In vitro antioxidant activities and volatile compounds from karanda (Carissa carandas L.) fruit wine

Abstract

Carissa carandas L. or karanda (in Thai called namdaeng or manaao ho) is widely used as a medicinal plant. Karanda juice was fermented for 22 days to produce alcohol using Saccharomyces cerevisiae TISTR5918. Total soluble solids or TSS of karanda juice (approximately 1.0°Brix) was adjusted to 24°Brix and samples were collected every 2 days for analysis of total soluble solids (TSS), pH and alcohol content. Yield of alcohol was measured at 12.50±0.35% in the final fermentation. TSS dropped gradually from 24°Brix to 9.17±0.58°Brix, whereas pH increased slightly from 2.47±0.06 to 2.80±0.00 (Day 0-22). Volatile compounds in karanda wine (KW) were examined and analyzed using gas chromatography-mass spectrometry (GC-MS). Volatile compounds detected in KW included 3-methyl-1-butanol, butanoic acid, butyrolactone, phenylethyl alcohol, butanedioic acid, benzene ethanol and 2-propenyl ester as a common flavor and aroma in wine. Heavy metals (Pb, As, Cu and Cd) determined by atomic absorption spectroscopy (AAS) were present in lower than their maximum allowed concentrations. Methanol was detected at only 0.005% in KW analyzed by gas chromatography equipped with a flame ionization detector (GC-FID). Antioxidant activities were determined by three methods comprising diphenyl picrylhydrazyl radical scavenging assay (DPPH), radical cation decolorization assay (ABTS) and reducing power. The IC 50 values of DPPH and ABTS were 0.84±0.03% and 3.28±0.03%, respectively, and the EC 50 of reducing power was 11.03±0.11%. Total phenolic content, measured according to the Folin-Ciocalteu procedure, was determined as 746.64±3.10 mg GAE/100 ml sample.