Physicochemical properties of water-soluble myofibrillar proteins prepared from chicken breast muscle

The solubility of skeletal muscle myofibrillar proteins in water was examined. The solubility of the proteins was found to be sensitive to ionic strength and pH of the solution. At the ionic strength of less than 12 mM and neutral pH, more than 80% of myofibrillar proteins were solubilized. Heating at a temperature of more than 70°C was required for the proteins to retain their solubility. The solubility of freeze‐dried protein powder prepared from water‐soluble myofibrillar proteins was also examined, and it was found that addition of trehalose and heating were essential for re‐solubilization in water. Amino acid composition of water‐soluble myofibrillar proteins was found to be almost the same as that of myofibrillar proteins.     

水稻抽穗后叶色及N素含量变化同产量及食味的关系

为了解析抽穗后叶色及N素含量变化规律及其同产量、食味特性值和食味的关系,以2011年参加水稻区域试验的13个水稻品种（系）为供试材料,采用惯行法栽培管理进行了试验。抽穗至成熟期间,使用SPAD502和CCN6000 AGRIEXPERT每10天测定一次各品种（系）的叶色和N素含量;收获后各品种、重复单独测产,从重复Ⅰ中取样,使用德国生产的连续流动分析仪测定食味特性值（直链淀粉和蛋白质含量）;食味品尝试验最后进行,品尝员由16名师生参加,分2天进行。结果显示：抽穗后叶色值和N素含量呈现逐渐降低的趋势,成熟前期下降幅度较大;产量、直链淀粉含量、蛋白质含量和食味综合评价间均不存在显著的相关关系;抽穗期的叶色值和N素含量同籽粒中蛋白质含量存在显著正相关,但同产量、直链淀粉含量以及食味综合评价的相关均不显著。为此,根据抽穗期叶色值或N素含量进行低蛋白质含量品种（系）的选择是可行的。     

中日合作水稻品质·食味研究的现状和展望

介绍了中国水稻食味研究取得的成果和正在开展的研究工作,对今后水稻食味研究的发展做了展望。随着中国社会经济的迅速发展,人们的饮食结构发生了变化,对主食稻米的需求正在由数量型向品质食味型转变。影响水稻食味的三大因素包括遗传特性、产地特点和生产技术,其中,首选遗传特性。中国水稻食味育种工作已经展开,优质食味米配套生产技术的研...     

Effects of meat species on the postprandial thermic effect in rats

We examined animal species differences in the postprandial thermic effect of meat and investigated the postprandial thermic effect of mutton in rats. After intake of experimental diets containing each meat, body temperatures of rats fed mutton or venison were significantly higher than that of rats fed rabbit meat. After intake of experimental diets containing fractionized mutton, the body temperatures of rats fed diets containing lean mutton protein were higher than those of rats fed diets without lean mutton protein. In a two‐dimensional fluorescence difference gel electrophoresis study of brown adipose tissue, it was shown that the intake of mutton up‐regulated the expression of many signaling molecules that are involved in energy metabolism. The postprandial thermic effect of mutton seems to be due not to catecholamine and adrenocorticotropic hormone but to thyroid hormones. The results suggest that intake of lean mutton protein stimulates the secretion of thyroid hormones and facilitates energy metabolism in rats.