甲醇芽孢杆菌凝乳酶对马苏里拉干酪加工特性的影响

为了探究甲醇芽孢杆菌（Bacillus methanolicus）凝乳酶在马苏里拉干酪加工中的应用,分别以使用甲醇芽孢杆菌凝乳酶、混合酶制剂（含质量分数10%甲醇芽孢杆菌凝乳酶和90%商品凝乳酶）制作的马苏里拉干酪作为实验组,以商品凝乳酶干酪作为对照组,测定不同组别干酪成熟期间的蛋白水解特性、质构、风味和微观结构变化,研究甲醇芽孢杆菌凝乳酶对马苏里拉干酪加工特性的影响。结果表明,实验组干酪在成熟过程中pH值（4.6～5.3）、微生物数量（8.80～9.68（lg（CFU/g）））与对照组无显著差异（P＞0.05）;实验组干酪水分质量分数（混合酶干酪为（43.21±1.17）%、甲醇芽孢杆菌凝乳酶干酪为（46.15±0.94）%）均显著高于对照组（（41.08±1.04）%）,得率（混合酶干酪为（9.27±0.17）%、甲醇芽孢杆菌凝乳酶干酪为（9.46±0.16）%）也显著高于对照组（（8.98±0.13）%）（P＜0.05）;且实验组干酪的蛋白水解特性（pH 4.6时可溶性蛋白、酪蛋白水解程度和游离氨基酸质量分数）以及风味物质种类和相对含量等指标也优于对照组干酪。但是实验组中甲醇芽孢杆菌凝乳酶干酪保形性相对欠佳,感官评定得分偏低,混合酶干酪与对照组质构及感官基本得分一致,因此甲醇芽孢杆菌凝乳酶可以作为商品酶的部分代替品应用于干酪的生产中。     

酶解乳蛋白制取乳源肽的研究

用酸性蛋白酶、中性蛋白酶和碱性蛋白酶对牛乳蛋白进行水解，研究了水解工艺，并通过正交试验对工艺进行了优化。结果为：酸性蛋白酶水解牛乳蛋白的最佳工艺条件是：水解温度50℃，时间120min，pH值3．0，加酶量8．0％；中性蛋白酶水解温度50℃，时间90min，pH值7．0，加酶量1．60％；碱性蛋白酶水解温度60℃，时间105min，pH值9．0，加酶量8．0％。中性蛋白酶水解物苦昧最小，最适宜作食品。     

蒸发器杀菌温度控制的研究

以RNJM02-240型双效降膜式蒸发器为例，探讨了奶粉生产过程中，浓缩段蒸发器杀菌温度保持不住的原因，通过理论计算及实际应用两方面进行分析指出，蒸发器杀菌温度保持不住的主要原因为杀菌器加热温差过大，即各级物料预热面积设计过小：物料比较特殊，即物料性质比较特殊及易挂垢或结焦；实际实用物料与原设计物料参数偏离过大；物料处理量过大，远远超过了设计值：操作不当，即蒸发器在生产过程中，系统参数控制不稳定等都会使杀菌温度保持不住。     

浅析巴氏杀菌奶在中国的发展前景

介绍了巴氏杀菌奶的生产加工工艺,阐述了制约我国巴氏杀菌奶发展的主要因素,通过对国内外乳业巴氏杀菌奶发展形势的对比,说明巴氏杀菌奶在我国有着广阔的发展空间。     

牛奶/大豆蛋白纤维混纺织物的染整工艺

介绍了牛奶／大豆蛋白纤维的特点及染整工艺。小样试验中，测试了强碱、pH值对织物的影响，比较了酶退浆、低碱煮练剂DKB退浆、Na2CO3退浆的退浆效果；探讨了双氧水漂白中温度、H2O2浓度、还原剂漂洗等工艺参数；列举了牛奶／大豆蛋白纤维大样试验的工艺流程和具体工艺参数，包括烧毛、漂白、定形、染色和特种整理（抗皱、柔软）等工序。     

A survey of the occurrence and properties of methicillin‐resistant Staphylococcus aureus and methicillin‐resistant Staphylococcus intermedius in water buffalo milk and dairy products in Turkey

Antimicrobial resistance, β‐lactamase activity and mecA gene of Staphylococcus aureus and Staphylococcus intermedius isolated from raw water buffalo milk and dairy products in Turkey were determined. All strains showed resistance to at least one antibiotic but none was resistant to vancomycin. Of the 97 S. aureus and 35 S. intermedius strains, 9 (9.2%) and 2 (5.7%) were resistant to oxacillin and harboured mecA gene. β‐lactamase activity of 13.4% and 5.7% of S. aureus and S. intermedius strains was positive, respectively. Overall, 2.5% and 0.55% of the samples were contaminated with methicillin‐resistant S. aureus and S. intermedius, respectively.     

