The stability of phytochemical compounds in matured turmeric leaves (Curcuma domestica), Galang Al (Alpinia galanga) and Kantan Flower (Etlingera elatior) subject to different drying treatments / Zaibunnisa Abdul Haiyee and Assoc. Prof. Dr. Noorlaila Ahmad

Phytochemicals are plant substances that protect our cells from free radicals and support proper function of enzyme systems. However, most of the phytochemical compounds are
sensitive to light, heat and storage conditions. In this study, the turmeric leaves, galangal and kantan flower were dried until the moisture content approximately 10% to prevent microbial growth during storage. The main objective of this study is to determine the effect of sun drying, oven drying and freeze drying on ascorbic acid, total polyphenolic compounds and total carotenoids in these plants. Results obtained shows that ascorbic acid, total polyphenolic compounds and total carotenoids were sensitive to heat and oxidation during drying treatments. Freeze drying at -35°C for 48 hours resulted in significantly (p<0.05) better retention of ascorbic acid and total polyphenolic compounds in turmeric leaves, galangal and kantan flower as compared to sun drying and oven drying. The exposure of herbal plants to direct sunshine leads to significant destruction of ascorbic acid, total polyphenols and carotenoids. Oven drying (50°C) is the best alternative to freeze-drying in order to retain the maximum amount of ascorbic acid, total polyphenol and carotene in turmeric leaves, galangal and kantan flower.