Contribution of Agricultural Produce Spice Zingiber Officinale to a Sustainable Food System: Green Extraction and Stability Study of Antioxidant Compounds

Abstract

Abstract The present study has focused on the extraction and utilization of antioxidant compounds from the agricultural produce Zingiber officinale for its sustainable use in terms of stabilizing food from oxidation. Two extraction methods, traditional soxhlet and green supercritical CO2 (SC-CO2), were used to compare yields of antioxidant (6-gingerol) rich extracts. For the SC-CO2 method, operating parameters including pressure (10000-20000 kPa), temperature (30- 40°C) and CO2 flow rate (5-20 g/min.) were optimized to get maximum recovery of [6]-gingerol rich extracts. The results of the extraction study revealed that ginger extract collected after soxhlet extraction (GE1) gives more yield (3.85%) than the extract (2.41%) collected after SC-CO2 extraction (GE2) at an optimum condition of 20000 kPa pressure, 40°C temperature and 20 g/min. flow rate. Contrarily, the yield of [6]-gingerol was found to be greater in GE2 (389 mg/g) than GE1. Total phenol (TPC) and flavonoid (TFC) content of GE1 and GE2 were measured against equivalent concentrations of gallic acid and quercetin. TPC and TFC of GE1 show slightly higher values (38.50 mg GAE/g, 5.62 mg QE/g) than GE2. At the concentration of 3000 μg/mL, DPPH percent inhibition activity of GE1 was again higher (up to 94%) than GE2 (up to 82%). Stability study result of both GE1 and GE2 revealed on the basis of antioxidant indices, showed desirable antioxidant index by stabilizing all three experimented oils and also found to be comparable with synthetic antioxidants (BHA, BHT). Therefore, it could be concluded that [6]-gingerol rich extracts from the SC-CO2 method have comparable phenol flavonoid, antioxidant and stability potential as those found in ginger extracts from the traditional soxhlet method.