A study of functional components antioxidant activity and sensory characteristics of Gastrodiae Rhizoma by steaming-drying cycles

Abstract

ABSTRACT Objectives : The objective of this study is to determine the best numbers o f steaming-drying cycles of Gastrodiae Rhizoma for both efficacy and taste. We investigated various characteristics among Gastrodiae Rhizoma samples (GSD1, GSD3, GSD5 and GSD7) through the number of steaming-dryi ng cycles increased.Methods : Gastrodiae Rhizoma were steamed and dried at different repeated numbers. They wer e divided into samples (GSD1; steamed and dried once, GSD3; steamed and dried three times, GSD5; steamed and dried five times, GSD7; steamed and dried seven times) for experiment. The y were extracted using water, freeze dried and powdered to analyze proximate composition, free sugar amount, f unctional components, antioxidant activity and sensory evaluation.Results : Proximate composition and the amount of free sugars of Gastrodiae Rhizoma did not have meaningful differences among samples. Phenolic and flavonoid content of sa mples were increased by increasing steaming-drying numbers. Gastrodin content had different values and GSD7 was th e highest in comparison with others. Increasing steaming-drying numbers led to a increasing in radic al and nitrate scavenging activity in samples. Regarding to sensory evaluation, GSD5 was selected as the best sample according to its highest hedonic score mean (5.54/7) among all samples for appearance, color, taste an d overall acceptability.Conclusions : The results indicated that 5th-cycling sample was effective in views of functional components, antioxidant activity and sensory characteristics. Moreover, it was suggested that steaming-drying process improved remarkably the effects of Gastrodiae Rhizoma.Key words : Gastrodiae Rhizoma, steaming-drying cycles, gastrodin, antioxidant activity, sens ory characteristics