{"title":"Biological Activities of Steamed Miang (Camellia sinensis (L.) Kuntze var. assamica (J.W. Mast.) Kitam) Juice Extracts","authors":"Vipanee Chumsai-Na-Ayudhya, N. Thongwai","doi":"10.17706/ijbbb.2020.10.2.66-73","DOIUrl":null,"url":null,"abstract":"Miang (Camellia sinensis (L.) Kuntze var. assamica (J.W. Mast.) Kitam.) is an Assam tea which is mainly found in northern Thailand. Fermented Miang is made from young and semi-mature Miang leaves by the local wisdom. Briefly, Miang leaves are harvested and steamed for approximately 2 hours prior to cooling down and subsequently packed into a container with close lid. Fermentation process will take place and run for 1-3 months normally. Steaming step renders a high quantity of steamed Miang juices (SMJ) which will be discarded afterwards. Evaluation of this biological waste will bring about ways of making value-added products. The purpose of this study aims to investigate the effects of steaming time and ages of Miang leaves on biological activities of SMJ obtained. Fresh, young and semi-mature, Miang leaves were collected and steamed for 30 minutes, 1, 2 and 3 hours. Meanwhile, young and old Miang leaves were steamed for 2 hours as compared with the conventional method. All SMJ were further evaporated and lyophilized to obtain SMJ crude extracts (CE). The 3-hour SMJ-CE had the highest antioxidant activity and total phenolic content (p<0.05), 548.4±13 μg GAE/ g extract and 460.24±11.8 μg GAE/g extract, respectively. Comparing between SMJ-CE of young and old Miang leaves, the antioxidant activity and total phenolic content of the young leaves SMJ-CE was significantly higher than the old leaves SMJ-CE (p<0.05). Moreover, all SMJ-CE had antibacterial activities to inhibit growth of some gastrointestinal pathogenic bacteria including Bacillus cereus, Escherichia coli, Escherichia coli O157:H7, Salmonella Typhi, Shigella dysenteriae, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus (MRSA) and Vibrio cholerae with the young leaves SMJ-CE showed the highest activities. The information obtained will be further used as a guideline in food and cosmetic application using SMJ-CE as a raw material.","PeriodicalId":13816,"journal":{"name":"International Journal of Bioscience, Biochemistry and Bioinformatics","volume":"1 1","pages":"66-73"},"PeriodicalIF":0.0000,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Bioscience, Biochemistry and Bioinformatics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.17706/ijbbb.2020.10.2.66-73","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Miang (Camellia sinensis (L.) Kuntze var. assamica (J.W. Mast.) Kitam.) is an Assam tea which is mainly found in northern Thailand. Fermented Miang is made from young and semi-mature Miang leaves by the local wisdom. Briefly, Miang leaves are harvested and steamed for approximately 2 hours prior to cooling down and subsequently packed into a container with close lid. Fermentation process will take place and run for 1-3 months normally. Steaming step renders a high quantity of steamed Miang juices (SMJ) which will be discarded afterwards. Evaluation of this biological waste will bring about ways of making value-added products. The purpose of this study aims to investigate the effects of steaming time and ages of Miang leaves on biological activities of SMJ obtained. Fresh, young and semi-mature, Miang leaves were collected and steamed for 30 minutes, 1, 2 and 3 hours. Meanwhile, young and old Miang leaves were steamed for 2 hours as compared with the conventional method. All SMJ were further evaporated and lyophilized to obtain SMJ crude extracts (CE). The 3-hour SMJ-CE had the highest antioxidant activity and total phenolic content (p<0.05), 548.4±13 μg GAE/ g extract and 460.24±11.8 μg GAE/g extract, respectively. Comparing between SMJ-CE of young and old Miang leaves, the antioxidant activity and total phenolic content of the young leaves SMJ-CE was significantly higher than the old leaves SMJ-CE (p<0.05). Moreover, all SMJ-CE had antibacterial activities to inhibit growth of some gastrointestinal pathogenic bacteria including Bacillus cereus, Escherichia coli, Escherichia coli O157:H7, Salmonella Typhi, Shigella dysenteriae, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus (MRSA) and Vibrio cholerae with the young leaves SMJ-CE showed the highest activities. The information obtained will be further used as a guideline in food and cosmetic application using SMJ-CE as a raw material.