| The recent abundant evidence show that the pathogenesis of chronic diseases anddegenerative diseases associated with oxidative stress. The natural antioxidants have been ofinterest to biochemists and health professionals because they may prevent and treathypertension, coronary heart disease, atherosclerosis and other diseases. Soybean (Glycinemax L. Merr.) has been widely utilized as a food supplement and key ingredients in Chineseherbal medicine for hundreds of years. Soybeans are the most cultivated leguminous speciesin our country. Recent researches have stated that soybeans contain many phytochemicals,namely, phenolic acids, isoflavones and anthocyanins. These active ingredients have strongantioxidant activity, which may inhibit the oxidation reaction, remove reactive oxygen specieseffectively and protect the body from oxidative damage of biological macromolecules. Theseed material for the present experiment comprised12small soybeans. The objectives of thepresent investigation were to evaluate physicochemical, hydration and textural properties ofseeds, analyze the antioxidant activity and to study the effect of the roasting and germinationon the antioxidant ability of small soybeans. The main conclusions are as follows:(1) The small soybeans contain approximately40.21~43.74%protein,18.74~20.18%carbohydrates,14.20~16.90%crude fat,4.00~4.74%ash. There was no significant differencebetween small yellow soybeans and small black soybeans in crude protein, carbohydrates, fat,ash content. The small black soybeans from Hengshan district had the highest protein content,reaching43.74%, the small yellow soybeans from Dingbian district had the highest crude fatcontent, reaching16.90%, the small black soybeans from Fugu district had the highestcarbohydrates, reaching20.18%. In addition to the small black soybeans from Pianguandistrict grain shape is oblong, the other11kinds of small soybeans are kidney-shaped type.The smll yellow soybeans grain shape rather long and full. Samll black soybeans like flat oval.The small yellow soybeans showed greater hundred-grain weight, volume-weight, graindensity and porosity than small black soybeans. The small soybeans of the water-absorbingand swelling tendency are different.(2) In this research, antioxidant activity of12small soybeans (Glycine max L. Merr.) wasanalyzed. The seed samples were extracted from a mixture of80%methanol and70%acetoneand used for the evaluation of the antioxidant potential. In conclusion, the TPC and TFC ofsmall black soybeans were3.3-fold and5.53-fold higher than the average TPC and TFC of small yellow soybeans, respectively. In addition, small black soybeans possessed higher levelsof anthocyanin content (from189.45mg/100g to212.43mg/100g) than small yellowsoybeans. The small black soybeans from Jingbian had the highest TPC (14.47±0.10mgGAE/g). The small black soybeans from Fugu showed the highest TFC（19.20mg RE/g） andanthocyanin（212.43mg/100g） content. The FRAP value of the small black soybeans wasalmost sevenfold higher than the average FRAP value of the small yellow soybeans. TheDPPH· and·OH scavenging activities of the small black soybeans were twofold higher thanthose of the small yellow soybeans. The ABTS·+scavenging activity of the small blacksoybeans was4.8-fold higher than that of the small yellow soybeans. The antioxidant assaymethod about metal ion chelation is a different anti-oxidative mechanism. In addition to thesmall black soybeans from Zizhou and Fugu, other small black soybeans may have as muchor even more Fe2+chelating ability than small yellow soybeans. Small black soybeanspossessed higher levels of anti-oxidative substance and free radical scavenging capacity thansmall yellow soybeans. The small black soybeans from Jingbian, Fugu and Shenmu showedhigh free radical scavenging activities. A significantly positive correlation was found betweenfree radical scavenging ability and TPC/TFC, whereas a highly significant negativecorrelation was observed between TPC/TFC and Hunter color values (L, a, b, and chromavalues). Therefore, small black soybeans from the districts of Jingbian, Fugu, Shenmu, andHengshan can serve as excellent sources of antioxidants and may be used in functional food,cosmetic, and pharmaceutical applications.(3) In this research, the small soybeans from Dingbian，Hengshan，Yanchi，Fugu andcontrol were analyzed. We investigated the changes in antioxidant activity due to differentroasting conditions, and the factors that caused the changes, by measuring total phenoliccontent and Hunter color values (L, a, b values). After roasting, compared to raw soybeanflour, the roasting flour had a lower L value, a higher a value and a lower b value. Differentroasting temperatures have a significant effect on the antioxidant activity of small soybeans.Our results indicated that the roasted small soybeans showed the lowest total phenolic contentat150℃, showed the highest total phenolic content at200℃. At100℃roasting, smallblack soybeans can maintain a high anthocyanin content, but we found a sharply decreasinganthocyanin content from150to200℃. The roasted small black soybean at200℃, FRAPvalues and DPPH· scavenging activity had increased. The·OH scavenging activity of theroasted small black soybean is lower than unroasted small black soybean. The small yellowsoybeans and control have the ability to scavenge O-2· by roasting at200℃. TheO-2· scavenging activity of the roasted small black soybeans is lower than unroasted smallblack soybeans. By roasting at150℃, the small black soybeans had the lowest O-2· scavenging activity.(4) In this research, the small soybeans from Dingbian，Hengshan，Yanchi and Fugu wereanalyzed. Results showed that germination had positive enhancement effects on bioactivecompounds in small soybeans. The TPC, FRAP values, free radical scavenging capacity andFe2+chelating ability were increased, as compared to non-germinated small soybeans. In thecase of germinated small yellow soybeans, the maximum increase showed in the earlygermination (0h-24h), in this period, the small yellow soybeans showed the highest TPC,FRAP values and high free radical scavenging activities. But the small black soybeansshowed strong antioxidant activity in the late germination (48h-72h). |
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