母乳化奶粉发展概况

近年,新型母乳化奶粉在国外颇为流行,但存在一些问题:①对婴儿营养学和人乳物理学、化学和生理学知识不足,一定程度限制母乳化程度。②生产成本相对较高。③生理活性和某些特殊成分上模拟人乳程度不够。我国五十年代出现糕干粉、奶糕等品种,七十年代才有婴儿配方乳粉Ⅰ,八十年代市场上出现婴儿配方乳粉Ⅱ(母     

不同加工工艺对婴儿配方奶粉中唾液酸存在形态的影响

人乳中唾液酸含量丰富,它对婴儿成长发育起到重要作用。然而,国内对于婴儿配方奶粉中唾液酸添加的工艺研究几乎没有开展。为了使婴儿配方奶粉中的唾液酸含量更接近人乳,本研究采用干法和湿法两种加工工艺将游离唾液酸添加到婴儿配方奶粉中,确定了两种加工工艺的婴儿配方奶粉中游离唾液酸的添加量范围,并且根据人乳中唾液酸存在模式,选择了最佳添加量。结果表明:干法生产每吨婴儿配方奶粉添加1.4~2.8 kg游离唾液酸,婴儿配方奶粉中的唾液酸含量为348~559 mg/L;湿法生产时游离唾液酸的添加量为400~800 mg/L,婴儿配方奶粉中唾液酸的含量为343~557 mg/L。尽管两种工艺均能满足婴儿配方奶粉中唾液酸含量标准,但干法工艺相比湿法工艺游离唾液酸的损耗小,节约经济成本。研究发现,随着游离唾液酸添加量逐渐增大,蛋白质结合唾液酸比例逐渐降低。当干法生产添加量为2.8 kg/t,湿法生产添加量为800 mg/L时,唾液酸在婴儿配方奶粉中的存在模式与人乳接近。     

人乳营养成分及其生理功能

人乳是婴儿最天然的理想食品,是婴儿早期的主要营养物质来源,含有丰富的营养物质及生物活性成分,包括蛋白质、脂肪、碳水化合物、矿物质、维生素及分泌型免疫球蛋白、牛磺酸等。人乳中各成分含量适中,比例适宜,有利于婴儿早期生长发育及随后的健康成长,并具有促进婴儿肠道、神经、免疫等系统发育的作用。文章概述了人乳中主要的营养成分及其生理功能,与牛乳做对比,为婴儿的喂养管理提供基础,进而为牛乳基婴幼儿配方奶粉的设计提供理论指导,对生产母乳化的婴幼儿配方奶粉具有重要意义。     

母乳和婴儿配方奶粉中唾液酸体外模拟消化研究

以母乳为对照,模拟婴儿胃肠消化环境对3组实验室自制不同唾液酸添加量的婴儿配方奶粉进行体外模拟消化研究,测定母乳和婴儿配方奶粉中的唾液酸体外胃消化率、肠消化率和总消化率。研究结果表明:母乳和婴儿配方奶粉中的唾液酸主要在肠内消化;干法生产添加唾液酸的婴儿配方奶粉,当添加量为2.8kg/t时,婴儿配方奶粉中唾液酸的消化率与母乳接近。     

婴儿配方奶粉中不饱和脂肪酸的分析

分析了国内外多个品牌婴儿配方奶粉中的不饱和脂肪酸,以及这些不饱和脂肪酸在甘油三酯sn-2位的分布情况。婴儿配方奶粉中主要的不饱和脂肪酸为油酸、亚油酸和α-亚麻酸,同时绝大多数婴儿奶粉强化了花生四烯酸和二十二碳六烯酸,但这些脂肪酸在不同品牌间差别很大。结合人乳脂肪酸和婴儿配方奶粉法规,对婴儿配方奶粉中的不饱和脂肪酸做了进一步剖析,旨在为婴儿配方奶粉配方的改进提供理论和实践基础。     

益生菌粉强化对婴儿配方奶粉渗透压影响的研究

为研究益生菌粉对婴儿配方奶粉渗透压带来的影响。对市售23款婴儿配方奶粉渗透压及其中6款婴儿配方奶粉冲调液强化益生菌粉后的渗透压进行了分析,并分析了相应冲调液5℃冷藏24h的渗透压变化。结果表明市售婴儿配方和早产/低出生体重婴儿配方的渗透压范围为280~320mOsm/kg·H₂O,与母乳的渗透压水平范围一致,而乳蛋白部分水解配方和无乳糖配方的渗透压较低(<210mOsm/kg·H₂O);同种益生菌粉对于不同婴儿配方的渗透压影响相同,但不同的益生菌粉引起配方渗透压的增高值不同;婴儿配方奶粉冲调液强化益生菌粉或不强化益生菌粉,5℃冷藏24h,渗透压经单因素方差分析显示无统计学差异(P>0.05)。婴儿配方奶粉冲调液若强化益生菌粉,建议冲调体积尽量放大,以降低益生菌粉对于奶粉渗透压水平的影响。     

