混合果肉羊乳扣碗酪的加工工艺研究

研制全新的具有民族特色并且适合大多数人口味的奶酪食品。采用单因素多水平试验及正交试验方法,研究出混合果肉羊乳扣碗酪的加工工艺。为:白砂糖、琼脂熬汁→过滤→杀菌→添加到过滤杀菌的羊奶中调配→冷却→加江米酒→分装→冷凝→纯化→成品。产品配方为:新鲜山羊奶400g,8%桃果肉,8%梨果肉,9%葡萄干,果肉用30%的砂糖液煮制8min最佳,7.5%白砂糖,0.5%琼脂以及1.5%江米酒。该果肉扣碗酪具有水果的保健功效,营养全面,丰富我国的乳品市场和促进羊奶产业的发展。     

乳中硫氰酸盐对人类健康的风险评估

全面综述了乳中硫氰酸盐对人类健康的风险。介绍了硫氰酸盐在生鲜乳中保鲜使用情况,乳中硫氰酸盐的正常生理浓度和检测方法,乳及人体内硫氰酸盐的来源和影响因素,乳中硫氰酸盐对人类健康的毒性作用及风险评估。     

牛奶中蛋白质含量的直接电位测定方法研究

在碱性条件下牛奶中的两性氨基酸与甲醛溶液反应,氨基上的两个氢原子被次甲基所取代,失去了氨基的碱性特性,释放出游离的羧基,从而使牛奶的电化学特性发生变化。据此,笔者提出并建立了一种全新的快速测定牛奶中蛋白质含量的直接电位方法。实验研究结果表明,其蛋白质含量的线性测定范围为2.4～3.0%,回收率高达95%以上。该方法具有操作使用简单方便快捷准确等特点,在乳品企业的生产实践中具有一定的推广使用价值。     

Productive,Physiological and Biochemical Changes in Imported and Locally Born Friesian and Holstein Lactating Cows under Hot Summer Conditions of Egypt

Twenty each of healthy lactating Friesian and Holstein cows were studied. They were of similar age and body weight, nonpregnant in their third lactation and 80–100 days post partum. The investigation was carried out for 8 weeks on two farms at the same time during the hot summer season in Egypt. The first farm was in Demietta (North east of the Nile Delta, 31° 40 N) on 20 Friesian cows and the second was in Fakous (East of the Nile Delta, 30° 40 N) on 20 Holstein cows. On each of the two farms, 10 cows were newly imported and 10 were born in Egypt.The average daily milk yield and total milk production in the third lactation of the newly imported cows were significantly higher than those of the locally born cows for both Friesians and Holsteins. At the same time, the T₄, T₃, urea-N, haematological values and AST enzyme activity in the newly imported cows were significantly lower than those in the locally born ones in both breeds, while the locally born cows showed significantly lower values for rectal temperature and respiration rate, as well as for AST and Alk-P enzyme activities, than the newly imported cows of either breed.Holstein cows surpassed the Friesians in milk production, as well as thyroid hormone secretion and cholesterol, haemoglobin, packed cell volume and erythrocyte count values. The opposite was found for serum total protein, urea-N and creatinine concentrations, leukocyte count and AST, ALT and Alk-P enzyme activities.     

利用乳汁体细胞研究共轭亚油酸钙对奶牛乳腺基因表达的作用

8头泌乳中期的奶牛被随机分为2组,分别是对照组（每头牛：基础日粮＋棕榈酸钙200g／d）和试验组（每头牛：基础日粮＋共轭亚油酸钙200g／d）,试验期14d,检测了奶产量、乳成分,分析奶牛的血液变化,并采用荧光定量PCR对乳汁体细胞中脂蛋白脂酶（LPL）、乙酰辅酶A羧化酶（ACACA）的基因表达进行检测。结果显示,与对照组相比,试验组奶牛的乳产量、乳蛋白、乳糖和乳汁体细胞含量没有显著影响,但是显著降低了乳脂肪含量（P〈0．05）,对照组和试验组奶牛乳脂肪含量分别为0．0326g／mL和0．0244g／mL。检测血液指标发现,共轭亚油酸钙显著升高了奶牛血液中高密度脂蛋白的含量（P〈0．05）。基因分析发现,试验组奶牛乳汁体细胞中LPL、ACA—CA的基因表达显著下调,表明共轭亚油酸钙抑制了奶牛乳腺细胞脂肪酸合成酶的基因表达。     

Effects of feeding roasted safflower seeds (variety IL-111) and fish oil on dry matter intake, performance and milk fatty acid profiles in dairy cattle

