[关键词]
[摘要]
本文分析了三华李汁发酵乳杆菌发酵降酸期间乳酸菌活菌数、糖组分、有机酸、pH、可滴定酸、总酚、抗氧化活性、花色苷、色泽的变化规律。结果表明,在30 ℃的条件下,发酵乳杆菌缓慢生长,发酵6 d后,菌种数量趋于稳定;发酵期间,菌株对糖的利用较缓慢,仅利用少量的葡萄糖维持代谢生长,而对苹果酸的消耗较快。随着苹果酸的大量消耗以及少量乳酸的生成,三华李汁的pH值快速上升,可滴定酸含量迅速下降;发酵8 d后,菌种数量由初始的7.01 log CFU/mL增加到7.91 log CFU/mL,苹果酸被完全消耗,葡萄糖保留73.82%,果糖保留97.7%,pH值上升了0.38,可滴定含量下降了43.7%,总酚保留82.23%,抗氧化活性(ORAC值)升高了14.90%,花色苷保留50%以上,三华李汁的色泽变化不显著(p>0.05)。因此,利用乳酸菌发酵三华李汁,不仅能够降低三华李汁酸度,而且很好地保留了三华李本身的营养成分。
[Key word]
[Abstract]
The changes in the viable count of Lactobacillus fermentum, sugar component, organic acids content, pH value, titratable acid content, total phenolic content, antioxidant capacity, anthocyanin content, and color of the Sanhua plum juice during the deacidification by fermentation with L. fermentum were investigated in this paper. The results showed that the L. fermentum grew slowly in the plum juice at 30 ℃, and its population appeared to be stable after six days of fermentation. During the fermentation, L. fermentum consumed the sugar in the plum juice slowly, using only a small amount of glucose to maintain its metabolism and growth, while consuming malic acid rapidly. With the depletion of malic acid and production of a small amount of lactic acid, the pH of the plum juice increased quickly with a rapid reduction in the total titratable acid content. After eight days of fermentation, the population of L. fermentum in the plum juice increased from 7.01 log CFU/mL to 7.91 log CFU/mL, the malic acid was completely consumed, while 73.82% of the glucose and 97.7% of the fructose remained. The pH value increased by 0.38, titratable acid content reduced by 43.7%, while 82.23% of the total phenolics remained. The antioxidant activity (oxygen radical absorbance capacity (ORAC) value) increased by 14.90%, 50% of anthocyanin remained, and no significant changes (p>0.05) were observed in the color of the juice sample. Hence, the use of L. fermentum for the fermentation of Sanhua plum juice can not only reduce the acidity of the plum juice, but also retain the nutrient content of plum juice well.
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[基金项目]
广东省自然科学基金研究团队项目(2015BAD31B03);广东省特支计划科技创新拔尖青年人才项目(2014TQ01N120);广州市科技计划项目(2014Y2-00099)