Title: Effect of storage conditions and temperature on dried lemon myrtle leaves quality

Authors: Ainaa Abdul Kahar; Ong Sze Pheng; Nicholas J. Watson; Law Chung Lim

Addresses: Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia ' Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia ' Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia ' Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia

Abstract: The impact of various packing conditions and storage temperatures on the colour and biochemical content of lemon myrtle leaves (LML), dehydrated using different drying processes is presented in this research. LML were dried and stored using a heat pump dryer, an oven and a vacuum dryer. The dried LML was subjected to quantitative tests on radical scavenging activity, total phenolic content and ferric reducing antioxidant power on a monthly basis for six months after drying was performed. Normal and vacuum packaging were used to package the dried LML, and each pack was stored at either ambient temperature of 25°C (RT) or chilled at 4°C. As a comparison to non-vacuum packed LML, vacuum packing resulted in greater colour and biochemical content preservation. For the heat pump dried sample, this technique paired with storage at a cold temperature (4°C) resulted in greater retention of its green colour, total phenolic content, radical scavenging activity and ferric reducing antioxidant power percentages (49%, 72%, and 56%, respectively). The vacuum dried sample, on the other hand, had the lowest colour and biochemical content retention in vacuum packing, and the similar pattern was seen in the oven dried and heat pump dried samples.

Keywords: oven drying; heat pump drying; vacuum drying; biochemical content; storage; vacuum packaging; lemon myrtle leaves; LML.

DOI: 10.1504/IJPTI.2022.125889

International Journal of Postharvest Technology and Innovation, 2022 Vol.8 No.4, pp.292 - 312

Accepted: 21 Feb 2022
Published online: 03 Oct 2022 *