不同品种生鲜驴乳营养成分比较

对不同品种生鲜驴乳中常规营养成分,如脂肪、蛋白质、乳糖、干物质含量、维生素C、氨基酸和矿物质等进行比较分析。结果显示,不同品种鲜驴乳中蛋白质、脂肪、水分、干物质、乳糖、维生素C、滴定酸度和pH值变化范围分别为 1.38 g/100 g～ 1.77 g/100 g、0.75 g/100 g～ 1.08 g/100 g、88.89 g/100 g～ 90.64 g/100 g、9.38 g/100 g～ 12.64 g/100 g、4.32 g/100 g～5.56 g/100 g、2.01 g/100 g～3.12 g/100 g、4.48°T～4.74°T、7.09～7.18。德州黑驴生鲜乳显示出最高的氨基酸总量（1 867.89 mg/kg）,德州黑驴生鲜乳中的必需氨基酸显著高于疆岳驴、新疆驴、果拉驴（P<0.05）。德州黑驴生鲜乳中钙、硒含量较其他品种要高,而果拉驴生鲜乳中磷、锌含量较其他品种要高。     

驴乳营养成分和生物活性研究进展

中医古籍记载,驴乳具有清热解毒、润燥止渴等功效。欧洲和南美,驴乳流行作为人乳的替代品。研究表明,驴乳含有蛋白质、必需脂肪酸、矿物质、维生素等丰富的营养成分,而且其含量与人乳接近,有利于人体吸收和利用。生物活性研究表明,驴乳的蛋白质构成特点使驴乳致敏性低,可用于对牛乳过敏的婴儿。驴乳富含溶菌酶,具有抗菌功能。随着我国驴产业链的发展,驴乳资源将越来越丰富,市场和应用前景广阔。     

驴乳营养成分和生物活性研究进展

中医古籍记载,驴乳具有清热解毒、润燥止渴等功效.欧洲和南美,驴乳流行作为人乳的替代品.研究表明,驴乳含有蛋白质、必需脂肪酸、矿物质、维生素等丰富的营养成分,而且其含量与人乳接近,有利于人体吸收和利用.生物活性研究表明,驴乳的蛋白质构成特点使驴乳致敏性低,可用于对牛乳过敏的婴儿.驴乳富含溶菌酶,具有抗菌功能.随着我国驴产业链的发展,驴乳资源将越来越丰富,市场和应用前景广阔.     

驴乳的主要成分及与其它乳的分析比较

本文分析了驴乳的基本组成,并和其它哺乳动物的乳汁成分进行对照.驴乳蛋白中乳清蛋白含量较高,灰分含最较低,组成接近人乳,适合做婴儿和老年人及体弱多病的人群的食品或婴幼儿配方乳品.     

舍饲新疆褐牛初乳产量及乳成分测定

测定10头全舍饲新疆褐牛母牛分娩后2，24，48，72，96，120h的初乳产量、常规营养成分、IgG和矿物元素含量。结果表明，母牛分娩后2h(第1次)所挤初乳产量平均为4.73kg，72h内初乳平均总产量为46．6kg，占成母牛305d平均产奶量的0．9％；120h内初乳平均总产量为85．1kg，占305d平均产奶量的1．65％。2h挤出的初乳其蛋白质、脂肪、乳糖、灰分的含量分别为12．59，6．5，2．87，1．11g／100g，是常乳的3．93，1．76，0．57，1．48倍；IgG质量浓度为60．56g／L，是常乳的108．14倍；Ca，P，Na，Mg，Fe，Zn的含量分别为186．03，167．10，89．65，23.31，0．30，2．25mg／100g，是常乳的1．66，2．01，1．81，2．05，2．14，6．43倍。随泌乳期的延长，初乳中除乳糖以外的各种成份均迅速下降，在48h以内，以蛋白质和IgG的下降幅度最大，分别达62.27％和93．40％。至第120h，除蛋白质及矿物元素的Zn以外，各种成分已和常乳相接近。新疆褐牛分娩后不同时间段初乳成分的变化规律和荷斯坦牛相似。     

关于制定新疆驴乳和驴乳粉地方标准的研究

驴乳具有蛋白质中乳清蛋白比率高，低脂肪、低胆固醇，富舍不饱和脂肪酸等营养特点，有较大的开发利用价值，新疆已在全国率先推出了驴乳粉产品。论述了制定驴乳及驴乳粉地方标准的必要性；根据对驴乳和驴乳粉化学成分的测定结果，参照牛乳和乳粉的相关国家标准和行业标准，提出了制定《生鲜驴乳收购标准》及《驴乳粉和调味驴乳粉》两个地方标准的建议；并对标准中涉及的名称定义、技术要求、项目设定、技术指标等内容提出了具体意见。     

南湖菱营养成分及无机元素含量分析

对南湖菱果肉的营养成分及无机元素的含量进行分析测定。结果表明，南湖菱果肉中所合营养成分，其中干物质中蛋白质的含量为14．21％、淀粉为68．95％、灰分为3．96％；鲜物质中维生素C的含量为2．24mg／100g、水分为84．90％。南湖菱中含有常见的18种氨基酸，其中包括人体营养必需的8种氮基酸，氨基酸总量占干物质的13．45％；必需氨基酸占氨基酸总量的36．74％；人体必需微量元素Zn、Fe、Cu、Ca、Mn的含量较高，重金属元素Pb和总As含量均未超过国家标准。本实验为评价南湖菱的品质和更好地开发利用南湖菱提供了科学依据。     

甜菜品种资源的品质研究

本文分析了我国部分甜菜品种资源的蔗糖、钾、钠、α－氮含量及分布趋势。结果表明蔗糖平均含量为15．56±2．17％，部分材料的含量主要集中在15～18．9％之间，占分析材料的58．5％；钾平均含量为3．68±152meq／100g，多数材料含量集中在2－4meq／100g之间，约占67％；钠平均含量为4．48±2．11meq／100g，含量集中在4－7meq／100g之间的材料占50％；α－氮平均含量为2．4±2．15meq／100g，多数材料的含量低于2meq／100g，约占55％。在三大生态区的甜菜资源材料中，东北生态区材料蔗糖平均含量最高，钾和钠平均含量最低，α－氮平均含量属于中等水平。同时筛选出一批优质材料。     

乳酸菌在腌制酸菜中最适发酵条件的研究

通过从酸菜汁中分离选育出的二株植物乳杆菌和短乳杆菌的发酵条件的研究，利用液体深层发酵，得出了在大白菜发酵中的最适发酵条件。发酵温度为35℃，NaCl含量1％至2％，接种量为4％，生渍工艺、发酵成熟时间为48h，乳酸含量为1．25g/mL，生渍加0.5％的蔗糖，成熟时间则为36h，乳酸含量1．4g／mL。对照自然发酵成熟时间需要72h以上，乳酸含量0．8％。接菌发酵产品色泽、口味优于自然发酵。     

马乳和驴乳中营养成分及加工技术研究进展

马乳及驴乳作为特色乳之一，具有较高的营养价值及功能特性，受到消费者的关注。然而，马乳及驴乳中溶菌酶、乳铁蛋白等特征性活性成分对热处理、酸碱等敏感，在产品加工方面有待进一步研究。因此，本文对比分析了马乳、驴乳与母乳、牛乳中营养成分的差异及生物活性功能，对目前马乳及驴乳的加工处理技术研究进行系统的评价，为马乳及驴乳产品加工和品质调控提供参考。     

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.