低乳糖牛奶生产工艺参数的研究

针对乳糖酶缺乏者的乳糖不耐受问题，研究如何生产乳糖水解率为60％以上的低乳糖牛奶。通过38，20，6℃不同水解温度，0．5，0．8，1．0，1．5g／kgN同乳糖酶添加量，不同作用时间等因素的单因素试验，确定了制作低乳糖牛奶的工艺参数。     

一种新型乳糖酶在制备低乳糖牛奶中的应用研究

目的通过检测一种新型乳糖酶在不同条件下对牛乳中乳糖的水解率,研究其在制备低乳糖牛奶的最适条件。方法产乳糖酶基因工程菌株发酵并提取乳糖酶,分别在10,25和37℃条件下按不同比例添加该新型乳糖酶液,使用HPLC检测其乳糖水解率。结果该酶在10℃（0．9％）水解率可达83％以上,25℃（0．9％）水解率93％以上,37℃（0.3％）水解率94％以上。结论该酶在低温下具有良好的乳糖水解率,在工业上具有广阔的应用前景。     

低乳糖牛奶的研究开发

为解决乳糖不耐症,采用两种乳糖酶分解牛乳中的乳糖,并测试其酶解率,同时对低乳糖乳的生产工艺进行了探讨。实验结果表明,对于液体乳糖酶:在30℃下,用量为0.010%、0.025%、0.050%时经过4、2和1h后可将还原乳中的乳糖水解到70%左右;在低温4℃下、0.025%的液体酶经过12h后也能达到同样的效果。对于固体酶,在39℃下,酶的添加量为0.060%、0.090%、0.120%时,分别经过3.5、3和2h的振荡酶解后,乳糖的水解率也可达到70%以上。     

乳清白酒发酵工艺的研究

利用乳清中的乳糖及丰富的营养物质，将乳清与黑龙江传统白酒酿造原料玉米混合发酵，提高白酒出酒率并改善白酒风味。乳糖水解条件：乳糖酶0．3U／kg，水解温度35℃，水解时间为3h，水解率可达57．23％。酵母菌发酵温度28℃，接菌量0.7％。白酒出酒率从40％提高到61％，口感得到明显改善。     

酶法生产低乳糖牛奶的工艺条件研究

采用正交实验考察低乳糖牛奶生产过程中乳糖酶用量、酶解时间、酶解温度以及pH值4个因素对乳糖水解率的影响,最终确定乳糖酶用量为1500NLU/L、水解时间为3h、水解温度为38℃、pH为6.8,此时乳糖水解率达到75.2%,酸度与微生物指标也符合要求。同时改进了低乳糖牛奶的后段加工工艺,解决了产品褐变严重的问题。     

酶解制备低乳糖牛奶的优化研究

针对低乳糖牛奶制备中的酶解工艺进行优化研究,采用正交试验设计考察了乳糖酶用量、酶解时间、酶解温度和pH等因素对乳糖水解率的影响。试验结果表明,最佳酶解工艺条件为：乳糖用量4000Nlu/L,酶解时间3h,酶解温度39℃,pH6.8,乳糖水解率可达76.6%,达到生产低乳糖牛奶产品的要求,满足乳糖不耐受症患者的需求。     

气相色谱法快速测定牛奶中脂肪酸

牛奶中高级脂肪酸经甲酯化后，利用气相色谱法测定，结果表明十二碳以上的长链脂肪酸的线性范围好，相关系数为r=0．9991以上，回收率在89．0％～109％之间。方法简便，快速。     

柱前衍生化HPLC法分析牛奶中乳糖动态水解研究

采用1-苯基-3-甲基5-吡唑啉酮（PMP）对牛奶中的糖类进行衍生化处理，将其转化成紫外光下具有强吸收的物质．从而能利用高效液相法快速准确地监测牛奶中乳糖酶的动态水解趋势。结果表明，乳糖酶水解牛奶乳糖的最佳时间为3—4h．并且发现该方法可以直接用于乳糖含量的分析，为低乳糖奶制品的研究开发和检测分析提供参考。     

