柞蚕蛹多肽的抗氧化性及稳定性研究

Investigation on Antioxidant and Stability of Tussah Pupa Polypeptide

研究柞蚕蛹多肽的抗氧化性及环境稳定性,并进行了体外模拟胃肠消化试验。测定其DPPH自由基清除能力、还原力、超氧阴离子自由基清除能力和羟基自由基清除能力,及pH值、温度、光照、金属离子、食品添加剂、防腐剂及模拟胃肠消化对其稳定性的影响。结果表明:柞蚕蛹多肽的DPPH清除能力、还原力、超氧阴离子自由基清除能力、羟基清除能力较好;在酸性至中性环境下稳定性较好,强碱条件下会迅速失活;光照和热处理都会使柞蚕蛹多肽稳定性降低;在Fe3+作用下柞蚕蛹多肽的活性明显低于其他金属离子;低浓度的NaCl添加,可以使柞蚕蛹多肽对DPPH的清除率小幅度的提升、柠檬酸添加量的增加会使柞蚕蛹多肽DPPH自由基清除能力先提升后趋于平缓,柞蚕蛹多肽在白砂糖的作用下活性始终较为稳定;对柞蚕蛹多肽抗氧化稳定性的影响,苯甲酸钠>山梨酸钾;柞蚕蛹多肽的胃肠消化抗氧化稳定性较低,消化过程中其DPPH清除率逐渐降低。经胃消化阶段其清除率由59.09%降低至24.05%,再经肠消化后下降至9.4%。

In this study,the antioxidant and environmental stability of tussah’s pupa polypeptide were studied,and a simulated in vitro gastrointestinal digestion test was conducted.The effects of DPPH free radical scavenging ability,reducing power,superoxide anion radical scavenging ability and hydroxyl radical scavenging ability,as well as pH,temperature,light,metal ions,food additives,preservatives and simulated gastrointestinal digestion on the stability were surveyed and evaluated respectively.The results showed that the tussah’s pupa polypeptide has better DPPH free radical scavenging ability,reducing power,superoxide anion radical scavenging ability and hydroxyl radical scavenging ability;it has good stability in acidic to neutral environment but will decline rapidly in strong alkaline environment;light and heat treatment will reduce the stability of tussah pupa polypeptide;the activity under the action of Fe3+was significantly lower than that under other metal ions;the addition of low concentration NaCl could increase the DPPH clearance rate by a small margin,while increasing the amount of citric acid would make the DPPH free radical scavenging ability of the tussah pupa polypeptide increase first and then remain unchanged.Furthermore,the addition of white sugar had no significant effect on the activity;sodium benzoate had a greater effect on the antioxidant stability of polypeptides than potassium sorbate;the tussah pupa polypeptide presented low antioxidant stability during simulated gastrointestinal digestion with the gradual decrease of DPPH clearance.During the gastric digestion stage,the clearance rate decreased from 59.09%to 24.05%,and then decreased to 9.4%after intestinal digestion.