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.
