不同品种山药的营养成分分析及其水提物的体外抗氧化能力研究

目的:对不同品种山药的营养成分进行测定,区别其成分上的差异,对山药的营养价值研究、资源合理开发利用及品种研究提供一定依据。方法:分别采用微量凯氏定氮、酸水解、蒽铜-硫酸比色法、火焰原子吸收光谱法等对不同品种山药(蕲春山药、铁棍山药、淮山药)的蛋白质、淀粉、氨基酸、多糖、微量元素及黄酮含量等营养成分进行测定。同时以三种山药为原料,制备得山药水提物,测定其体外抗氧化能力,包括:还原力、羟基自由基清除率、DPPH自由基清除率。结果:蕲春山药含氨基酸总量1601.7 mg/100 g,蛋白质10.62%,淀粉22.0%,多糖7.42%,微量元素Fe:1.089 mg/g、Cu:0.371 mg/g、Co:0.257 mg/g、K:2.011 mg/g,黄酮2.48%。其中蛋白质、氨基酸总量均显著(p<0.05)高于铁棍山药和淮山药。铁棍山药含氨基酸总量1058.0 mg/100 g,蛋白质4.24%,淀粉15.2%,多糖9.26%,微量元素Ca、Zn、Mg、Na含量分别为7.484、0.449、2.067、0.359 mg/g,黄酮4.06%。与蕲春山药和淮山药相比,铁棍山药多糖、黄酮含量最多。淮山药含氨基酸总量967.3 mg/100 g,蛋白质5.76%,淀粉18.4%,多糖8.68%,微量元素P含量0.457 mg/g,黄酮3.80%,其营养成分比较均衡。此外,不同品种山药水提物的体外抗体氧化能力不同。其中,还原力:V_C > 蕲春山药水提物 > 铁棍山药水提物 > 淮山药水提物。羟基清除率:V_C > 蕲春山药水提物 > 铁棍山药水提物 > 淮山药水提物。DPPH清除率:V_C > 铁棍山药水提物 > 蕲春山药水提物 > 淮山药水提物。结论:蕲春山药蛋白质、淀粉丰富,清爽可口,食用性强。铁棍山药多糖、黄酮含量高,可做药用。淮山药营养均衡,可食用可药用。三种山药水提物在体外均有一定抗氧化作用。

Analysis of nutritious compositions in Rhizoma Dioscoreae from different varieties and antioxidant properties of their water extracts in vitro

Objective:The nutrient composition of different varieties of Rhizoma Dioscoreae was determined to differentiate the difference of its composition,which may provide some basis for the study of nutritional value,reasonable development and utilization of resources and research of varieties. Method:The nutritious compositions of protein,amylum,amino acids,polysaccharide,trace element and flavonoids from different varieties were determined by Kjeldahl nitrogen determination,acid hydrolysis,anthracene copper-vitriol colorimetry,flame atomic absorption spectrometry and so on. Moreover,the water extracts were prepared with three kinds of Rhizoma Dioscoreae as raw materials and the total reducing power,inhibition rate of OH· and DPPH· of water extract were analyzed in vitro,respectively. Results:The results showed that amino acids,protein,amylum,polysaccharide content of D. batatas"Qi"were 1601.7 mg/100 g,10.62%,22.0% and 7.42%,respectively. Trace element content of ferrum,copper,cobalt,kalium and flavonoids was 1.089 mg/g,0.371 mg/g,0.257 mg/g,2.011 mg/g and 2.48%,respectively. Total protein,amino acids and amylum contents were much higher(p<0.05)than those of Dioscorea opposita Thunb.cv.Tiegun and Dioscorea oppostita Thunb. The results showed that amino acids,protein,amylum,polysaccharide,flavonoids content of Dioscorea opposita Thunb.cv.Tiegun were 1058.0 mg/100 g,4.24%,15.2%,9.26%,4.06%,respectively.Trace element content of calcium,zinc,magnesium and sodium was 7.484,0.449,2.067 and 0.359 mg/g,respectively. Thus the polysaccharides and flavonoids was the richest in Dioscorea opposita Thunb.cv.Tiegun. While amino acids,protein,amylum,polysaccharide,trace element phosphorus,flavonoids content of Dioscorea oppostita Thunb were 967.3 mg/100 g,5.76%,18.4%,8.68%,0.457 mg/g,3.80%,respectively. Its nutritious compositions were balanced. Moreover,the different Rhizoma Dioscoreae possess different antioxidant activities. Total reducing power:V_C > D. batatas "Qi" > Dioscorea opposita Thunb.cv.Tiegun > Dioscorea oppostita Thunb. Inhibition rate of OH·:V_C > D.batatas "Qi" > Dioscorea opposita Thunb.cv.Tiegun > Dioscorea oppostita Thunb. Inhibition rate of DPPH·:V_C > Dioscorea opposita Thunb.cv.Tiegun > D.batatas "Qi" > Dioscorea oppostita Thunb. Conclusion:D. batatas"Qi"was a delicious food with characteristics of high contents of protein and amylum. Dioscorea opposita Thunb.cv.Tiegun could be used as medicine due to its high contents of polysaccharide and flavonoids. Dioscorea oppostita Thunb could be food as well as medicine due to its balanced nutrition. The water extracts of three kinds of Rhizoma Dioscoreae had certain antioxidant effect in vitro.