Antimicrobial and antioxidant activities of extracts from the blacks in Thanh Hoa Province, Vietnam | |
| Author | Huang, Luying |
| Call Number | AIT Thesis no.FB-13-14 |
| Subject(s) | Tea--Vietnam--Thanh Hoa Antioxidants |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Food Engineering and Bioprocess Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. no.FB-13-14 |
| Abstract | The aim of this study was to evaluate the antioxidant and antimicrobial activities of extracts from underutilized black tea from Vietnam. Response surface methodology was applied to obtain a higher total phenolic content (TPC) in crude tea extract by using ultrasonic assisted extraction. The results of the response TPCand independent factorswere found to fit the second-order polynomial equations that obtained by applying in a multiple regression analysis, and relationship between all the independent factors: different concentrations of ethanol and temperature and time were studied. It found that all the independent factors were significant terms for extraction, and ethanol concentrations and temperature were the most significant terms to obtain a high TPC. Antimicrobial activities of water and ethanol extracts were studies. It found that both water and ethanol extracts had significant effect against the growth of Staphylococcusaureus.Different extraction methods hadsignificant effect on antioxidant capacities and quality attributes of tea drinks. Tea extracted from lower temperature (60 °C) with water bath has a higher sensory score and overall acceptability, however with a lower antioxidant capacity compared tothe tea extracted from higher temperature (80 °C) with water bath. Ultrasonic assisted extraction combined with lower temperature (60 °C)can improve the antioxidant capacity of the tea drinks |
| Year | 2013 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. no.FB-13-14 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Anal, Anil Kumar; |
| Examination Committee(s) | Athapol Noomhorm;Muanmai Apintanapong; |
| Scholarship Donor(s) | China Scholarship Council (CSC); |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2013 |