低乳糖牛奶的研制

本文主要研究探讨了低乳糖牛奶产品的配方组成及其生产工艺条件等。实验研究结果表明，该产品具有营养丰富全面、口味香甜纯正以及稳定性能良好和无褐变等特点，其乳糖的水解率高达70％以上，可以有效的预防人体乳糖不耐症的发生。     

低乳糖牛奶的研制

本文主要研究探讨了低乳糖牛奶产品的配方组成及其生产工艺条件等。实验研究结果表明，该产品具有营养丰富全面、口味香甜纯正以及稳定性能良好和无褐变等特点，其乳糖的水解率高达70％以上，可以有效的预防人体乳糖不耐症的发生。     

乳糖在人体内的营养特性

乳糖是乳中惟一的碳水化合物,最易被人体吸收,被人体吸收后可变成多肽、氨基酸和脂肪酸,从而提高乳蛋白和乳脂的利用率。由于乳糖酶的缺乏,许多患有乳糖不耐受的人不能食用乳制品。从乳糖的含量、乳糖的消化代谢过程和乳糖不耐受的分类以及乳糖的营养功能进行阐述。     

酵母乳糖酶对牛乳乳糖水解作用的研究

采用乳酸克鲁维酵母的乳糖酶(β-乳糖苷酶)对乳糖溶液、喷雾干燥脱脂奶以及全脂奶进行了试验,以确定将乳糖转化成单糖的最适条件。当牛奶中酶浓度为3u/ml时,于40℃反应2小时或4℃反应24小时,约60％的乳糖得以水解。随着乳糖浓度的增高,水解程度也有所提高。当酶浓度为10U/ml时,于40℃反应2小时,90％乳糖得以水解。用自制的乳酸克鲁维酵母的乳糖酶和加拿大lactaid Inc.生产的乳糖酶制剂lactaid水解乳糖无大的差异。     

Factors affecting variations in the detailed fatty acid profile of Mediterranean buffalo milk determined by 2-dimensional gas chromatography

Buffalo milk is the world's second most widely produced milk, and increasing attention is being paid to its composition, particularly the fatty acid profile. The objectives of the present study were (1) to characterize the fatty acid composition of Mediterranean buffalo milk, and (2) to investigate potential sources of variation in the buffalo milk fatty acid profile. We determined the profile of 69 fatty acid traits in 272 individual samples of Mediterranean buffalo milk using gas chromatography. In total, 51 individual fatty acids were identified: 24 saturated fatty acids, 13 monounsaturated fatty acids, and 14 polyunsaturated fatty acids. The major individual fatty acids in buffalo milk were in the order 16:0, 18:1 cis-9, 14:0, and 18:0. Saturated fatty acids were the predominant fraction in buffalo milk fat (70.49%); monounsaturated and polyunsaturated fatty acids were at 25.95 and 3.54%, respectively. Adopting a classification based on carbon-chain length, we found that medium-chain fatty acids (11–16 carbons) represented the greater part (53.7%) of the fatty acid fraction of buffalo milk, whereas long-chain fatty acids (17–24 carbons) and short-chain fatty acids (4–10 carbons) accounted for 32.73 and 9.72%, respectively. The n-3 and n-6 fatty acids were 0.46 and 1.77%, respectively. The main conjugated linoleic acid, rumenic acid, represented 0.45% of total milk fatty acids. Herd/test date and stage of lactation were confirmed as important sources of variation in the fatty acid profile of buffalo milk. The percentages of short-chain and medium-chain fatty acids in buffalo milk increased in early lactation (+0.6 and +3.5%, respectively), whereas long-chain fatty acids decreased (?4.2%). The only exception to this pattern was butyric acid, which linearly decreased from the beginning of lactation, confirmation that its synthesis is independent of malonyl-CoA. These results seem to suggest that in early lactation the mobilization of energy reserves may have less influence on the fatty acid profile of buffalo milk than that of cow milk, probably due to a shorter and less severe period of negative energy balance. Parity affected the profiles of a few traits and had the most significant effects on branched-chain fatty acids. This work provided a detailed overview of the fatty acid profile in buffalo milk including also those fatty acids present in small concentrations, which may have beneficial effects for human health. Our results contributed also to increase the knowledge about the effects of some of the major factors affecting buffalo production traits and fatty acid concentrations in milk, and consequently its technological and nutritional properties.     

