functional compounds and flavorings with the view to future using these ingredients in a snack product.
“If you look at the extrusion process in that way, it opens up a whole new range of possibilities,” he told BakeryandSnacks.com at Campden BRI’s Snacks Technology conference earlier this month.
“There’s this perception of extrusion purely being used for snack products; well, not necessarily.”
It could be used to enable higher levels of functional compounds from raw material and even previously inaccessible compounds from waste materials and by-product.
“There’s this great potential for functionality that could come out of the extrusion process, with potentially widespread health benefits.”
Nutrition and by-products
Plunkett said his team was looking at changing the carbohydrate portion of materials, particularly reducing or modifying molecular weight of things like beta glucans and arabinoxylans – “all of which we think has got possible health implications”.
“…My PHD students are looking at products which may have an impact on colorectal cancer, so the known-on effects of this are potentially huge,” he said.
Research already showed that for beta glucans, a particular molecular weight exhibited a particular response on the immune system, but current extraction levels tended to be a very small proportion of the material.
“What we’re now postulating is that you may be able to take that material, and under different extrusion conditions, change the amount you can actually extract,” - it could, in essence, ‘blow out’ the material for easier access to molecular compounds, he explained.
With brewer’s spent grain that contained frolic acid – the precursor to vanillin – he said extrusion opened up the typically tight matrix for easier enzyme extraction.
“A lot of these waste products are bound tightly together. If you look at spent grain, you’ve got cellulose, proteins; all tied together and it’s very, very difficult to disrupt that and break it up, which is why it makes a great building material. From a food point of view, however, we need to break that apart.”
Academic push needed
Plunkett said research at the moment was unable to provide enough evidence to prove it was possible to extract enough material with enough functionality to work as an ingredient.
But, he said his team at Manchester was now “starting to lay the foundations”.
“We have huge challenges in terms of nutrition and sustainability globally, for every product not just snacks. But extrusion has a real good role in this; it’s got many possibilities. We can use materials that at first glance don’t look particularly appetizing; we can transform materials; and induce functionality… It’s very exciting really,” he said.