Abstract:
In this experiment,the optimum fermentation conditions of
Lycium barbarum by
Lactobacillus bulgaricus and
Streptococcus thermophilus were studied,and the changes of physicochemical indexes and the flavor components in the fermentation process were analyzed. Based on the sensory score of fermented products,the optimum technological parameters for fermentation of
Lycium barbarum by lactic acid bacteria were determined as follows:A combination of
Lactobacillus bulgaricus and
Streptococcus thermophilus 1:1,a ratio of material to water of 8:1 g/100 mL,an inoculation amount of 4%,and fermentation time 24 h. The sensory score of the fermentation broth under the fermentation conditions was 81 scores. During the fermentation of
Lycium barbarum by lactic acid bacteria,the titratable acid increased gradually,the pH value and reducing sugar content decreased continuously,and the number of viable bacteria,soluble solid content and soluble protein content increased first and then decreased. 63 kinds of volatile substances were separated from the fermented
Lycium barbarum liquid using solid-phase microextraction and gas chromatography-mass spectrometry,including 12 esters,16 aldehydes,15 ketones,13 alcohols,4 acids,and 3 aromatic heterocycles. Among them,41 new flavor substances had been produced. After 24 h of fermentation,the relative content of flavor substances of aldehydes,ketones decreased,and the relative content of flavor substances of esters,acids and aromatic heterocycles increased.