| Author | Piyatida Tiangtham |
| Call Number | AIT Thesis no.FB-07-04 |
| Subject(s) | Mulberry--Drying
|
| 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. FB-07-04 |
| Abstract | Two different conventional extraction methods, room temperature extraction (RTE) and ultrasonic-assisted extraction (UAE) were compared in term of total polyphenols extraction. The result showed that extraction by RTE gave more total polyphenols content than UAE (28.49 gGA/kg). For microwave-assisted extraction (MAE), the different of microwave power level (low, medium-low and medium), extraction time (1, 2, 3, 5, 7 and 10 min) and methanol concentration (0, 30, 50, 70 and 100%) were investigated. The result showed that the optimum condition of MAE was MAE at medium low microwave power level (165.15 watt), controlling the temperature in the range of 60-70°C for 2 min by using 70% methanol as solvent, the ratio of ground dried mulberry leaves and 70% methanol was 0.1 g : 50 ml. It was found that at optimal condition of MAE gave the quantity of total polyphenols significantly more than UAE for 20 min and RTE for 24 hour at the same ratio of sample and solvent. The antioxidant activity of different concentration (0.05, 0.5, 1, 5 and 10 mg/ml) of extracted mulberry leaves obtained by UAE and MAE were compared based on Diphenyl-l-picrylhydrazyl (DPPH) method. It was found that extraction by MAE showed higher antioxidant activity than UAE at the same concentration. The highest antioxidant activity was found in extracted mulberry leaves obtained by MAE at 10 mg/ml concentration (81.51%). Also, the efficient concentration (EC50) of extracted mulberry leaves obtained by MAE was less than by UAE. However extracted mulberry leaves had less the antioxidant activity than both of commercial antioxidant namely ascorbic acid and butylated hydroxyanisole (BHA) at the same concentration. Mulberry leaves extract (MLE) was tried on pork patties to study the antioxidant activity. MLE were added to this product at different levels (0.1%, 0.25% and 0.5%) and stored for 15 days at 4°C. The results showed that addition of 0.5% MLE in pork patties retarded lipid oxidation more than additions of 0.25% MLE, 0.5%a-tocopherol, 0.1% MLE and ,control (without antioxidant), respectively. Cooked pork patties treated with 0.5% MLE had more green in color compared to cooked pork patties treated with 0.1% and 0.25% MLE. During 15 days refrigerated storage time, it was indicated that there is similar development trend between Thiobarbituric acid-reactive substances ,(TBARS) values and Warmed-over flavor (WOF) score. The most effective antioxidant was BHA due to the slightly change of TBARS values and WOF scores during refrigerated storage. |
| Year | 2007 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. FB-07-04 |
| 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) | Athapol Noomhorm; |
| Examination Committee(s) | Rakshit, Sudip Kumar;Salokhe, Vilas M; |
| Scholarship Donor(s) | THAILAND (HM King); |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2007 |