Nutritional, functional properties of insect protein characterised

There is a growing interest in alternatives to traditional animal protein sources, leading companies to explore myriad new plant sources, biotech alternatives, and insects. Researchers from West Virginia University (WVU) recently experimented with protein isolation techniques to characterise the nutritional and functional properties of insect protein, potentially positioning insect powder for broader use in food applications.

Kristen Matak, a professor of animal and nutritional sciences at WVU and part of the research team, commented: "The global demand for sustainable sources of protein has created a shift from traditional sources like meat to other sources that were otherwise overlooked. Edible insects and insect flours are promising as meat alternatives because they are typically rich in protein and contain all of the essential amino acids."

Insect powders are currently available commercially, but uptake has been limited; one path could be to deliver a more concentrated protein version. While protein isolation is widely used on different sources to purify and up-concentrate protein levels, the technique has not been used across all types of potential protein sources. In the current study, published in LWT (DOI:10.1016/j.lwt.2021.112314), the WVU used a patented protein isolation procedure on cricket, locust, and silkworm pupae powders. The isolated protein was assessed for macro-nutrient proximate composition, full amino acid composition, protein pH solubility, and SDS-PAGE/densitometry.

The cricket and locust powders contained >70 g of crude protein per 100 g of powder; silkworm pupae powder contained >50 g of crude protein per 100 g powder. The powders exceeded FAO/WHO recommendations for eight of the nine essential amino acids (EAAs) for adults, but not infants. Total EAAs were 21.8 g to 23.7 g per 100 g sample, dry basis. Nearly 70% of insect protein dissolved in alkaline pH, but only 7% at a 4-6 pH. The SDS-PAGE/densitrometry showed four protein fractions—cuticle proteins, actin-arginine kinase, hemocyanin, and myosin—with various distribution among the powders.

Researchers concluded protein could be efficiently isolated from insect powders using pH-solubility-precipitation, resulting in isolates with high nutritional and functional quality. In a press release, Jacek Jaczynski, professor of food science and muscle food safety at WVU and a co-author of the study, commented: "With insects, our point is to selectively extract those nutrients, like proteins and lipids. We have to find a way to extract and isolate high quality nutrients and develop prototypes that will jive well with our taste buds."