Milk fat globule membrane supplementation protects againstβ-lactoglobul-ininduced food allergy in mice via upregulation of regulatory T cells and enhancement of intestinal barrier in a microbiota-derived short-chain fatty acids manner

Milk fat globule membrane(MFGM),which contains abundant glycoproteins and phospholipids,exerts beneficial effects on intestinal health and immunomodulation.The aim of this study was to evaluate the protective effects and possible underlying mechanisms of MFGM on cow’s milk allergy(CMA)in aβ-lactoglobulin(BLG)-induced allergic mice model.MFGM was supplemented to allergic mice induced by BLG at a dose of 400 mg/kg body weight.Results demonstrated that MFGM alleviated food allergy symptoms,decreased serum levels of lipopolysaccharide,pro-inflammatory cytokines,immunoglobulin(Ig)E,Ig G1,and Th2 cytokines including interleukin(IL)-4,while increased serum levels of Th1 cytokines including interferon-γand regulatory T cells(Tregs)cytokines including IL-10 and transforming growth factor-β.MFGM modulated gut microbiota and enhanced intestinal barrier of BLG-allergic mice,as evidenced by decreased relative abundance of Desulfobacterota,Rikenellaceae,Lachnospiraceae,and Desulfovibrionaceae,while increased relative abundance of Bacteroidetes,Lactobacillaceae and Muribaculaceae,and enhanced expressions of tight junction proteins including Occludin,Claudin-1 and zonula occludens-1.Furthermore,MFGM increased fecal short-chain fatty acids(SCFAs)levels,which elevated G protein-coupled receptor(GPR)43 and GPR109A expressions.The increased expressions of GPR43 and GPR109A induced CD103+dendritic cells accumulation and promoted Tregs differentiation in mesenteric lymph node to a certain extent.In summary,MFGM alleviated CMA in a BLG-induced allergic mice model through enhancing intestinal barrier and promoting Tregs differentiation,which may be correlated with SCFAs-mediated activation of GPRs.These findings suggest that MFGM may be useful as a promising functional ingredient against CMA.

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.

Evaluation of Total Fatty Acid Profiles of Two Types of Low-Fat Goat Milk Ice Creams

Effects of frozen-storage on fatty acids profiles and basic nutrient contents of two types of low-fat caprine milk ice creams were investigated during 0, 2, 4, 8 weeks of storage at -18°C. Two types of the experimental low-fat soft-serve goat ice creams were manufactured using whole (full-fat) milk and 2% fat goat milk with addition of commercial powdered vanilla flavor pre-mix containing 0.25% fat (Alpha Freeze, D466-A9047, Tampa, FL, USA). Fatty acid concentrations were quantified using a Thermo Electronic gas chromatography (GC)-MS (Model TRACE GC Ultra, Austin, TX, USA) equiped with an automatic sampler (Model AS-3000, Thermo Electronic Co.). The results showed that fat content was the only basic nutrient component exhibited the difference between the two types of ice creams, while no other components have shown differences between the two low-fat ice creams during the storage periods. The level of lauric acid (C12:0) was the highest among all 16 fatty acids, followed by palmitic (C16:0), linoleic (C18:1), and myristic acid (C14:0). The high levels of the medium chain fatty acids (C12:0 and C14:0) might have been derived from the goat milk as well as the palm oil asa part of the ingredients in the commercial ice cream premix. Among long chain fatty acids, palmitic acid (C16:0) was the highest, followed by oleic acid (C18:1) and stearic acid (C18:0). All of the long chain fatty acids contents were significantly higher (P < 0.05 or 0.01) in whole milk ice cream than those in 2% fat ice cream, except for the C22:0 and C24:00 acids. It was concluded that mean levels of the individual fatty acids in the caprine ice creams were significantly influenced by the types of milk fat used in the ice creams, but not by storage periods and storage × fat type interaction effects.

