薏苡仁酸奶的流变性及工艺条件的优化研究

实验用复原乳制备薏苡仁酸奶,研究其流变学性质。结果显示,与生鲜乳相比,复原乳酸奶粘度显著提高,但感官性质（口感、色泽、滋味等）下降,持水力也降低。通过均质处理可以提高酸奶的品质,最佳均质压力为20MPa,且当白砂糖的添加量为6%～8%,薏苡仁提取液添加量为4%时,薏苡仁酸奶品质最佳。     

原料乳中体细胞数与UHT乳中酪蛋白成分的关系研究

研究了原料乳中体细胞数与15批次UHT乳样本中酪蛋白成分之间的关系。将原料乳巴氏杀菌后进行超高温处理。分别于8,30,60,90和120 d采集贮藏于室温条件下的UHT乳样本,并使用高效液相色谱法对酪蛋白成分进行分析。体细胞数范围1.97×105～8×105 mL-1。体细胞数与原料乳或UHT乳中的κ-酪蛋白质量浓度之间没有相关性(P<0.05)。原料乳中αs2-酪蛋白和β-酪蛋白与体细胞数呈负相关(P<0.05)。UHT乳中,αs1-酪蛋白(P<0.05)和β-酪蛋白(P<0.05)与体细胞数在贮藏第8天呈负相关,αs2-(P<0.01)与体细胞数在贮藏第60天呈负相关。结果表明,原料乳中体细胞数较高与β-酪蛋白和αs-酪蛋白的大量水解有关,并且可能导致UHT乳在贮藏期内出现质量问题。     

The effect of breed,parity, and stage of lactation on conjugated linoleic acid (CLA) in milk fat from dairy cows

Dairy products are the main source of conjugated linoleic acid (CLA), a functional food component with health benefits. The major source of cis-9, trans-11 CLA in milk fat is endogenous synthesis via delta9-desaturase from trans-11 18:1, with the remainder from incomplete rumen biohydrogenation of linoleic acid. Diet has a major influence on milk fat CLA; however, effects of physiological factors have received little attention. Our objectives were to examine milk fat content of CLA and the CLA-desaturase index with regard to: 1) effect of breed, parity, and stage of lactation, and 2) variation among individuals and the relationship to milk and milk fat. Holstein (n = 113) and Brown Swiss (n = 106) cows were fed a single diet and milk sampled on the same day to avoid confounding effects of diet and season. Frequency distributions demonstrated that milk fat content of CLA and CLA-desaturase index varied over threefold among individuals, and this needs to be considered in the design of experiments. Holsteins had a higher milk fat content of CLA and CLA-desaturase index, but breed differences were minor. Parity and days in milk also had little or no relationship to the individual variation for these two CLA variables. Breed, parity, and days in milk accounted for < 0.1, < 0.3, and < 2.0% of total variation in CLA concentration in milk fat, respectively. Milk fat content of CLA and CLA-desaturase index were essentially independent of milk yield, milk fat percent, and milk fat yield. We speculate that the basis for the genetic variation among individuals is related to rumen output of trans-11 18:1 and to a lesser extent cis-9, trans-11 CLA, and to the tissue amount and activity of delta9-desaturase.     

Effect of pH adjustment at heating on the rheological properties of acid skim milk gels with added potato starch

The rheological properties of acid skim milk gels, prepared from milk with added potato starch and pH adjusted (pH 6.5–7.1) prior to heat treatment and acidification, were investigated. The storage modulus, G′, of the final acid gels was increased by heating the milk at higher pH and further increased by adding starch. The effect of pH at heating and addition of starch appeared to be additive and independent of each other up to a starch addition level of 1%. Above this starch level, the pH at heating had a lesser effect. This may have been due to the increased viscosity of the aqueous phase as a result of starch gelatinization or to direct contributions of the starch to the gel network structure. Confocal microscopy showed that milk proteins developed fewer but broader protein clusters at higher pH than at lower pH. Starch addition resulted in an increased density of the protein network.     

Fermentation characteristics and transit tolerance of Lactobacillus casei Zhang in reconstituted mare milk during storage

The fermentation characteristics of Lactobacillus casei Zhang in mare milk and transit tolerance during refrigerated storage for 28 days were evaluated. There were no dramatic changes in the viable counts of L. casei Zhang in the fermented mare milk samples during storage at various inoculation levels. L. casei Zhang showed good tolerance to the simulated transit juice and maintained high viability in mare milk (above 10⁸cfu/g) during storage. Our results showed that L. casei Zhang had good probiotic properties, and suggest that mare milk could serve as the vehicle for the delivery of L. casei Zhang.     

发酵银耳豆奶的研究

该文论述了以豆浆为原料 ,经过银耳菌丝体摇瓶发酵 ,在豆浆中产生大量的菌丝体 ,然后再配以其他原料加工成风味独特的发酵银耳豆奶。     

复方SOD奶粉的研究

介绍了复方SOD奶粉的配方成分、设计依据、工艺流程，同时进行了该配方的动物喂养试验，即①小鼠急性毒性试验；②果蝇生存试验；③抗氧化功能试验；④免疫调节作用试验；并对其抗衰老、提高机体免疫力的功能特性进行了讨论。结果表明，复方SOD奶粉除了适合大多数人群外，尤其适合中老年人与脑力、体力疲劳过度者。     

用SDS滴定奶粉中蛋白质的实验研究

目的:研究用十二烷基硫酸钠(sodium dodecyl sulfate,SDS)快速测定奶粉中蛋白质含量的实验条件。方法:一定量的奶粉用蒸馏水溶解后,在一定介质中用0.1000%的SDS溶液滴定,当被滴定溶液析出凝乳状的白色沉淀时,即为终点。研究了温度、pH值及奶粉中淀粉、蔗糖含量对测定的影响,确定了SDS溶液的滴定量与蛋白质含量的关系。结果:用该方法对同一奶粉测定8次,RSD=0.53%,用本法和凯氏定氮法对8份不同奶粉中的蛋白质含量测定,结果无显著性差异(p>0.05)。结论:该方法简便、准确、可靠,适合于奶粉中蛋白质的快速检测,检验一个样品仅仅用4min。     

人乳与牛乳N-链寡糖组对小鼠肠道菌群的影响

目的:探究人乳N-链寡糖组(human milk N-glycome,HMN)与牛乳N-链寡糖组(bovine milk N-glycome,BMN)对小鼠肠道菌群的影响.方法:以C57BL/6J雄性小鼠为对象,首先在体外测定粪便菌群中与N-链寡糖相关的糖苷酶活性,并模拟粪便菌群对HMN与BMN的利用;然后将小鼠随机分...     

不同蛋白酶对无糖豆奶粉溶解性的影响

通过在无糖豆奶粉生产过程中添加合适的蛋白酶，采用不同加酶量来控制水解度，研究了Neutrase中性蛋白酶、AS1.398中性蛋白酶和Alcalase碱性蛋白酶对无糖豆奶粉溶解性的影响。结果表明，Neutrase中性蛋白酶在实验添加量范围内，对提高无糖豆奶粉溶解性较AS1.398中性蛋白酶和Alcalase碱性蛋白酶显著；当Neutrase中性蛋白酶加酶量([E]／[S])为0.40％时，豆奶粉蛋白质溶解度指数(PSI)和固形物溶解度指数(DSI)较好，此时豆奶粉中蛋白质的水解度(DH)为4.44％。