超高效液相色谱-静电场轨道阱高分辨质谱鉴定核桃仁的脂质构成

利用超高效液相色谱-静电场轨道阱高分辨质谱系统鉴定了核桃的脂质组.在正负离子模式下获得脂质的一级质谱和二级质谱信息后,共鉴定出4大类525种脂质分子,包括250种甘油酯、221种磷脂、18种糖脂、36种鞘脂类,含量分别占总脂质的87％、12.97％、0.02％和0.01％.甘油二酯(diacylglycerol,DG)...     

微拟球藻总脂中甘油酯组成定量分析及EPA的存在形式研究

采用正己烷-乙醇混合溶剂提取微拟球藻总脂,分级后得到中性脂、糖脂和磷脂,采用薄层层析分离3组分,并采用气相色谱法定量分析各组分在总脂中的含量及脂肪酸组成,同时分析了EPA在各脂质中的分布。结果表明：微拟球藻总脂甘油酯的中性脂、糖脂、磷脂占比分别为3342%、38.22%和28.36%;中性脂主要组分为甘油三酯（TAG）和游离脂肪酸（FFA）,在总脂中的含量分别为9.27 g/100 g和5.79 g/100 g;糖脂主要组分为单半乳糖甘油二酯（MGDG）和双半乳糖甘油二酯（DGDG）,在总脂中的含量分别为14.03 g/100 g和5.81 g/100 g;磷脂主要组分为磷脂酰乙醇胺（PE）、磷脂酰胆碱（PC）和磷脂酰肌醇（PI）,在总脂中的含量分别为6.22、3.53 g/100 g和1.53 g/100 g。3类脂质之和占微拟球藻总脂的51.49%;不同脂类脂肪酸组成差别较大,EPA在甘油一酯（MAG）、MGDG、DGDG和PE中比例较高,分别占各组分脂肪酸总量的16.94%、3724%、1432%和10.51%,EPA在中性脂中分布最低,83.59%的EPA以糖脂形式存在。     

沙芥乳酸菌发酵饮料的工艺优化

选取植物乳杆菌、保加利亚乳杆菌以及嗜热链球菌3 种益生菌,对沙芥进行发酵处理,以发酵活菌数和酸度为参考指标,通过单因素试验以及正交试验确定复合菌的配比为植物乳杆菌∶嗜热链球菌∶保加利亚乳杆菌=4∶4∶3（质量比）,最佳发酵工艺：发酵温度33 ℃、发酵时间14 h、菌种接种量4%;基于此发酵工艺条件,测得沙芥发酵饮料所含活菌数达6.03×108 CFU/mL。     

荸荠保健酸奶的研制

以荸荠和鲜牛乳为主要原料,配以蔗糖和稳定剂,使用保加利亚乳杆菌和嗜热链球菌混合菌种发酵,制成风味独特、营养丰富的保健饮品。通过正交试验优选出最佳发酵工艺条件为：接入4%的保加利亚乳杆菌和嗜热链球菌（1∶1）,在42℃下发酵5h,后发酵时间为20h。     

3种经济类海胆的脂质组成差异分析

目的 对比分析国内3种常见经济类海胆的脂质组成。方法 以性腺基本指数、总脂含量、胆固醇含量、磷脂含量、甘油酯含量、脂肪酸组成、磷脂组成等为评价指标,结合统计分析技术比较不同种类海胆脂质组成的差异。结果 光棘球紫海胆、黄海胆和虾夷马粪海胆总脂占干基的(21.83±0.12)%～(27.21±0.10)%;其中磷脂和甘油酯是最主要的脂类组分,分别占(39.62±0.49)%～(49.39±0.73)%和(30.08±0.01)%～(38.65±0.03)%;磷脂中的主要组分为磷脂酰胆碱、磷脂酰乙醇胺和磷脂酰肌醇;总脂中脂肪酸主要为C16:0、C18:0、C20:1。对脂类相关数据进行标准化处理,并结合聚类分析和主成分分析,结果显示3种海胆性腺脂类物质中脂质组成、磷脂组成及脂肪酸组成差异明显。结论 光棘球紫海胆相对于其他两种海胆具有较高的营养价值和脂质优势,可作为C20:5n3、C22:6n3及磷脂等功能性脂质分子的重要膳食来源。     