Transfer of PUFA fatty acid protected and carnitin precursor on the ration of chemical composition of milk dairy goat

The experiment was conducted to investigate the effect of transfer of PUFA protected and carnitin precursor on the ration of chemical composition of milk dairy goat. In total, 10 female dairy goats of 2 - 4 years old Peranakan Etawah (PE) with body weight of 25 - 45 kg were used in this experiment. The feed material included a basal diet (control) based on yellow corn, rice bran, soya bean meal, coconut meal, tuna fish oil and lemuru fish oil. The method of the research was experimental in vivo using Randomized Completely Block Design (RCBD). There were 5 treatments in each experiment and 2 replications. The treatment consisted of P0 = control ration, P1 = P0 + 200 ppm L-carnitine on the ration, P2 = P1 + soya bean oil, P3 = P1 + protected tuna fish oil 5 ml or equal with 4% in the ration, and P4 = P1 + protected lemuru fish oil 5 ml or equal with 4% in the ration. The measured variable is chemical composition of milk dairy goat. The results of variance analysis showed that the effect of transfer of PUFA fatty acid in the rations contained 200 ppm L-carnitine significantly

Comparison of free fatty acid composition between low-fat and full-fat goat milk cheeses stored for 3 months under refrigeration

Differences in free fatty acid (FFA) compositions between low-fat (LF) and full-fat (FF: whole milk) goat cheeses were evaluated during 3 months at 4oC refrigeration. The two types of cheeses were manufactured using a bulk milk from the mixed herd of Saanen, Alpine, and Nubian goat breeds. LF cheeses were made using LF milk after cream separation. FFAs of all cheeses were extracted in diisoprophyl ether using polypropylene chromatography column, and FFA concentrations were quantified using a gas chromatograph equipped with a fused silica capillary column. Moisture, fat, protein contents (%) and pH of fresh LF and FF cheeses were: 55.1, 52.3;1.30, 25.6;35.7, 22.5;5.40, 5.42, respectively. The FFA contents (mg/g cheese) of fresh FF and LF cheeses prior to storage treatments for C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C16:0, C18:0, C18:1, and C18:2 were: 0.020, 0.072;0.070, 0.035;0.061, 0.055;0.181, 0.167;0.073, 0.047;0.174, 0.112;0.579, 0.152;0.308, 0.202;0.521, 0.174;and 0.057, 0.026, respectively. The respective FFA to total fatty acid ratios for 0, 1 and 3 months aged FF and LF cheeses were 8.44, 12.4;6.31, 16.91;12.03, 14.19. The LF cheeses generated more FFA than FF cheeses, while actual FFA content in FF cheese was significantly higher than in LF cheese. The FFA contents of LF cheese at 0, 1 and 3 months storage were 48.0, 96.8 and 36.4% of those of FF cheese, respectively. It was concluded LF cheese generated higher amount of FFA than FF cheese, although total FFA content was significantly (P<0.05) lower in LF cheese than in FF cheese.

Characterization of Antibacterial Activity and Potential as Probiotic of Lactic Acid Bacteria Isolated from Goat＇s Milk in Algeria

Lactic acid bacteria （LAB） were isolated from goat＇s milk in different north west region of Algeria. A total of 233 isolates were identified as LAB. However, only 11 strains showed excellent inhibition zones on agar when Salmonella lyphimorium ATCC 13311 was used as an indicator for preliminary detection of antagonistic activity. After elimination of inhibition due to acid and H202, Staphylococcus aureus ATCC 25923 was used for secondary screening for antagonistic activity of these 11 strains. It was found that only 9 strains exhibited a good inhibition zones on agar, and all of them could inhibit E. coli ATCC 25921 and Pseudomonas aeruginosa ATCC 27853 as the third and the forth indicators respectively. Lactococcus lactis subsp, cremoris, Lactobacillus casei subsp, casei, Lactobacillus casei subsp, rhamnosus, Streptococcus salivarius subsp, thermophilus and Lactococcus lactis biovar. diacetylactis were the strains that have a good antibacterial activity, survive in the gastrointestinal conditions and were sensible to the majority of the antibiotics. All isolated strains tolerate pH = 2 and high bile salt concentration.