Safflower seed has the highest concentration of linoleic acid among 80 oilseeds but little information exists on the effective use of SS for lactation cows. It was hypothesised that a diet supplemented with an Iranian SS variety (IL-111) in combination with fish oil (FO) would result in higher concentrations of trans-18:1 (including vaccenic acid) and conjugated linoleic acids in milk fat than feeding an unsupplemented control diet. Our objective was to determine the effects of feeding diets containing: (i) Control: (C); (ii) 25 g of roasted SS IL-111 (RSS); (iii) 20 g FO and (iv) 25 g RSS + 10 g FO (RSS + FO) per kilogram of dietary DM on feed intake, ruminal fermentation, milk production and fatty acid profile. Eight multiparous Holstein cows were used in a replicated 4 × 4 Latin square design study. The experiment had four periods of 21 days. Milk Fat percentage was lower (p < 0.01) with FO supplementation and averaged 19.0 and 21.5 g/kg milk with FO and RSS + FO compared with 30.3 and 32.5 g/kg with C and RSS. Feed intake also was lower (p < 0.01) with FO vs. C (23.1 vs. 24.5 kg/day) but feeding RSS resulted in greater feed intake compared with other treatments (26 kg/day). Despite lower feed intake with FO, milk production did not change from controls but feeding RSS + FO resulted in greater milk yield than controls (42.6 vs. 39.3 kg/day). Ruminal pH was greater (p < 0.01) in cows fed FO than other treatments. Supplemental FO alone or in combination with RSS resulted in dramatic increases (p < 0.01) in c9,t11-18:2 in milk fat (12.7 and 13.2 g/day vs. 5.8 and 7.02 with C and RSS). It was surprising to note that 25 g/kg RSS can improve feed intake.     

生鲜牛乳中β-内酰胺酶快速检测报告

[目的]为快速、准确检测出生鲜牛乳中β-内酰胺酶,保证牛奶卫生安全。[方法]采用Snap法(酶联免疫法)检测生鲜牛乳中β-内酰胺酶,对新疆巴州辖区内17个奶站进行抽样检测。[结果]17份样品结果全部为阴性。[结论]对巴州辖区内17个奶站的生鲜牛乳进行了抽样检测β-内酰胺酶项目,17份样品结果全部为阴性,合格数17份,合格率为100%。     

不同饲喂方式对南方奶牛产奶性能、养分消化和代谢的影响

研究了具有南方奶牛日粮类型特征的相同精粗比日粮的不同饲喂方式对奶牛的采食行为、产奶性能、全肠道养分表观消化率和血清代谢产物的影响。选用体重相近的12头荷斯坦奶牛,采用单因子设计,根据产奶量、胎次及泌乳天数随机分为2组（n=6）,分别为精粗分饲组（SI）和全混合日粮组（TMR）,精饲料：粗饲料均为50：50。试验结果表明：奶牛采食量无差异,在相同精粗比日粮下,TMR饲养技术极显著减少了奶牛的采食时间（P〈0.01）,显著增加了反刍时间（P〈0.05）,TMR组奶牛的乳脂率、4%标准奶产量、乳脂产量、乳糖产量和乳固形物产量分别比SI组显著提高11.20%、11.60%、17.50%、13.21%和9.86%（P〈0.05）,但对奶牛咀嚼行为、全肠道养分表观消化率和血清代谢产物影响不显著（P〉0.05）。在南方奶牛典型日粮采用TMR饲养技术时,与精粗分饲相比,可提高奶牛的产奶性能,但对奶牛的采食量、咀嚼行为、全肠道养分表观消化率和血清代谢产物没有显著影响。     

复合酵母培养物对奶牛产奶性能、氮排放及血液生化指标的影响

为研究饲料中添加复合酵母培养物对奶牛产奶性能、氮排放及血液生化指标的影响,选取年龄、体重、产奶量及泌乳期相近(135±15) d的荷斯坦奶牛24头,随机分为4组,每个处理6个重复,对照组和3个试验组的复合酵母培养物添加量分别为精料浓度的0,0.8%,1.0%,1.2%,随精料饲喂,测定产奶量、乳成分、氮排放及血液生化指标,结果表明,1)试验2组日均产奶量显著高于对照组(P<0.05),各试验组分别比对照组提高8.48%,10.05%,8.97%。2)复合酵母培养物能显著提高乳脂和乳蛋白率(P<0.05),显著降低牛奶体细胞数(P<0.05),以试验2组最低。3)在氮排放量上,试验2组显著低于对照组(P<0.05),各试验组比对照组分别降低8.47%,12.01%,9.36%。4)在血液生化指标方面,复合酵母培养物能提高血清中总蛋白、球蛋白、血糖、胰岛素水平(P<0.05),降低尿素氮水平(P<0.05)。由此可见,本试验条件下,综合考虑产奶量、乳成分、氮排放及血液生化指标,复合酵母培养物的最佳添加量为精料浓度的1.0%。