酪蛋白对凝固型羊奶酸奶发酵特性的影响

本文研究了羊奶复原乳中添加羊奶酪蛋白,在90℃、15min杀菌,蔗糖添加量7%,菌种添加量2%,乳固形物浓度12%,发酵温度43℃,后发酵温度4℃的条件下,羊奶酸奶发酵过程中,滴定酸度、粘度和持水性的变化。结果表明,羊奶粉中添加羊奶酪蛋白,对羊奶酸奶发酵过程中的滴定酸度影响不大,对粘度和持水性有明显影响;对后发酵过程中的滴定酸度、粘度和持水性有明显影响。     

羊奶奶酪制作核心技术的初步研究

[目的]本研究以羊乳为原料，结合奶酪工艺初步探讨了羊奶酪的主要技术参数。[方法]通过对羊奶的杀菌温度、发酵剂添加量、CaCl₂添加量、凝乳酶添加量等因素进行正交试验，以产品质构、综合感官评价为指标，得到最佳用量配比。[结果]羊奶奶酪的最佳工艺为：杀菌条件75~78 ℃，15 s，发酵剂添加量为1.4 %，CaCl₂的添加量为0.03%，凝乳酶添加量为0.01%，在传统奶酪制作工艺的基础上以此技术参数生产的羊奶奶酪口感、风味良好。[结论]本研究为完整羊奶奶酪技术的开发加工奠定了基础，为探寻适合中国羊乳原料及口味要求的羊奶奶酪工业化生产提供了技术依据。     

羊奶及其制品稳定性的研究进展

对羊奶的热稳定性、酒精稳定性、凝乳特性及羊奶制品(羊奶粉、羊奶酸奶)稳定性的影响因素进行综述.研究表明:温度、pH值、离子浓度等对羊奶的稳定性都有显著的影响.温度在120～140℃范围内时,随着加热温度的升高,羊奶的热稳定性明显降低;30～80℃范围内,酒精稳定性随温度的升高而降低.pH6.7时,羊乳的热稳定性最好,pH6.4～7.2时,随pH值升高,羊乳的酒精稳定性增强.无机盐离子Ca2+对羊奶热稳定性和酒精稳定性的影响作用相似,稳定性均随Ca2+浓度的增大而降低.对于羊奶制品,降低水分活度可以提高其贮藏稳定性,乳清蛋白和酪蛋白含量的增加会降低酸奶贮藏期间的滴定酸度、黏度及持水性.另外,发酵酸奶所用稳定剂的不同、贮藏温度的不同也会影响制品的稳定性.     

羊奶营养价值及羊奶奶酪生产研究状况

羊奶奶酪风味独特,口感细腻,易消化吸收,在许多方面都优于牛奶奶酪。本文主要介绍了羊奶的营养价值和保健功能,综述了目前羊奶奶酪的生产及研究情况。     

日本:羊奶或成为取代牛奶的新奶源

<正>牛奶虽然是日本市场的主流乳品,但出于对疯牛病、牛奶加工过程违法添加等问题的担忧,已经有日本人开始寻找新的奶源,比如羊奶。此外,还有水牛奶、鸵鸟奶等也在出售。羊奶因营养丰富、对人体更有益,越来越被推崇。在日本一些大超市中,现在已经可以看到羊奶奶片、羊奶奶酪等。在     

乳用绵羊的泌乳性能及其发展前景

奶绵羊在欧洲、美洲、阿拉伯国家及地区饲养的数量较多,绵羊奶及其制品很受人们的喜爱。近些年我国羊奶产业发展迅速,羊奶产量和价格上涨较快,用羊奶粉配制的婴儿奶粉非常受欢迎,市场规模超50亿元,但奶源基本以山羊奶为主,市场缺口很大。因此,研究肉毛奶兼用型绵羊品种,增加羊奶来源,是养羊业的发展方向。文章从世界奶绵羊发展状况、羊乳成分、奶绵羊品种及产奶性能、影响绵羊泌乳性能的因素、羊奶酪的生产和乳用绵羊发展预期等几个方面进行了综述,以供参考。     

国内新型乳品——奶酪

1奶酪的起源 人类大约在公元前9000年就能制造类似奶酪的食品.有证据表明,那时在伊朗绵羊已被人类驯化并向人类提供羊奶.人们将剩余的羊奶做成酸奶或奶酪. 自1851年美国出现了第一家工业化生产奶酪工厂以来,奶酪的生产发展很快,近年来世界奶酪产量一直保持上升势头.奶酪是乳制品中唯一在全世界保持产量连续增长的产品,其品种已多达40多种.主要分布在欧洲、北美洲和大洋洲的澳大利亚、新西兰等国家和地区.1998年日本进口的奶酪达15万吨,据报道,日本战后人均身高及身体素质有大幅度提高和奶酪有着密切的关系.     