嗜酸乳杆菌与嗜热链球菌混合培养制作保健型发酵乳的研究

对嗜酸乳杆菌和嗜热链球菌混合培养制作保健型发酵乳进行了研究，通过正交试验优化出了最佳生产工艺：加糖量为8%，嗜热链球菌和嗜酸乳杆菌比例为1∶4，接种量为4%，发酵温度为40℃.该发酵乳在4℃下贮存11天活菌数高于107cfu/ml，仍可具有良好的食疗保健作用。     

麦胚乳酸菌发酵饮品的工艺优化及品质分析

以麦胚为原料,利用复合乳酸菌发酵研制麦胚乳酸菌发酵饮品。以离心沉淀率为评价指标,优化稳定剂含量;采用单因素试验及正交试验,优化麦胚乳酸菌发酵饮品工艺条件,并测定其理化指标。结果表明,最佳稳定剂为羟丙基二淀粉磷酸酯0.5%、琼脂0.2%;最佳发酵工艺条件为嗜热链球菌（Streptococcus thermophiles）、保加利亚乳杆菌（Lactobacillus bulgaricus）、乳双歧杆菌（Bifidobacterium lactis）、鼠李糖乳杆菌（Lactobacillus rhamnosus）、植物乳杆菌（Lactobacillus plantarum）、嗜酸乳杆菌（Lactobacillus acidophilus）、干酪乳杆菌（Lactobacillus casei）按照配比1∶1∶1∶1∶1∶1∶1制备发酵剂,接种量0.03%,发酵时间24 h,发酵温度 42 ℃。在此最佳条件下,麦胚乳酸菌发酵饮品为乳酪色,质地黏稠,口感细腻,总蛋白3.53 g/100 g,总膳食纤维2.12 g/100 g,维生素E 1.28 mg/100 g,亚油酸669 mg/100 g,α-亚麻酸75.8 mg/100 g,乳酸活菌数2.1×109 CFU/mL。     

嗜热链球菌的分离筛选及与嗜酸乳杆菌共发酵制备酸奶的工艺研究

研究嗜热链球菌与嗜酸乳杆菌的生物学特性及共生作用。采用稀释涂布法和平板划线法,分离纯化嗜热链球菌,并鉴定和筛选优良发酵菌株。发酵条件为:加糖量7%,球杆菌混合比例l∶4,接种量4%(V/V),发酵温度40℃,效果最好。以嗜酸乳杆菌代替保加利亚乳杆菌与嗜热链球菌共发酵,通过优化的发酵工艺生产酸奶,可使酸奶的益生功能进一步增强。     

基于脂质组学法对母乳、牛乳及羊乳脂质的差异分析

基于超高效液相色谱-四极杆-飞行时间质谱技术对母乳、牛乳及羊乳的全脂质组分进行定量分析。通过分析共检出17种磷脂酰胆碱(phosphatidylcholines,PC)、11种神经酰胺(ceramide,Cer)、15种鞘磷脂(sphingomyelin,SM)、3种己糖苷神经酰胺(hexosylceramides,HexCer)、32种甘油二脂(diglyceride,DG)和2 5种甘油三酯(triglyceride, TG)。母乳与牛乳有3 6种存在显著差异的脂质,与羊乳有1 4种(P0.05)。结果表明,母乳极性脂含量(1 462.99μg/mL)显著低于羊乳而高于牛乳(P0.05),且母乳及牛乳遵循SMCerPCHexCer分布,羊乳则是CerSMHexCerPC。母乳与牛乳间存在显著差异的极性脂质主要为SM,其中SM(d14∶0/20∶0)和SM(d15∶0/24∶1)在母乳(15.90μg/mL和16.55μg/mL)中显著高于牛乳(P0.05),而羊乳与母乳间除PC(26∶0/0∶0)外,不存在其他显著差异的极性脂质。中性脂质方面,母乳中性脂质量浓度(47 749.40μg/mL)显著高于牛乳及羊乳(P0.05)。母乳与牛羊乳间存在显著性差异的中性脂质主要为TG,尤其母乳在TG(14∶0/16∶0/18∶0)与TG(16∶0/17∶0/18∶0)含量上显著低于牛羊乳(P0.05),同时3种乳在TG(17∶2/18∶0/20∶5)含量上均存在显著性差异(P0.05)。本研究不仅为婴幼儿配方奶粉的脂质研究提供理论依据,同时筛选出的差异脂质可作为鉴别牛羊乳的脂质标记物。     