Esterase Activities and Biochemical Properties of Lactic Acid Bacteria Isolated from Goat＇s Milk Cheese in Argentina

Twenty-two lactic acid bacteria （LAB） strains isolated from Argentinean goat dairy products were evaluated for its biochemical properties and esterase activities relevant to flavor development. Streptococcus thermophilus （UNSE314）, Lactobacillus （L.） delbrueckii subsp, bulgaricus （UNSE309）, L. rhamnosus （UNSE308）, L. plantarum （UNSE287, UNSE316, UNSE317） and Pediococcus pentosaceus （UNSE315） strains presented high acidifying activity. All strains tested metabolized citrate and produced diacetyl-acetoin in goat milk. Based on these results, 10 strains with the best performance in diverse technological properties were selected to determine esterolytic activity. In all evaluated strains, esterase specific activity （ESA） was detected on ct-naphthyl （ct-NA） acetate and 13-naphthyl （[3-NA） acetate, propionate, eaprylate and ct-NA butyrate. No activity was detected on [3-NA laurate. The highest values were detected when using a-NA instead of fI-NA derivatives as substrate. In Pediocoecus strains, wide variability in ESA were observed, which were species- and strain-specific. These results allow us to select strains with biochemical properties and esterase activities to design starter and adjunct cultures that contribute to flavor development during cheese ripening, thus preserving the typical organoleptic characteristics of Argentinean goat cheeses.

QuEChERS-液相色谱-串联质谱法测定乳及乳制品中活化酯及其代谢物阿拉酸式苯含量

该文研究了高效液相色谱-三重四级杆质谱法(HPLC-MS/MS)测定乳及乳制品中活化酯和阿拉酸式苯的测试方法。样品经甲酸乙腈(含1%甲酸(V/V))涡旋提取,分析液经QuEChERSdSPE EMR-Lipid除脂专用管净化,离心后过膜上机检测。测试方法以甲醇-0.1%甲酸水(V/V)为流动相,流速设置为0.2 mL/min,应用梯度洗脱程序,采用ACQUITY UPLC HSS T3色谱柱进行分离,电喷雾正、负离子模式(活化酯为ESI+、阿拉酸式苯为ESI-),多反应离子监测模式(MRM)检测,基质匹配外标法进行定量。对于乳及乳制品基质,活化酯和阿拉酸式苯在1~30 ng/mL 2的质量浓度与其相对应的峰面积之间线性关系良好,R^(2)均大于0.996,在0.01、0.02和0.1 mg/kg 3种不同浓度添加水平下,活化酯和阿拉酸式苯的平均回收率在91.8%~109.6%之间,相对标准偏差在1.3%~11.5%之间。该方法可满足残留检测的准确度、精密度和灵敏度的要求。

Advances in molecular regulation of goat lipid metabolism and FAS structure and function regulation

Goat milk is widely recognized for its nutritional value.Fatty acid synthase(FAS)is the crucial enzyme of fatty acid de novo synthesis.It plays an important role in the formation of goat milk fat.In this paper,we first introduced the molecular regulation process of goat milk fat metabolism based on the structure research of FAS.Secondly,we reviewed some key factors in FAS transcription and post-transcriptional regulation of the goat mammary gland and preliminarily constructed the expression network of the goat mammary gland FAS gene.The purpose of this paper is to systematically introduce the role of FAS in goat milk fat metabolism and to provide a reference for future studies on the mechanism of goat milk fat metabolism.

基于B/S架构及MySQL数据库的羊乳粉营养品质信息管理系统设计与构建

为向用户提供羊乳粉的营养品质等数据信息,促进羊乳产业发展,基于浏览器/服务器(browser/server,B/S)架构和MySQL数据库,以Java作为主要系统开发语言,采用前、后端分离技术,使用Docker平台进行微服务架构部署,设计并建立羊乳粉营养品质信息管理系统,实现羊乳粉各类数据信息的存储和可视化。本信息管理系统功能模块设置为系统管理、数据上传添加、快速查询及专题分析,可实现羊乳粉各种营养成分的快速、准确搜索,并能获取不同种类、地区羊乳粉品质差异情况,对羊乳粉产地进行初步判断。本信息管理系统操作简单、普适性强,有利于羊乳粉品质的科学研究、质量控制及品质提升,为用户安全消费羊乳粉提供了数据保证。

