| Legumes are rich sources of protein,carbohydrates,dietary fiber,minerals and vitamins.There was a positive association between the consumption of legumes and the reduction of the risk of cardiovascular diseases,obesity,diabetes type ? and certain types of cancer,and all these benefits are attributed to their high content of dietary fiber and phytochemicals,including phenolics.However,there was still a lack of conclusive and comprehensive reports about different kinds of legumes,especially at cultivar level.In the present study,ten kinds of legumes,red kidney beans,white kidney beans,soybeans,black soybeans,red beans,mung beans,cowpea,pea,lentils and broad beans,as well as twenty-six cultivars of kidney beans,were analyzed for nutritional composition.Furthermore,legumes were analyzed for phytochemicals including lipophilic phytochemicals and phenolcs using HPLC and LC-MS.Their antioxidant activities were determined by chemical methods.The main results were as follows:1.Nutritional anlysis of 10 kinds of dry beans.The fat content of 10 beans was significant difference.The highest fat content were found in soybean and black soybean,with a respect content of 14.92~22.19% and 14.13~20.45%,but the fat content of other beans were lower than 10%.?-linolenic acid(9c12c15c C18:3)and linoleic acid(9c12c C18:2)were the predominant fatty acids in many legumes,whereas C20:0 was the main fatty acid for some peas(73.25~78.75%).The protein content in soybean and black soybean(38.21~47.96%)were much higher than that in other beans(15.02~20.22%).Legumes were rich in lysine(0.90~2.23%).All the legumes contained high levels of dietary fiber(27.60~47.93%).Those legumes were rich sources of resistant starch(6.84~14.65%),except for soybean(?0.10%),black soybean(?0.20%)and some varieties of peas(1.84~2.17%).2.Antioxidant compounds in 10 kinds of dry beans.Soluble phenolic compounds: 6 types of anthocyanins were identified from 10 kinds of dry beans including delphinidin-3-galactoside,delphinidin-3-glucoside,cyanidin-galactoside,cyanidin-glucoside,petunidin-galactoside and pelargonidin-glucoside.The little black soybean from Shanxi Province contained highest anthocynidins(19.14 mg/100 g),total phenolic and exbihited the highest FRAP value(94.97 ?M Fe(II)/g).Lipophilic phytochemicals: All the dry beans contained ?-tocopherols and ?-tocopherols.However,?-tocoperol was only found in some of the samples.The soybean contained the highest total tocopherols content(90.40~120.96 ?g/g),followed by black soybean(66.13~100.76 ?g/g).All-trans-lutein and all-trans-zeaxanthin were the two major carotenoids in legumes.The highest amounts of carotenoids were found in lentils(4.53~21.34 ?g/g)and red kidney beans(8.29~20.95 ?g/g).The DPPH scavering activities were lower than 0.23 ?mol Trolox/g.3.Detailed characterization in nutritional compostion.The kidney beans contained low levels of lipid(1.05~2.83%).The predominant fatty acids were polyunsaturated fatty acids,accounting for 47.54~67.26% of total fatty acids.The kidney beans had a high level of protein(22.06~32.63%)and the ratio of essential amino acid to the total amino acid was ranged from 0.29 to 0.36.The kidney beans contained high levels of dietary fiber(29.32~46.77%)and resistant starch(9.16~18.09%).4.Antioxidant components of 26 kidney beans cultivars.Certain levels of total phenolics and flavonoids with respective values of 0.25~3.79 mg gallic acid equivalent/g dry weight and 0.19~7.05 mg rutin equivalent /g dry weight resulted in significant antioxidant activities.A good correlation was observed between TPC and FRAP values(R2 = 0.8030).The total tocopherol content was in the range of 12.83~68.35 ?g/g,predominantly ?-tocopherol,followed by ?-tocopherol.None of the carotenoids were detected in all the kidney bean samples.5.Color features,anthocyanins composition and antioxidant activities of the coats from 26 kidney bean cultivars were investigated.Based on the 5 common forms of anthocyanidins,16 types of anthocyanins were identified.The individual contents of pelargonidin,cyanidin,petunidin,delphinidin,malvidin and the total anthocyanindins were in the ranges of 0~0.71,0~1.44,0~0.41,0~4.45,0~0.27 and 0~5.84 mg/g of dry weight of bean coats,respectively.The color of kidney bean coats was diverse,and a good correlation was observed between c value and delphinidin content(R2 = 0.7454).The total phenolics content in 26 kidney beans cultivars were 0.25~35.11 mg galic acid/g.Significant differences of the antioxidant activities were observed.The FRAP and ORAC value were 34.00~1066.4 ?M Fe(II)/g ? 4.00~491.33 ?mol Trolox/g,respectively.Non-white bean coats which contained more anthocyanidins showed much higher antioxidant activities than the white ones which contained no anthocyanidins. |
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