Ethanolic extracts from mint (Mentha arvensis) and basil (Ocimum basilicum) leaves: Antioxidant, antimicrobial capacities and shelf-life extension of refrigerated squid mantle cut

Document Type : Original research

Authors

1 International center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand

2 Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China

3 Key Laboratory of Health Risk Factors for Seafood of Zhejiang Province, College of Food Science and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China

4 Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan 4-5-7, Tokyo, Minato-ku, 108-8477, Japan

Abstract

This research aimed to investigate antioxidant and antimicrobial activities of mint leaf ethanolic extract and basil leaf ethanolic extracts. The extract with highest bioactivities was applied as a preservative on squid mantle cut (SMC) to observe the shelf-life during refrigerated storage. Mint and basil leaves ethanolic extracts denoted as mint leaf ethanolic extract (ME) and basil leaf ethanolic extract (BE), respectively, were prepared using ethanol at varying concentrations as extracting media. To improve color, dechlorophyllization of all three mint leaf ethanolic extracts (MEs) and three basil leaf ethanolic extracts (BEs) was accomplished by sedimentation process, where chlorophyll contents were reduced. Among all extracts, total phenolic, flavonoid contents, antioxidant and antimicrobial activities were higher in ME-80 (ME using 80% ethanol with decholorophyllization) (P < 0.05). Linarin, kaempferol 3-O-rutinoside, quercetin and caffeic acid were the major phenolic compounds in ME-80. When ME-80 (0, 200 and 400 mg L-1) was applied by introducing the known amount of extracts dissolved in minimum volume of distilled water directly on squid mantle cut (SMC) and mixing thoroughly, SMC treated with 400 mg L-1 ME-80 (SMC-400) showed lower pH, total volatile base content (TVB), peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and microbial load than other samples during refrigerated storage of 9 days (P < 0.05). Hence, SMC-400 had a shelf-life of 6 days, whilst the control could be stored for only 3 days.

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