牦牛乳与其他哺乳动物乳常规营养成分的比较分析

通过牦牛乳与其他哺乳动物(反刍动物、马属动物、骆驼和人)乳进行产奶量、泌乳期和常规营养成分(蛋白质、脂肪、乳糖、干物质、灰分、矿物质和维生素)的比较分析,得出奶牛的泌乳期最长,产奶量最高,乳中的常规营养成分含量存在种间差异,但呈现出一定的种属特性。反刍动物乳中蛋白质、脂肪、干物质和灰分含量较高,矿物元素和维生素含量丰富;骆驼乳中常规营养成分含量介于反刍动物乳与马属动物乳之间;马属动物乳中的乳糖含量较高;人乳中除乳糖成分外其余常规营养成分普遍低于其他哺乳动物乳。     

双峰驼乳营养成分测定与特征分析

双峰驼乳营养丰富，具有一定的保健功能和药用价值，但营养成分缺乏系统的检测和评价。从内蒙古呼伦贝尔市鄂温克旗、阿拉善左旗和乌海采集双峰驼乳155头份，同时作为相伴研究采集内蒙古荷斯坦牛乳101头份、萨能山羊乳34头份，采用国标法测定5种常规营养素、脂肪酸、氨基酸和矿物质，并进行描述性统计和主成分分析。结果表明，每个营养素组都可使3种家畜乳在三维空间以物种聚类，说明营养素都有物种特征，也提示营养素组可用于乳的物种真实性判别。双峰驼乳蛋白质、脂肪、乳糖、水分和灰分含量分别为(3.60±0.98)、(4.90±1.74)、(4.98±0.64)、(85.55±2.66)、(0.85±0.10) g/100g,其中脂肪、乳糖和灰分含量均显著高于萨能山羊乳和荷斯坦牛乳(P<0.05);双峰驼乳C15∶0、C16∶1、C18∶0、C18∶3n3显著高于萨能山羊乳和荷斯坦牛乳(P<0.05);双峰驼乳必需氨基酸Met、Ile和非必需氨基酸Asp、Pro、Tyr、Arg均显著高于荷斯坦牛乳和萨能山羊乳(P<0.05);Ca、Zn、I等矿物质含量均显著高于荷斯坦牛乳(P<0.05)...     

不同哺乳动物乳中主要营养成分比较的研究进展

通过对牛乳、水牛乳、绵羊乳、山羊乳、骆驼乳和人乳中的蛋白质、脂肪、乳糖、矿物质和维生素等主要营养成分进行比较,发现山羊乳总体营养成分接近于人乳,对婴幼儿有极高的营养价值;绵羊乳和水牛乳中干物质含量较高,有利于开发成乳粉类产品;骆驼乳中含有丰富的不饱和脂肪酸,应在功能食品开发方面加以重视。     

贵州晴隆黑山羊体内重金属Pb、Cd蓄积量的测定及食用安全性研究

以贵州晴隆黑山羊为研究对象,分析检测了四个不同区域点黑山羊体内肠、胃、肾、肝、肌肉和骨不同部位组织器官中重金属Cd和Pb的蓄积分布,测定黑山羊不同组织器官中重金属Cd和Pb含量高低,研究是否符合食品安全标准。研究结果表明:四个区域内黑山羊体各组织器官重金属Cd的含量均低于国家食品安全标准中所规定的最大检出量,符合食品安全标准;四个区域内黑山羊羊骨中Pb含量超标,A区黑山羊羊肠和羊肉中Pb的含量均已超标,其他组织器官及B、C、D区域内黑山羊的各组织器官Pb含量均在国家标准以下,符合食品安全标准。     

