| Summary: | 碩士 === 國立嘉義大學 === 食品科學系研究所 === 106 === Black soybeans are rich in anthocyanins, flavonoids, and polysaccharides. They have good antioxidant and hypolipidemic effects, and thus they were considered beneficial to human. In recent years, the nutritional value of black soybeans has been gradually discovered, making it one of the key crops. For example, black soybean water and tea beverages have become more popular year by year, and consumers are paying more and more attention to these health-improving drinks. Previous experiments have been performed on the effect of roasting at 80, 120 and 150 °C for 50, 100 and 150 minutes on the functional properties of black soybean, and the results indicating 120 and 150 °C roasting could obtain good antioxidants ability. In this experiment, 130 °C roasting was added to search for conditions containing more antioxidants and better flavor. The results showed that the best one were roasted at 130 °C for 50 minutes. Such roasting condition was then used to prepare the black soybean tea for the hypolipidemic test using animal model. It was found that the roasted black soybean tea could reduce cholesterol and triglyceride levels in the blood of hamsters, and its antioxidant substances could increase the liver's antioxidant capacity and reduce liver damage. Black soybeans have a good antioxidant content and hypolipidemic effect. After being
roasted, the extracts also has the same effect. Therefore, based on these results, black soybean tea bags with good flavor and health effects can be developed. The second part of our study was to evaluate the potential of adding black soybean anthocyanins to nutritional supplement drinks. Anthocyanins are easily degraded by heat, light, and oxygen and lose their efficacy. Therefore, the effect of casein, soy protein and whey protein on the thermal stability of anthocyanins was also investigated in this study. In addition to black beans, roselle and pitaya (also containing high amount of anthocyanin) was also used for comparison. After preheating, all three proteins could reduce the degradation of anthocyanins of black beans and pitaya, but roselle only improved the
thermal stability in casein. The results of formulated drinks were similar to those of protein solution. Regardless of protein solution or formulated drinks, after heated at 121°C for 15 minutes, the degradation of anthocyanins was more than heating 80°C for 2 hours. Based on the results, we concluded that proteins can improves the thermal stability of anthocyanins in pasteurized products, while it is less effective for the drinks required commercial sterilization.
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