凝固型鹰嘴豆酸乳的发酵工艺研究

以鹰嘴豆和复原乳为主要原料,通过保加利亚乳杆菌和嗜热链球菌发酵得到鹰嘴豆酸奶。结果表明:膨胀鹰嘴豆以6倍质量的水进行磨浆,再与复原乳以1∶1混合,通过保加利亚乳杆菌和嗜热链球菌1∶1混合发酵,接种量6%,加糖量5%,发酵温度42℃,发酵时间6～7 h。     

COMPOSITION OF THE LIPIDS OF CUCUMBER AND PEPPERS

SUMMARY— Cucumber and green peppers contain 103 mg and 400 mg total lipid per 100g raw vegetable tissue. The neutral lipids, phospholipids and glycolipids comprise 39, 49 and 15% of the cucumber lipids and 82, 2 and 16% of the pepper lipids respectively. The neutral lipids of both were composed mainly of glycerides. In the peppers the triglycerides accounted for 60% of the total lipids. Cucumber, had less glycerides but contained several unidentified sterols. Phosphatidylcholine was the major class in both vegetables accounting for 46 and 76% of the phospholipids of cucumber and pepper respectively. Palmitic, linoleic and linolenic acids were the principal fatty acid components. The lipids of peppers were very rich in linoleic acid (70%) whereas those of the cucumbers contained relatively more linolenic acid.     

Total milk fat extraction and quantification of polar and neutral lipids of cow,goat, and ewe milk by using a pressurized liquid system and chromatographic techniques

Although milk polar lipids such as phospholipids and sphingolipids located in the milk fat globule membrane constitute 0.1 to 1% of the total milk fat, those lipid fractions are gaining increasing interest because of their potential beneficial effects on human health and technological properties. In this context, the accurate quantification of the milk polar lipids is crucial for comparison of different milk species, products, or dairy treatments. Although the official International Organization for Standardization-International Dairy Federation method for milk lipid extraction gives satisfactory results for neutral lipids, it has important disadvantages in terms of polar lipid losses. Other methods using mixtures of solvents such as chloroform:methanol are highly efficient for extracting polar lipids but are also associated with low sample throughput, long time, and large solvent consumption. As an alternative, we have optimized the milk fat extraction yield by using a pressurized liquid extraction (PLE) method at different temperatures and times in comparison with those traditional lipid extraction procedures using 2:1 chloroform:methanol as a mixture of solvents. Comparison of classical extraction methods with the developed PLE procedure were carried out using raw whole milk from different species (cows, ewes, and goats) and considering fat yield, fatty acid methyl ester composition, triacylglyceride species, cholesterol content, and lipid class compositions, with special attention to polar lipids such as phospholipids and sphingolipids. The developed PLE procedure was validated for milk fat extraction and the results show that this method performs a complete or close to complete extraction of all lipid classes and in less time than the official and Folch methods. In conclusion, the PLE method optimized in this study could be an alternative to carry out milk fat extraction as a routine method.     

