几种乳制品中脂肪酸的特点

分析比较了各种乳制品中脂肪酸的含量,发现奶粉(南北)和炼乳中饱和脂肪酸含量较高;纯羊奶中的多不饱和脂肪酸和亚油酸是所研究乳制品中含量最高的;发酵酸奶和奶酪中CLA含量较高;而炼乳、干奶片、黄油和奶酪中反式脂肪酸含量则较高。经比较了牛奶和奶粉中脂肪酸含量发现,奶粉中可能添加了40%的棕榈酸。纯羊奶和酸羊奶中短链脂肪酸含量高达15.784%和12.802%,这也是羊膻味的重要来源。     

基于SDE/GC-MS制备的藏酥油香精及其应用

为开发藏酥油风味香精,采用同时蒸馏萃取方法制备样品,利用GC-MS技术对天然藏酥油中的风味物质进行了分离、鉴定,经NIST谱图库比对,共确定了32个相似度在90以上的化合物,采用面积归一化法确定了各组分的相对含量,其中羧酸类12个,占71.81%;酮类6个,占9.33%;酯类5个,占1.49%;醇类3个,占4.44%;烯类2个,占1.46%;内酯类、醛类、醚类和酚类化合物各1个,分别占0.71%、0.24%、3.53%和13.75%。以GC-MS鉴定结果为依据,结合调香技术制备藏酥油香精,并将其应用于植物性藏酥油的开发。将植物性藏酥油与天然藏酥油在酥油茶中的应用进行感官评定,结果显示:植物性藏酥油在奶香、茶感和协调性方面优于天然藏酥油;滑口度和脂肪感稍逊于天然藏酥油。本文为开发藏酥油风味系列产品提供数据依据。     

牦牛酥油理化性质研究

对牦牛酥油的基本性质和脂肪酸组成进行了分析。牦牛酥油脂肪质量分数仅为87.77%,高水分含量引起了油脂的酸败,牦牛酥油熔化行为与结晶行为并不是相对可逆过程,根据熔化曲线可以将牦牛酥油分成三个组分:高熔点组分(24.32~38.72℃)、中熔点组分(16.60~20.73℃)和低熔点组分(1.50~15.38℃)。牦牛酥油脂肪酸质量分数最多的为饱和脂肪酸(60.56%),其次为单不饱和脂肪酸(35.05%)和多不饱和脂肪酸(4.39%)。     

奶制品及反刍动物肉类食物中n-11位反式脂肪酸含量研究

目的检测部分奶制品和牛、羊肉类食品中反式脂肪酸含量,为评估我国居民膳食中反式脂肪酸摄入量提供基础数据。方法采集奶油、鲜奶、酸奶、奶粉及配方奶粉,不同部位牛、羊肉制品等食物样品56件。应用气相色谱结合银离子薄层层析方法测定样品中反式油酸含量。结果以牛奶为原料加工生产的奶油样品含有n-11反式油酸,以植物油为原料的奶油制品不含反式脂肪酸。酸奶中含n-11反式油酸,奶饮料中脂肪含量很低,未检测出反式脂肪酸。两种奶酪、纯奶粉、多数配方奶粉及多数牛、羊肉类食物样品中含有n-11反式油酸。所有样品均不含n-9反式油酸。结论鲜奶、纯奶粉、牛羊肉类食品及多数奶其制品中含n-11反式油酸。不同部位的牛羊肉类食品,不同品牌的奶制品的n-11反式油酸存在较大差异。     

不同酥油理化特性及脂肪酸组成分析

对食用酥油和工业酥油的理化特性和脂肪酸组成进行了研究.结果表明:脂肪是食用酥油和工业酥油的主要组成成分,含量分别为87.58％和98.87％;食用酥油与工业酥油的酸值(KOH)分别为1.23、5.71 mg/g,过氧化值分别为0.475 7、1.003 6 meq/kg,折光指数(50℃)分别为1.443 5、1.438 8,皂化值(KOH)分别为122.97、130.60 mg/g,碘值(Ⅰ)分别为30.41、44.50 g/100 g,黏度(50℃)分别为29.2、25.2 mPa·s,熔点分别为42.3、47.5℃;食用酥油与工业酥油饱和脂肪酸和不饱和脂肪酸的含量分别为84.83％、15.17％和76.37％、23.63％.     

