Effect of fermentation on the antioxidant properties and phenolic compounds of Bambangan (Mangifera pajang) fruit

Abstract

The study aimed to determine the antioxidant activities and phenolic compounds of Bambangan (Mangifera pajang), a type of wild fruit belongs to the family of Anacardiaceae during fermentation at room (28 °C) and elevated temperature (35 °C). The antioxidant capacity was estimated based on 2,2-diphenyl-1-picyrlhydrazyl (DPPH) scavenging activity, ferric-ion-reducing power (FRAP), 2,2´-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation assay and oxygen-radical absorbing capacity (ORAC). A reversed phase high performance liquid chromatography (HPLC) was used to identify the phenolic compounds. Samples of bambangan fermented at 35 °C achieved the highest FRAP (141.42 mM Fe(II)/g extract) and ABTS values (5.00 mmol TE/g) within the first six days as compared to the samples fermented at room temperature (28 °C), which required 10 days to achieve the highest FRAP and ABTS values. No significant difference was found (p > 0.05) on the antioxidant activity of the samples that were kept at prolonged fermentation and storage. The total phenolic content (TPC) increased throughout the fermentation with the highest value of 44.69 $\pm$ 0.01 mg GAE/g. Gallic acid, chlorogenic acid, vanillin, $\rho$ -coumaric acid and rutin are the major phenolic compounds identified in the fermented product. The results suggested that the antioxidant capacity of bambangan is affected by the fermentation temperature and the fermented product could be a source of antioxidants.

Keywords: Antioxidant; Bambangan; Fermentation; Phenolic composition; Underutilized fruit.

Fig. 1

HPLC chromatograms of extract from Bambangan fermented at a room temperature, (28 °C) on day-12 and b 35 °C on day-4 which displayed the most diverse phenolic compounds throughout the fermentation process. Identified phenolic compounds are 1-Gallic acid, 2-Chlorogenic acid, 3-Vanillin, 4-ρ-coumaric acid and 5-Rutin