鸡胚蓝莓新鲜羊奶酪的制作方法

本文研究了以羊奶为主要原料,生产添加了鸡胚营养液以及蓝莓等强化物料且改善风味的新鲜羊奶酪的工艺。产品生产周期短,为2～3天,味美醇香,营养丰富,且实现了规模化生产。     

山羊奶营养及加工工艺特性

山羊奶是一种营养完全的食品,含有能促进人类生长发育以及维持健康的必须营养成分.它所含各种营养成分的比例,大体适合人类的生理需要.发展山羊奶业不仅是对中国奶业数量上的补充,而且在品质上,与牛奶相比更具潜力.山羊奶与牛奶的蛋白质组成结构不一样,故其蛋白电荷不同,从而影响蛋白质的稳定性.所以羊奶比牛奶稳定性要差很多.     

奶中之王——山羊奶

一说起奶,人们就会想到牛奶,好像只有奶牛才会产奶。其实在全世界范围内,奶山羊的饲养量要比奶牛多,且呈不断增长趋势。奶山羊的数量之所以不断增加,是因为它的奶有着更大的实用价值。羊奶酪蛋白含量低,乳清蛋白含量高(酪蛋白与乳清蛋白的比例山羊奶为75∶25,牛奶为85∶15),而且组成羊奶蛋白质的氨基酸与人奶相近。羊奶脂肪球直径约为2!m,是牛奶的1/2,富含短链脂肪酸(约为牛奶的5倍),不含脂肪凝集素(牛奶有),在灭菌后食用几乎可全部消化吸收。因之,在母乳缺乏或提早断奶时,羊奶是婴幼儿的最佳代乳品。100g羊奶中10种维生素总量为780!g,比牛…     

Polymorphism of caprine milk alphas1-casein in relation to performance of four Polish goat breeds

Polymorphism of goat milk alphas1-casein was determined and potential relations between genetic variants of this protein fraction and goat performance were evaluated. The investigations were performed on 598 goats assigned to of 4 breed groups (White improved 254 units, Coloured improved--124, White non-improved--146 and Coloured non-improved--74). For each goat, alphas1-casein polymorphism was determined in polyacrylamide gel by the PAGE-SDS method and percentage of milk alphas1-casein and gene frequency established. There was evaluated goat performance at successive lactations. In the goat population investigated, AA, AB, BB, AE, BE and EE alphas1-casein genotypes were identified. In all four breeds, alphas1-casein genotype EE clearly predominated (27.2-39.2%), recognized as "medium" and its share was higher in the groups of non-improved goats. It was conditioned by high frequency of gene E alphas1-casein (0.419-0.622). Generally, EE genotype percentage was higher in the non-improved goat groups. The improved goats, though, obtained higher productivity in each of the lactation studied. Analysis of relationships between alphas1-casein genetic variants and goats performance confirmed a significant influence on milk, protein and fat yields only in the Coloured improved goat group. There was revealed a more general tendency indicating a significant impact of "strong" alphas1-casein genotypes on a concentration of basic milk components, i.e. fat and protein, especially casein. In a group of goats producing milk of the highest casein content (over 2.4%) and protein (over 3.0%), the animals showing "strong" alphas1-casein variants dominated (85 and 70 %).     

Serologic prevalence of caprine arthritis-encephalitis virus in California goat dairies

Fifty-three percent of goats in 13 California goat dairies had antibodies to caprine arthritis-encephalitis virus (CAEV), as determined by agar-gel immunodiffusion. Those goat dairies that reared kids on pasteurized milk had a lower seroprevalence than those that did not. Age, rearing kids on unpasteurized milk, and the presence of large joints were associated with antibodies to CAEV. Breed was associated with seroreactivity, but the association was confounded by other factors. Sex was not associated with antibodies to CAEV. The relationship between age and antibodies to CAEV was observed for goats reared on pasteurized or unpasteurized milk, which indicated that continued horizontal (contact) transmission may be important on these dairies and limited the effect of a pasteurized rearing program on control of CAEV infection.     