母乳和婴儿配方奶粉营养研究进展

母乳几乎是所有婴儿最佳的食物营养来源。除了提供婴儿身体生长,母乳作为一种具有生物活性的营养体,有许多其他的益处,包括调节婴儿肠道功能、免疫功能和大脑发育。虽然新生儿都强烈建议母乳喂养,但母乳喂养并不总是都能实现的。婴儿配方奶粉是工业生产的婴儿食品的替代品。婴儿配方奶粉是尽可能地模拟母乳营养成分而开发的。该文回顾了母乳和婴儿配方奶粉的营养信息,以便更好地理解母乳喂养和婴儿配方奶粉喂养对婴儿营养补充的重要性。     

我国母乳代用品(代乳食品)发展历史回顾

阐述了我国母乳代用品的发展历史。指出了母乳代用品可分为两大类：以谷物为基础的母乳代用品在我国有着悠久的历史；以乳为基础的母乳代用品是从20世纪70年代黑龙江省乳品工业研究所相继承担轻工业部、国家、黑龙江省三个科研项目(婴儿配方奶粉Ⅰ，婴儿配方奶粉Ⅱ，婴儿配方奶粉Ⅲ)的研究、投产、推广至全国开始，并以三个产品的质量标准为依据，回顾了国家制定了婴儿配方奶粉标准而发展起来的全过程。     

母乳化奶粉的营养价值

母乳化奶粉是一种仿人乳营养成分的新型奶粉,它以牛奶为原料,添加婴儿易消化的乳清蛋白和一些不饱和脂肪酸、矿物质、维生素等成分制成。为比较“母乳化奶粉”和“全脂奶粉”的营养价值,我们选择0～6个月婴儿,观察其生长发育和蛋白质、无机盐的利用情况。     

不同脂肪来源婴儿配方乳粉与母乳脂质组成的差异分析

研究4 种不同脂肪来源的婴儿配方乳粉与母乳在总脂肪酸、sn-2位脂肪酸及甘油三酯上的脂质组成差异。结果表明,从样品中共检测出27 种脂肪酸及87 种甘油三酯,与母乳相比,4 种婴儿配方乳粉含有更多的饱和脂肪酸,较少的多不饱和脂肪酸,且母乳中超过70%的饱和脂肪酸酯化在甘油三酯的sn-2位,而4 种婴儿配方乳粉甘油三酯sn-2位更多的被不饱和脂肪酸占据,尤其是植物油基IF1和IF2,sn-2位不饱和脂肪酸高达80%。在甘油三酯组成方面,母乳中1-油酸-2-棕榈酸-3-亚油酸甘油三酯、1,3-二油酸-2-棕榈酸甘油三酯及一些中长链甘油三酯显著高于4 种婴儿配方乳粉（P＜0.05）,而婴儿配方乳粉含有更多的三油酸甘油三酯、1-油酸-2,3-二亚油酸甘油三酯及一些中链甘油三酯（P＜0.05）,并且脂肪来源的不同会显著影响婴儿配方乳粉的脂质组成,同为植物油基的IF1和IF2具有更相似的甘油三酯、脂肪酸组成及分布,并与添加了乳脂成分的IF3和IF4形成明显区分,且牛乳/植物油混合基婴儿配方乳粉在整体脂质组成上更加接近母乳。最后,基于多变量分析,发现共有16 种甘油三酯可用于区分人乳和婴儿配方奶粉。本研究结果有助于研发更接近人乳的婴儿配方乳粉。     

Calibration of infrared milk analyzers: modified milk versus producer milk

Mid-infrared (MIR) milk analyzers are traditionally calibrated using sets of preserved raw individual producer milk samples. The goal of this study was to determine if the use of sets of preserved pasteurized modified milks improved calibration performance of MIR milk analyzers compared with calibration sets of producer milks. The preserved pasteurized modified milk sets exhibited more consistent day-to-day and set-to-set calibration slope and intercept values for all components compared with the preserved raw producer milk calibration sets. Pasteurized modified milk calibration samples achieved smaller confidence interval (CI) around the regression line (i.e., calibration uncertainty). Use of modified milk calibration sets with a larger component range, more even distribution of component concentrations within the ranges, and the lower correlation of fat and protein concentrations than producer milk calibration sets produced a smaller 95% CI for the regression line due to the elimination of moderate and high leverage samples. The CI for the producer calibration sets were about 2 to 12 times greater than the CI for the modified milk calibration sets, depending on the component. Modified milk calibration samples have the potential to produce MIR milk analyzer calibrations that will perform better in validation checks than producer milk-based calibrations by reducing the mean difference and standard deviation of the difference between instrument values and reference chemistry.     