海南黑山羊宰后贮存过程中肉用品质的变化

为研究海南黑山羊之间肉用品质的差异,实验选取海南群英黑山羊和东山羊背最长肌作为实验对象,对其肉色、pH、剪切力、保水性以及挥发性化合物等指标进行测定分析。结果发现:宰后羊肉在(3±1)℃条件下避光冷藏,在(3~5)d群英黑山羊的L~*、a~*和保水性显著高于东山羊(p0.05),东山羊的剪切力显著高于群英黑山羊(p0.05),在己醛、庚醛、1-戊烯-3-醇和2-乙基呋喃含量上,东山羊均显著高于普通黑山羊(p0.05)。研究表明,在宰后贮藏过程中群英黑山羊肉的脂质氧化程度较低,肉色较好,嫩度和风味较为优良,这对指导海南黑山羊肉的生产起到一定的现实意义。     

母乳中宏量营养成分含量与新生儿相关因素的分析

实验采用队列研究的方法,收集华北地区和中南地区共四个城市乳母分娩后3~5 d、12~14 d、1月、2月、3月、4月和6月的母乳,测定中国现阶段健康乳母不同泌乳阶段母乳中脂肪、总蛋白质、乳糖、干物质、总能量和真蛋白质等宏量营养成分的动态变化,同时研究分娩方式和婴儿性别与各宏量营养成分之间的关系。母乳中宏量营养成分含量的测定采用MIRIS HMA母乳分析仪。结果表明初乳中顺产组的母乳中总蛋白质和真蛋白质含量显著高于剖宫产组的(p0.05),过渡乳中脂肪、总蛋白质、乳糖、干物质、总能量和真蛋白质等宏量营养成分含量在顺产、剖宫产两组间均无显著性差异(p0.05),成熟乳(6月时)中剖宫产组的母乳中乳糖和干物质含量显著高于顺产组的(p0.05)。此外,初乳和过渡乳中脂肪、总蛋白质、乳糖、干物质、总能量和真蛋白质等宏量营养成分含量在男孩、女孩两组间均无显著性差异(p0.05),但是成熟乳中女孩组3月时的母乳中脂肪和总能量含量,4月时的总蛋白质和真蛋白质含量显著高于男孩组的(p0.05)。不同分娩方式及婴儿性别对母乳中宏量营养成分的含量有一定影响。     

麦蓝菜对奶牛产奶量及乳成分的影响

选用15头体质量、胎次、产奶量均相近中国荷斯坦奶牛,随机分为A、B、C三组(n=5)∶A组(对照组)饲喂基础日粮;B组(试验组1)饲喂基础日粮+50 g麦蓝菜种子;C组(试验组2)饲喂基础日粮+150 g麦蓝菜植株.试验周期24 d,每天测定各组奶牛产奶量及乳成分,研究麦蓝菜对奶牛产奶量及乳成分的影响.结果表明:B组较A组产奶量提高了15.56％ (P＜0.01),牛奶乳蛋白和干物质分别提高了11.9％和5.1％(P＜0.01),乳脂率提高了9.4％(P＜0.05),A、B两组间乳糖含量差异不显著;C组较A组产奶量提高了3.48％(P＜0.01),牛奶乳蛋白和干物质体分别提高了6.3％和4.9％(P＜0.01),乳脂率和乳糖分别提高了9.1％和6.6％(P＜0.05).研究表明,基础日粮中添加麦蓝菜植株和种子均可以显著提高奶牛产奶量和乳品质.     

莎能奶山羊初乳化学组成成分的研究

对不同泌乳期的莎能奶山羊初乳的化学组成成分进行了分析。结果表明,莎能奶山羊初乳中总干物质、灰分、蛋白质、脂肪含量均随泌乳期延长呈下降趋势。分娩后第一次(3h)所挤初乳中各指标含量最高,其中总干物质含量为21.32%,灰分含量为1.57%,蛋白质含量为10.24%,脂肪含量为6.61%(12h),之后下降趋势都趋于平缓。分娩后第一次(3h)所挤初乳中乳糖含量最低,为1.93%,之后随泌乳期延长乳糖含量呈上升趋势。     

