Enhancing physicochemical properties, organic acids, antioxidant capacity, amino acids and volatile compounds for ‘Summer Black’ grape juice by lactic acid bacteria fermentation

Abstract

To investigate the effect of lactic acid bacteria fermentation on the quality of ‘Summer Black’ grape juice, this study characterized the differences in physicochemical properties, organic acids, antioxidant capacity, amino acids and volatile compounds among different treatments. The results showed that the pH and total sugar of all fermentation groups were lower than those of the CK (control group) sample. ZR ( Lactobacillus plantarum ) sample had the highest DPPH and OH − scavenging ability, and the total phenol and total flavonoid content of SR ( Streptococcus thermophilus ) sample were increased by 5.2% and 4.1%, respectively. The contents of tartaric acid, malic acid, and citric acid were improved significantly by LAB fermentation. The content of Asp, Thr, Ser, Glu, and Gly in the SR sample was significantly higher than in the CK sample. Phenylethyl alcohol, lactic ethyl ester, L-menthol, citronellol, and nerol were produced by LAB fermentation, giving fruit and floral aroma, and streptococcus thermophilus has a higher potential to enhance the aromatic flavor of ‘Summer Black’ grape juice. 20 chemical indicators were determined to explain the differences between groups by OPLS-DA. • Fermentation of ‘Summer Black’ grape juice with 6 Lactic Acid Bacteria Strains. • Lactic acid bacteria fermentation reduces the content of bitter amino acids. • Streptococcus thermophilus has the potential to improve fragrance. • Amino acids showed significant correlation with volatile compound. • 20 chemical indicators were selected to explain inter-group differences.