婴儿配方乳粉中必需脂肪酸调配的研究

通过对婴儿配方乳粉中必需脂肪酸调配的研究实验，引用正交实验，得出最佳结果：按棕榈油10％、玉米油0．4％、葵花籽油0．4%、椰子油0．4％(均为质量分数)的比例进行油脂复配时，可使婴儿配方乳粉中亚油酸含量为34．10mg／g，亚麻酸含量为3．30mg／g，亚油酸和亚麻酸的比例在10：1(质量比)的范围，使配方粉中必需脂肪酸的含量和比例接近母乳，产品的综合评定最佳。     

马奶和成熟母乳甘油三酯中脂肪酸组成及分布

脂肪酸的组成和位置分布影响乳脂肪的物理和营养特性。本文测定了马奶和母乳总脂肪酸组分并且通过脂肪酶水解马奶和母乳脂肪,薄层色谱分离出2-甘油一酯,甲酯化后气相色谱测定了母乳和马奶中sn-2脂肪酸。结果表明,母乳中棕榈酸、油酸、亚油酸含量分别为19.07%、36.43%、23.73%,马奶中含量分别为24.47%、17.40%、4.78%。母乳sn-2位脂肪酸中饱和脂肪酸占59.41%,其中含棕榈酸48.36%,肉豆蔻酸6.00%,马奶sn-2位脂肪酸中饱和脂肪酸占71.46%,含棕榈酸47.00%,肉豆蔻酸12.48%。母乳脂肪酸的分布并非随机的,马奶脂肪酸分布类似于母乳,为母乳脂肪替代物的研究提供一定的数据支持及底物参考。     

母乳、牛乳及山羊乳脂肪酸组成的差异分析

采用气质联用法(GC-MS)测定东北区域不同泌乳期的母乳及牛乳和山羊乳常乳脂肪酸组成,并对其组成和含量进行差异分析,旨在为母乳脂质组学及以牛羊乳为基质的婴儿配方食品提供一定的理论基础。结果表明:母乳中主要脂肪酸为棕榈酸、油酸、亚油酸等,其中油酸含量最为丰富。饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)含量在不同泌乳期存在差异,其中SFA差异显著(p<0.05),初乳、过渡乳和成熟乳SFA含量分别为36.16%、37.89%、38.10%。牛乳和山羊乳主要以SFA为主,山羊乳SFA含量最高(69.07%),SFA中辛酸和癸酸是羊乳的特征脂肪酸,其含量显著高于母乳和牛乳(p<0.05)。山羊乳中中链脂肪酸(MCFA)含量最高(21.03%),是牛乳的1.5倍。其中,母乳SFA:MUFA:PUFA的比例为1.41:1.29:1,牛乳为19.12:9.98:1,山羊乳为11.14:3.98:1,山羊乳脂肪酸组成在比例上更加接近母乳。山羊乳在婴儿配方食品开发方面有更高的优势和开发空间。     

Survey of the fatty acid composition of retail milk in the United States including regional and seasonal variations

Consumers are increasingly aware that food components have the potential to influence human health maintenance and disease prevention, and dietary fatty acids (FA) have been of special interest. It has been 25 years since the last survey of US milk FA composition, and during this interval substantial changes in dairy rations have occurred, including increased use of total mixed rations and byproduct feeds as well as the routine use of lipid and FA supplements. Furthermore, analytical procedures have improved allowing greater detail in the routine analysis of FA, especially trans FA. Our objective was to survey US milk fat and determine its FA composition. We obtained samples of fluid milk from 56 milk processing plants across the US every 3 mo for one year to capture seasonal and geographical variations. Processing plants were selected based on the criteria that they represented 50% or more of the fluid milk produced in that area. An overall summary of the milk fat analysis indicated that saturated fatty acids comprised 63.7% of total milk FA with palmitic and stearic acids representing the majority (44.1 and 18.3% of total saturated fatty acids, respectively). Unsaturated fatty acids were 33.2% of total milk FA with oleic acid predominating (71.0% of total unsaturated fatty acids). These values are comparable to those of the previous survey in 1984, considering differences in analytical techniques. Trans FA represented 3.2% of total FA, with vaccenic acid being the major trans isomer (46.5% of total trans FA). Cis-9, trans-11 18:2 conjugated linoleic acid represented 0.55% total milk FA, and the major n-3 FA (linolenic acid, 18:3) composed 0.38%. Analyses for seasonal and regional effects indicated statistical differences for some FA, but these were minor from an overall human nutrition perspective as the FA profile for all samples were numerically similar. Overall, the present study provides a valuable database for current FA composition of US fluid milk, and results demonstrate that the milk fatty acid profile is remarkably consistent across geographic regions and seasons from the perspective of human dietary intake of milk fat.     

