Physicochemical properties of house cricket (Acheta domesticus) protein and antioxidant stability of its enzymatic hydrolysate under pH, temperature and in vitro digestion

Abstract

House cricket (Acheta domesticus) is a sustainable protein source but faces low consumer acceptance for direct consumption. To enhance its usability, cricket protein isolate (CPI) and its enzymatic hydrolysates (CPH) were characterized as potential functional ingredients. Cricket powder contained 71% protein, with an amino acid profile comparable to animal proteins. CPI exhibited favourable functional properties, including high water-binding capacity (4.9 g water/g sample), emulsifying activity (EAI approx. 5.5 m²/g), and stable emulsifying performance (ESI). Protein solubility was lowest at pH 4.0, indicating the isoelectric point (pI), while foaming ability increased under alkaline conditions but decreased near the pI. Hydrolysis with alcalase and flavourzyme achieved higher degrees of hydrolysis and enhanced antioxidant activity. CPH showed thermal-activated and acid-stable antioxidative activity. These results demonstrate the potential of cricket proteins as functional and antioxidant-rich ingredients, supporting the development of innovative, more acceptable insect-based foods.