Antioxidant activity and DNA damage protection by total carotenoids and vitamin C from fresh and cooked G. cowa leaves | |
| Author | Rujira Chaiyasit |
| Call Number | AIT Thesis no.FB-09-12 |
| Subject(s) | Antioxidants Vitamin C DNA damage |
| 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-09-12 |
| Abstract | The objective of this work was to study the anti-oxidant activity of G. cowa leaves, the changes that occurred during its processing and the protection it could provide to DNA from UV light and highly oxidative reagents like hydrogen peroxide. Initially the effect of extraction solvent on carotenoids content, ascorbic acid content and their antioxidant activity from fresh G. cowa leaves was studied. We extracted carotenoids from G. cowa fresh leaf, using a mixture of hexane, acetone and ethanol. Maximum amount of carotenoids content was obtained with mixture of hexane and ethanol (22.28 p-carotene/kg fresh weight). Antioxidant activity of the extracts obtained using this solvent was assessed by measuring DPPH radical scavenging (%), and found to 61.82%. Therefore, the mixture solvent of hexane and ethanol were select for further determination of total carotenoids content and antioxidant activity in fresh and cooked G. cowa leaves. Three types of processing of the leaves were done after cooking for 15 minutes at 100°C in boiling water, baking and steaming treatment, total carotenoids content and their antioxidant activity of boiling, baking and steaming was found to be different for each method. For boiling and baking, carotenoid content and their antioxidant activity increased initially and after being boiled for 5 minutes decreased. On steaming cooking, the carotenoid content and their antioxidant activity showed a continuously increased during steam from 3 minutes to 10 minutes and then decrease till the end of steaming time studied (15 minutes). Ascorbic acid extraction was best with 0.5% metaphospharic acid (155.41 mg ascorbic acidlkg fresh weight) and the percentage of DPPH radical was 85.81 %. The 0.5% metaphospharic acid use to determined content of G. cowa leaves after they were processed by boiling, baking and steaming at 100°C for 10 minutes. All methods had an effect on ascorbic acid content. Ascorbic acid content from boiling method decreased to 0.75 mg ascorbic acid/kg fresh weight, from baking method decreased to 1.81 mg ascorbic acidlkg fresh weight and for steaming method decreased to 64.35 mg ascorbic acidlkg fresh weight. A good relationship was observed between ascorbic acid content and antioxidant activity. In the study of DNA damage protection by carotenoids and ascorbic acid from fresh and cooked G. cowa leaves it was found that carotenoid extracts of G. cowa leaves after boiling, baking and steaming method could protect DNA from damage by hydrogen peroxide oxidation. However, ascorbic extracts of G. cowa leaves after boiling, baking and steaming method could not protect DNA from damage |
| Year | 2009 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. no. FB-09-12 |
| 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) | Rakshit, Sudip Kumar; |
| Examination Committee(s) | Athapol Noomhorm;Amararatne Yakupitiyage; |
| Scholarship Donor(s) | RTG Fellowship; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2009 |