Selection of Lactic Acid Bacteria Suitable for Fermented Tomato Juice and Changes in Components Due to Fermentation

In order to optimize production of fermented tomato juice, suitable lactic acid bacteria were selected, and the changes in constituents during fermentation were investigated. Fermentation and sensory evaluation showed that Lactobacillus bulgaricus IAM-1120 and L. helveticus JCM-1120 produced a preferable juice among ten strains of lactic acid bacteria. These two strains produced much lower diacetyl and acetoin than the other strains in tomato juice that contains a high level of citric acid. These results suggested that the minimal production of these compounds from citric acid as well as sugar was an important factor for selection of bacteria in preferable fermented vegetable juice. Moreover, a decrease in hexanal, a representative aldehyde in tomato juice, appeared to contribute to taste improvement after fermentation. The nutritional requirements for amino acids, vitamins and bases for the growth of the two bacterial strains were also characterized.