加工工艺对糙米乳稳定性及主要品质的影响

为解决储存过程中糙米乳淀粉、蛋白质、纤维素沉淀及脂肪等小分子的上浮,导致的产品分层及沉淀问题,采用酶解、离心、胶体磨或均质等工艺处理来改善产品的组织状态,提高其稳定性。经α-淀粉酶、糖化酶、纤维素酶及蛋白酶酶解后,糙米乳的稳定性得到改善;采用卧式螺旋卸料沉降离心机对糙米乳进行离心处理,其最佳离心参数为主机频率38 Hz,副机频率35 Hz;随着胶体磨处理时间的延长,糙米乳悬浮稳定性逐渐增加,离心沉淀率逐渐降低,当处理时间超过3 min后,糙米乳的悬浮稳定性与离心沉淀率变化放缓;在20 MPa压力下均质2次,糙米乳的悬浮稳定性与离心沉淀率均达到最佳;且糙米乳营养全面、滋味良好,其理化指标符合QB/T 4221—2011《谷物类饮料》的要求。     

提高花生乳(奶)乳化稳定性的技术措施

花生乳是风味独特、营养丰富的植物蛋白饮料，但其产品稳定性差，常出现乳液分层，甚至沉淀，影响产品质量。针对上述问题提出提高花生乳(奶)乳化稳定性的技术措施。     

乳酸发酵糯米汁莲浆豆乳饮料的工艺研究

以大豆、糯米、莲子为原料，用嗜热乳链球菌和保加利亚乳杆菌（１：１）的混合菌种为发酵剂，制得一种新型的营养保健性植物乳酸奶。实验初步探讨了该饮料的主要制作工艺，确定了最佳发酵条件。同时针对该饮料易发生沉淀、分层等现象，实验选用ＰＧＡ、Ｃ．Ｍ．Ｃ作稳定剂，较为成功地解决了饮料的稳定性问题。     

玉米豌豆全谷物复合汁悬浮稳定性的研究

以鲜嫩黄玉米、黄豌豆为原料,开发出玉米、豌豆营养健康全谷物复合汁。研究了玉米、豌豆淀粉的有限酶法水解、高压均质等工艺条件对全谷物复合汁悬浮稳定性的影响。结果表明:α-淀粉酶有限水解玉米、豌豆淀粉可降低全谷物复合汁的沉淀系数,增加悬浮稳定性。随着均质压力和均质时间的增加,复合汁的上浮系数和沉淀系数均减小。经过酶解(α-淀粉酶用量4U/g汁,时间50min)、均质(压力40MPa,时间20min)等工艺制备的全谷物复合汁具有良好的悬浮稳定性,25℃贮存60d后上浮系数和沉淀系数分别为3.15%和2.3%。     

黑米双歧酸奶的研制

该产品以黑米为原料，应用乳酸菌和双歧杆菌混合发酵。发酵温度43℃，时间6小时，产品不仅保留了黑米原有的营养成份和天然芳香，而且酸甜适口，含有一定的话菌数。该工艺简便可行。     

黑米双歧酸奶的研制

该产品以黑米为原料，应用乳酸菌和双歧杆菌混合发酵。发酵温度４３℃，时间６小时，产品，不仅保留发黑米原有的营养成份和天然芳香，而且酸甜适口，含有一定的活菌数。该工艺简便可行。     

浓香型花生乳的研制

研究花生品种、焙烤火候、稳定剂种类以及均质、杀菌工艺条件对产品风味、稳定性的影响。结果表明：花生品种四粒红、鲁花因脂肪含量较高，做出的产品口感浓香；180℃，30min焙烤的花生，色泽焦黄，口感香而不糊；稳定剂选择具有悬浮作用的胶体配合合适的乳化剂，均质压力选择30MPa两遍均质后，可保证产品在18个月内，无明显脂肪上浮及沉淀；121℃／30min高温灭菌，保证产品风味及稳定性的基础上，使产品达到商业无菌的要求。     

