Extraction technique influences the physico-chemical characteristics and functional properties of edible crickets (Acheta domesticus) protein concentrate

Abstract

Protein extracts from edible insects have not been exploited fully in product development due to limited information on extraction and functionality of the protein extracts. Therefore there was a need to evaluate the effect of selected protein extraction methods on the physico-chemical characteristics and functional properties of extracted proteins. Farmed edible crickets were obtained from JKUAT farm in Kenya, freeze dried and ground to powder. The proteins were extracted using two methods namely; hexane and aqueous extraction. Yield was determined gravimetrically and colour by colourimetric method. The crude protein, crude fibre, crude fat, crude ash and available carbohydrates were determined using standard analytical methods. Protein digestibility was determined using enzymatic digestion methods while protein fractions were extracted and quantified gravimetrically. The water holding capacity was determined using standard AACC procedure. Emulsion capacity and stability, foaming capacity and foam stability were also investigated. HE recorded the highest yield. Lightness and hue angle were significantly affected by the extraction method with hexane extraction recording higher values compared to aqueous extraction (P < 0.0001, P = 0.0003). The proximate components except crude fiber were affected by the extraction method. Aqueous extraction recorded significantly higher values for globulin (19.42%), prolamin (6.26%) and glutelin (10.10%) (P < 0.0001). There was no significance difference in water holding capacity and oil adsorption capacity. However AE precipitate recorded higher values for emulsion capacity (41.70%), emulsion stability (33.61%), foaming capacity (11.11%) and foam stability (10.15%). Extraction methods had an effect on physio- chemical and functional characteristics of the protein concentrates.