Fermented Goat Milk and Cow Milk Produced by Different Starters of Lactic Acid Bacteria： Quality Studies

Lactic acid bacteria （LAB） is widely used as culture starters in dairy fermentation. The aim of this study was to investigate the quality of fermented goat milk and cow milk, as well as the viability of LAB in the same products. Fermentations were performed with pasteurized goat milk or cow milk added with skim milk （18% of solids） using three separately different starters; yoghurt starter （a combination of Streptococcus thermophilus FNCC-0040 and Lactobacillus bulgaricus FNCC-0041）, single starter of Lactobacillus acidophilus FNCC-0029 and Lactobacillus casei FNCC-0051. The parameters observed were pH, acidity, nutritional quality including protein, fat and lactose content and product＇s viscosity. Acidity, pH and viability of LAB were also monitored during storage at refrigerated temperature （4 ℃） for 28 days. Results show that the different LAB starters did not affect the pH, acidity, lactose and protein content. Differences on LAB starters affected fat content and viscosity. The highest score of viscosity （30.00 Pa.s ± 7.02 Pa.s） was observed on products fermented by yoghurt starters, followed by products obtained using starter of L. acidophilus （17.7 ±11.4） and L. casei （8.62 ±0.35）. Protein content, acidity, pH and viscosity were not significantly different between products obtained from goat milk and cow milk. Fat content in fermented goat milk was higher （5.03% ±0.62%） than in fermented cow milk （3.52% ±0.37%）, however, lactose content was higher in fermented cow milk （5.16% ±0.40%） than in fermented goat milk （4.53% ±0.35%）. Total LAB concentration in fermented cow milk during storage was 8.03± 0.52 logt0 cfu/mL, while in fermented goat milk was 7.81 loglo cfu/mL ± 0.67 loglo cfu/mL. There was a 10.83% decrease in LAB viability in fermented cow milk and 11.40% in fermented goat milk after 28 days of storage. In conclusion, quality of fermented milk is affected by the starters applied, raw milk source and storage period.

Composition of Triacylglycerols in Fats of Cow and Goat Milk Produced in Four Zones of Mexico

The study of the triacylglycerols (TAG) by gas chromatography (GC) using capillary columns is an efficient technique for the determination of some characteristics of quality of fats and oils. The objective of the present study was to determine by GC the content of TAG present in fat of cow and goat milk produced in four zones of Mexico. According to criteria established in Mexican Standardization, 25 samples were obtained of 1 L of ultra-pasteurized cow milk (UHT) and 27 and 48 of raw cow and goat milk, respectively. The fat was extracted from all of the milk samples by detergent solution, and was stored at –20℃ until its analysis. The chromatographic conditions made it possible to identify and quantify TAG of 28 to 54 numbers of carbons, which were analyzed under descriptive and inferential statistical techniques. For the cow milk fat, the statistical analyses indicated significant difference (p < 0.05) in the TAG C34, C50 and C52, and for the goat milk fat in the TAG of C36 to C52. No equality of means was found among the TAG of the cow and goat milk fat. This study offers an advance in the characterization of the TAG present in the cow and goat milk fat produced in Mexico.

Fluorescence-based PCR Detection of Goat Milk Powder Mixed with Cow Milk

[Objectives]To amplify and identify the specific gene fragments of cattle and sheep by real-time fluorescence-based PCR,and quickly and accurately identify the adulteration problem of goat milk powder according to the differences of mitochondrial genes among different species.[Methods]The specificity,limit of detection and repeatability test were carried out by isolating somatic cells,extracting template DNA and determining the reaction conditions of real-time fluorescence-based PCR.[Results]The real-time fluorescence-based PCR method could be used to identify the bovine and ovine-derived materials of milk powder with high specificity,high sensitivity and good repeatability,and the limit of detection of milk components in goat milk powder could reach 0.01%.[Conclusions]The real-time fluorescence-based PCR method can be used to quickly and accurately detect the milk components in goat milk powder,and provide some technical support for the adulteration detection of dairy industry.

