| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 97 === Abstract
This study investigated the total content and composition of flavonoids, isoflavones and phenolic acids in water infusion and soaked bean acetonitrile extract of mung bean, adzuki bean, soybean and black soybean as influence by soaking temperature and time. The antioxidative activity and inhibition on ��-glucosidase and ��-amylase activity and glycation were also examined. Results of HPLC analysis plus wavelengh scanning of photodiode array detector showed that levels of flavonoids and isoflavones in infusion increased with soaking time and temperature. With an exception of adzuki bean, the two contents in acetonitrile extract were enriched after soaking and were higher than that of infusions. After soaking at 7oC for 48 hours, level of isoflavones in acetonitrile extract of soybean (974 ± 8.4 μg/ml) was highest.
Infusion and acetonitrile extract from adzuki bean and black soybean exhibited relatively high antioxidant activities. Infusions except that from soybean, had higher activities and correlations with total phenolics and flavonoids as compared to acetonitrile extracts. Among four beans tested, black soybean infusion was the highest in relation to scavenging DPPH and ABTS radicals and chelating Fe2+, where IC50 was 0.009, 0.007 and 0.216 mg/ml, respectively. Also the activities correlated well to total phenolics and flavonoids.
The antioxidant activities of infusion and acetonitrile extract were mainly from the contribution of major compounds. Of which, those in the former were polar but unknown, whereas those in the later were several known flavonoids and isoflavones.
The infusion of black soybean had strongest inhibition (IC50 = 0.637-0.825 mg/ml) on ��-glucosidase and ��-amylase activity. In acetonitrile extracts, inhibition from that of adzuki bean on ��-glucosidase and of mung bean on ��-amylase activity were the hightest, with an IC50 of 1.254 and 0.384 mg/ml, respectively. The black soybean infusion and acetonitrile extract also exhibited the highest inhibition on glycation and the inhibitory effect had a good correlation with total phenolics.
Key words: Mung bean, adzuki bean, soybean, black soybean, antioxidant activity, glucosidase activity, glycation.
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