Functional properties and essential amino acid composition of proteins extracted from black soldier fly larvae reared on canteen leftovers

Abstract

This study investigated the functional properties and essential amino acid composition of proteins extracted from black soldier fly larvae which represent a good source of proteins (30.12% dry matter). The proteins extracted in alkaline conditions (pH 11) were then isolated using two different recovery methods, (i) ultrafiltration, and (ii) isoelectric precipitation. Ultrafiltration provided higher purity of proteins (96.42%) but a lower extraction yield (24.30%) compared to isoelectric precipitation which provided a protein purity of 76.02% and higher extraction yield (37.22%). All essential amino acids were present in adequate quantities for human requirements. The fraction of proteins obtained by ultrafiltration had significantly higher oil holding capacity and foaming capacity than isoelectrically precipitated proteins. The protein fractions obtained by ultrafiltration and isoelectric precipitation had oil holding capacity of 125.8% and 81.6%, while the foaming capacity was 141.9% and 114.3%, respectively. These technological functionalities can be used to improve human food characteristics, thus resulting in enhanced consumer acceptance. Industrial relevanceThe food industry seeks alternative and sustainable sources of proteins, such as insect proteins, to reduce the environmental impact (i.e., greenhouse gas emissions). Consumers' acceptance is the main barrier to adopting edible insects in commercial applications. The acceptance increases when the insect proteins are incorporated in food products as ingredients rather than consuming the whole insect. Hence, this study focuses not only on extraction of proteins but also on functional properties of those proteins making it easier to target specific food formulations (i.e., whipped toppings), which require specific functionalities (i.e., foaming capacity and stability). The protein purity was increased by including an ultrafiltration step. The proteins obtained through the ultrafiltration method showed better oil holding capacity and foaming stability compared to proteins obtained by isoelectric precipitation. The strategies assessed in the present study help enhance the purity of larval proteins and improve their functional properties, thereby opening up new opportunities to incorporate this ingredient into targeted food formulations and improve consumer acceptance.