支链脂肪酸在羊体内的合成过程及其对乳肉膻味影响的研究进展

随着生产生活物资丰富,人们对于食品质量和饮食健康的关注持续增加。羊乳和羊肉产品因其易消化、营养丰富等特性逐渐赢得消费者的青睐。然而,羊乳和羊肉产品的膻味特征在一定程度上降低了消费者的接受度和购买意愿。研究表明,4-甲基辛酸、4-乙基辛酸、4-甲基壬酸3种挥发性支链脂肪酸的沉积,是羊乳和羊肉产品膻味的主要成因。本文综述了支链脂肪酸在羊体内的合成机理及其对羊乳和羊肉产品膻味的贡献及影响因素,以期为羊乳和羊肉产品膻味的定性和调控提供依据。

基于牛磺酸 叶酸和维A为特征指标羊乳掺假的 分析研究

为了初步准确判断羊乳是否掺假,通过建立高效液相色谱法和气相色谱法对纯牛羊乳及其乳粉制品中牛磺酸、叶酸和维A含量进行测定,总结不同样品中3种生长因子的含量变化规律,并结合主成分分析(PCA)建立研究方法。该方法简便且准确性高,可应用于羊乳的初步真伪鉴别,为建立健全乳品质量检验技术体系,保障乳品市场的规范化运行提供了依据。

山羊原奶中可培养乳酸菌多样性及菌株的体外益生特性分析

本研究旨在了解新疆地区山羊原奶中乳酸菌的益生特性、加工特性和安全性,以期为开发功能性乳品奠定一定的基础。实验采用16S rRNA基因测序结合Rep-PCR指纹分型技术对分离出的乳酸菌菌株进行遗传差异分析,检测它们对酸和胆盐的耐受性并对耐受性较好的菌株进行模拟胃肠液耐受性、细胞表面特性(疏水性和自凝聚)、抗菌活性、工艺逆境耐受性(溶菌酶、热)及药敏试验,来评价菌株的体外益生特性和安全性,通过主成分分析筛选最优的益生菌株。研究从15份山羊乳样品中共分离得到23株乳酸菌,包括Leuconostoc mesenteroides(9株)、Lactiplantibacillus plantarum(6株)、Latilactobacillus curvatus(4株)、Enterococcus faecium(2株)、Enterococcus durans(2株)。基于对酸和胆盐耐受性进行初筛的结果表明,有7株菌具有较好的耐受性。其中,2株植物乳植物杆菌(L. plantarum SY43-10和L. plantarum SY43-4)的模拟胃液和肠液处理后活菌数均高于5 lg CFU/mL;24 h自凝集率大于27%、并具有良好疏水性;热和溶菌酶处理后的活菌数仍大于7 lg CFU/mL;药敏试验显示2株菌对氨苄西林和氯霉素表现敏感,对头孢西丁、红霉素和青霉素表现中度敏感或敏感。因此,菌株SY43-10和SY43-4可作为优良的益生菌株,通过体内实验进一步应用于发酵乳品和功能性产品。

Responses in splanchnic and mammary amino acid metabolism to short-term graded removal of methionine in lactating goats