巴氏杀菌乳生产工艺的研究

介绍了巴氏杀茵乳的生产工艺，针对乳制品中易出现蛋白质沉淀和脂肪上浮等现象，选择了合适的生产工艺及复合乳化稳定剂，以提高产品稳定性及产品档次。结果表明，当酪朊酸钠的用量为0．1％，CMC0.1％，PGA0．05％时，巴氏杀菌乳的稳定性最好；当杀菌温度为70℃，10min时，杀菌效果最为理想。     

果蔬蛋白营养饮品的工艺研究

以西番莲、胡萝卜、牛奶为主要原料，经科学配方并强化多种维生素、矿物质研制成一种果蔬复合型高营养饮料。在工艺上主要解决了酸性乳饮料因蛋白质含量高而出现沉淀和分层、杀菌及维生素保存的问题。     

花生蛋白肽对核桃乳贮藏稳定性的影响

以核桃乳质量为基准,添加0.1％、0.2％、0.3％的花生蛋白肽添加到核桃乳中,探索花生蛋白肽对核桃乳乳化稳定性以及氧化稳定性的影响,测定了核桃乳的脂肪上浮率、离心沉淀率、黏度、分层指数、粒径以及脂质氧化程度.结果表明:随着储藏时间的增加,核桃乳的稳定性下降,添加花生蛋白肽能够显著降低核桃乳的脂肪上浮率和离心沉淀率、增...     

液态羊乳的加工研究进展

进入营养健康时代,消费需求不断升级,功能、营养、个性化的产品越来越受到重视。羊乳一直是人类营养的重要组成部分,与牛乳相比,羊乳的营养价值相对较高,凝乳的形成更柔软,乳脂肪小球的比例更高,致敏性低,与人乳更接近,是许多重要营养素的良好膳食来源。除了羊乳的许多有益作用外,饲养山羊和绵羊的优势,如动物成本较低、对饲料和水的需求较少及通常不需要大型牲畜所需的专门住房,也是促进全球羊乳生产改善的原因。然而,羊乳的热稳定性差,加工和贮藏过程中容易出现蛋白变性、沉淀、结块等质量缺陷,常温加工技术仍不成熟、货架期品质稳定性亟待提升。因此,本文对液态羊乳的加工技术、加工现状以及发展动态进行综述,为进一步开发常温液态羊乳奠定理论基础。     

Evaluation of increased vitamin D fortification in high-temperature, short-time-processed 2% milk, UHT-processed 2% fat chocolate milk, and low-fat strawberry yogurt

The objective of this study was to determine the effect of increased vitamin D fortification (250 IU/serving) of high-temperature, short-time (HTST)-processed 2% fat milk, UHT-processed 2% fat chocolate milk, and low-fat strawberry yogurt on the sensory characteristics and stability of vitamin D during processing and storage. Three replicates of HTST pasteurized 2% fat milk, UHT pasteurized 2% fat chocolate milk, and low-fat strawberry yogurt were manufactured. Each of the 3 replicates for all products contained a control (no vitamin D fortification), a treatment group with 100 IU vitamin D/serving (current level of vitamin D fortification), and a treatment group with 250 IU vitamin D/serving. A cold-water dispersible vitamin D₃ concentrate was used for all fortifications. The HTST-processed 2% fat milk was stored for 21 d, with vitamin D analysis done before processing and on d 0, 14, and 21. Sensory analysis was conducted on d 14. The UHT-processed 2% fat chocolate milk was stored for 60 d, with vitamin D analysis done before processing and on d 0, 40, and 60. Sensory analysis was conducted on d 40. Low-fat strawberry yogurt was stored for 42 d, with vitamin D analysis done before processing, and on d 0, 28, and 42. Sensory analysis was conducted on d 28. Vitamin D levels in the fortified products were found to be similar to the target levels of fortification (100 and 250 IU vitamin D per serving) for all products, indicating no loss of vitamin D during processing. Vitamin D was also found to be stable over the shelf life of each product. Increasing the fortification of vitamin D from 100 to 250 IU/serving did not result in a change in the sensory characteristics of HTST-processed 2% fat milk, UHT-processed 2% fat chocolate milk, or low-fat strawberry yogurt. These results indicate that it is feasible to increase vitamin D fortification from 100 to 250 IU per serving in these products.     