奶山羊产奶性状候选基因的研究进展

本文介绍了影响奶山羊产奶性状的几个主要候选基因,如酪蛋白基因、乳清蛋白基因、硬脂酰辅酶A去饱和酶基因、生长激素基因、甘油二酯酰基转移酶基因等在奶山羊上的研究进展。     

A comparison of three serological tests in the diagnosis of caprine brucellosis.

The serum agglutination test (SAT), the Rose Bengal plate test (RBPT) and the milk ring test (MRT) were used in the diagnosis of caprine brucellosis. There was a close correlation between the SAT and RBPT when both tests were negative but the RBPT failed to detect 79.82 per cent of sera in excess of 50 iu. Also, owing to the relatively poor milking potential of the Nigerian goat and the false positive results with the MRT, it is concluded that the SAT offers a better serological diagnostic tool for caprine brucellosis in this locality.     

Prevalence, causes and laboratory diagnosis of subclinical mastitis in the goat

Five goat herds were examined to determine the prevalence and causes of subclinical mastitis and to assess the value of some laboratory tests currently used on milk samples as aids in the diagnosis of caprine mastitis. In the 170 samples taken from the pairs of mammary glands of 85 goats, the prevalence of infection in the different herds ranged from 15 per cent to 79 per cent of halves. Just over one-third (36 per cent) of all halves were infected, the organisms isolated being coagulase-negative staphylococci (80 per cent), coagulase-positive staphylococci (16 per cent), alpha-haemolytic streptococci (2 per cent) and Pasteurella haemolytica (2 per cent). Neither anaerobic organisms nor mycoplasmas were found. Tests confirmed that the coagulase-positive staphylococci were pathogens but that the coagulase-negative staphylococci rarely caused detectable disease in the caprine udder. The large between-herd variation in the geometric mean cell counts of uninfected milk samples means that somatic cell counts, the Whiteside test and the California mastitis test, are unreliable as aids in the diagnosis of caprine mastitis.     

驴乳营养成分研究进展

驴乳因其乳清蛋白、乳糖、溶菌酶、不饱和脂肪酸和VC含量较高而酪蛋白及脂肪含量较低的特点，被誉为人乳的理想替代品，同时具有低致敏性、抑菌性和抗癌活性等多种生理功能。本文介绍驴乳的营养成分特点，包括蛋白质、氨基酸、脂肪、矿物质、维生素等，并与人乳、牛乳、水牛乳、羊乳和骆驼乳进行比较，以期为驴乳的综合加工与利用提供参考。     

羊乳酒精稳定性的研究

试验研究了pH值、Ca2＋、温度和螯合剂对羊乳酒精稳定性的影响。结果表明,当pH在6.4～7.2时,随着pH值的升高,羊乳酒精稳定性增强;Ca2＋在0.0025mol/L～0.02mol/L时,随着Ca2＋浓度的增大,羊乳的酒精稳定性降低;温度在30℃～80℃时,随着温度的升高,羊乳的酒精稳定性降低。同时,在羊乳中添加磷酸二氢钠、磷酸氢二钠、三聚磷酸钠、焦磷酸钠、柠檬酸钠和EDTA钠都能够增强羊乳的酒精稳定性。     

红枣羊乳啤的制备及其稳定性

为丰富羊乳产品,开阔羊乳市场,给消费者带来更多的消费选择,实验以山羊乳、麦芽、红枣、酒花为主要原料,分别通过乳酸菌的乳酸发酵和酵母菌的酒精发酵后,将得到的红枣羊乳酸液和啤酒原浆按一定体积比配比,制备出兼具酸乳、啤酒、碳酸饮料风味和保健功能的新型红枣羊乳啤饮料,并通过测定沉淀率和稳定系数对其稳定性进行分析。结果表明：当红枣羊乳酸液与啤酒原浆的体积比为1∶1,红枣羊乳酸液中红枣汁添加量12%、羧甲基纤维素钠添加量0.2%、果胶添加量0.15%、蔗糖酯添加量0.1%、白砂糖添加量4%时生产的红枣羊乳啤口感最佳,稳定性最好。