驼、牛、羊乳中脂肪酸含量的比较分析

采用气相色谱法对驼、牛、羊乳3 种乳中脂肪酸（fatty acids,FA）种类及含量进行比较。结果表明,3 种乳脂肪酸种类和含量差异显著。驼乳检测出33 种脂肪酸,棕榈酸相对含量最高（（23.73±2.17）%）;驼乳的多不饱和脂肪酸（polyunsaturated fatty acids,PUFA）相对含量（（4.09±0.54）%）显著高于牛乳和羊乳;牛乳中检测出29 种脂肪酸,棕榈酸相对含量最高（（27.44±2.45）%）;羊乳检测出34 种脂肪酸,且油酸相对含量最高（（30.89±3.57）%）。3 种乳中羊乳单不饱和脂肪酸（monounsaturated fatty acids,MUFA）含量最高（（35.26±3.86）%）。此外,结合主成分分析和相关性分析方法,对驼乳的脂肪酸含量进行进一步分析,结果显示,驼乳的饱和脂肪酸（saturated fatty acids,SFA）∶MUFA∶PUFA为1∶0.60∶0.08,驼乳更接近联合国粮食及农业组织/世界卫生组织推荐SFA∶MUFA∶PUFA为1∶1∶1。PUFA与短链脂肪酸（short-chain fatty acids,SCFA）、长链脂肪酸（long-chain fatty acids,LCFA）呈负相关,与n-6 FA相关性最大（0.978）;SCFA与LCFA呈正相关,n-6 FA与n-3 FA呈正相关。     

牦牛乳脂肪酸组成分析

乳脂的营养价值很高,牦牛乳中含有大量的脂肪酸,主要脂肪酸为辛酸、月桂酸、肉豆蔻酸、十五碳酸、棕榈酸、棕榈油酸、珍珠酸、硬脂酸、油酸、亚油酸、亚麻酸.目前脂肪的提取方法和甲酯化方法没有确定统一的方案,本研究对牦牛乳采用不同的脂肪提取方法和甲酯化方法,旨在找到分析牦牛乳中主要脂肪酸的最佳方案.乳脂肪酸的组成直接影响乳的营养、风味以及加工品质,乳脂肪酸功能及乳脂肪酸组成的调控成为当前反刍动物营养研究的热点,因此分析牦牛乳中脂肪酸的组成,对于认识其营养价值具有重要意义.     

Kidney bean (Phaseolus vulgaris L.) milk substitute as a novel plant-based drink: Fatty acid profile,antioxidant activity,in-vitro phenolic bio-accessibility and sensory characteristics

Recently, plant-based milk alternatives have gained popularity due to healthy food trends, sustainability concerns, and environmental repercussions. The current study is unique for the investigation of in vitro phenolic bioaccessibility, fatty acid composition, and sensory evaluation of plant-based milk from two different local kidney bean varieties grown in Turkey, oval and cherry. Kidney bean milk had 1.92–2.32% protein, which was slightly greater than other commercial plant-based milk alternatives. The majority of the fatty acids in the samples were α-linolenic acid (25.66–27.78%) and palmitic acid (18.95–23.08%). The total antioxidant capacity bio-accessibility of kidney bean milk was 154%–295% by cupric reducing antioxidant capacity (CUPRAC) and 50%–186% by α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging method while the total phenolic content bio-accessibility varied between 207%–266%. Overall acceptance of kidney bean milks varied between 2.9 and 4.1 out of 10. These findings presented that kidney bean milk is an alternative for the food industry with its rich bio-accessible antioxidant capacity and fatty acid profile although intense beany flavor detected during sensory analysis.