山羊奶与牛奶和人奶营养成分的比较

对山羊奶、牛奶和人奶中蛋白质、脂肪、维生素、矿物质等主要营养成分进行了比较,分析了3种奶中主要营养成分的差别。通过比较发现,山羊奶在总体营养成分方面优于牛奶,更接近人奶。但山羊奶存在铁、叶酸和维生素B12含量较低以及羊奶膻味的问题,应在营养上对这方面加以重视。     

Decreased milk yield is associated with delayed milk ejection

To determine whether individual cow milking vacuum (within the short milk tube and the liner mouthpiece) could be substituted for milk flow technology to identify delayed (bimodal) milk ejection, and the possible relationship between bimodal milk flow and milk yield, we recorded milking data from 663 Holstein cows on a 3,600-cow Michigan dairy that milked 3 times per day. Overall, delayed milk ejection occurred in 45.6% of the milkings, and 98% of the cows with delayed milk ejection also had bimodal flow. Multivariable analysis revealed that milk yield during each individual cow milking was positively associated with increasing lactation number but negatively associated with increasing days in milk and delayed milk ejection. As the time between unit attachment and the estimated milk letdown (the lag period) increased, milk yield decreased; relative to a lag of <30 s, milk yield decreased by 1.8 and 3.1 kg for lags of 30–59 and ≥60 s, respectively. The final multivariate model had an adjusted coefficient of determination of 0.27. The negative association between delayed milk ejection and decreased milk yield in this study suggested that milking vacuum parameters from individual cows could serve as a useful tool to qualitatively estimate milk flow within a herd and that this information may be used to enhance herd productivity.     

Effect of leaving milk trucks empty and idle for 6 h between raw milk loads

The US Pasteurized Milk Ordinance (PMO) allows milk tanker trucks to be used repeatedly for 24 h before mandatory clean-in-place cleaning, but no specifications are given for the length of time a tanker can be empty between loads. We defined a worst-case hauling scenario as a hauling vessel left empty and dirty (idle) for extended periods between loads, especially in warm weather. Initial studies were conducted using 5-gallon milk cans (pilot-scale) as a proof-of-concept and to demonstrate that extended idle time intervals could contribute to compromised raw milk quality. Based on pilot-scale results, a commercial hauling study was conducted through partnership with a Pacific Northwest dairy co-op to verify that extended idle times of 6 h between loads have minimal influence on the microbiological populations and enzyme activity in subsequent loads of milk. Milk cans were used to haul raw milk (load 1), emptied, incubated at 30°C for 3, 6, 10, and 20 h, and refilled with commercially pasteurized whole milk (load 2) to measure cross-contamination. For the commercial-scale study, a single tanker was filled with milk from a farm known to have poorer quality milk (farm A, load 1), emptied, and refilled immediately (0 h) or after a delay (6 h) with milk from a farm known to have superior quality milk (farm B, load 2). In both experiments, milk samples were obtained from each farm's bulk tank and from the milk can or tanker before unloading. Each sample was microbiologically assessed for standard plate count (SPC), lactic acid bacteria (LAB), and coliform counts. Selected isolates were assessed for lipolytic and proteolytic activity using spirit blue agar and skim milk agar, respectively. The pilot-scale experiment effectively demonstrated that extended periods of idle (>3 h) of soiled hauling vessels can significantly affect the microbiological quality of raw milk in subsequent loads; however, extended idle times of 6 h or less would not measurably compromise milk quality in subsequent loads in commercial tankers. Current tanker sanitation practices appear to be sufficient for maintaining raw milk SPC, LAB, and coliform levels, which are important measures of milk quality.     

Invited review: Corrected milk: Reconsideration of common equations and milk energy estimates

