Lipid Content and Fatty Acid Composition in Bamboo Shoots

Lipids from bamboo shoots (Phyllostachys pubescens), peeled and divided from top to base, were extracted and fractionated into three classes, and each class separated into constituent components by thin-layer chromatography (TLC). Fatty acid composition and amount of separated lipids were determined. Total lipids (TL) ranged from 800 (top) to 380 mg (base) per 100g fresh weight and the ratio of nonpolar lipids (NPL):glycolipids (GL):phospholipids (PL) was about 17:27:56. The main fatty acids of the three lipid classes were palmitic, linoleic and linolenic acids, but composition was remarkably different among these fractions. The fatty acid composition of triglycerides (TG) was similar to the original NPL. Palmitic acid was almost all located in 1-, 3-position, linoleic acid mainly located in 2-position of TG, while linolenic acid was distributed in each position. Digalactosyl diglyceride (DGDG) and monogalactosyl diglyceride (MGDG) were the main components of GL; the average of the former had about 37% linoleic and 29% linolenic acids, while the latter had about 25% linoleic and 62% linolenic acids. Bamboo shoots contained 9 PL fractions, the major being phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE). PC contained about 48% linoleic, 31% palmitic and 11% linolenic acids, and PE also had the similar tendency as PC.     

Cocobean Tissue Culture: Lipid Composition and Fatty Acid Metabolism

Cocoabean callus cultures were established and grew satisfactorily on an agar medium for more than 2 yr. Cell suspension cultures were initiated from the callus. The fresh weight of cells increased over 20-fold in 14 days. The lipid content of callus and cells was 5.3 and 6.5%, respectively. The fatty acid composition of cocoa callus and cell suspension cultures resembled that of immature cocoabeans since they contained high amounts of linoleic acid. Stereospecific distribution of fatty acids in triglycerides from cocoa callus and cells was similar to that of ripe cocoabeans. Exogenous acetate and fatty acids were readily incorporated into lipids by cocoa cell suspension cultures. Exogenous stearic acid increased triglyceride content twofold but did not change fatty acid composition of triglycerides. Coconut water alone or in combination with sucrose also increased triglyceride content with a concomitant increase in oleic acid from 10% to 33% and a decrease in linoleic acid from 37% to 19%.     

Oilseed Lipid Supplements and Fatty Acid Composition of Cow Milk: A Meta-Analysis

Numerous experiments have studied the use of oilseed supplements in cow diets to alter milk fatty acid (FA) composition, but no quantitative synthesis of these studies is currently available. This article reports a meta-analysis of the response of cow milk FA composition to oilseed lipid supplements from linseed, rapeseed, soybeans, and sunflower seed. First, from a database of 145 oilseed supplementation experiments, we collected the mean FA percentages observed with unsupplemented diets and diets supplemented with the 4 oilseeds given as seeds (after various types of processing), as oils (including Ca salts and amides), or in protected forms. Second, we studied the response of the major milk FA percentages to increasing amounts of supplemental lipids from the 4 oilseeds. Responses were nonsignificant, linear, or quadratic, depending on the FA studied and the supplement. Effects of interfering factors, such as supplement form, forage component of the diet, or lactation stage, were difficult to assess from the available data. Third, we studied the response of the major milk FA percentages to increasing dietary intakes of linoleic or linolenic acids, taken separately. Overall, these results confirm the high plasticity of milk FA composition, with the widest variations being observed in the percentages of medium-chain versus C18 FA, and among the C18 in 18:0, cis-18:1, and trans-18:1. The percentages of the polyunsaturated FA cis-9 cis-12-18:2 and 18:3 were less variable, except when protected lipids (mostly formaldehyde treated) were supplied. However, trans-18:1 and polyunsaturated FA (including conjugated linoleic acid) exhibited the greatest variations when expressed relative to their respective basal values (for unsupplemented diets). Oils, compared with seeds, induced greater percentages of trans-18:1 and tended to decrease C6 to C12 FA more. Intakes of 18:2- and 18:3-rich lipid sources did not differ greatly in their effects on short- and medium-chain FA and trans-18:1 percentages, although the profiles of individual 18:1 and 18:2 isomers in milk differed. This meta-analysis provides quantitative estimates, obtained from the extensive literature produced over more than 40 yr, of the impact of oilseed supplements on milk FA composition.     

