| Summary: | 碩士 === 國立嘉義大學 === 食品科學系研究所 === 106 === Peanut is an important economical crop worldwide with diverse product patterns for consumption. Peanut seeds contain high quality proteins, along with other healthy micronutrients. After processing and rendering the unique peanutty aroma, the processed peanut contained foods are one of the world's most popular consuming products. In recent years, peanut polyphenols have received increasing attention, in particular stilbenoids comprising resveratrol (Res). Many studies have shown that these stilbenoids are potent antioxidants, bearing anti-inflammatory, active in prevention of cardiovascular disease and exhibiting anti-cancer antivities. Stilbenoid biosynthesis of stilbenoids as phytoalexins during peanut seed germination was significantly enhanced and then the related research and product developments have attracted public attention with general interest. In this study, the main purpose was addressed on stability characterization of the stilbenoids in the peanut sprout products and feasibility of further use of the products as ingredients for processing of functional foods. Stilbenoid stability was measured manily based on quantitative changes of Res, arachidin-1 (Ar-1), arachidin-3 (Ar-3) and isopentadienylresveratrol (IPD). Peanut kernels were subjected to germination and then sliced and spread on a try for drying in an air-forced oven. The appropriate dry-heat-treated slices were ground into peanut sprout butter and/or subjected to solvent defatting and pulverizing in preparation of bio-activated peanut sprout powder (BPSP) and both were frozen stored (- 20oC) for later use. Aliquots of BPSP samples in a series of crucibles were heated at 120 to 200oC for 30 min and followed by stilbenoid analysis. It was observed that cotents of Ar-1 were slightly increased at 120 and 140oC, while other stilbenoid contents were decreased as heat temperature rose. The appropriate dry-heat-treated slices were ground into peanut sprout butter and/or subjected to solvent defatting and pulverizing in preparation of bio-activated peanut sprout powder (BPSP) and both were frozen stored (- 20oC) for later use. When a thin layer of BPSP was irradiated with 254 nm UV light for 4 h, contents of the stilbenoids changed in an ignored range. When BPSP was further extracted with 80% methanol and the extract was heated at 100oC for 2 h, stilbenoid contents decreased slightly while as heating time increased a further gradual decrease of the contents was detected. Irradiation of the extracts with UV light, Res contents decreased slightly at the early stage and then decreased gradually with time of irradiation, while contents of other stilbenoids decreased gradually with an increase of irradiation time. When the extracts were dissolved in buffer solutions with varied pH values, the stilbenoids were comparatively stable in acidic (pH 2-6) condition and unstable in alkaline environments, particularly being very unstable at pH 12. When the peanut sprout butters were subjected to gamma ray irradiation for various doses, total viable counts decreased with an increase of irradiation dose and complete sterilization was achieved at doses of 10-30 KGy. Under these irradiation doses, the stilbenoid profile was not changed. Based on the fact that BPSP is rich in protein and bears novel amino acid composition, it was used in partial substitution of wheat flour for preparation of cake and biscuit products. After baking at relatively high temperature (160 to 190oC) to produce the final products and following by taking samples for stilbenoid analysis and oxidative stability assessment, the added BPSP stilbenoids were not decreased and antioxidative stabilities of the products were obviously improved. As generalized, with an attempt to use peanut sprout powder and/or peanut sprout butter in dietary supplement development and used as an ingrident for processing of functional foods, it is strongly suggested to avoid over-heating, long time exposure of UV light irradiation and direct interaction with alkaline material. Through these novel processes, it is of efficacy to minimize changes of the stilbenoids and maintain the unique health-benefited functional activities to meet the general desire of the consumers.
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