Four multi-catheterized lactating goats were used in a 4×4 Latin square experiment to investigate the responses of amino acid metabolism in portal-drained viscera(PDV),liver,and mammary glands to short-term varying supplies of methionine(Met).During the last 45 h in each experimental period,goats were fasted for 12 h and then abomasally infused with an amino acid(AA)mixture plus glucose for 33 h.Treatments consisted of graded removal of Met from an infused AA mixture to achieve Met content in the infusate of 100%(complete),60%,30%,or 0%that in casein.Graded Met removal decreased the pro-duction of milk,milk protein,lactose,and fat linearly whilst also decreasing arterial Met concentration linearly(P<0.05).Meanwhile,net PDV uptake and liver removal of Met decreased linearly(P<0.05)due to decreased Met affinity of PDV and liver(P<0.05).Net mammary uptake of Met(P>0.1)was maintained as Met supply declined.This was achieved through increased mammary affinity(P<0.05)and increased mammary blood flow(P<0.05)totally offsetting the negative effect of decreased circu-lating Met concentration.Graded removal of Met from the infusate linearly decreased mammary uptake-to-milk output ratios of Met(P<0.05)and tended to decrease essential amino acid(EAA)linearly(0.05<P<0.1).Treatments also linearly decreased circulating concentration of prolactin and linearly increased insulin concentration(P<0.05).In conclusion,results of the present study indicated there were several mechanisms used to mitigate a Met deficiency,including reduced catabolism of Met in PDV,liver,and peripheral tissue(including mammary glands)and a linear increase in mammary blood flow.The observed decreases in milk protein production as Met supply decreased appear to be a result of regulatory events which may have been driven by decreased circulating prolactin,rather than as a result of decreased mammary Met uptake.

牛羊乳脂肪球膜稳定性及非靶向脂质组学差异研究

以我国关中地区中国荷斯坦牛与奶山羊为研究对象,基于非靶向脂质组学技术,分析乳脂肪球膜脂质,筛选膜上差异脂质。结果表明,在牛羊乳MFGM中分别检测到3004种和2857种脂质。牛乳中磷脂、糖脂、固醇和鞘脂分别占除甘油酯外其他脂质总含量75.94%、8.29%、3.82%和3.76%,羊乳中分别为66.98%、12.42%、4.27%、3.57%。此外,牛羊MFGM上存在1496种显著性差异脂质,其中TG(17︰0/10︰0/22︰6)、TG(16︰0e/8︰0/18︰1)、TG(8︰0/10︰4/14︰2)、TG(14︰0/14︰0/22︰6)和DG(15︰0/16︰0)等甘油酯分子与CL(87︰12)、PE(41︰2e)、SM(t39︰7)、CL(66︰1)、MePC(29︰2e)、PE(16︰0/16︰1)和PI(18︰1/20︰3)等MFGM脂质分子可用于牛羊乳分类鉴定以及区别检测靶点,为牛羊乳脂质检测提供理论基础。

茯砖茶与羊乳复合乳体系的抗氧化、物理及消化稳定性研究

以陕西省特色的茯砖茶和羊乳为原料,以抗氧化稳定性、物理稳定性和消化稳定性为主要指标,研究茯砖茶与羊乳复合乳体系的稳定性.试验结果表明,25℃放置7 d的过程中,茯砖茶与羊乳复合乳体系抗氧化活性总体呈降低趋势,含活性金花菌的复合乳体系(样品1)的抗氧化稳定性最好,含无活性金花菌的复合乳体系(样品2)次之,不含金花菌的复合乳体系(样品3)最差.物理稳定性试验结果显示,茯砖茶与羊乳复合乳体系随着放置时间的延长,物理稳定性也不断降低,样品3的物理稳定性强于样品1、样品2;扫描电镜显微表征显示,茶汤中的金花菌与羊乳酪蛋白可形成复合物,从而降低了复合体系的物理稳定性.消化稳定性试验结果表明,随着消化时间的延长,酪蛋白体外消化率均不断增大,但与对照组相比,茯砖茶与羊乳复合乳体系抑制了乳蛋白的消化,且胃消化阶段抑制效果强于肠消化阶段,样品2的抑制效果最强,样品1次之,样品3最差.研究结果为进一步开发研制茯砖茶羊奶奶茶新产品提供了重要理论依据与技术支撑.

