Effect of Lactic Acid Fermentation on Total Phenolic Content and Antioxidant Activity of Fig Fruit Juice (Ficus carica)

摘要

Background: Fig (Ficus carica) is used for a disease therapy due to its relatively complete nutrition and active compounds as sugar, mineral, vitamin, organic acid and phenolic compounds. A high phenolic compound in fig is related closely to its fruit activity as an antioxidant. Yet, its difficult for phenolic compound to be absorbed by the human body, so a fermentation is required. Objectives: This research aims to determine the effect of lactic acid fermentation on total phenolic content and antioxidant activity offig fruit juice. Method: Fig fruit juice was fermented at 37°C for 24 hours using 4 types of starter bacteria as Lactobacillus acidophilus, L. bulgaricus, L. casei and L. plantarum. The total phenolic content testing was conducted using the spectrophotometry method using sulfanilic acid reagent. The antioxidant activity was tested using the spectrophotometry method using DPPH reagent. Results: The fermentation result of fig fruit juice using Lactobacillus bulgaricus demonstrates the highest increase of total phenolic content (TPC=0.45%) and the biggest antioxidant activity (IC50=76.55 ppm) compared to the unfermented ones (TPC=0.09%; IC50=76.7 ppm). The fermentation result of fig fruit juice using other bacteria also demonstrates the increase of total phenolic content with a smaller antioxidant activity compared to the unfermented ones, yet it is still included as a strong activity. Conclusion: Based on the results, it can be concluded that the lactic acid fermentation is able to increase the total phenolic content and preserve the antioxidant activity.