Characterization of freeze-dried, oven-dried and blanched house crickets (Acheta domesticus) and Jamaican field crickets (Gryllus assimilis) by means of their physicochemical properties and volatile compounds

Abstract

Edible insects are repeatedly being considered as underutilized food candidate due to their high nutritional value. Although frequent acceptance of whole insects to consumer is still challenging, incorporation of insects in food as powder or paste has been suggested to increase their acceptability. Hence, Acheta domesticus and Gryllus assimilis were subjected to freeze drying, oven drying, and blanching to acquire a clear insight on the impact of the processing methods on the nutritional and physical properties of both species. Result showed that these three methods had limited effects on the proximate composition, fatty acid and amino acid profile but had significant impact on other parameters for both species. Vitamin B12 in A. domesticus did not change but G. assimilis changed due to the treatment. Freeze drying showed better lightness (L* value) and lower browning index for both cricket species. Oven drying and blanching resulted in lower lipid oxidation values than freeze drying for both cricket species; though lipid oxidation was in all cases well below the rejection limit. Esters were the predominant group of volatile compound in freeze and oven-dried cricket while least amount of volatiles were found in blanched cricket. The volatiles resulted from fatty acid oxidation were higher in freeze-dried crickets, while Maillard reaction products were found in oven-dried samples. Although freeze drying showed higher colour quality, oven drying exerted superior effect in terms of nutritional and flavour characteristics followed by blanching treatment.