乳酸菌发酵蓝莓汁工艺优化及功能特性研究

Optimization of fermentation process and functional characteristics of blueberry juice by lactic acid bacteria

为开发营养健康的新型乳酸菌发酵蓝莓果汁,以新鲜蓝莓为原料,采用乳酸菌发酵工艺制备蓝莓汁,研究发酵对蓝莓汁中各种组分、活菌数及抗氧化活性的影响,并采用响应面试验优化发酵工艺条件。结果表明:蓝莓汁的最佳发酵工艺条件为发酵时间24 h、发酵温度37℃、乳酸菌接种量0.1%、蔗糖添加量6%;发酵温度和初始接种量对抗氧化酶活性影响极显著,接种量和时间交互作用极显著;最佳发酵工艺条件下,蓝莓汁中总酚含量413.40 mg/L,花青素含量206.40 mg/L,超氧化物歧化酶活力261.63 U/mL,活菌数2.18×10^(11)CFU/mL;发酵后蓝莓汁对DPPH清除率达到99.40%;运用高效液相色谱检测蓝莓汁在发酵过程中花青素单体的含量,发现花青素单体组分种类没有变化,含量变化显著,其主要成分锦葵色素-3-O-半乳糖苷含量显著增加,发酵24 h时为59.59μg/mL,与发酵前相比增加了16.87%。因此,发酵能提高蓝莓汁中活性物质含量,使蓝莓汁具有更高的抗氧化活性。

In order to investigate the fermentation characteristics of blueberry juice fermented by lactic acid bacteria,fresh blueberry was used as raw materials,and the fermented blueberry juice was prepared by lactic acid bacteria fermentation.On the basis of single factor experiment,the optimal preparation conditions of blueberry juice fermented by lactic acid bacteria were obtained using the Box-Behnken center combination test and response surface analysis method with SOD enzyme activity as an indicator.The total phenols,anthocyanins,total sugars,viable bacteria and antioxidant activity of blueberry juice before and after fermentation were determined.The results showed that the optimal technological conditions for preparing fermented blueberry juice were:the fermentation time was 24 h,the fermentation temperature was 37℃,the inoculation amount of lactic acid bacteria was 0.1%,and the addition amount of sucrose was 6%.Under the optimum conditions,The SOD enzyme activity of fermented blueberry juice was 261.63 U/mL,which was close to the theoretical value.The number of viable lactic acid bacteria was 2.18×10^(11)CFU/mL.The fermentation temperature and initial inoculation amount had a significant effect on antioxi dant enzyme activity,and the interaction between inoculation amount and time was very significant,the in-teraction of other factors was not significant.Compared with that before fermentation,the content of total phenols and total anthocyanins in fermented blueberry juice increased,which was 413.40 mg/L and 206.40 mg/L respectively.The antioxidant activity of fermented blueberry juice was improved.The scavenging rate of ABTS+and·OH radical by fermented blueberry juice increased significantly,and the scavenging rate of DPPH radical reached 99.4%.The anthocyanin monomer in the fermentation of blueberry juice was detected by HPLC.The results showed that the species of anthocyanin monomer components did not change,but the content changed significantly.Among them,the content of anthocyanin components of 6 monomers increased first and then decreased with the extension of fermentation time,the content of antho-cyanin components of 4 monomers decreased with the extension of fermentation time,and the content of an-thocyanin components of 3 monomers increased significantly with the extension of fermentation time.The main anthocyanin monomer in blueberry juice was malvidin-3-O-galactoside,and the content was 59.59μg/mL after fermentation for 24 h.The content of the other two main components,malvidin-3-O-gluco-side(t_(R)=31.006 min)and cyanidin-3-O-galactoside(t_(R)=23.394 min),decreased significantly with the extension of fermentation time.The results can provide a theoretical basis for the comprehensive utilization of blueberry resources.