Contents of Trace Metal Elements in Cow Milk Impacted by Different Feedstuffs

Feedstuff intake plays key role in impacting the yield and quality of milk. In this study, we discussed the contents of trace metal elements in cow milk impacted by different feedstuffs. We detected the contents of Pb, Cd, As, Cu, Mg, Ca, Fe and Zn in different feedstuffs and milk by atomic absorption spectrophotometry. The determinations of Pb, Cd and As contents were by graphite furnace A_AS and Cu, Mg, Ca, Fe and Zn was by flame atomic absorption spectrometry. The results showed that Pb, Cd, As and Cu presented in feedstuffs, but Pb, Cd and As were lowly detected in milk samples, and Cu was not detected in milk samples. The content of Mg in concentrates was lower than that in forages. However, the content of Mg in milk from concentrate feed was higher than that in forage feed. This suggested that the utilization of Mg in concentrate feed was higher than that in forage feed. The contents of Ca and Zn were opposite to Mg, and the utilization of Ca and Zn in forage feed was higher than that in concentrate feed. There was no obviously change law of Fe in different feedstuffs and milk samples. The relationship between the contents of trace metal elements in milk to feedstuffs would provide a theoretical basis for dairy farming. It would be useful for improving the milk yield and milk quality of dairy production.

Control of Ewe and Goat Cheeses Labelling on the Croatian Market

The aim of the research was to examine ewe and goat cheese labelling on the market of the Republic of Croatia. During the four years (2012-2016) of the research, 133 cheeses from retail supermarket chains were selected by the random-choice method by the responsible inspection of the Republic of Croatia and analysed at the Reference Laboratory for Milk and Dairy Products of the Department of Dairy Science at the Faculty of Agriculture University of Zagreb. To check the correct labelling of cheeses, the chemical composition of cheese was examined: the fat content, the dry matter content, the fat in dry matter content, and the water content in the fat-free cheese compound were calculated according to the Ordinance on Cheeses and Cheese Products, which refers to cheeses manufactured in the Republic of Croatia, and Regulation EU (2011) of the European Parliament and the Council on providing information to consumers about food products, which covers foreign cheeses. The presence of cow milk in cheeses labelled as products manufactured exclusively from ewe or goat milk was tested by the reference method using iso-electric focusing to determine any adulteration according to Commission Regulation (2008). The results of analysis in this research show the condition of the quality and correct labelling of ewe and goat cheeses on the market of the Republic of Croatia. Of the 133 cheeses analysed, 67 cheeses (50%) did not correspond to the values stated on the declaration or to legal regulations, while the presence of cow milk was found in 30% of the cheeses analysed. The research results indicate the need to carry out continuous systematic control in the interest of protecting consumers and those manufacturers who are following good manufacturing practices.

Effect of Bospro on High and Mid-to-Low Milk Yielding Chinese-Holstein Cow

A total of 90 cows from two farms (farm A 30 cows, farm B 60 cows) were used to study the effect of Bospro on milk production, milk quality and subclinical mastitis incidence. The cows in the test group were supplied with 20 g of Bospro per head per day and meanwhile, the percentage of milk fat, protein and lactose and moisture of the milk samples were analysed. The results showed that the milk yield of both high production and mid-to-low milk producting cows increased by 3.3% to 5.3% respectively compared with their control group of cows, but there was no changes on the milk content between the treated and the control cows. The treated cows also showed an increased body weight (P>0.05) and significantly reduced incidence of mastitis, as Compared with that of the control group.The experiment dcmonstrats that Bospro can increase milk yield, but not at the expense of milk quality and body weight.

基于顶空固相微萃取-气相色谱-质谱法分析加速氧化过程中全脂牛羊乳粉挥发性化合物

为探究全脂牛羊乳粉在储存过程中风味物质的变化,本研究采用顶空固相微萃取-气相色谱-质谱技术对加速氧化过程中全脂牛羊乳粉挥发性化合物进行分析。研究表明,全脂牛乳粉和全脂羊乳粉中分别鉴定出56、63种挥发性物质,主要为酸类、醇类、羰基类、酯类、芳香族类、杂环类等挥发性化合物。通过主成分分析和聚类热图分析,在全脂牛羊乳粉中筛选出10种显著性差异挥发性化合物,全脂牛乳粉在储存过程中丁酸相对含量降低,2-壬酮、1-氯戊烷相对含量升高;全脂羊乳粉中壬醛、辛酸、丙酸、丁羟甲苯相对含量降低,苯甲醛、2-庚酮、烯丙基正丙酯相对含量升高。

