Study on retention of metabolites composition in misai kucing (orthosiphon stamineus) by heat pump assisted solar drying
Gan, S.H.; Thing Chai Tham; Mei Xiang Ng; Chua, L.S.; Aziz, R.; Baba, M.R.; Abdullah, L.C.; Ong, S.P.; Law, C.L.
Journal of Food Processing and Preservation 41(6): e13262
ISSN/ISBN: 0145-8892 DOI: 10.1111/jfpp.13262
In this research, the effects of different drying methods on the two biomarker compounds concentrations, such as sinensetin (SEN) and rosmarinic acid (RA) of Orthosiphon staminues Benth leaves, flowers, stems and mix were investigated. SEN and RA retention among the dehydrated samples were maximum 83.07% in leaves and 92.54% in flowers, respectively by heat pump assisted solar drying method. For heat pump assisted solar dried samples, there are no significant differences (p > .05) in the retention of SEN and RA as compared to fresh samples. However, there are significant differences (p<0.05) in SEN and RA retention in solar dried leaves, flowers, stems and mix as compared to fresh samples. Besides, an optimization study was performed to evaluate the optimal drying conditions for obtaining high SEN yields from Misai Kucing's leaves, flowers, stems and mixes with high RA contents within the drying parameters. Practical applicationsSun drying is the standard practice adopted by most of the Malaysian Orthosiphon staminues (or also known as Misai Kucing) herbal producers due to its low capital and processing cost. However, long drying time was taken by sun drying due to unpredictable weather conditions and the active ingredients are degraded due to very high drying temperature in long processing time under sun exposure. Hence, a combining solar energy and other effective drying method such as heat pump technology are needed. Heat pump assisted solar dryer systems can overcome all the difficulties by solar drying solely and satisfy important demands in industrial drying with respect to product quality control, reduced energy consumption and reduced environmental impact. The objective of this research was to determine the relationship between the drying methods (sun drying and heat pump assisted solar drying) and bioactive metabolites compositions of different parts in Orthosiphon staminues plant.