Buffalo milk fat globules and their biological membrane: in situ structural investigations

Milk fat globules and their surrounding biological membrane (the MFGM) are not well understood despite the importance of these milk components in human nutrition and the role of fat globules in determining the properties of dairy products. The objectives of this study were to investigate these unique colloidal assemblies and the microstructure of the MFGM in buffalo milk, which is the second largest global source of dairy products. In-situ structural investigations were performed at room temperature using confocal microscopy with multiple fluorescent probes (Nile Red, Rh-DOPE, the lectin WGA-488). Microscopic observations showed cytoplasmic crescents around fat globules and the heterogeneous distribution of glycosylated molecules and polar lipids with the occurrence of lipid domains. The lipid domains in the buffalo MFGM appear to form by the segregation of lipids with a high phase transition temperature (e.g. sphingomyelin and saturated phosphatidylcholine molecular species) and cholesterol resulting in a gel phase or a Lo phase forming circular domains. The structure of the buffalo MFGM results from a non-random mixing of components, consistent with observations for other species. Structural heterogeneities of the MFGM could affect the processability of buffalo fat globules and the bioavailability of milk lipids.     

Effects of ultrasound on the fermentation profile of fermented milk products incorporated with lactic acid bacteria

Ultrasonic processing of fermented milk products has created much interest in current research on dairy products. This has been employed in cultured milk products to enhance the emulsification of milk fat and to intensify the fermentation process. Benefits including remarkable product stability, reduced processing time and enhanced quality are being recorded. Ultrasound (US) altered the colour and flavour profile of milk; however, the effect of US-induced fermentation on the synthesis of flavour compounds in milk has not been reported in the literature. This review paper presents a comprehensive scenario on the impact of power US on the fermentation profile and quality of ultrasonically processed dairy products. A theoretical background on US and details of its effect on the metabolic performance of lactic acid bacteria are presented. Finally, it describes how the quality attributes of fermented milk gels are modified due to the intensification of the fermentation process with US.     

绵羊奶组成和营养特性

绵羊奶是我国乳制品工业的"新增量",养殖规模和产奶量快速上升,然而,我国目前的绵羊奶产业水平还处于初级阶段,规模化加工制品几乎为零.绵羊奶营养价值高,总固形物在各种乳源中含量最高,除了具有较高含量的蛋白质、脂肪、矿物质和维生素以外,绵羊奶的活性功能因子丰富,乳铁蛋白、活性肽、乳脂肪球膜及低聚糖的组成、含量和生物活性与牛...     

Effects of milk powders in milk chocolate

The physical characteristics of milk powders used in chocolate can have significant impact on the processing conditions needed to make that chocolate and the physical and organoleptic properties of the finished product. Four milk powders with different particle characteristics (size, shape, density) and "free" milk fat levels (easily extracted with organic solvent) were evaluated for their effect on the processing conditions and characteristics of chocolates in which they were used. Many aspects of chocolate manufacture and storage (tempering conditions, melt rheology, hardness, bloom stability) were dependent on the level of free milk fat in the milk powder. However, particle characteristics of the milk powder also influenced the physical and sensory properties of the final products.     

非热加工技术在低或无致敏婴幼儿配方粉中应用的研究进展

牛乳营养丰富，对婴幼儿来说，是母乳较好的替代品，绝大多数婴幼儿配方粉都是基于牛乳制备的，非热加工技术在降低牛乳过敏原致敏性，减少营养成分损失等方面表现出较多优势。本文介绍了牛乳中主要过敏原的结构和B细胞表位，总结了低或无致敏婴儿配方粉的研究进展，重点阐述了非热加工技术包括高压、微波、发酵及其与酶解联合处理对乳蛋白致敏性的影响，以及在婴幼儿配方粉中的应用，并对其未来的发展做出了展望，以期能够为营养充足、适口、低或无致敏性新型婴幼儿配方粉的开发提供理论依据。     

Major advances in concentrated and dry milk products, cheese, and milk fat-based spreads