不同泌乳期山羊乳与牛乳中类固醇激素含量差异

目的:了解不同泌乳期山羊乳与牛乳中类固醇激素含量差异。方法:采用超高效液相色谱-串联质谱方法,分析不同泌乳期山羊乳和牛乳中类固醇激素含量。以0.5 mmol/L氟化铵溶液和甲醇作为流动相进行梯度洗脱,采用电喷雾离子化质谱的多反应监测模式对目标分析物进行定性和定量检测。结果:山羊乳与牛乳样品中共检出11种类固醇激素,分别为17α-羟基孕烯醇酮、17α-羟基孕酮、表睾酮、孕烯醇酮、孕酮、雄烯二酮、睾酮、雌二醇、雌激素、皮质醇和可的松,其中,泌乳初期山羊乳与牛乳相比,17α-羟基孕烯醇酮、雌激素、皮质醇含量差异显著(P<0.05),孕酮、孕烯醇酮含量差异极显著(P<0.01);泌乳盛期17α-羟基孕烯醇酮、17α-羟基孕酮、雄烯二酮、可的松含量差异显著(P<0.05),孕酮、孕烯醇酮含量差异极显著(P<0.01);泌乳末期17α-羟基孕酮、雄烯二酮、雌激素、皮质醇含量差异显著(P<0.05),17α-羟基孕烯醇酮、孕烯醇酮、孕酮含量差异极显著(P<0.01)。结论:山羊乳与牛乳中类固醇激素含量的差异可能是由于妊娠状态不同导致。

东弗里生绵羊奶与牛奶和山羊奶生乳品质的比较

本文综述了东弗里生绵羊所产羊奶中固形物、蛋白质等基本物质和不饱和脂肪酸等功能性物质的含量,比较了其与牛奶、山羊奶的营养成分差异,并对东弗里生绵羊奶的前景进行了展望和建议。

Determination of Fatty-Acid Composition in Oils of Animal Origin by Near-Infrared Spectroscopy

The authentication of milk requires the use of sophisticated and expensive analytical techniques. There is a huge need for reliable and cheap analytical technologies for use as fast and effective screening methods. This paper proposes the use of myristic acid in the authentication of cow, mare, camel and goat milk, using near infrared spectrometry. Comparison has been made with traditional gas chromatography methods, so that both methods can be used in the authentication of different types of dairy products.

基于多频扩散波谱法分析发酵羊乳和牛乳的微流变学特性及贮藏稳定性

以羊乳和牛乳为原料制备发酵乳,采用多频扩散波谱法分析不同发酵乳的微流变特性,并对贮藏期间的滴定酸度、活菌数、黏度、持水力和质构参数进行测定,对比分析发酵羊乳和牛乳的贮藏稳定性。结果表明:羊乳较牛乳所用发酵时间长,分别为7.5 h和6.5 h,发酵羊乳所用发酵时间较长。对保加利亚乳杆菌和嗜热链球菌的增殖和存活没有影响。在贮藏21 d时pH均大于4.2,滴定酸度小于100°T,未发现后酸化现象。发酵过程中微流变学分析显示,发酵羊乳形成凝胶的EI值较低,SLB值较高,形成了弹性较小的凝胶结构,整体结构特征更趋向于液体,反应了发酵羊乳形成的凝胶结构较弱,稳定性较差。在贮藏期间,发酵羊乳的黏度、持水性和各质构参数均小于同一贮藏时间点的发酵牛乳(P<0.05),显示发酵羊乳在贮藏期间的稳定性较发酵牛乳差。本研究为发酵羊乳和牛乳实际生产提供数据参考和理论依据,为发酵羊乳的推广提供借鉴,同时可以为不同乳源发酵乳研究提供方法和思路。

牛、羊乳粉的DSC热学性质比较及掺假分析

为明确羊乳粉、牛乳粉的热学特征,采用差示扫描量热法(differential scanning calorimetry,DSC)对真空冷冻干燥制备的全脂羊、牛乳粉样品以及高比例掺假(75%、50%、25%)和低比例掺假(10%、5%、3%、1%)牛乳粉的混合羊乳粉样品进行热力学分析。结果表明,全脂羊乳粉和全脂牛乳粉在DSC热学指标上存在差异,全脂牛乳粉相比全脂羊乳粉缺失一个脂肪特征熔融吸热峰b,蛋白质熔融吸热峰c峰值温度和热焓值较低,而乳糖熔化分解峰e热焓值较高。对于掺入不同比例牛乳粉的羊乳粉,通过检测是否存在吸热峰b及其热焓值,可判断样品掺假牛乳粉比例是否在25%以下及判断掺入牛乳粉的量;在不同比例掺假样品中检测乳糖熔化分解峰e的焓值可判断羊乳粉掺入牛乳粉的掺假量。因此,DSC技术可以实现对羊乳粉、牛乳粉热学性质的分析和评价,也可作为乳制品行业质量保证和真实性鉴别的潜在分析工具。

