Microflora analysis and influence of stirring on maturation process of fermented extract made from plants

Recently, consumers have been showing more concern about health and there is a growing market for health related food and drinks. We have studied a fermented soft drink made from vegetables and elucidated some microbial properties during fermentation and maturation. Some instability in fermentation was found and improvements in the fermentation process were considered. In the present study, we produced fermented extract made from several plants, such as vegetables and mushroom, with stirring once a day and without stirring, and compared their microbial floras, organic acids and pH through fermentation and maturation. Throughout the fermentation and maturation, the number of microorganisms, especially acid-producing bacteria, of the stirred sample were remarkably less than without stirring. From the sample without stirring, we isolated Staphylococcus sp. and Lactobacillus sp., which may be major lactic acid-producing bacteria. Those strains were not isolated from the sample with stirring, and lactic acid content was much lower in the aerated sample than in the unstirred sample. Those data indicated that aeration to microorganisms during the fermentation was not beneficial to quality.