Influence of ginger cultivars and maturity stages on oleoresin, 6-gingerol, polyphenol contents and antioxidant property

Zingiber officinale Rosc, commonly called Ginger, is an underground rhizome widely used as a spice in the food and beverage industries. The prominent bioactive component of ginger is [6]-gingerol. The present study focuses on influence of the variety and maturity stage of ginger on [6]-gingerol content. Ten authentic cultivars of ginger were collected from ICAR-Indian Institute of Spice Research, Calicut, Kerala, India and analyzed for oleoresin, [6]-gingerol, polyphenol and antioxidant activity. Among these varieties, ING 5 variety gave the maximum oleoresin yield (11.05%) followed by ING 6 (10.5%). The [6]-gingerol content (7.59%) and the total polyphenol content (TPC) and antioxidant activity (85 +/- 0.5% at 200 ppm) were maximum in ING 6. Among these varieties, ING 6 was cultivated in Mysore for maturity studies. From 150 to 270 days of planting fresh ginger rhizomes showed oleoresin in the 6-10% range and [6]-gingerol was 2.26- 7.28%. Volatile oil (1.03 +/- 0.2%) content did not show much change. With an increase in maturity, TPC and antioxidant activity also increased proportionally from 60 to 90% when compared to butylated hydroxyanisole (BHA).