Chromatographic Column Fractionation and Fatty Acid Composition of Different Lipid Classes of Linseed Oil

Linseed oil is fractionated on silicic acid column, with subsequent identification of different lipid classes by thin layer chromatography. Sterol esters, triglycerides, free fatty acids, sterols and phospholipids represent 0.15, 92.25, 3.30, 1.15 and 1.16%, respectively of linseed lipids. The total saturated fatty acid content of the phospholipid fraction is higher than that of the oil, the triglyceride fraction and the free fatty acid fraction. Linolenic acid, which is the major fatty acid in linseed triglycerides (47.5%), makes 18.2% of the phospholipid fatty acids. Oleic acid is the major fatty acid in the phospholipid fraction (35.2%), while it constitutes 19.3% of the triglycerides fatty acids.     

Acclimation Temperature affects Activities of 5'-Nucleotidase and Acid Phosphatase and Lipid and Fatty Acid Composition in Carp Muscle Microsomes

The Km values of 5′-nucleotidase against IMP markedly increased below 6°C in the case of 32°C-acclimated carp muscle microsomes. This caused a break point at 6°C in the Arrhenius plot of 5′-nucleotidase activity against IMP at a low concentration. The discontinuity of temperature dependency was not found when a surfactant had been introduced. Muscle microsomes of carp acclimated at 32°C contained much more cholesterol and saturated fatty acid than those of 10°C-acclimated carp. Therefore, the difference of lipid composition seemed to be closely related to the change in kinetics of microsomal 5′-nucleotidase.     

Foaming and Emulsifying Properties of Whey Protein Concentrates As Affected by Lipid Composition

Freeze-dried WPC, containing 35 and 75% protein were manufactured by pretreating whey with calcium chloride and heat. These and commercial WPC were subjected to proximate analysis and lipid classes, phospholipid classes, free fatty acids (FFA), and monoacylglycerols (MAG) composition were determined. Solubility, thermal, foaming, and emulsifying properties of the WPC were studied. Pretreatment increased calcium and phosphorus contents and decreased the contents of all other minerals. The pretreatment had no effect on solubility, denaturation enthalpy, and onset temperature of denaturation of WPC. These values were comparable to those of commercial WPC. Foaming capacity and emulsion stability were unaffected, but foam stability increased and emulsifying capacity decreased due to pretreatment. Overall, total lipids and lipid class contents of experimental WPC were too low to affect surface properties of WPC.     

温度对四株海洋绿藻总脂含量和脂肪酸组成的影响

文章用f／2培养基，在16℃、22℃、28℃对小球藻属（C19、C95和C97）和裂丝藻属（C102株）的四株绿藻的总脂含量及脂肪酸组成进行了研究。四株绿藻的总脂含量均在16℃时最高，C19为35．6％，C95为19．1％，C97为28．4％，C102为38．2％。温度对EPA（20：5（n-3））和多不饱和脂肪酸（PUFA）含量影响显著，三株小球藻C95、C97和C102的EPA含量随温度的变化相似，均在22℃时达到最大值，分别为19．5％、24．8％和8．2％，杆状裂丝藻C19在28℃时EPA含量达到最大值11．7％。     

温度对四株海洋绿藻总脂含量和脂肪酸组成的影响

文章用f/2培养基,在16℃、22℃、28℃对小球藻属(C19、C95和C97)和裂丝藻属(C102株)的四株绿藻的总脂含量及脂肪酸组成进行了研究.四株绿藻的总脂含量均在16℃时最高,C19为35.6%,C95为19.1%,C97为28.4%,C102为38.2%.温度对EPA(20:5(n-3))和多不饱和脂肪酸(PUFA)含量影响显著,三株小球藻C95、C97和C102的EPA含量随温度的变化相似,均在22℃时达到最大值,分别为19.5%、24.8%和8.2%,杆状裂丝藻C19在28℃时EPA含量达到最大值11.7%.     

板栗油脂肪酸组成的分析

为了开发我国板栗资源，采用气相色谱法对板栗油脂肪酸组成进行了分析。经分析检测出7种脂肪酸，含量分别是豆蔻酸0，123％、棕榈酸13．933％、棕榈油酸0．451％、硬脂酸0．770％、油酸43．691％、亚油酸33．988％、亚麻酸6．355％，这对板栗油的研究、开发利用提供了基础数据。     

苦皮藤籽油脂肪酸组成分析

湖北不同地区苦皮滕籽的千粒重有所不同，但含油量基本相同。采用气相色谱法对苦皮藤籽油的脂肪酸组成及含量进行了分析，并与同科的2种植物和其他2种杀虫植物籽油的脂肪酸组成及含量相比较。结果表明，苦皮藤籽油的不饱和脂肪酸较高达71．1％；亚麻酸为18．2％，远远高于其他几种植物。该结果为充分利用苦皮藤这一资源提供了科学依据。     

