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本研究连续一年观测了摩拉水牛、尼里-拉菲水牛、一代杂水牛和三品杂水牛4个种水牛乳64%的不同季节的酒精阳性发生率、乳成分、理化性质,并比较了酒精阳性乳、阴性乳与乳样总体的差异。结果表明,纯种河流型水牛(摩拉水牛、尼里-拉菲水牛)乳酒精阳性率低于两个杂交水牛(三品杂水牛、一代杂水牛),各品种水牛乳均以2~4月和8~10月的阳性率为最高。低酸度酒精阳性乳(12~18oT)占据了酒精阳性乳的52.9%~64.1%。酒精阳性乳的乳蛋白、乳固体、非脂乳固体、酸度均显著高于阴性乳和乳样总体平均值,但冰点低于乳样总体平均值。可见不同品种水牛乳不能用同一酒精浓度进行检验;酒精阳性率可反映水牛应激或营养状况;较高的乳蛋白、非脂乳固体、总乳固体、酸度以及较低的冰点是酒精阳性水牛乳的特征;酸度和冰点是品种间酒精阳性率差异的主要因素。 相似文献
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针对乳品厂酒精试验存在的一些问题,对酒精试验检测方法进行改进,以提高酒精试验的精确度、准确度。分别采用牛奶与酒精1:1和1:2的两种方法检测,在20℃下检测奶样(原料乳和成品),测定不同pH值下酒精试验敏感性和稳定性的变化(用酒精度表示)。结果表明,无论是对于原料乳还是成品其酒精稳定性均随pH值的增加而增大,所以欲判断乳样新鲜程度应是由该乳样的pH值和酒精度两项指标所共同决定,而不是由酒精度这一项单一指标所决定:无论是对于原料乳还是成品其牛奶与酒精1:2的变异系数都明显小于牛奶与酒精1:1的变异系数,从而看出牛奶与酒精1:2大大提高了酒精试验的精确度、准确度。 相似文献
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乳铁蛋白是天然存在于人乳或牛奶中的一种含铁糖蛋白。据测定,人乳中乳铁蛋白的含量约为同量牛奶的10倍!营养学界认为,乳铁蛋白的主要作用是抗菌、抗病毒、消炎及增强机体免疫力等。这就是母乳喂养的婴儿不易生病的原因,母乳中含有的乳铁蛋白是优异的“天然抗菌蛋白”。早在20世纪40年代,西方研究人员在分离牛奶中的蛋白质类成分时,发现有一种浅红色的物质, 相似文献
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采用高效液相色谱法针对不同品牌巴氏杀菌乳中的糠醛类化合物质量分数展开研究,结果显示大部分巴氏杀菌乳中羟甲基糠醛质量分数在10μg/100 g牛奶以下,少部分品牌在15~30μg/100 g之间,糠醛质量分数均在3μg/100 g以下,未检测到2-呋喃甲基酮和甲基糠醛。进而选择3个巴氏杀菌乳产品,对其保质期内糠醛类化合物质量分数变化展开研究。随着储存时间的延长,巴氏杀菌乳中的糠醛类化合物质量分数整体呈现下降趋势。 相似文献
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牛奶的风味是评价牛奶品质的一项重要的感官指标。要获得风味纯正的原料乳,必须从牛奶的饲养、挤奶、贮运到乳品加工的各个环节加以管理控制。本文主要分析了原料乳不良风味的形成因素,并提出相应的控制措施,为牛场及乳品厂生产风味纯正的乳制品提供参考。原料乳正常风味形成机理 相似文献
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牛奶中混有血液和血红蛋白时,在临床上称为血乳。临床乳房炎发病比较急,主要以红肿热痛、机能障碍为特征,乳汁有明显的变化,奶量急剧下降、有絮状物、乳凝块、脓汁等,乳汁变稀,重者呈水样、甚至呈血样,机体伴有发烧、精神沉郁等,从而产生大量异常乳,如血乳。为了确保牛奶质量,有必要在原料乳收购过程中,进行血乳项目的检测,特别是乳房炎病等多发季节。本文对原方法中试剂配置方法进行改进研究,提高了检验效率,并降低了剧毒药品对试验人员的人身危害。本方法检出限为0.05mg/kg。 相似文献
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Figueroa-González I Quijano G Ramírez G Cruz-Guerrero A 《Journal of the science of food and agriculture》2011,91(8):1341-1348
Owing to their health benefits, probiotics and prebiotics are nowadays widely used in yogurts and fermented milks, which are leader products of functional foods worldwide. The world market for functional foods has grown rapidly in the last three decades, with an estimated size in 2003 of ca US$ 33 billion, while the European market estimation exceeded US$ 2 billion in the same year. However, the production of probiotics and prebiotics at industrial scale faces several challenges, including the search for economical and abundant raw materials for prebiotic production, the low-cost production of probiotics and the improvement of probiotic viability after storage or during the manufacturing process of the functional food. In this review, functional foods based on probiotics and prebiotics are introduced as a key biotechnological field with tremendous potential for innovation. A concise state of the art addressing the fundamentals and challenges for the development of new probiotic- and prebiotic-based foods is presented, the niches for future research being clearly identified and discussed. 相似文献
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常用消毒灭菌法及其机理与应用 总被引:3,自引:0,他引:3
介绍了采用消毒灭菌方法,有加热消毒法,紫外线辐射法和化学药剂消毒法。常用化学药剂有醛类、含氯消毒剂、醇类消毒剂以及高锰酸钾、生石灰等,阐释了消毒与灭菌两个概念的区别。 相似文献
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Wim Verbeke Federico J.A. Pérez-Cueto Marcia D. de Barcellos Athanasios Krystallis Klaus G. Grunert 《Meat science》2010
