【摘要】 以紫花苜蓿为研究对象,对不同部位茎叶的基本成分和不同粒度苜蓿叶粉的功能特性指标进行测定与分析,并对不同粒度苜蓿叶粉的比表面积、孔径、化学基团、表面超微结构进行测定与观察。结果表明:苜蓿叶中可溶性膳食纤维、蛋白质、脂肪、灰分的含量均高于茎秆,且上部叶片中的含量最高,分别为12.25%、28.62%、6.23%、11.35%。苜蓿叶的粉碎粒度在0.063～0.250 mm范围内时,随着粉碎粒度的减小,持水力、膨胀力先增大后减小,粒度为0.125～0.160 mm时达到最大,分别为5.57 g/g、4.40 mL/g;持油力由2.83 g/g降至1.84 g/g;阳离子交换能力、对胆固醇和亚硝酸钠的吸附能力逐渐增强;比表面积、累积孔体积、部分化学基团数量均增加,最可几孔直径减小。苜蓿叶的粉碎粒度为0.125～0.160 mm时,具有较好的持水力、膨胀力,适用于开发改善肠道功能、预防肥胖的食品;粉碎粒度为0.063～0.080 mm时,具有较好的胆固醇吸附能力、亚硝酸钠吸附能力和阳离子交换能力,适用于开发预防高血压、冠心病、癌症的食品。更多还原

【Abstract】 The chemical components of stems and leaves from different positions were determined, and the functional characteristics, specific surface area, pore size, chemical groups and surface ultrastructure of alfalfa leaf powders with different particle sizes were measured. The results showed that the contents of soluble dietary fiber, protein, fat and ash in alfalfa leaves were higher than those in stems, with the highest values being found in upper leaves, which were 12.25%, 28.62%, 6.23% and 11.35%, respectively. As the particle size decreased in the range of 0.063–0.250 mm, water-holding capacity and swelling capacity first increase and then decrease, reaching their maximum values of 5.57 g/g and 4.40 mL/g, respectively when the particle size was 0.125–0.160 mm; oil-holding capacity decreased from 2.83 to 1.84 g/g; cation exchange capacity, cholesterol adsorption capacity and sodium nitrite adsorption capacity gradually increased. Specific surface area, cumulative pore volume and the number of some chemical groups increased, while the most probable pore diameter decreased. Alfalfa leaf powder with particle size of 0.125–0.160 mm had better water-holding capacity and expansibility and was therefore suitable for developing functional foods to improve intestinal functions and prevent obesity. In contrast, alfalfa leaf powder with particle size of 0.063–0.080 mm had better adsorption capacity for cholesterol and sodium nitrite and cation exchange capacity, making it suitable for use in functional foods to prevent hypertension, heart disease and cancer.更多还原