Corrected milk equations were developed in attempts to bring milk weights to a standardized basis for comparison by expressing the weight and composition of milk as corrected to the energy content of milk of a specific composition. Expressed as milk weights familiar on farm and in commerce, this approach integrates energy contributions of the dissimilar components to make the mass units more comparable. Such values are applied in evaluating feed efficiency, lactation performance, and global milk production, as functional units for lifecycle assessments, and in translation of research results. Corrected milk equations are derived from equations relating milk gross energy to milk composition. First, a milk energy equation is used to calculate the energy value of the milk composition to correct to (e.g., 0.695 Mcal/kg for milk with 3.5% fat, 3.05% true protein, and 4.85% lactose). That energy value is divided into the energy equation to give the corrected milk equation. Confusion has arisen, as different equations purport to correct to the same milk composition; their differences are based on uses of different energy equations or divisors. Accuracy of corrected milk equations depends on the accuracy of the energy equations used to create them. Energy equations have evolved over time as different milk component analyses have become more available. Inclusion of multiple milk components more accurately predicts milk energy content than does fat content alone. Omission of components from an equation requires the assumption that their content in milk is constant or highly correlated with an included component. Neither of these assumptions is true. Milk energy equations evaluated on a small data set of measured milk values have demonstrated that equations that incorporate protein, fat, and lactose contents multiplied by the gross energy of each component more closely predict milk energy than equations containing fewer components or regression-derived equations. This provides a tentative recommendation for using energy equations that include the 3 main milk components and their gross energy multipliers for predicting milk energy and deriving corrected milk equations. Accuracy of energy equations is affected by the accuracy of gross energy values of individual components and variability of milk composition. Lactose has consistent reported gross energy values. In contrast, gross energy of milk fat and protein vary as their compositional profiles change. Future refinements could assess accuracy of milk fat and protein gross energy and whether that appreciably improves milk energy predictions. Fat gross energy has potential to be calculated using the milk fatty acid profile, although the influence on gross energy may be small. For research, direct reporting of milk energy values, rather than corrected milk, provides the most explicit, least manipulated form of the data. However, provision of corrected milk values in addition to information on components can serve to translate the energy information to a form familiar to and widely used in the field. When reporting corrected milk data, the corrected milk equation, citation for the energy equation used, and composition and energy contents of the corrected milk must be described to make clear what the values represent.     

An approach to the detection of synthetic milk in dairy milk: 4. Effect of the addition of synthetic milk on the flow behaviour of pure cow milk

The flow behaviour of cow milk, synthetic milk and their blends was evaluated with a Haake rheometer. Changes in flow behaviour are thought to be due to detergent, an important constituent of synthetic milk, which emulsifies the vegetable fat in the aqueous phase. The results are of value in detecting very low levels (1–10%) of synthetic milk in cow milk.     

毛细管电泳法对乳及乳制品中乳源蛋白的研究

采用毛细管电泳方法对原料乳、市售鲜奶、不同厂家的巴氏灭菌乳、不同厂家和产地超高温灭菌乳(UHT)、调味乳、乳酸饮料、复原乳、酸奶、奶粉中蛋白成分进行检测。选择聚乙烯醇涂层毛细管,采用柠檬酸缓冲体系,在紫外检测214nm、分离电压20kV条件下对乳及乳制品中的α一乳白蛋白(α-La)、β一乳球蛋白(β-Lg)、α-酪蛋白(α-CN)、β-酪蛋白(β-CN)和k-酪蛋白(k-CN)进行分离测定。结果表明:五种蛋白的含量在原料乳(巴氏灭菌乳、市售鲜奶)、UHT乳、酸奶、调味乳、乳酸饮料、复原乳中依次降低,而UHT乳含量随保质期的增加而减少,奶粉中蛋白质含量因其适应人群而有差异。乳及乳制品中蛋白质的含量与其存在形式、产地及加工工艺相关。     

Effects of heating temperatures and addition of reconstituted milk on the heat indicators in milk

The objective of the present study was to evaluate the effect of heating temperatures and reconstituted milk on heat treatment indicators in milk by comparing the heat damage between raw milk and raw milk plus reconstituted milk (composite milk). The contents of lactulose, furosine, beta-lactoglobulin, and lactoperoxidase were determined after the heat indicators were heated to 65 to 115 °C for 15 s both in raw milk and composite milk. In the raw milk, the lactulose and furosine contents increased with increased heating temperature, while the beta-lactoglobulin content and lactoperoxidase activity decreased. The lactulose and furosine contents were increased after the addition of reconstituted milk. The reconstituted milk also significantly (P < 0.05) reduced the concentration of beta-lactoglobulin in the milk. Both heat treatment and an addition of reconstituted milk decreased the lactoperoxidase activity significantly (P < 0.05), and the lactoperoxidase activity was undetectable at 85 °C. The ratios of lactulose to furosine in pasteurized milk were higher than that in composite pasteurized milk. It is concluded that lactulose, furosine, and beta-lactoglobulin are suitable indicators of high heat pasteurization or raw milk, while lactoperoxidase may be used in monitoring mild heat pasteurization. Practical Application: Adequate heat treatment is necessary to destroy the microbes in raw milk. However, excessive heat treatment can result in inactivation of active compounds or loss of nutrients. The present study showed that the concentrations of lactulose, furosine, beta-lactoglobulin, and the activity of lactoperoxidase are sensitive to processing temperature and can serve as indicators of milk pasteurization.     

奶啤的研制

以牛奶、麦芽和酒花为主要原料,通过二次生物发酵研制出具有奶香和啤酒风味的奶啤饮料。通过实验确定奶啤的最佳配方及生产工艺流程并对奶啤的稳定性进行探讨,从而研制出即有啤酒的低酒精度、泡沫丰富和适度的二氧化碳,又具有酸乳饮料的酸甜可口、营养全面的奶啤饮料。     

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.