山羊奶对酸奶贮存过程中微生物学质量和粘度的影响

山羊奶和牛奶中加入奶粉 (1% ,2 %或 3%或不加 )所制成的酸奶样品。与牛奶 (11.75% )相比山羊奶干物质含量较低 (10 .72 % ) ,但干物质中蛋白、脂肪和灰分含量较高。山羊乳培养时间比牛乳大约长 50ｍｉｎ ,前者持续约 5.4ｈ。在 8℃、9天贮存期间 ,监测滴定酸度、ｐＨ值、粘度及乳杆菌和链球菌活菌计数的变化。与牛乳制成的酸奶相比 ,山羊乳酸奶具有柔软的稠度和较低的粘度 ,整个贮存期山羊乳酸奶也有较高的酸度。在山羊乳和牛乳酸奶样品中加入奶粉伴随着滴定酸度增加 ,加入奶粉也增加两种酸奶的粘度 ,特别是牛乳酸奶。贮藏期中粘度没有较大…     

山羊奶理化性状研究——Ⅲ 常乳主要理化性状及其变化

本文对西农萨能奶山羊(西农羊),英国萨能奶山羊(英国羊)和关中奶山羊(关中羊)常乳概略成分、比重、pH、Ca和P含量及其在各个泌乳月变化进行了系统的测定与分析。研究结果表明:三个被试品种常乳中之主要组分含量均与国外报告资料相近。pH值在各泌乳月中变化不大,酸度在泌乳后期略有上升;总干物质和脂肪含量在泌乳高峰期(第3—5泌乳月)最低;比重和蛋白质含量也有相似的变化趋势,但后期蛋白质变化更明显。灰分随泌乳期进行逐渐上升,尤其在泌乳后期,乳糖变化趋势与灰分相反,二者呈负相关。     

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.     

Within-milking variation in milk composition and fatty acid profile of Holstein dairy cows

Changes in milk composition during a milking are well characterized, but variation in milk fatty acid (FA) profile is not well described and may affect the accuracy of in-line milk composition analyzers and could potentially be used for selective segregation of milk. Within-milking samples were collected from 8 multiparous high-producing Holstein cows (54.86 ± 6.8 kg of milk/d; mean ± standard deviation). A milk-sampling device was designed to allow collection of multiple samples during a milking without loss of vacuum or interruption of milk subsampling. Milk was collected during consecutive morning and afternoon milkings (12-h intervals) and was replicated 1 wk later. Each sample represented approximately 20% of the milking and was analyzed for fat, true protein, and lactose concentration and FA profile. Milk fat concentration markedly increased over the course of milk let down (4.4 and 4.2 percentage units at the a.m. and p.m. milking, respectively), whereas milk fat globule size did not change. Milk protein and lactose concentration decreased slightly during milking. Modest changes in milk FA profile were also observed, as milk de novo and 16-C FA concentrations increased approximately 10 and 8%, respectively, whereas the concentration of preformed FA decreased about 7% during the milking. In agreement, mean milk FA chain length and unsaturation modestly decreased during milking (0.59 and 0.014 U, respectively). The observed changes in milk fat concentration during a milking are consistent with previous reports and reflect the dynamic nature of milk fat secretion from the mammary gland. Changes in milk FA profile are not expected to practically affect the accuracy of spectroscopy methods for determination of milk fat concentration. Furthermore, the small variation in FA profile during a milking limits the use of within-milking milk segregation to tailor milk FA profile.     

Effect of incomplete milking on milk production rate and composition with 2 daily milkings

The primary aim of this study was to assess the effects of incomplete milking on milk secretion and milk composition at the quarter level. Twelve cows were enrolled beginning at 5 d in milk and remained on study through 47 d in milk. Half of each contralateral udder was incompletely milked (treatment), detaching the teat cup early to leave approximately 30% of the total milk yield behind. This target milk remaining in the gland was based on weekly calibration milking measurements of quarter total milk yield. Control quarters were milked completely until milk flow had decreased to 0 kg/min based on visual assessment. Harvested milk yield was measured twice daily at each milking, and milk components (fat, protein, lactose, solids nonfat, milk urea nitrogen) and somatic cell count, were measured twice weekly at the quarter level. The experimental unit in this design was the half-udder, and a mixed-model approach was used to assess the main and interactive effects of experiment week and treatment on milk production rate, milk remaining in the gland, and milk composition. The effect of treatment on milk production rate was significant, with the average control half-udder producing 0.97 kg/h and the treatment half-udder 0.73 kg/h. The effect of week on milk production rate and the interaction of week × treatment were also significant. The effect of treatment on milk remaining in the gland was significant, illustrating that an increase in milk remaining in the cisternal compartment had been achieved. We detected a significant decrease in milk lactose percentage in treatment half-udders, and a significant increase in somatic cell count (log₁₀). The increase was relatively small, from a geometric mean of 26,300 cells/mL in control quarters to 48,300 cells/mL in treatment quarters. The decrease in milk production rate in treatment half-udders supports current knowledge about how mammary epithelial cell secretion, proliferation, and apoptosis are modulated by autocrine-paracrine factors.     

