Physical and oxidative stability of 5 % fish oil-in-water emulsions stabilized with lesser mealworm (Alphitobius diaperinus larva) protein hydrolysates pretreated with ultrasound and pulsed electric fields

Abstract

Lesser mealworm (Alphitobius diaperinus larva) meal was pretreated with ultrasound (US) or pulsed electric fields (PEF) and hydrolyzed using Alcalase or Trypsin enzymes. The resulting hydrolysates were evaluated for their ability to maintain physical and oxidative stability of 5 % fish oil-in-water emulsions. The effects of the pretreatment on enzymatic hydrolysis were assessed by measuring the degree of hydrolysis (DH), protein yield, and molecular weight distribution. Hydrolysates with 19-28 % DH were produced. Physical stability was evaluated in terms of creaming index, Turbiscan stability index, ζ-potential, and droplet size. Emulsions stabilized with US-pretreated Trypsin hydrolysates presented the smallest droplet sizes (0.626 μm). Primary and volatile secondary oxidation products were measured during storage. However, none of the hydrolysate-stabilized emulsions exhibited greater oxidative stability than sodium caseinate, the reference protein. These results suggest that although US-pretreated Trypsin hydrolysates exhibit potential as emulsifiers, additional antioxidants are needed to effectively control lipid oxidation.