Water-soluble proteins extracted from two species of grasshoppers, Patanga succincta (WSPP) and Chondracris roseapbrunner (WSPC), were characterized as well as their functional properties and antioxidant activities were investigated. e extraction yield, on a wet weight basis, was 7.35% and 7.46% for WSPP and WSPC, respectively. e most abundant amino acid in both proteins was glutamic acid, followed by aspartic, alanine, and leucine, in that order. e electrophoretic study revealed that proteins with MW of 29, 42, 50, 69, and 146 kDa were the major protein components in WSPP and WSPC. FTIR analysis showed that those proteins remained their structural integrity. e surface hydrophobicity at pH 7 of WSPC was higher than WSPP, but the sulfhydryl group content did not show significant difference between the proteins from two species. Both grasshopper proteins were mostly soluble in strong acidic and alkaline aqueous solutions with a minimum value at pH 4. ose proteins exhibited poor emulsifying properties and foaming capacity, but they had greater foaming stability compared with bovine serum albumin (BSA) (p < 0.05). WSPC showed greater DPPH • and ABTS •+ scavenging activities and ferric-reducing antioxidant power (FRAP) than did WSPP (p < 0.05). erefore, based on characteristics and functional properties, water-soluble proteins from both edible grasshoppers can be used as an ingredient in food applications.

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The need for novel and diverse sources of protein to feed the growing world population is urgent and stark. At the same time, peoples’ eating habits and values are also changing, with more consumers considering alternatives to traditional sources of protein. Novel protein sources not only need to provide essential amino acids and nutrition, but also cater to taste, convenience, cost economics, and personal needs. They also need to be ethically produced, with a smaller environmental footprint, and when feasible, closer to consumer. Insect protein has been researched intensively in recent years with promises to best fulfill these needs. As the insect protein field and industry are expanding and getting more mature at this stage, this review summarizes their properties and applications within the context of the food and feed industry. The important functional properties that make insect proteins useful are also discussed.

Lipid acyl hydrolase (LAH; patatin) was purified from potato tubers by ammonium sulfate fractionation followed by anion-exchange and affinity chromatography. The major protein band of 40-43 kDa on SDS-PAGE appeared to be patatin, and it stained positive for lipase activity on native PAGE. Selectivity of a Celite-immobilized potato LAH in esterification reactions with n-acyl fatty acids (FA; C4, C6, C8, C10, C12, C14, C16, and C18) and alcohol acceptors (n-propanol, 2-propanol, 1,3-propanediol, and glycerol; 1,2-propanediol was not sufficiently reactive) was studied in isooctane. Immobilized LAH was highly selective for medium chain FAs (C8/C10) with a secondary optimum for chain lengths of C14/16. Water activity (a(w)) influenced activity and FA selectivity of the enzyme. Initial rates of ester synthesis were greatest at a(w) of 0.90 for all alcohol acceptors except for glycerol, where greatest initial rates were observed at a(w) of 0.19. Immobilized LAH preparations exhibited a bell-shape pH profile with optimum activity at pH 6-7 for ester synthesis, and no effect of pH on FA selectivity was observed.

Acid oil is a by-product in the neutralization step of vegetable oil refining and is an alternative source of biodiesel fuel. A model substrate of acid oil, which is composed of TAG and FFA, was used in experiments on the conversion to FAME by immobilized Candida antarctica lipase. FFA in the mixture of TAG/FFA were efficiently esterified with methanol (MeOH), but the water generated by the esterification significantly inhibited methanolysis of TAG. We thus attempted to convert a mixture of TAG/FFA to FAME by a two-step process comprising methyl esterification of FFA and methanolysis of TAG by immobilized C. antarctica lipase. The first reaction was conducted at 30°C in a mixture of TAG/FFA (1:1, wt/wt) and 10 wt% MeOH using 0.5 wt% immobilized lipase, resulting in efficient esterification of FFA. The reaction mixture after 24 h was composed of 49.1 wt% TAG, 1.3 wt% FFA, 49.1 wt% FAME, and negligible amounts of DAG and MAG (<0.5 wt%). The reaction mixture was then dehydrated and used as a substrate for the second reaction, which was conducted at 30°C in a solution of the dehydrated mixture and 5.5 wt% MeOH using 6 wt% immobilized lipase. The activity of the lipase increased gradually when the reaction was repeated by transferring the enzyme to a fresh substrate mixture. The activity reached a maximum after 6 cycles, and the content of FAME achieved was >98.5 wt% after a 24-h reaction. The immobilized lipase was very stable in the first-and second-step reactions and could be used for >100 d without significant loss of activity.Paper no. J11126 in JAOCS 82, 825-831 (November 2005).