Processing Effects on Phytochemical Content and Antioxidative Potential of Ginger Zingiber officale

Abstract

Ginger (Zingiber officinale) is rich in antioxidants and phytochemicals with anti-inflammatory, antimicrobial and anticancer properties. Ginger has been used as a condiment and for the treatment of ailments for many years. However, there are limited studies on the antioxidant and scavenging power of processed ginger. The objectives of this study were to determine the effects that processing has on the total phenolic and flavanoid content of ginger and its antioxidant potential using 1,1-Diphenyl-2-picrylhydrazyl (DPPH), Radical-Scavenging Activity and Ferric Reducing Antioxidant Power (FRAP). Fresh ginger (FG) was used as a control with oven drying (OD) sun drying (SD) and freeze drying (FD) as processing methods. Freeze-dried ginger (77.87%) showed a significantly higher (p < 0.05) free radical scavenging ability as compared to other treatment groups (18.40% - 72.90%). However, sundried ginger had the highest ferric-reducing antioxidant power at 35.28 ± 0.69 mmol Fe (II)/mg ginger. Total phenolic content content (mg GAE/100g) for fresh, oven died, sun-dried, and freeze-dried were 514.02 ± 3.92, 796.46 ± 8.16, 878.76 ± 13.17, and 1021.15 ± 12.95, respectively. Flavanoid content of processed ginger was highest in freeze-dried samples (458.82 CE/100g ginger).