基于脂质组学揭示饲喂裂殖藻粉对山羊乳脂质的影响

基于气相色谱法和超高效液相色谱-四极杆-飞行时间串联质谱法探究饲喂裂殖藻粉(Schizochytrium spp.)对山羊乳脂肪酸组成及全脂质组成的影响,并与市售纯牛乳和二十二碳六烯酸(docosahexaenoic acid,DHA)牛乳进行差异性分析。结果表明,山羊乳脂肪含量显著高于牛乳,肉豆蔻酸、棕榈酸和油酸是乳中主要的脂肪酸组成。饲喂裂殖藻粉能显著增加山羊乳中DHA含量。甘油三酯是2种乳中主要的脂质成分,山羊乳中磷脂含量显著高于牛乳。DHA在乳品脂质中主要以甘油酯型DHA形式存在,山羊乳较牛乳含更丰富的磷脂型DHA。裂殖藻粉添加量50 g/d为山羊乳中DHA富集的最佳添加量。通过在日粮中添加DHA原料,能够进一步提高山羊乳的营养价值,解决目前膳食DHA来源单一的问题。本研究为婴幼儿配方奶粉及富DHA功能性乳脂产品的开发和营养调控提供有力的理论依据和参考,并为乳制品类型的鉴定提供方法与数据基础。

羊奶乳清蛋白的分离提取研究

为获得品质更好的羊奶乳清蛋白,以鲜羊奶为原料,分别采用离心法、酸等电点沉淀法(盐酸法、乙酸法和柠檬酸法)和乙醇分级沉淀法对羊奶中的乳清蛋白进行分离提取,通过测定所得乳清蛋白性质,评估各方法的分离提取效果。结果表明,酸沉淀法分离的乳清酪蛋白残留量较少,其中盐酸法提取的乳清酪蛋白去除率为(75.90±0.30)%。乙酸法获得乳清的粒径显著高于其他4种方法(P<0.05)。3种酸沉淀法提取乳清的Zeta电位无显著差异(P>0.05)。经过酸法提取的乳清中β-折叠结构转向了α-螺旋结构。离心和盐酸法提取的乳清中游离巯基含量显著高于乙酸法获得乳清(P<0.05)。综上,乙酸分离提取效果最佳,提取的乳清品质最好,是一种有效的、科学的羊奶乳清蛋白分离方法。

奶山羊品种和养殖区对羊乳支链脂肪酸组成的影响

支链脂肪酸作为新兴生物活性物质备受关注。羊乳营养价值丰富,其支链脂肪酸组成和含量与母乳最为接近,分析影响羊乳中支链脂肪酸组成的因素对羊乳资源高值化利用具有重要的研究意义。本研究采用气相色谱-质谱法对萨能奶山羊、关中奶山羊2个品种和山东、陕西地区4个养殖区奶山羊的羊乳支链脂肪酸组成进行比较分析。结果表明:萨能奶山羊的羊乳中支链脂肪酸成分组成较关中奶山羊的羊乳中支链脂肪酸成分组成丰富,山东萨能奶山羊anteiso-C17∶0显著高于陕西省3个养殖区,陕西省3个养殖区羊乳的异构支链脂肪酸占比存在显著差异性(P<0.05)。本文从支链脂肪酸组成角度揭示了萨能奶山羊的乳营养更丰富,陕西地区萨能山羊乳和山东地区关中山羊乳中支链脂肪酸组成更加贴近母乳。

高效液相色谱法测定传统发酵乳中的有机酸组成

利用高效液相色谱(HPLC)法研究了传统发酵乳中的7种有机酸的分离测定条件,同时对青海省传统发酵乳酸牦牛奶、酸山羊奶和酸马奶等40个样品的乳酸、乙酸和柠檬酸含量进行了测定。结果表明,选择浓度为0.010 mol/L磷酸—磷酸二氢钠(pH=2.0)和甲醇(体积比为98︰2)做流动相,流速为0.5 mL/min,紫外检测波长为210 nm时可以较好地分离测定发酵乳中的乳酸、乙酸和柠檬酸。该方法不仅相对标准偏差小(0.35%～1.23%),回收率高(95.4%～103.8%),线性相关系数高(乳酸r>0.99994,醋酸r>0.99997,柠檬酸r>0.99999),而且具有较高的准确度和精确度;通过发酵乳样品的有机酸含量测定发现,发酵乳中除主要含有乳酸外还有微量的乙酸、柠檬酸和痕量的甲酸、苹果酸、琥珀酸及丙酸。3种家畜奶发酵乳中各种有机酸含量有较大差别。