山羊奶的营养成分研究进展

近年来,羊奶及其产品在市场中占有的比例日益增高,羊奶在营养成分构成上与牛奶有较大不同。此文将羊奶与牛奶、母乳进行对比,对羊奶的蛋白质及氨基酸、非蛋白氮、脂肪及脂肪酸、碳水化合物、维生素、矿物质及微量元素的组成及特性研究进展进行了综述。     

UHT奶的质量与原料奶的关系

主要论述了原料奶中的微生物尤其是嗜热性芽孢，低温性细菌及蛋白质的稳定性对ＵＨＴ奶的影响。     

原料奶质量对UHT奶制品的影响及控制

主要论述了原料奶的理化指标及微生物指标对ＵＨＴ奶质量的影响，以及控制方法。     

Nonbovine milk and its products as sources of probiotics delivery: An overview of its viability,functionality and product quality characteristics

Dairy products are the most predominant food carriers for probiotics, providing adequate therapeutic and functional benefits to the host when sufficient probiotics are maintained. Bovine milk currently dominates the global probiotic food market, but there is an increasing trend of applying nonbovine milk from other dairy animals as probiotic carrier food matrices as described in this review. Nonbovine dairy products can be considered suitable food matrices for probiotic delivery due to their excellent probiotic viability (mostly >log 7 cfu/mL or g) during shelf life, functional properties and product quality characteristics, being considered desirable and novel dairy products.     

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.     

Presence of Campylobacter and Arcobacter species in in-line milk filters of farms authorized to produce and sell raw milk and of a water buffalo dairy farm in Italy

The objectives of this study were to investigate the presence of Campylobacter spp. and Arcobacter spp. in dairy herds authorized for the production and sale of raw milk and in a water buffalo dairy farm, and to test the antimicrobial susceptibility of the isolates. A total of 196 in-line milk filters were collected from 14 dairy farms (13 bovine and 1 water buffalo) for detection of Campylobacter spp. and Arcobacter spp. by microbiological culture. For each farm investigated, 1 isolate for each Campylobacter and Arcobacter species isolated was tested using the Etest method (AB Biodisk, Solna, Sweden) to evaluate the susceptibility to ciprofloxacin, tetracycline, chloramphenicol, ampicillin, erythromycin, and gentamicin. A total of 52 isolates were detected in 49 milk filters in 12 farms (85.7%) out of 14 and the isolates were identified as Campylobacter jejuni (6), Campylobacter hyointestinalis ssp. hyointestinalis (8), Campylobacter concisus (1), Campylobacter fetus ssp. fetus (1), Arcobacter butzleri (22), and Arcobacter cryaerophilus (14). The small number of isolates tested for antimicrobial susceptibility precludes any epidemiological consideration but highlights that all Campylobacter isolates were susceptible to macrolides, which are the first-choice drugs for the treatment of campylobacteriosis, and that resistance to fluoroquinolones and tetracycline was detected; for Arcobacter isolates, resistance to ampicillin and chloramphenicol was detected. The sale of raw milk for human consumption by self-service automatic vending machines has been allowed in Italy since 2004 and the presence of C. jejuni in in-line milk filters confirms that raw milk consumption is a significant risk factor for human infection. The high occurrence of emerging Campylobacter spp. and Arcobacter spp. discovered in dairy farms authorized for production and sale of raw milk represents an emerging hazard for human health.