Changes and degradation kinetics of some bioactive compounds in dried Orthosiphon aristatus (Java tea) leaves during elevated temperature storage

Abstract

<p>BACKGROUND Orthosiphon aristatus is a traditional medicinal herb mostly used in South East Asia, and has many health benefits. The packaging types and storage temperatures were investigated in order to select the best condition to produce high bioactive compounds (BC) of two kinds of dried Orthosiphon aristatus leaves.</p> <p>RESULTS Blanched leaves were vacuum packed in polypropylene (PP) and aluminum foil laminated with polyethylene terephthalate and polyethylene (PET/Al/PE) and dried in a freeze dryer (B_FD) or heat pump‐assisted dehumidified dryer (B_HPD60) at 60°C prior to storage at 15°, 25° and 35°C for 6 months. Leaves in PET/Al/PE bags had higher total phenolic content (TPC), antioxidant activity (AOA) and BC than in PP bags (p≤0.05). Storage at 15 °C retained the highest TPC and AOA in PET/Al/PE bags (p≤0.05). The degradation kinetics for BC, sinensetin and eupatorin, followed first‐order kinetics. Half‐lives (t1/2) for BC in PET/Al/PE were higher than in PP and were the highest at 15°C for both packaging types.</p> <p>CONCLUSIONS Low temperature and PET/Al/PE bags provided the highest bioactive compound retention. The dried leaves from B_HPD60 and packed in PET/Al/PE bags had higher resistant to degradation of sinensetin than B_FD in PP bags.</p>