酶法催化制备酥油基母乳脂肪替代脂

母乳脂肪为婴儿提供45%～60%的能量来源。然而,由于脂肪结构和含量不同,以牛乳和其它植物油为主的婴儿配方奶粉的脂肪消化吸收率比人乳低20%～25%,因此制备与母乳脂肪结构和组成相似的替代脂是本领域的研究热点。本文选用与母乳脂肪相似度较高的酥油为主要原料,脂肪酸乙酯为酰基供体,采用固定化脂肪酶RM IM催化,通过响应面法优化酶法的催化反应条件,得到最佳工艺条件为68℃下用质量分数10%的RM IM(水活0.61)催化物质的量比为2.13∶1∶1的酥油、葵花籽油乙酯和油酸乙酯。在模型验证中分析其主要脂肪酸:总亚油酸含量以及sn-2棕榈酸相对含量的实际值分别为17.59%和56.40%,与预测值基本一致,可作为母乳脂肪替代脂的又一来源。本研究结果为合成母乳脂肪替代脂(HMFS)提供了新的可能性。     

不同地区酥油脂溶性维生素和脂肪酸组成分析

对林芝和那曲酥油脂溶性维生素和脂肪酸组成进行研究。结果表明:酥油中维生素E含量均为最高,分别为2020μg/100 g和1900μg/100 g,其次是维生素A含量,分别为345μg/100 g和311μg/100 g,维生素E和维生素A含量均差异显著(p<0.05)。维生素D3含量相对较少,维生素K2未检出。两种酥油分别检测到25种和20种脂肪酸,饱和脂肪酸含量及脂肪酸总量差异不显著(p>0.05),不饱和脂肪酸含量及功能性脂肪酸含量差异显著(p<0.05),饱和脂肪酸含量均占到总量的1/2以上,棕榈酸、硬脂酸含量最多。单不饱和脂肪酸含量分别为24.22%和32.66%,差异显著(p<0.05)。功能性脂肪酸主要有油酸(19.2%和29.7%)、亚油酸(0.52%和4.20%)、亚麻酸(0.65%和0.26%)、花生四烯酸(0.27%和0.15%),林芝酥油还含有少量的EPA(0.06%)和DPA(0.17%)。     

牦牛酥油贮藏期间脂肪酸和健康评估指数变化

该研究通过测定青藏高原牦牛酥油脂肪酸情况,计算动脉粥样硬化指数(atherogenic index, AI)、血栓形成指数(thrombopoiesis index, TI)、促健康指数(health promotion index, HPI)和低胆固醇血症/高胆固醇血症比率(hypocholesterolemia/hypercholesterolemia ratio, HH)4个健康指数,探索和揭示贮藏期间牦牛酥油脂肪酸的组成特征、功能活性脂肪酸及健康指数变化。采用青海省海北藏族自治州和甘肃甘南藏族自治州的牦牛酥油,在4℃下贮藏0、1、2、3、4、5个月,利用GC-MS进行脂肪酸分析。结果显示,在整个贮藏期内牦牛酥油中棕榈酸、油酸、硬脂酸为优势脂肪酸,海北和甘南酥油多不饱和脂肪酸(polyunsaturated fatty acids, PUFA)相对含量分别为5.99%～4.62%和7.77%～6.60%;单不饱和脂肪酸(monounsaturated fatty acids, MUFA)含量分别为28.61%～26.42%和29.51%～26.95%;甘南酥油奇数碳链脂肪酸(od...     

牦牛酥油及其磷脂对C57BL/6J小鼠脂代谢的影响

将SPF级C57BL/6J小鼠随机分为5组,即对照组、黄酥油组、白酥油组、黄酥油磷脂组和白酥油磷脂组,用牦牛酥油和牦牛酥油磷脂饲喂小鼠。饲喂1个月和5个月后分别测定小鼠血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)水平和血糖浓度,并进行肝脏和腹腔脂肪病理观察及脂肪组织脂肪酸组成分析。结果表明:长期饲喂牦牛酥油会使小鼠体重增加,而饲喂牦牛酥油磷脂小鼠体重增加较少。随着饲喂时间的延长各试验组均可提升小鼠血清HDL-C水平,小鼠血清TC、TG、LDL-C水平和血糖浓度由高到低依次为酥油组、磷脂组、对照组。饲喂1个月后各组小鼠肝脏和腹腔脂肪结构正常完整,未见明显组织病变,而饲喂5个月后,与对照组相比,黄酥油组、白酥油组、黄酥油磷脂组、白酥油磷脂组可见不同程度的炎症细胞浸润和脂质沉积。与饲喂1个月相比,饲喂5个月牦牛酥油磷脂可使小鼠脂肪组织中不饱和脂肪酸含量升高。与对照组相比,饲喂牦牛酥油和牦牛酥油磷脂可极显著提高小鼠脂肪组织中支链脂肪酸含量。     

