苹果酵素的制备及其抗氧化功能研究

Study on preparation and antioxidant function of apple enzyme

为了探究不同菌种组合发酵对苹果酵素抗氧化功能的影响,研究了酿酒酵母+乳酸菌(鼠李糖乳杆菌或植物乳杆菌)组合发酵制备苹果酵素的工艺以及酵素的抗氧化功能.以陕西洛川富士苹果为主要原料,以超氧化物歧化酶(SOD)活力、总酸含量为评价指标,通过单因素和响应面试验优化了苹果酵素制备工艺,并对酵素的抗氧化功能进行了初步检测.苹果酵素最佳制备工艺关键参数为:苹果汁中添加5.5%w/v蔗糖并调节苹果汁pH至4.5,接种酿酒酵母进行发酵,发酵温度29℃,接种量1%v/v,发酵20 h后苹果汁发酵液SOD活力达到峰值(149.32±2.58 U/mL);而后调节发酵液pH至6.2,接种鼠李糖乳杆菌继续发酵,发酵温度37℃,接种量1%v/v,发酵时间23 h.制备的苹果酵素SOD活力为158.54±1.32 U/mL,酿酒酵母浓度为7.66±0.20 lg CFU/mL,鼠李糖乳杆菌浓度为6.47±0.14 lg CFU/mL,总酸含量为3.98±0.34 g/L.苹果酵素羟基自由基清除率、铁离子还原力以及总酚含量相比于对照组(未发酵苹果汁)分别提高了90.70%、77.78%和93.23%,表现出良好的抗氧化性.上述结果表明:酿酒酵母+鼠李糖乳杆菌组合发酵可显著改善苹果抗氧化功能特性.

In order to explore the effect of the combined fermentation of different strains on the antioxidant function of apple enzyme,the process of preparing apple enzyme by combination fermentation of Saccharomyces cerevisiae and lactic acid bacteria(Lactobacillus rhamnosus or Lactobacillus plantarum)and the antioxidant function of enzyme were studied.Taking Shaanxi Luochuan Fuji apple as the main raw material,the preparation process of apple enzyme was optimized by single factor and response surface experiments with superoxide dismutase(SOD)activity and total acid content as evaluation indexes,and the antioxidant function of enzyme was preliminarily tested.The key parameters of the optimal preparation process of apple enzyme were as follows:after addition of 5.5%w/v sucrose to apple juice and adjusting the pH of apple juice to 4.5,the fermentation was carried out by inoculating 1%v/v of Saccharomyces cerevisiae at 29℃,and the SOD activity of apple juice reached the peak value of 149.32±2.58 U/mL after 20 h of fermentation.Then the pH of the fermentation broth was adjusted to 6.2,and 1%v/v of Lactobacillus rhamnosus was inoculated to continue fermentation at 37℃for 23 h.The prepared apple enzyme SOD activity was 158.54±1.32 U/mL,the concentration of Saccharomyces cerevisiae was 7.66±0.20 lg CFU/mL,the concentration of Lactobacillus rhamnosus was 6.47±0.14 lg CFU/mL,and the total acid content was 3.98±0.34 g/L.Compared with the control group(unfermented apple juice),the hydroxyl radical scavenging rate,iron ion reducing power and total phenol content of apple enzyme increased by 90.70%,77.78%and 93.23%,respectively,showing good antioxidant activity.The above results showed that segmentation fermentation of Saccharomyces cerevisiae and Lactobacillus rhamnosus could improve the antioxidant function of apple.