二步发酵法在西番莲果皮酵素加工中的应用

以西番莲果皮为对象,研究酿酒酵母菌、乳酸菌二步发酵工艺,制备乳酸菌和酿酒酵母菌活菌数高、多酚保留好、风味醇和的果皮浆。通过单因素和正交优化实验,以酿酒酵母菌和乳酸菌活菌数、总酚、乙醇生成量为指标,分别优选了单一乳酸菌和酿酒酵母菌发酵的工艺参数,在此基础上,通过测定总酸含量、活菌数、总酚含量等指标的变化,确定二步法发酵西番莲果皮浆的工艺参数为：发酵总时间40 h,酿酒酵母菌初始接种量1.5%,在29 ℃下发酵16 h后,再接入2.0%复合乳杆菌（干酪乳杆菌∶植物乳杆菌=1∶1）,在37 ℃下继续发酵24 h至终点。制备的西番莲果皮发酵液中,复合乳杆菌活菌数为8.93 lg CFU/mL,酿酒酵母菌活菌数为7.78 lg CFU/mL,总酚含量为24.00 μg/mL,总酸含量为4.40 mg/mL。二步发酵法发挥了酿酒酵母菌产香、产乙醇抑制杂菌,以及乳酸菌提高酸度、保留多酚物质的优点。

Two-Step Fermentation Technology of Passionfruit Pericarp

The two-step fermentation process of Saccharomyces cerevisiae and lactic acid bacteria was studied to prepare passionfruit pericarp pulp with high viability of lactic acid bacteria and Saccharomyces cerevisiae, good retention of polyphenols and mellow flavor. Through single factor and orthogonal experiments, the fermentation process parameters of single lactic acid bacteria and yeast were optimized by taking the number of live S. cerevisiae and lactic acid bacteria, total phenol and ethanol production as the indexes. On this basis, by measuring the changes of total acid content, viable bacteria number and total phenol content, the technological parameters of the two-step fermentation of passionflower pericarp pulp were determined. The total fermentation time was 40 h. The initial inoculation amount of the mother bacteria was 1.5%. After 16 h of fermentation at 29 ℃, 2.0% mixed Lactobacillus (L. casei∶L. plantarum = 1∶1) was added, and the fermentation continued at 37 ℃ for 24 h. In the fermentation broth, the number of live Lactobacillus was 8.9 lg CFU/mL, the number of live S. cerevisiae was 7.78 lg CFU/mL, the total phenol content was 24.0 μg/mL, and the total acid content was 4.4 mg/mL. The two-step fermentation method had the advantages of S. cerevisiae producing aroma, ethanol inhibiting impurities, and lactic acid bacteria improving acidity and retaining polyphenols.