Advances in dairy foods and dairy foods processing since 1981 have influenced consumers and processors of dairy products. Consumer benefits include dairy products with enhanced nutrition and product functionality for specific applications. Processors convert raw milk to finished product with improved efficiencies and have developed processing technologies to improve traditional products and to introduce new products for expanding the dairy foods market. Membrane processing evolved from a laboratory technique to a major industrial process for milk and whey processing. Ultra-filtration and reverse osmosis have been used extensively in fractionation of milk and whey components. Advances in cheese manufacturing methods have included mechanization of the making process. Membrane processing has allowed uniform composition of the cheese milk and starter cultures have become more predictable. Cheese vats have become larger and enclosed as well as computer controlled. Researchers have learned to control many of the functional properties of cheese by understanding the role of fat and calcium distribution, as bound or unbound, in the cheese matrix. Processed cheese (cheese, foods, spreads, and products) maintain their importance in the industry as many product types can be produced to meet market needs and provide stable products for an extended shelf life. Cheese delivers concentrated nutrients of milk and bio-active peptides to consumers. The technologies for the production of concentrated and dried milk and whey products have not changed greatly in the last 25 yr. The size and efficiencies of the equipment have increased. Use of reverse osmosis in place of vacuum condensing has been proposed. Modifying the fatty acid composition of milkfat to alter the nutritional and functional properties of dairy spread has been a focus of research in the last 2 decades. Conjugated linoleic acid, which can be increased in milkfat by alteration of the cow's diet, has been reported to have anticancer, anti-atherogenic, antidiabetic, and antiobesity effects for human health. Separating milk fat into fractions has been accomplished to provide specific fractions to improve butter spreadability, modulate chocolate meltability, and provide texture for low-fat cheeses.     

天然牛乳脂肪分离及应用研究进展

牛乳脂肪(乳脂)是一种天然的牛奶成分,主要加工成稀奶油、奶油和奶油粉等产品,具有良好的风味和营养价值。随着人们对乳脂营养价值及风味的认识更为全面,我国天然乳脂消费和加工逐年增加。为了扩大乳脂产品的应用范围,越来越多的改性技术被用于优化乳脂类产品,本文对适用于乳脂的不同物理改性技术进行了综述,着重探讨以干法分提为主的现有改性技术中存在的问题和局限,并概述了干法分提技术在奶油产品中的应用,从而为乳脂深加工提供参考。     

Factors affecting the concentration of sphingomyelin in bovine milk

Sphingomyelin is a phospholipid located in the outer leaflet of the plasma membrane of most cells and is a component of the milk fat globule membrane. Sphingomyelin and its digestion products participate in several antiproliferative pathways that may suppress oncogenesis. Although milk and dairy products are important sources of sphingomyelin in the human diet, little is known about factors that influence sphingomyelin concentrations in milk fat or whether concentrations can be modified via the nutrition of cows. Sphingomyelin concentrations were determined in milk from Holstein and Jersey cows matched for parity and stage of lactation. Sphingomyelin was more concentrated in milk fat from Holstein cows than in milk fat from Jersey cows (1,044 vs. 839 μg/g of fat). Concentrations in whole milk did not differ because of greater milk fat content for milk from Jerseys. Differences between breeds may be related to the greater fat globule size in milk from Jerseys. Sphingomyelin content in whole milk increased with increasing days in milk because of associated increases in milk fat content. Regardless of breed, primiparous cows had greater amounts of stearic acid and less palmitic acid in sphingomyelin than did older cows. The sphingomyelin concentration in milk fat of cows in a commercial Jersey herd was lower for cows in their fourth or greater parity. Sphingomyelin content in whole milk was greater for cows in late lactation because of greater milk fat content. Feed restriction of multiparous Holstein cows to 37% of ad libitum dry matter intake increased milk fat content but did not affect milk sphingomyelin content or milk fat globule size. Supplementation of the diet with 4% soybean oil did not affect milk composition, sphingomyelin content, or milk fat globule size. Milk was sampled seasonally from 7 herds throughout Illinois during a 2-yr period. Sphingomyelin concentration in milk fat was greatest during summer and least during winter, but whole milk concentrations did not vary across seasons. We conclude that 1) sphingomyelin content of milk fat is greater in milk from Holsteins than that from Jerseys, 2) sphingomyelin content in whole milk increases with stage of lactation, and 3) sphingomyelin content of milk fat is greater during summer. However, efforts to produce milk with a greater sphingomyelin content through altering management and nutrition are unlikely to be successful.