牛奶咖啡饮料的稳定性研究

牛奶咖啡饮料是以咖啡提取液或速溶咖啡粉为主要原料,加入乳粉、白砂糖、稳定剂及其他辅料并经过有效杀菌后制作成的一种中性含乳咖啡饮料,其在货架期内很容易产生脂肪上浮、蛋白絮凝和沉淀,严重影响产品品质。因此,需要筛选添加合适的稳定剂来保证产品的稳定性。本实验利用快速稳定性分析仪LUMiFuge结合目测观察法、粒径分析法、离心沉淀率测定的方法,研究了磷酸盐、乳化剂和增稠剂对牛奶咖啡体系稳定性的影响,确定了最优的稳定剂种类:磷酸盐选取六偏磷酸钠、乳化剂选取羟基化大豆磷脂、增稠剂选取MCC。     

白牦牛乳软质干酪的加工及其质构特性的研究

以甘肃天祝牧区白牦牛乳为原料制作软质干酪。优化了加工白牦牛乳软质干酪的工艺参数,并测定其保藏期前后的理化指标和质构。结果表明,牦牛乳软质干酪在发酵剂添加量2g/100mL,凝乳温度35℃,凝乳pH5.9,CaCl2添加量0.01g/100mL时,品质最佳,出品率为22.5g/100g;保藏30d后的软质干酪与新鲜干酪相比,其非脂物质水分含量(P0.01)、干物质脂肪含量(P0.01)、胶着性(P0.05)、硬度(P0.01)和咀嚼性(P0.01)均有显著变化。     

Effects of feeding hull-less barley on production performance,milk fatty acid composition,and nutrient digestibility of lactating dairy cows

The objectives of this study were to evaluate production performance, milk fatty acid composition, and nutrient digestibility in high-producing dairy cows consuming diets containing corn and hull-less barley (cultivar Amaze 10) in different proportions as the grain source. Eight primiparous and 16 multiparous Holstein cows were assigned to 1 of 4 diets in a replicated 4 × 4 Latin square design with 21-d periods. Cows were fed once daily (1200 h) by means of a Calan gate system (American Calan Inc., Northwood, NH). All diets contained ～20% grain (dry matter basis). Treatments consisted of 100% corn (0B), 67% corn and 33% hull-less barley (33B), 33% corn and 67% hull-less barley (67B), and 100% hull-less barley (100B) as the grain sources. Total-tract nutrient digestibility was estimated using lanthanum chloride (LaCl₃) as an external marker. Dry matter intake differed quadratically among treatments, being lowest for 67B and highest for 0B and 100B. Feeding hull-less barley did not affect milk yield, and milk fat concentration differed cubically among treatments. The cubic response was attributed to the higher milk fat concentration observed for the diet containing 67B. Neither the concentrations in milk of protein and lactose nor the yields of protein and lactose differed among treatments. The proportion of de novo synthesized fatty acids in milk did not differ among treatments. The apparent total-tract digestibility of dry matter, crude protein, and neutral detergent fiber did not differ among treatments. Although a quadratic effect was observed, starch digestibility was minimally affected by treatments. In conclusion, this study indicates that hull-less barley grain is as good as corn grain as an energy source when formulating diets for high-producing dairy cows.     

草莓汁发酵乳饮料的研制

研制了一种以发酵乳和草莓汁为主要原料加工调制成的发酵乳饮料,在确定饮料所含发酵乳量（添加量定为35%）的基础上,阐述了草莓汁发酵乳饮料的生产工艺和最佳配方.得出最佳工艺配方为：发酵乳35%、草莓汁15%、白砂糖10%、复合稳定剂0.6%、酸液0.2%、适量的香精（均为质量分数）.