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。     

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。     

低乳糖牛奶的工艺参数研究

研究了乳糖酶的特性及生产低乳糖牛奶的方法。乳糖酶(MaxilactL2000)水解的最适pH为6.6,最适温度为35℃,由于该温度亦是微生物生长的最适温度,故生产低乳糖牛奶的工艺参数定为6℃,以避免微生物对产品卫生质量的影响。通过实验及分析,确定工业化生产的最适条件是添加酶量为1.0‰,在6℃下水解20h。生产出的低乳糖牛奶,乳糖水解率达到70%以上,可以减少乳糖不耐受症状。     

酶法制备低乳糖牛奶的研究

该文主要研究探讨酶法生产低乳糖牛奶产品的工艺条件及配方。试验研究结果表明,乳糖酶加量为1500NLU/L、酶解时间3·0h,乳糖的水解率可达60%以上,可满足部分患有乳糖不耐症人群的需要,增加了牛奶制品的花色品种。     

低乳糖奶粉的研制

以牛乳为原料,应用来源于乳酸克鲁维酵母产生的乳糖酶（MAXILACT乳糖酶）对牛乳中的乳糖进行水解,经杀菌灭酶、真空浓缩、喷雾干燥,开发了具有营养和保健功效的低乳糖奶粉。MAXILACT乳糖酶最适水解条件pH值为6.6～6.8,水解温度30～40℃。结合乳糖酶在水解过程中,由于微生物对牛乳的影响,低乳糖奶粉生产过程中,牛乳的水解温度10℃,水解时间8 h,乳糖酶添加量0.8 g/L,牛乳经乳糖酶水解,其乳糖水解率达到60%以上。利用乳糖酶对牛乳进行乳糖水解,经杀菌灭酶、真空浓缩、喷雾干燥,在工艺上可行、技术上合理、设备上可操作,产品各项指标均达到低乳糖奶粉的质量指标。     

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。     

固定化乳糖酶制备低乳糖牛奶初步研究

本文利用实验室自制的固定化乳糖酶进行了制备低乳糖牛奶的初步研究。实验结果表明,制备的低乳糖牛奶乳糖的水解率达50％以上,口味香甜纯正,可以有效的预防人体乳糖不耐症的发生。     

帝斯曼创新食品配料与解决方案成就美好生活

<正>帝斯曼紧密关注健康潮流,不遗余力地在确保安全、营养、健康的前提下以绿色天然的方式保留与提升食品的天然美味,这一理念体现在其一系列产品中。针对乳糖不耐受或有消化问题的消费者,帝斯曼最新推出乳糖酶研究成果——Maxilact LGi和LAGX是两款具有创新意义的乳糖酶,可以为无乳糖或低乳糖产品提供最长时间的纯净口感。今年是帝斯曼公司作为乳糖酶Maxilact领先生产商的50周年纪念。帝斯曼是第一家为牛奶、冰淇淋、     

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。     

Growth of Pseudomonas weihenstephanensis,Pseudomonas proteolytica and Pseudomonas sp. in raw milk: Impact of residual heat-stable enzyme activity on stability of UHT milk during shelf-life

One of the reasons for spoilage of UHT milk during shelf-life is the presence of residual proteolytic activity produced from Pseudomonas spp. during storage of raw milk. The aim of this study was to describe the product defects occurring in indirectly heated UHT milk during shelf-life, and to establish a correlation between proteolytic activity and onset of product spoilage. UHT milk was produced from raw milk incubated with different Pseudomonas strains, and examined over four months during storage at 20 °C. Inactivation kinetics of the peptidases were determined. In UHT milk, product defects occurred in the order: bitterness – particles – creaming – sediment – gelation in all the samples containing peptidases (apparent enzyme activity ≥ 0.03 pkat mL⁻¹). A linear correlation was found between proteolytic activity and onset of product defects, apart from onset of gelation.     

超高温灭菌乳的主要质量问题及控制措施

本文对影响超高温灭菌乳质量的主要问题进行了阐述，其主要影响因素是原料乳的质量和超高温灭菌过程的几个重要方面。对超高温生产过程中的杀菌温度和保温时间，脱气和均质，无菌输送，无菌包装和无菌灌装阶段工艺设备进行分析，参照应用设备结构工艺特点，找出各阶段中影响超高温灭菌乳质量的主要因素，并提出控制措施。另一方面，对影响超高温灭菌乳质量的另一重要因素原料乳质量，根据乳的特性及采用的加工方法，提出控制措施，保证产品质量的稳定。     

PROGRESS AND DEVELOPMENT OF UHT MILK AND MILK PRODUCTS IN THE UK DAIRY INDUSTRY

The paper covers the history of UHT sales in the UK and explains reasons for the small sale of UHT milk. Sales are expected to rise significantly - more sterilized milk is being replaced by UHT, and skimmed milk and flavoured milks being promoted. UHT product sales are encouraging with cream, custards, desserts and ice-cream established. With continual price increases, caterers and shops would want to reduce waste and require non-perishable goods. UHT processing could be beneficial to dairies for doorstep delivery as well as shop sales. Particular mention is made of the success dairies have had with aseptically packed juice.     

