高固形物浓度对酵母酶解及其产物抗氧化性的影响

Effect of High Solid Content on Enzymolysis by Yeasts and Antioxidant Activity of the Products

高固形物浓度的酶解是近年来国际食品探究的热点之一。本文利用木瓜蛋白酶水解不同固形物浓度的活性面包酵母,并对酶解液的氨氮、总氮、可溶固形物含量、还原糖、总糖、渗透压、抗氧化活性以及褐变程度进行了检测,探究高固形物浓度对酵母酶解及其产物抗氧化性的影响。结果表明,随着固形物浓度的提高,酵母酶解液中的氨氮、总氮,可溶性固形含量、还原糖、总糖、渗透压随之提高,提高固形物浓度有利于提高酵母酶解效率。通过对酵母酶解液抗氧化活性的测定发现,固形物浓度为30%时,酶解液具有较高的DPPH和羟自由基清除活性,酶解13 h时,其IC50值分别为0.83±0.09 mg/mL和21.53±1.18 mg/mL;酶解21 h时,其IC50值分别为1.01±0.13 mg/mL和23.17±1.33 mg/mL。在高浓度固形物酶解液中,适当添加SDS有助于降低其褐变程度。

Enzymolysis with high solid content（HSC） is one of the current hotspots in food research worldwide.In this study,active yeasts from bread containing different levels of solid content were hydrolyzed using papain.The levels of ammonia nitrogen,total nitrogen,soluble solids,reducing sugar,and total sugar,as well as osmotic pressure,antioxidant activity,and extent of browning of the enzymatic hydrolysate were measured to determine the effect of HSC on enzymolysis and the antioxidant activity of yeast enzymolysis products.The results showed that the levels of ammonia nitrogen,total nitrogen,soluble solids,reducing sugar,total sugar,and osmotic pressure increased with increasing solid content,suggesting that increasing solid content could promote the efficiency of yeast enzymolysis.Antioxidant activity measurement demonstrated that when the solid content was 30%,the enzymolysis hydrolysate had a relatively high diphenylpicrylhydrazyl（DPPH） and hydroxyl radical scavenging activity,with half maximal inhibitory concentration（IC50） of 0.83±0.09 mg/mL and 21.53±1.18 mg/mL,respectively,after 13 hours of enzymolysis;whereas the IC50 reached 1.01±0.13 mg/ml and 23.17±1.33 mg/mL,respectively,after 21 hours of enzymolysis.The addition of an appropriate amount of SDS could decrease the degree of browning of yeast.