降解山楂汁中柠檬酸酵母菌的筛选及其降酸特性研究

Screening Yeast Degrading Citric Acid in Hawthorn Fruit Juice and Its Degrading Characteristics

采用酸碱滴定法和高效液相色谱法对山楂汁中主要有机酸进行分析 ,结果表明柠檬酸占总酸的 83.5 % ;分别以柠檬酸和山楂黄酮为唯一碳源 ,筛选能降解柠檬酸而不利用山楂黄酮的酵母菌 ,结果获得 6株菌 ;再以山楂汁为培养基进行复筛 ,得到一株酵母菌 ,该菌能有效降解山楂汁中柠檬酸而对山楂黄酮的影响较小 ;经鉴定这株菌属于毕赤酵母属 ,定名为Pichiasp .Y1。发酵特性研究表明该菌在山楂汁中 2 0℃培养 3d ,总酸量从 19.6 0g L下降到3 5 2g L ,而对黄酮含量无显著影响。

The objective of the study was to screen yeasts that were capable of degrading organic acids, and maintaining the flavonoids in hawthorn fruit juice. Citric acid, as the main organic acid in the juice, was 83.5% in total acidity by acid-base titration and HPLC. Six strains were obtained, which could degrade the citric acid but not the flavonoids in the media with citric acid or the flavonoids as sole carbon source. The best strain of the six was selected with hawthorn fruit juice as medium. The strain was identified to belong to the genus Pichia and was named as Pichia sp. Y1. Incubated the Pichia sp. Y1 in the juice for 3d, at 20℃,DO 34%～40%, the total acids content in the juice decreased from 19.6g/L to 3.52g/L, meanwhile, the change of flavonoids content was not significant.