Fermented Apple Juice by Two Commercial Lactobacillus species: Changes of Physicochemical Composition and Antioxidant Activity

The present study was aimed to compare the changes of physiochemical composition, antioxidant activities of fermented apple juice with non-fermented apple juice by two commercial lactic acid bacteria (LAB), Lactobacillus casei CICC 20975 and Lactobacillus bulgaricus CICC 21101. The antioxidant activity was evaluated by three systems including DPPH, ABTS free radical scavenging methods and Fe3+ reducing power. The results showed that fermentation significantly increased the content of total phenols in apple juice (P<0.05). After fermentation, all malic acid was converted into lactic acid during fermentation with the lactic acid content up to 381.78 mg/kg. Free proline 21.55 mg/kg and lysine 21.99 mg/kg were also significantly increased. Similarly, fermented apple juice showed significantly higher antioxidant activities when compared to non-fermented apple juice. The scavenging activity of DPPH, ABTS free radical and the reducing power of Fe3+ in fermented apple juice increased by 22.4%, 35.0%, 9.7%, respectively. In conclusion, fermented apple juice by two commercial lactic acid bacteria (L. casei CICC 20975 and L. bulgaricus CICC 21101) exhibited a more satisfied property and possessed great application potentials.