Blood and Milk Lipid Responses Induced by Growth Hormone Administration in Lactating Cows

Nine multiparous Holstein cows (average 5.8 yr, 63 to 132 days postpartum) were in a 28-day single reversal experiment in the Beltsville open circuit respiration chambers with two 14-day injection periods (placebo versus bovine growth hormone, 51.5 IU/day). With growth hormone treatment, milk fat percentage increased 25 to 29%, milk fat yield increased 41%, and cows averaged ?13.7 Mcal/day energy balance. There were small increases of triglycerides and 1,2-diglycerides, core lipids, and small decreases of cholesterol and phospholipids, the membrane lipids. Fat from growth hormone treatment had 6% less short (6:0, 8:0, 10:0) and medium (12:0, 14:0, 14:1, 15:0, 16:0) chain fatty acids and 6% more long chain 18:1 fatty acids. Plasma of cows treated with growth hormone had an increase of concentrations of free fatty acids, but no shifts were apparent among other lipid classes. Analysis of total plasma fatty acids did not show any net changes, but within individual plasma lipid classes, 18:1 increased and 18:2 decreased. Overall changes of blood and milk lipids are consistent with the concept that adipose tissue reserves were mobilized in response to hormone treatment and that these mobilized lipids were the major carbon source for the 41% increase of milk fat secretion. Increases of de novo synthesis of short and medium chain fatty acids also occurred but much less. Cows treated with growth hormone were in negative energy balance, and the mechanism may differ when cows are in positive energy balance.     

Lipolysis in intramuscular lipids during processing of traditional Xuanwei ham

Lipolysis in intramuscular lipids during the processing of Chinese Xuanwei ham has been studied by analyzing the changes of glycerides, phospholipids and free fatty acids in biceps femoris muscle. Results showed that the glycerides accounted for 73.2% of total lipid content in fresh ham, the phospholipids represented 25.3% and the free fatty acids 2.3% of the total lipid content, respectively. A rapid lipolysis of phospholipids occurred during the first 4 months of processing and slowed down during the rest period. A preferential hydrolysis for palmitic, linoleic and arachidonic acids in phospholipid fraction was observed. Glycerides only changed a little throughout the process, while an increase of free fatty acids during processing was observed. The results suggest that phospholipids are the main substrate of lipolysis in the intramuscular lipids of Chinese Xuanwei ham.     

Effects of milk products fermented by Bifidobacterium longum on blood lipids in rats and healthy adult male volunteers

The effects of milk products fermented by Bifidobacterium longum strain BL1, a probiotic strain, on blood lipids in rats and humans were studied. Rats were fed a cholesterol-enriched experimental diet, supplemented with lyophilized powders of 1) acid milk (control), 2) milk fermented with a mixed culture of ordinary yogurt starters composed of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (SL), and 3) bifidobacterium milk fermented with the probiotic B. longum strain BL1, respectively. The bifidobacterium milk feeding brought about significant lowering of the serum concentrations of total cholesterol, low-density lipoprotein cholesterol, and triglycerides, in comparison with the control, while no change in high-density lipoprotein cholesterol concentration was observed. On the other hand, supplementation with SL milk resulted in only slight, nonsignificant decreases in serum lipid concentrations in comparison with the control. In the human study, 32 subjects with serum total cholesterol ranging from 220 to 280 mg/dl were randomly assigned to two treatments: 1) intake of a low-fat drinking yogurt prepared with ordinary yogurt starters composed of S. thermophilus and L. delbrueckii subsp. bulgaricus (P-group) and 2) intake of a low-fat drinking yogurt prepared with the two ordinary yogurt starters plus B. longum strain BL1 (B-group). After intake for 4 wk at 3 x 100 ml/day, reduction of serum total cholesterol was observed in approximately half of the B-group subjects; a particularly significant decrease in serum total cholesterol was found among subjects with moderate hypercholesterolemia (serum total cholesterol > 240 mg/dl). However, the serum lipid concentrations in the P-group subjects were almost stable during the experimental periods. The present results indicate the potential of the probiotic B. longum strain BL1 in serum lipid improvement.     