国产婴幼儿配方奶粉中脂肪酸检测结果及分析

为研究国产婴幼儿配方奶粉中脂肪酸的种类和含量情况,在国内市场随机抽取40批国产婴幼儿配方奶粉,使用气相色谱法对婴幼儿配方奶粉中的37种脂肪酸进行检测并分析。结果表明,脂肪酸含量和种类均符合国家标准规定,说明国内市售的国产婴幼儿配方奶粉在脂肪酸的种类和含量方面总体情况良好。     

Buffalo vs. cow milk fat globules: Size distribution,zeta-potential,compositions in total fatty acids and in polar lipids from the milk fat globule membrane

Although buffalo milk is the second most produced milk in the world, and of primary nutritional importance in various parts of the world, few studies have focused on the physicochemical properties of buffalo milk fat globules. This study is a comparative analysis of buffalo and cow milk fat globules. The larger size of buffalo fat globules, 5 vs. 3.5 μm, was related to the higher amount of fat in the buffalo milks: 73.4 ± 9.9 vs. 41.3 ± 3.7 g/kg for cow milk. Buffalo milks contained significantly lower amount of polar lipids expressed per gram of lipids (0.26% vs. 0.36%), but significantly higher amount of polar lipids per litre of milk (+26%). Buffalo and cow milk fat globule membranes contain the same classes of polar lipids; phosphatidylethanolamine, sphingomyelin (SM) and phosphatidylcholine (PC) being the main constituents. A significant higher percentage of PC and lower percentage of SM were found for buffalo milks. The fatty acid analysis revealed that saturated fatty acids, mainly palmitic acid, trans fatty acids, linolenic acid (ω3) and conjugated linolenic acid were higher in buffalo milk than in cow milk. Such results will contribute to the improvement of the quality of buffalo milk-based dairy products.     

肃南牦牛不同部位脂肪中脂肪酸组成分析

目的 为建立科学的牦牛脂肪中脂肪酸评价方法,利用主成分分析法对牦牛不同部位脂肪品质进行综合评价,以期为指导高品质牦牛产品加工和品质评价提供依据。方法 本试验采集肃南牦牛肋条表面、臀肌、肾周、肠周及皮下5个不同部位的脂肪,测定牦牛不同部位脂肪AV、POV,并采用GC-MS技术对5个不同部位脂肪中脂肪酸组成及含量进行测定,采用面积归一化法进行定量,探究肃南牦牛不同部位脂肪组成成分的差异性,并结合多元统计分析讨论脂肪酸成分含量对不同部位脂肪品质的影响。结果 以脂肪酸种类及含量为评定指标,在5个不同部位中均检出36种脂肪酸,以硬脂酸为主,含量都在70~160 g/100g之间;其次是油酸、棕榈酸和亚油酸含量较高。对不同部位的SFA、MUFA、PUFA含量分析表明,皮下脂肪UFA/SFA比值较大,风味较佳、适口性更好。PCA分析表明前三个主成分的累积贡献率高达99.41%,很好的实现了牦牛5个不同部位脂肪的区分。结论 牦牛脂肪中脂肪酸种类丰富,富含多不饱和脂肪酸。不同部位脂肪酸含量有着显著性差异,PCA分析对牦牛不同部位脂肪品质进行综合评价是客观、可行的,为牦牛不同部位脂肪鉴别提供了快速、准确的新方法。     

Food chain approach to lowering the saturated fat of milk and dairy products

Lactating cow diets were supplemented with high‐oleic acid sunflower oil over two production periods spanning two years, to modify the milk fat, partially replacing saturated fatty acids with cis‐monounsaturated fatty acids. The resulting milk was used for ultrahigh‐temperature milk, butter and Cheddar cheese production, and fatty acid profiles were compared with those of conventionally produced products. Fat from products made with modified milk had lower saturated fatty acids and higher cis‐ and trans‐monounsaturated fatty acid concentrations than that of conventional products. This was consistent over both production periods, demonstrating that this food chain approach could be adopted on a wider scale.     

PROXIMATE AND LIPID COMPOSITION OF NONDAIRY IMITATION MILK IN COMPARISON WITH MILK

Comparative studies of milk and nondairy imitation milks showed that their proximate compositions were similar. Qualitative and quantitative studies revealed that saturated fatty acids were abundant in milk, while unsaturated fatty acids (C _18:1 and C _18:2 ) were predominant in nondairy imitation milks. This was confirmed by the higher melting points of the fat fractions of milk compared with those of nondairy imitation milks. Finally, lipid peroxidation level of samples were low as determined by the 2-thiobarbituric acid test.     

