Abstract:Using Lactobacillus paracasei SR10-1, Lactobacillus casei H1, and Lactobacillus fermentum GZSC-1 to ferment Rosa roxburghii Tratt juice as the research object, the quality changes of Rosa roxburghii Tratt juice before and after fermentation were compared. Gas chromatography-ion mobility spectroscopy (GC-IMS) and electronic nose (E-nose) technology were used to analyze the composition and differences of volatile flavor compounds in Rosa roxburghii Tratt juice fermented by different lactic acid bacteria. The results showed that the loss rate of VC and SOD in SR10-1 fermented Rosa roxburghii Tratt juice was the lowest (P <0.05), and the tannin degradation rate in H1 fermented Rosa roxburghii Tratt juice was the highest, reaching (41.37±1.08)%. The electronic nose analysis showed that the aroma profiles of Rosa roxburghii Tratt juice fermented by three lactic acid bacteria were similar, however, the aroma contribution of SR10-1 fermented Rosa roxburghii Tratt juice was the highest. A total of 54 volatile components were isolated from three groups of lactic acid bacteria fermented samples, diluted 4-fold Rosa roxburghii Tratt juice, and original sample of Rosa roxburghii Tratt juice by GC-IMS, and 44 compounds were identified, mainly including esters, aldehydes, alcohols, and acids. The volatile flavor substances shared by the three different lactic acid bacteria fermented samples included leaf alcohol, ethanol, propyl acetate, 3-pentanone, ethyl acetate, acetone, and so on. Dimethyl sulfide, acetone, and ethyl butyrate were the characteristic flavor compounds of SR10-1, GZSC-1, and H1 fermented samples, respectively. The main flavor components of H1 and GZSC-1 fermented samples were similar, which was consistent with the electronic nose results. These results indicated that the fermentation of Rosa roxburghii Tratt juice by lactic acid bacteria retained the main nutrients of Rosa roxburghii Tratt juice, generated new metabolic substances, enhanced the fruit flavor of Rosa roxburghii Tratt juice, and positively affected the flavor improvement of Rosa roxburghii Tratt juice.
