Phenolic profiles, antioxidant capacities and flavour volatiles in fig (Ficus carica L.) juices from five cultivars fermented by Lactobacillus plantarum and Lactobacillus acidophilus

Summary The purpose of this study was to investigate the fermentation characteristics of five varieties of fig juices ( Ficus carica cv. Siluhongyu, Siluhuangjin, Silufeicui, Jinaofen and Fengchanhuang) by two select strains ( Lactobacillus plantarum and Lactobacillus acidophilus ), based on the changes of physicochemical parameters, bioactive components, antioxidant activities and flavour volatiles. Viable counts were above 9.5 log CFU mL −1 throughout the fermentation process, indicating that fig juices were suitable substrates for strain proliferation. Total phenolic and flavonoid contents were significantly enhanced during fermentation, particularly with Siluhuangjin by L. plantarum and Silufeicui by L. acidophilus , exhibiting the highest total phenolic (465 mg GAE L −1 ) and total flavonoid contents (152 mg RE L −1 ), respectively. Accordingly, antioxidant activities based on SOD, DPPH, ABTS and FRAP methods were significantly improved after fermentation ( P < 0.05). SOD and ABTS were positively correlated with contents of protocatechuic acid and caffeic acid, respectively ( P < 0.05). Furthermore, alcohols, ketones and terpenoids contents were increased, while aldehydes content was decreased significantly after fermentation ( P < 0.05), suggesting the improved flavour characteristics of fermented fig juices.