Could a grain by-product offer a potential new natural preservative?

Researchers from the US are investigating how this clean-label ingredient could extend shelf life.

15 January 2019
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As consumers seek out more natural ingredients, an antioxidant found in grain bran could have potential use as a food preservative. Not just that, it could also help reduce food waste as it would utilise what is currently a production side stream.

Researchers from Penn State University investigated a class of compounds called alkylresorcinols, which are produced by grain plants like wheat, rye and barley to prevent mould and bacteria developing in the kernels.

Andrew Elder, who worked on the study, said the discovery of a new source of natural antioxidant could be significant for the food industry as demand for clean-label ingredients continues to grow.

He told Food Spark’s sister site Food Navigator that there is currently a big push to replace synthetic ingredients with natural alternatives.

“Consumers want clean labels. They want synthetic, chemical-sounding ingredients removed because of the fact that they don’t recognise them and that some of them have purported toxicity,” he commented.

The increasing demand for clean label is driving development in a number of categories. It spans everything from natural colouring for products to clean ingredients in confectionery, where for, example, New Zealand company Taura Natural Ingredients pioneered a new technology that allowed for fruit to be turned into a form akin to that of a gummy bear.

Natural is number one

But the food industry has struggled to find natural antioxidants that are as effective as synthetic ones, according to Elder.

“There are not many natural alternatives for synthetic antioxidants. Our work is focused on identifying new natural antioxidants to extend the shelf life of food and meet consumer demands,” he said.

An added benefit of the plant-based antioxidant is the potential to cut food waste in the supply chain, as the compounds come from the bran layer of cereal plants, which the food industry usually discards or uses for animal feed.

The age-old problem of pumping up the antioxidant level has also been on the mind of a number of producers, as previously reported by Food Spark.

Chocolate manufacturers like CasaLuker have been investigating how to boost the antioxidant levels in its chocolate and it has a new method to make cocoa powder with a high polyphenol content that could be used in cocoa-based food, beverages and even supplements.

Other have looked to guayusa leaves, which deliver a caffeine fix with added antioxidants and have been incorporated into a chocolate bar by Ecuadorian chocolate company Pacari, as well as in the canned energy drink Yusa from Brit-based company BFT Drinks.

Doubly healthy

Part of the Penn State study involved developing a technique to extract and purify the antioxidant compounds from rye bran.

Its effectiveness was then tested on preserving omega-3 oil, which was selected because of a growing desire to add healthy oils to foods that would not normally contain them, according to the study authors. However, adding omega-3 rich oils often results in a shorter shelf life, causing foods to spoil more quickly.

“Most people consume omega-3s from marine sources,” explained Elder. “As they break down, they can make the product smell and taste fishy. Consumers then throw these products out and don’t buy them again, and this results in an economic loss.”

However, antioxidants work to slow down the rate at which omega-3 fatty acids degrade, preserving their health benefits and preventing from spoiling as quickly.

While the testing was successful with the new compounds, it wasn’t all good news. Comparisons with two other antioxidants widely used in the food industry – the natural vitamin E and the synthetic butylated hydroxytoluene – showed the Penn State inventions were less effective.

The researchers aren’t giving up though and have plans for future work, noting the compound extracts they used in the study weren’t completely pure and a blend of different compounds were also used that had different molecular structures.

“We’re trying to identify natural antioxidants that are consumer-friendly, safe and effective,” Elder added.

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