牛乳与山羊乳中乳桥蛋白的比较研究

山羊乳是近年来备受瞩目的动物乳源,含有在婴儿早期发育中发挥多种生物活性的乳源性骨桥蛋白(osteopontin,OPN),也被称为乳桥蛋白(lactopontin,LPN),但目前关于山羊乳LPN的研究还较少,对于其结构特点及与牛乳LPN的差异还未见相关报告。通过对山羊乳和牛乳中LPN进行序列相似度分析,并进行富集和测定,比较两者在磷酸化修饰的差异,探讨山羊乳LPN与牛乳LPN结构的异同。结果显示,山羊乳和牛乳LPN完全相同的氨基酸比例高达90.94%,并且均存在同样的整合素蛋白结合序列。山羊乳LPN未鉴定到O-糖基化修饰,山羊乳LPN和牛乳LPN的磷酸化修饰位点基本一致,但同一位点的磷酸化修饰位点覆盖率在两者间略有差异。结果说明,山羊乳LPN可能具有与牛乳LPN相似的生物活性。

不同泌乳阶段山羊乳与牛乳中核苷酸物质含量的差异性分析

【目的】探究不同泌乳阶段的山羊乳与牛乳中核苷酸物质含量的差异性,为功能羊乳产品的差异化利用提供科学依据。【方法】采集山羊和奶牛泌乳初期不同时间(2,7,15 d),泌乳盛期不同时间(30,50,100 d)和泌乳末期(200 d)的奶样,采用快速溶剂萃取技术处理后再采用高效液相色谱串联质谱(LC-MS/MS)法,精确测定次黄嘌呤、尿苷、黄嘌呤、羟基嘌呤、腺嘌呤核苷酸、次黄嘌呤核苷酸、尿嘧啶核苷酸、胞嘧啶核苷酸和鸟嘌呤核苷酸等9种核苷酸物质的含量。【结果】次黄嘌呤、尿苷、黄嘌呤、羟基嘌呤、腺嘌呤核苷酸、次黄嘌呤核苷酸、尿嘧啶核苷酸、胞嘧啶核苷酸和鸟嘌呤核苷酸等9种核苷酸物质在整个试验期山羊乳中均检出;腺嘌呤核苷酸、尿嘧啶核苷酸、次黄嘌呤核苷酸仅在泌乳初期2~15 d牛乳中检出,鸟嘌呤核苷酸在泌乳2~100 d牛乳中检出,次黄嘌呤在整个试验期牛乳中均未检出,其他4种核苷酸物质(黄嘌呤、羟基嘌呤、胞嘧啶核苷酸和尿苷)在整个试验期牛乳中均检出。除次黄嘌呤和牛乳中的羟基嘌呤外,牛乳和羊乳中的其他核苷酸物质含量均随泌乳时间的延长总体呈下降趋势。山羊乳中腺嘌呤核苷酸、尿嘧啶核苷酸、次黄嘌呤核苷酸、胞嘧啶核苷酸、鸟嘌呤核苷酸、尿苷和黄嘌呤含量显著或极显著高于牛乳;山羊乳中羟基嘌呤含量在泌乳2~15 d显著高于牛乳(P<0.05),在泌乳30~200 d极显著低于牛乳(P<0.01)。【结论】不同泌乳阶段山羊乳与牛乳中核苷酸物质含量存在明显差异,这可能与山羊与奶牛的泌乳方式不同有关。

牛羊乳比例对Malatya干酪成熟品质及抗氧化特性的影响

以不同牛羊乳比例(1∶0、3∶1、1∶1、1∶3、0∶1)制备的Malatya干酪为研究对象,探究掺入牛乳比例对传统Malatya干酪成熟过程中得率、理化特性、质构、色值、熔融温度、感官品质、蛋白水解及抗氧化特性的影响。结果表明:干酪中掺入牛乳比例越高,蛋白含量越低,水分含量越高,硬度和咀嚼性降低,亮度、白度值更低。随着成熟期的增加,蛋白水解能力逐渐增加,干酪抗氧化活性在成熟60 d时达到最大值后降低。此外,掺入50%牛乳时干酪得率与纯羊乳组干酪无显著差异(P>0.05),且感官评价值在掺入50%牛乳达到最大值。掺入50%牛乳时干酪蛋白水解性能与纯羊乳组无显著差异,掺入50%牛乳干酪组的1,1-二苯基-2-三硝基苯肼自由基清除率、超氧阴离子自由基清除率、还原力、总抗氧化能力与传统Malatya干酪无显著差异(P>0.05)。基于干酪得率、感官评价以及抗氧化性等指标,可知掺入50%牛乳制备干酪是传统Malatya干酪最佳的替代形式,具有较好的品质及抗氧化特性。

