Investigation of the possibility of fermentation of red grape juice and rice flour by Lactobacillus plantarum and Lactobacillus casei

The aim of the current study was to evaluate the possibility of the bacterial growth and substrate metabolism during the fermentation of red grape juice and the mixture of red grape juice and rice flour solution using Lactobacillus plantarum and Lactobacillus casei. In recent years, cereal-based beverages have been used as functional compounds such as antioxidants, dietary fiber, minerals, probiotics, and vitamins in diets. In this research, fermentation of red grape juice (media 1) and 1:1 mixture of red grape juice and rice flour solution (media 2) by two strains of gram positive and homofermentative lactic acid bacteria: L. plantarum and L. casei (individually and mixed) was examined. Fermentation was carried out at 37 degrees C for 48 hr. Microbial population, pH, acidity, sugar, and organic acid metabolism were measured during the fermentation period. Data showed that in media 2 fermented with mixed culture of both L. plantarum and L. casei, acidity and microbial population increased sharply at the initial stages of fermentation, and the most percentage of lactic acid production occurred. Red grape juice fermented with mixture of L. plantarum and L. casei showed the most sugar consumption (p < .05). Results indicated that the use of the mixture of red grape juice and rice flour solution can be a proper substrate for producing lactic acid.

Automated summary

The aim of this study was to evaluate bacteria growth and substrate metabolism during the fermentation of red grape juice and a mixture of red grape juice and rice flour solution using Lactobacillus plantarum and Lactobacillus casei. Results showed that fermentation with a mixed culture of both bacteria increased acidity and microbial population, with the most lactic acid production occurring in the mixture. Additionally, the mixture of L. plantarum and L. casei showed the highest sugar consumption, indicating it can be a suitable substrate for lactic acid production.