The oxidative and lipolytic stability of Yayık butter produced from different species of mammals milk (cow,sheep, goat) yoghurt

Yay?k butter, made from yoghurt, is one of the traditional dairy products in Anatolia In this study, some properties of Yay?k butter produced from cow, sheep, and goat yoghurts have been observed during 30 days of storage at 4–5 °C. In this purpose yoghurts were produced from different species milks then these yoghurts were used as a raw material for production of Yay?k butters samples. On the first day of the storage, differences in pH of serum among the butter produced from different mammals were statistically significant. The highest value of lactic acid was measured in the sample of sheep butter (SB). The level of lactic acid in Yay?k butters was significantly different. Goat butter (GB) had weaker oxidative stability and significantly higher peroxide value than those of other samples. The highest accumulation of the free fatty acids has been detected in sample GB. All samples of Yay?k butter received almost the same score on the first day of the storage, but on day 30 some flavour defects in sample GB were noted by the panelists.     

Butter composition and texture from cows with different milk fatty acid compositions fed fish oil or roasted soybeans

Changing the milk fatty acid composition can improve the nutritional and physical properties of dairy products and their acceptability to consumers. A more healthful milk fatty acid composition can be achieved by altering the cow's diet, for example, by feeding supplemental fish oil (FO) or roasted soybeans (RSB), or by selecting cows with a more unsaturated milk fatty acid composition. We examined whether feeding supplemental FO or RSB to cows that had a more unsaturated milk fatty acid composition acted additively to produce butter with improved fatty acid composition and texture. Using a 3 × 3 Latin square design with 2 replications, we fed diets to multiparous Holstein cows (60 to 200 DIM) chosen for producing either more or less unsaturated milk fatty acid composition (n = 6 for each group) for three 3-wk periods. The control diet contained 3.7% crude fat and the 2 experimental diets contained, on a dry matter basis, 0.8% of additional lipids in the form of 0.9% of FO or 5% of RSB. The milk, collected in the third week of feeding, was used to make butter, which was analyzed for its fatty acid composition and physical properties. Dry matter intake, milk yield, and milk composition were not significantly affected by cow diet or by cow selection. Cows that produced a more unsaturated and healthful milk fat prior to the feeding study, according to a “health-promoting index” [HPI = (sum of % of unsaturated fatty acids)/ (%12:0 + 4 × %14:0 + %16:0)], maintained a higher HPI in their butter during the feeding study than did cows with a low HPI. Milk from cows fed supplemental FO or RSB yielded more unsaturated butters with a higher HPI. This butter also was softer when the cows were fed RSB. Feeding RSB to cows chosen for their high milk HPI yielded the most unsaturated butter with the highest HPI and softest texture. Thus, selecting cows with a more health-promoting milk fatty acid composition and feeding supplemental RSB can be used in combination to produce butter that has a consumer-friendly texture and a healthful fatty acid profile.     

当雄牦牛肉的营养和风味特性

以市售西门塔尔牛肉（下文简称“市售牛肉”）作为对照组,研究当雄牦牛肉的营养和风味特性。采用高效液相色谱、气相色谱-质谱联用、凯氏定氮等方法分别分析当雄牦牛肉和市售牛肉中蛋白质、氨基酸、脂肪酸、挥发性风味物质、矿物质和维生素差异。结果表明：当雄牦牛肉中蛋白质含量（22.89 g/100 g）显著高于市售牛肉（P＜0.05）,剪切力及蒸煮损失率显著低于市售牛肉（P＜0.05）;当雄牦牛肉中VB1、VE含量显著高于市售牛肉（P＜0.05）,2 种牛肉中的VB2、VA含量无显著差异;当雄牦牛肉中总氨基酸、必需氨基酸、总脂肪酸及不饱和脂肪酸含量均显著高于市售牛肉（P＜0.05）;微量元素分析结果发现,当雄牦牛肉中锰、硒、镁、铁、钙元素的含量均显著高于市售牛肉（P＜0.05）;当雄牦牛肉及市售牛肉中分别检测出58、43 种挥发性风味物质,牦牛肉中醇类和酯类的种类及含量均高于市售牛肉,而市售牛肉中酚类、醛类、酮类及含氮化合物的含量均较高。因此,当雄牦牛肉具有较好的食用营养品质。     

Comparative milk fatty acid analysis of different dairy species

This study compared the fatty acid (FA) profile of milk from different dairy mammals: buffalo, camel, cow, goat and yak. Data from milk samples and reports in the literature were processed using principal component analysis. The results showed that camel milk contained the lowest levels of C4:0–C12:0 and highest levels of unsaturated fatty acids. Goat milk had the highest level of C8:0–C14:0 FA. Characteristic differences were observed for yak and buffalo milk, which differed from cow milk by their higher levels of saturated fatty acids and lower levels of polyunsaturated fatty acids. It is therefore suggested that each animal species’ milk has its own specific milk FA profile.