Effects of Different Drying Methods on Antioxidant Properties of Malaysian Ginger
Iswaibah Mustafa, Nyuk Ling Chin, Yus Aniza Yusof, M F Husin
Abstract
Abstract Malaysian ginger is one the sought herbs that contains a lot of beneficial properties that could contribute to health. However, most usage of ginger from its fresh form which is prone to microorganisms’ spoilage. Therefore, effects of shade, sun, oven, vacuum oven, and freeze drying on phytochemical contents, ferric reducing antioxidant power (FRAP), phosphomolybdenum assays, 2,2’azinobis (3-ethylbenzothiozoline-6-sulfonic acid) disodium salt (ABTS ·+ ), 2,2-diphenyl-1-picryl-hydrazyl (DPPH · ), hydroxyl (OH · ) radical and metal chelating properties of Halia Bara were studied. Dried and fresh ginger crude extracts were extracted with ethanol. The freeze-dried extract had highest level of total phenolic of about 20.07 mg GAE/g dry extract as compared to fresh ginger extract at 10.52 mg GAE/g dry extract. For antioxidant activity of FRAP and phosphomolybdenum, sun-dried extract exhibited the highest values with increase of 3.95-fold and 4.29-fold from fresh ginger extract, respectively. In scavenging ABTS ·+ radical, sun-dried extract also exhibited the highest values with increase of 2.07-fold from fresh ginger extract. Sun-dried extracts also had the lowest IC50 of 14.69 μg/ml. The ascorbic acid of ginger types was below 1.5 mg AA/g extract. Sun-dried ginger extract exhibited most significant antioxidant potential and as free radical scavengers.