不同来源乳品与不同胎龄新生儿血清中IgE结合比较

[目的]牛奶蛋白过敏在新生儿中发病率逐年升高,且以IgE介导的牛奶过敏临床多见,因此能否寻找能进行替代的乳品也是治疗牛奶蛋白过敏的另一途径。本研究旨在比较不同来源乳品对不同胎龄新生儿血清IgE的结合情况。[方法]纳入早产儿和足月儿血清,分别用母乳、羊奶配方奶粉、牛奶配方奶粉与血清孵育,采用ELISA方法比较各乳品与新生儿血清中IgE结合情况。[结果]在足月儿中母乳与IgE的结合显著高于其他两组配方奶粉组(P<0.05);在早产儿中,三种不同来源的乳品与IgE的结合没有显著性差异。牛奶配方奶粉与早产儿血清中IgE结合的相对数量显著高于足月儿组(P<0.05),而羊奶配方奶与早产儿、足月儿血清中IgE结合无显著差异,母乳的结合结果也无显著差异。[结论]提示羊奶配方奶粉在与IgE结合方面比牛奶配方奶粉更接近于母乳。

Effects of the substitution of cow’s milk with soymilk on the micronutrients,microbial,and sensory qualities of yoghurt

The consumption of imported dairy products is high especially in developing countries including Nigeria where little or no milk is produced locally which makes the products expensive,out of reach to common consumers and also inconvenient for lactose intolerance and vegans.Soymilk,as plant-based milk was substituted for cow’s milk in parts and in whole for the production of yoghurt and the effect of substitution was evaluated on the minerals,vitamins,microbial,and sensory properties of the products using the established methods.Significant differences(p<0.05)exits among the yoghurt samples in the micronutrient contents.The soymilk substitution produced yoghurts with trace/macro mineral contents’range of 0.14–28.50 mg/100 g and vitamin contents(ranged 0.02–0.43 mg/100 g)that were of comparable range of values with the yoghurt made with 100%cow’s milk(0.21–29.60 mg/100 g minerals and 0.05–0.58 mg/100 g vitamins).Generally,no significant difference(p<0.05)was observed in most of the sensory attributes evaluated(range 8.00–8.01)in the entire samples(except in the 100%soymilk yoghurt).The microbial analysis proved the safety of the entire products for consumption.These showed the positive effect of substituting soymilk for cow’s milk at all the levels used,thus,the lactose intolerance and vegans can find alternative to dairy yoghurt in the 100%soymilk substitution and enjoy the functional health benefits of yoghurt.Also,the total dependence on importation of dairy milk and cost of production of composited milk yoghurt could be reduced to improve the nation’s economy and make the product economically accessible to common man.

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。

顶空固相微萃取-气质联用法分析羊乳和牛乳中挥发性化合物

采用顶空固相微萃取技术对羊乳和牛乳挥发性化合物进行萃取,再经气相色谱-质谱联用仪检测。从羊乳中共检出49种挥发性化合物,主要由酸类、烃类、酮类和芳香族类化合物组成;牛乳中共检出33种挥发性化合物,主要由酸类、烃类、醇类和酮类化合物组成。羊乳和牛乳中检出22种相同化合物,其中酸类7种、烃类4种、芳香族类3种、酯类2种、酮类2种、醇类1种、醛类1种和其他类2种。羊乳中的挥发性成分,尤其是挥发性酸类化合物比牛乳更为复杂。

毛细管电泳技术检测羊乳婴幼儿配方粉中的牛乳成分

婴幼儿配方乳粉的乳源鉴别对于保障产品安全和真实性至关重要。采用毛细管电泳技术对羊乳来源的婴幼儿配方粉中的牛乳成分进行检测。通过比较不同乳源产品中主要蛋白质组分的电泳图谱,筛选出牛乳表征蛋白峰。通过方法验证以及检测市售样品,证实毛细管凝胶电泳在准确度、精密度及重复性方面表现良好,筛选的表征蛋白峰峰面积与羊乳中牛乳含量呈现良好线性相关性(R^2>0.99),检测灵敏度0.5%,表明该方法可用于羊乳来源婴幼儿配方粉中牛乳成分的定性和定量检测。