Study on Extraction and Antioxidant Activities of Functional Components from ESM

• 1、School of Food Science and Technology,Jiangnan University,Jiangsu Wuxi,214122

Abstract：Eggshell membranes (ESM) have high nutritional value because they are rich in proteins, mucopolysaccharides, etc. However, due to their poor water solubility, the application of ESM are still limited. In this study, ESM were treated by alkaline condition and then enzymatic hydrolysis to produce shell membrane peptides, and mucopolysaccharide with a higher content was also obtained, which expand the applied range of ESM. Results indicated that the optimal conditions of alkaline pretreatment was that NaOH concentration was 0.25M , temperature was 30℃, time was 3h, solid-liquid ratio was 1:10; The optimum condition for enzymatic hydrolysis was that the addition of alkaline protease was 5% (w/w), temperature was 55℃, time was 6h. Under these conditions, the total nitrogen recovery was 49.58%, the yield of D-glucuronic acid was 7.08mg/g, and the ABTS+ free radical capacity was 52.47% at 0.2mg/mL. The molecular weight, antioxidant property and amino acid composition of enzymatic hydrolysates were further analyzed. High performance liquid chromatography (HPLC) results showed that the main component of the product was oligopeptide, which accounts for 81.78%. And then the product was separated into 4 fractions with different molecular weight ranges, of which <3kD fraction had the strongest antioxidant capacity. Amino acid composition analysis suggested that the antioxidant activity was related to the amino acid composition, and the content of antioxidant-linked amino acids in <3kD component was as high as 85.93%.

Keywords： eggshell membrane enzymatic hydrolysis alkaline pretreatment antioxidant activity amino acid analysis