Characteristics of lipids in buckwheat grain and isolated starch and their changes after hydrothermal processing

Studies were carried out on bond and free lipids of buckwheat grain and isolated starch. As regards free and bond lipids, fraction composition (percentages of neutral and polar fraction) and fatty acids were determined. It was found that the content of free lipids in buckwheat grain was twice higher than of bond lipids. On the other hand, in case of starch percentage of free lipids was twice lower than of bond lipids. As regards free and bond lipids of buckwheat grain and starch, main fraction was represented by the neutral one. Percentages of glycolipids and phospholipids amounted to only from 5 to 7%. Fatty acids were predominated by unsaturated acids C_18:2 and C_18:1. Fire and steam hydrothermal processing resulted in several quantitative changes, the most important ones being an increase of free lipid content in the grain and of bond lipid content in the starch, changes in the percentage of glycolipids and phospholipids, an increase of saturation of free lipid fatty acids in the grain, and of saturation of bond lipid fatty acids in the starch.     

Effect of Inoculation Level of Lactobacillus rhamnosus and Yogurt Cultures on Conjugated Linoleic Acid Content and Quality Attributes of Fermented Milk Products

ABSTRACT:  The effect of inoculation concentration of Lactobacillus rhamnosus and yogurt cultures and storage time on conjugated linoleic acid (CLA) content and quality attributes of fermented milk products was determined. Yogurt culture ( Lactobacillus bulgaricus and Streptococcus thermophilus, 1:1 ratio, YC ) , L. rhamnosus (LB), and LB co-cultured with yogurt culture, were inoculated at 10⁶, 10⁷, 10⁸ CFU/mL into a milk with hydrolyzed soy oil as the lipid source. CLA content, microbial counts, acidity, texture, and volatile flavor profile of the fermented milk products were stable during storage at 4 °C for 14 d. Total CLA contents ranged from 0.51 to 1.00 mg CLA/g lipid following 14 d of storage. Inoculation level of L. rhamnosus and yogurt cultures had no significant effect on CLA content and texture, but affected acidity and the volatile flavor profile of the fermented milk products. The fermented milk products produced by L. rhamnosus co-cultured with yogurt culture with 10⁷ CFU/mL total inoculation level resulted in a high CLA content and desirable quality characteristics. This research demonstrated that the optimal inoculation concentration and the combination of L. rhamnosus and yogurt cultures were important factors to produce fermented milk products with CLA content and acceptable quality attributes.     

凝结芽孢杆菌发酵乳的工艺优化

该研究对凝结芽孢杆菌发酵乳生产工艺进行了优化。以凝结芽孢杆菌13002、保加利亚乳杆菌CGMCC 1.290、嗜热链球菌CGMCC 1.2741共发酵的新型发酵乳为研究对象,以不同菌种复配比、菌种接种量、发酵基低聚果糖添加量进行单因素实验,再以感官评分为响应值,通过Box-Behnken中心组合建立数学模型研究发酵乳的最佳生产工艺。结果表明,菌种复配比（凝结芽孢杆菌：（嗜热链球菌:保加利亚乳杆菌=1:1））3:1、低聚果糖添加量1.50%、接种量1.50%为最佳工艺条件。在该优化条件下,测定发酵乳的平均滴定酸度值为90.59,与模型预测酸度值（93.25）拟和率达97.15%,说明此凝结芽孢杆菌发酵乳具有一定的竞争优势,为新型发酵乳研发提供理论基础和拓展思路。     

Properties,analysis and purification of milk polar lipids

The phospholipids and sphingolipids in milk are gaining interest due to their nutritional and technological qualities. Sphingolipids and their derivatives are highly bioactive compounds with anti-cancer, bacteriostatic and cholesterol-lowering properties. Several low-value process streams of the dairy industry contain considerable amounts of polar lipid and exert potential for further purification. This review deals with the structure of the main dairy polar lipids, their origin and molecular arrangement, their occurrence in raw milk and other dairy products, their methodology of analysis and purification and their nutritional and technological properties.