Effect of Whey Pretreatment on Composition and Functional Properties of Whey Protein Concentrate

The effect of pretreatment upon the composition and physicochemical and functional properties of whey, ultrafiltration (UF) retentate and freeze-dried and spray-dried whey protein concentrates (WPC) was investigated. Pretreatment was by cooling cheese whey to 0-5°C, adding calcium chloride, adjusting to pH 7.3, warming to 50°C, and removing the insoluble precipitate that formed by centrifugation or decantation. UF permeation flux rate of pretreated whey was about double that for control whey. Pretreated whey was essentially turbidity free, contained 85% less milkfat, 37% more calcium and 40% less phosphorus than whey. Pretreated whey WPC proteins were slightly more soluble at pH 3, but less functional for emulsification than whey WPC proteins. Neither whey WPC proteins nor pretreated whey WPC proteins was functional for foaming at 6% protein concentration.     

A Simple and Rapid Extraction Method to Evaluate the Fatty Acid Composition and Nutritional Value of Goji Berry Lipid

In this paper, the results of a study on lipid fraction from goji berries are reported. A rapid and simple method based on magnetic stirring with chloroform/methanol mixture and final clean-up with deionized water was developed, which avoided the presence of polar substances in the final extract. The proposed method was compared with conventional (Folch and Soxhlet methods) and unconventional (hexane/2-propanol or methyl-tert-butyl ether extraction) procedures. Sixteen commercial goji samples have been extracted by the developed method; then, the fatty acid composition was determined by high-resolution gas chromatography-flame ionization detector (HRGC-FID) analysis of derivatized samples. Generally, the results obtained underlined the important role of goji berry as a natural source of unsaturated fatty acids (78.0–86.0 %) with a high content of n-6 polyunsaturated fatty acids (PUFA, 48.2–60.2 %), a satisfactory n-6/n-3 PUFA ratio, and a good PUFA/saturated fatty acid ratio.     

三种绿藻总脂肪和脂肪酸的测定

用重量法测定了三种绿藻的总脂肪含量、气相色谱法测定了它们的脂肪酸百分含量。结果表明,三种绿藻的总脂肪含量在17.69%～21.44%之间。亚心形扁藻和青岛大扁藻的脂肪酸组分中的不饱和脂肪酸以C18：3w3含量最多;微绿球藻则以C20：5w3含量最多。     

In Situ Preparation of Fatty Acid Methyl Esters for Analysis of Fatty Acid Composition in Foods

Lipid extraction preceding fatty acid methyl esters (FAME) preparation for gas chromatography is time-consuming and cumbersome. We omitted the lipid extraction and performed in situ transesterification (ISTE) by heating lipid-containing foods at 90°for 10 min after adding 0.5N NaOH in methanol for methanolysis and continued heating another 10 min for further methylation after adding 14% BF₃ in methanol. FAME prepared by ISTE showed fatty acid composition virtually identical to FAME prepared after lipid extraction from powder, liquid, phospholipid-rich, and tissue products. Due to its simplicity, speed, and reduced organic solvent usage, ISTE should be useful to determine overall fatty acid composition of foods.     

热风干燥过程对梅鱼脂肪酸的影响

用气相色谱法研究了梅鱼脂肪酸的组成,共检测出23种脂肪酸,其主要成分为棕榈酸,棕榈油酸,油酸,二十二碳六烯酸(DHA)和二十碳五烯酸(EPA)。同时,研究热风干燥加工过程中干燥时间和温度对梅鱼脂肪酸的影响。结果表明:干燥时间和温度对梅鱼脂肪酸有很大的影响。干燥时间越长,温度越高,多不饱和脂肪酸氧化程度越高。在72℃下干燥时,干燥时间应选择在6h以内。56℃和64℃的热风温度对脂肪酸的影响较小,能较好地保留梅鱼的营养价值。     

桑椹籽油的提取及其脂肪酸组成分析

以桑椹籽为原料,通过单因素试验、正交试验研究了漫提溶剂、料液比、浸提温度、浸提时间等因素对桑椹籽油提取率的影响,确定了溶剂浸提桑椹籽油的最佳工艺条件,并采用气相色谱对桑椹籽油的脂肪酸组成进行了分析.结果表明,各影响因素的主次顺序为:浸提温度>料液比>浸提时间;溶剂提取桑椹籽油的最佳工艺参数为:石油醚为提取剂,浸提温度为40℃,浸提时间5 h,料液比(g·mL-1)为1 10.在此条件下,桑椹籽油的提取率为28.62%;桑椹籽油中总不饱和脂肪酸含量为84.59%,其中亚油酸含量高达74.86%.