双孢菇菇柄酵素发酵条件优化及其抗氧化活性分析

本文以双孢菇菇柄为原料，以植物乳杆菌接种量、糖添加量和发酵时间为主要因素，总酚含量为评判指标，在单因素实验基础上，通过响应面试验研究优化了双孢菇菇柄酵素发酵工艺，并对酵素产品发酵前后及在4 ℃和25 ℃贮藏5 d的其抗氧化能力进行了研究。结果表明，菇柄酵素发酵的最佳条件为植物乳杆菌接种量3%、糖添加量9.50%、发酵时间24 h，酵素产品总酚含量值可达2.20 mg/mL，与预测值2.19 mg/mL相符；研究发现发酵后菇柄酵素的总酚、抗坏血酸含量分别为2.20 mg/mL与44.40 μg/mL，DPPH、ABTS自由基清除率、铁离子还原力和总抗氧化能力分别为51.93%、52.11%、0.70、28.09 U/mL，与发酵前比较有明显地提高。进一步对4 ℃和25 ℃贮藏条件下酵素的抗氧化活性分析表明，4 ℃贮藏的酵素，在贮藏0 d时DPPH、ABTS自由基清除能力、铁离子还原力和抗氧化能力均较强，在贮藏1 d后，酵素的抗氧化能力开始急剧下降，同时25 ℃条件下贮藏的酵素抗氧化能力显著低于4 ℃贮藏（P<0.05）。

Optimization of Fermentation Conditions and Antioxidant Activity of Agaricus bisporus Stipe Enzyme

In this paper, Agaricus bisporus stipe was used as the raw material, Lactobacillus plantarum inoculation amount, sugar addition amount and fermentation time were the main factors, and the total phenol content was used as the evaluation index. Based on single factor experiments, the Agaricus bisporus stipe enzyme was optimized by response surface experiments. Fermentation process, and the antioxidant capacity of the enzyme products before and after fermentation and storage at 4 ℃ and 25 ℃ for 5 d were studied. The results showed that the optimal process conditions for fermentation of Agaricus bisporus stipe enzyme were: Lactobacillus plantarum inoculation amount was 3%, 9.50% of sugar added, and fermentation time was 24 h. The total phenol content of the enzyme product could reach 2.20 mg/mL, which was equal to the predicted value of 2.19 mg/mL. The study found that the contents of total phenol and ascorbic acid in the Agaricus bisporus stipe enzyme were 2.20 mg/mL and 44.40 μg/mL, respectively. The DPPH free radical scavenging capacity, ABTS free radical scavenging capacity, ferric ion reducing antioxidant power and total antioxidant capacity were 51.93%, 52.11%, 0.70, 28.09 U/mL, respectively, which were significantly higher than those before fermentation. Further analysis of the antioxidant activity of the enzymes under the storage conditions of 4 ℃ and 25 ℃ showed that the enzymes stored at 4 ℃ had stronger DPPH, ABTS radical scavenging ability, iron ion reducing ability and antioxidant ability at 0 d storage. After 1 d storage, the antioxidant capacity of the enzyme began to decline sharply, and the antioxidant capacity of the enzyme stored at 25 °C was significantly lower than that stored at 4 °C (P<0.05).