Functional Profile of Enzymatic Hydrolysates in Food Proteins

Abstract

Food allergy is a matter of global concern, proteins being a popular allergen worldwide. Enzymatic protein hydrolysates serve as hypoallergenic components in functional foods. This article describes enzymatic hydrolysates of egg and soy proteins as potential antigens, sensitizers, and antioxidants. The research featured soy protein isolate and egg albumin. The protein hydrolysates were obtained in a two-step process with pepsin and trypsin to measure hydrolysis, total antioxidant activity, and residual antigenicity. The sensitizing ability of native proteins and their hydrolysates was studied using a delayed-type hypersensitivity (DTH) skin test of paw swelling in mice. The egg albumin and soy protein were hydrolyzed by sequentially adding the proteases, i.e., pepsin and trypsin. The degree of protein hydrolysis was calculated against total nitrogen and its contents in non-hydrolyzed raw materials and hydrolysate. It was 82.6% for the egg hydrolysate and 88.3% for the soy hydrolysate, the total antioxidant activity being 114.3 and 91.4 mg/100 mL, respectively. The residual antigenicity of the hydrolysates determined by ELISA in a sandwich version was 1.55×10–4 and 3.30×10–4 RU, respectively. The native egg and soy proteins demonstrated good allergenic properties, and the DTH response index increased fivefold. The hydrolysates reduced the DTH response indices by an average of 3.5 for egg hydrolysate and 2.6 times for soy hydrolysate. The resulting enzymatic hydrolysates of egg albumin and soy protein demonstrated a high degree of hydrolysis and antioxidant activity. They had low residual antigenicity (10–4) and low sensitizing ability. The resulting enzymatic hydrolysates could be used as hypoallergenic components and antioxidants in new functional foods.

Keywords

• egg albumin
• soy protein
• hydrolysates
• residual antigenic activity
• sensitizing activity
• antioxidant activity