Fermentation of bergamot juice with Lactobacillus plantarum strains in pure and mixed fermentations: Chemical composition, antioxidant activity and sensorial properties

In this study, bergamot juice was fermented with pure and mixed cultures of L. plantarum subsp. plantarum PTCC 1896, L. plantarum AF1 and L. plantarum LP3 to make a fermented drink. Viable cell count, chemical composition, DPPH radical-scavenging activity and overall acceptance were studied during 72 h of fermentation and compared with the control sample. Results indicated that mixed ternary cultures had the highest growth resulting in higher microbial population compared to binary co-cultures followed by sole inoculation. Bergamot juices from ternary combination fermentation followed by PTCC-LP3 and AF1-LP3 binary combinations had markedly higher pH, glucose and fructose consumption, lactic acid and formic acid production, citric acid usage and radical-scavenging effect compared to single culture of L. plantarum strains and the control sample after the fermentation period. In contrast, no significant differences were observed between the samples in ascorbic acid content, with the initial value reaching from 266.3 mg/100g to about 231.6 mg/100g after 72 h of fermentation, indicating that the fruit juice is still a good source of ascorbic acid. Regarding general acceptance, all fermented juices received scores (ranging from 6.6 to 7.4) above the acceptability limit (6). Overall, since bergamot juice with selective fermentation had more antioxidant properties than the control sample fermented with natural flora and was also acceptable to the panelists, so fermentation of bergamot juice with selective combination of L. plantarum strains is recommended. This study provides new insights into fruit-based fermented non-dairy beverages production.