This paper presents the combined mid-term findings of the consumer research components of two EU Sixth Framework Programme integrated projects concerning meat, ProSafeBeef and Q-PorkChains. The consumer pillar of ProSafeBeef carried out eight focus group discussions in May 2008, in France, Germany, Spain and the UK. Q-PorkChains conducted a large-scale, web-based, consumer survey in January 2008 in Belgium, Denmark, Germany, Greece and Poland. The first project provides a set of qualitative data from a small cohort of focus groups and the second a set of quantitative data from a larger consumer sample. This paper draws together the main findings of both projects and provides a comprehensive overview of European citizens’ and consumers’ attitudes towards and preferences regarding beef and pork. In general, consumers consider meat to be a healthy and important component of the diet. Consumers support the development of technologies that can improve the health attributes of meat products and guarantee eating quality, but they have a negative view of what they see to be excessive manipulation and lack of naturalness in the production and processing of beef products. In the Q-PorkChains study consumer and citizen segments are identified and profiled. Consumer segments were built upon the frequency and variety of pork consumption. The citizen segments were built upon their attitudes towards pig production systems. Overall, the relationship between individuals’ views as citizens and their behaviour as consumers was found to be quite weak and did not appear to greatly or systematically influence meat-buying habits. Future studies in both projects will concentrate on consumers’ acceptance of innovative meat product concepts and products, with the aim of boosting consumer trust and invigorating the European beef and pork industries. 相似文献
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The objectives of the current study were to investigate the relationship between body condition score (BCS) and dairy form and changes in genetic parameters for BCS and dairy form within and across lactations and age. Body condition score and dairy form were obtained from the Holstein Association USA, Inc. Records were edited to include those cows classified between 24 and 60 mo of age and between 0 and 335 d in milk (DIM). A minimum of 20 daughters per sire and 15 cows per herd-classification visit were required. The dataset consisted of 135,178 records from 119,215 cows. Repeatability, multiple trait, and random regression models were used to analyze the data. All models included fixed effects for herd-classification visit, age within lactations 1, 2, and 3 or higher, and 5th-order polynomials for DIM. Random effects included sire and permanent environment for all models. Random regression models included age at classification nested within sire or DIM and lactation number nested within sire. Genetic variance for both BCS and dairy form was lowest in early lactation and highest in midlactation. Genetic correlations within and across lactations were high. The genetic correlation between DIM 0 in lactation 1 and DIM 305 in lactation 3 was estimated to be 0.77 for BCS and 0.60 for dairy form. The genetic correlation estimate between 30 mo of age at classification and 50 mo of age at classification was 0.94 for both dairy form and BCS. The repeatability models appeared to generate accurate evaluations for BCS or dairy form at all ages and stages of lactation. 相似文献
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酚类物质的结构与性质及其与葡萄及葡萄酒的关系 总被引:20,自引:0,他引:20
酚类物质是一类大而复杂的化合物。葡萄与葡萄酒中常见的酚类物质可分为类黄酮和非类黄酮两大类,它们是葡萄中重要的次生代谢产物,与葡萄的抗病性、采后生理、贮存、保鲜等密切相关。葡萄酒中的酚类物质来自于葡萄果实、果梗、酵母代谢以及橡木桶,参与形成葡萄酒的味道、骨架、结构和颜色等,对红葡萄酒的特征和质量尤其重要。 相似文献