Assessment of Brazilian consumers' perception about the presence of stabilisers in UHT milk: A study using virtual focus groups

Several countries use stabilisers in the product to avoid undesirable alterations, such as aggregation/gelation of proteins after thermal processing of UHT milk. Brazilian consumers' perception of these additives was investigated using virtual focus groups. Several relevant factors to the decision of consumers were elicited. The results show that most consumers do not have the habit of reading the UHT milk label and demonstrate a lack of knowledge about using stabilisers in UHT milk, even confusing it with preservatives. It is noted that the dairy sector must improve its communication strategies for UHT milk consumers.     

Proteolysis in ultra‐heat‐treated skim milk after exposure to multispecies biofilms under conditions modelling a milk tanker

Bacteria from milk tankers can form multispecies biofilms and produce heat‐stable enzymes. In this study, milk was exposed to multispecies biofilms in stainless steel vessels and was then used to produce ultra‐heat‐treated (UHT) milk, which was stored for 5 months. The UHT milks were assessed for microbial counts, free peptide concentration and pH. The free peptide concentration, which indicated proteolysis, was higher in UHT milk that had been exposed to multispecies biofilms than in untreated UHT milk. Biofilm formation may be promoted in milk tankers that are not properly cleaned, which may compromise the quality of the final dairy product.     

UHT Milk Processing—Effect on Process Energy Requirements

Energy requirements for processing milk using a free falling film steam infusion ultra-high temperature (UHT) sterilization process and a high temperature-short time (HTST) pasteurization process were determined and compared. Product flow rate was 2500 kg/hr. Milk to milk regeneration was used with both processes. UHT process temperatures were 138, 143, 149, and 154°C. The energy requirements for the UHT and HTST processes ranged between 573 and 667 kJ/kg milk and 217 and 228 kJ/kg milk, respectively. Although the UHT process consumed between 345 and 450 W/kg milk additional energy in the plant, the UHT sterilization of milk has been estimated to result in a net energy savings of 547 - 652 kJ/kg milk because the product does not require post-processing refrigeration.     

中小型乳品厂UHT奶的二次污染问题原因探讨

本文主要从设备的角度以实例探讨了我国中小型乳品厂无菌包装鲜奶超高温灭菌后受到二次污染的主要原因。针对这些原因，提出了解决办法，从而在生产过程中严格检查和控制这些关键点，以防止UHT鲜奶的二次污染。     

基于ASP的UHT奶安全可追溯网络化系统的研究

在UHT奶产业链调研分析总结的基础上，利用网络数据库技术设计建立了网络化的UHT奶安全可追溯系统。该系统采用浏览器与Web服务器技术（B／S结构），客户端是浏览器，不需要其他客户端设备。利用DrearnweaverMX2004开发系统网络界面，通过ASP和SQLServer网络数据库技术把安全追溯系统放在互联网上．奶牛场和加工企业通过网络上传收集的追溯信息．储存到企业服务器数据库。加工厂可以通过浏览器快速再现单个产品详细的生产信息．快速确定此产品原料乳的来源和同批次产品去向。即时发现UHT奶产业链中存在的问题，更好的保证产品的质量安全：奶牛场可以快速查询原料乳的生产和验收信息，及时掌握奶牛的产奶情况；消费者可以方便快速的查询所买单个产品的相关信息。增强了UHT奶产业链的透明度，保障消费者的合法权益。     

嗜冷茵对UHT奶品质影响的研究

嗜冷菌产生耐热蛋白酶和脂肪酶是UHT奶在长期存放过程中产生劣变的主要原因之一。原料乳中蛋白酶、脂肪酶的活性与产品长期保存时的品质呈负相关。通过控制原料奶乳中嗜冷菌数,测定蛋白酶和脂肪酶活力,对原料奶进行分级和评价是确保UHT奶品质的一种有效手段,本实验为乳品企业嗜冷菌的检测提供了理论依据。     

高效液相色谱-四级杆/静电场轨道阱质谱法鉴别 复原乳的掺假

目的以高效液相色谱-四级杆/静电场轨道阱质谱为检测平台,研究巴氏灭菌乳、UHT乳和复原乳中全部内源性物质的变化。方法首先建立乳制品的总离子流色谱图,运用SIMCA软件结合模型方法对数据进行分析,建立复原乳和非复原乳的主成分分析模型和正交偏最小二乘-判别分析模型。结果主成分分析得分图的结果显示,巴氏灭菌乳、UHT乳和复原乳的指纹图谱间存在一定差异。正交偏最小二乘-判别分析模型的S-plot和变量重要性因子筛选出对分类影响显著的物质。其中正、负离子模式分别筛选出18种和8种可能与复原乳相关的标志物。结论本研究所选标志物能够为复原乳的掺假鉴别研究提供参考依据,为执法部门的监督工作提供技术支持。这些标记物的结构鉴定仍有待研究。