An overview on the role of lipids and fatty acids in barley grain and their products during beer brewing

In recent decades, research in barley has led to improvements in several biochemical and chemical characteristics (e.g. protein, starch, β glucans) associated with malt composition and end product quality (e.g. beer). Although lipids and fatty acids (FA) represent between 1 to 3% of the grain weight (dw), they can play an important role in barley grain and malt derived materials. However, the role of lipids and FA in both barley and malt quality is still not well understood. The aim of this article is to provide an overview on the role of lipids and FA in the chemical and industrial properties of barley grain, malt and wort.     

不同营养强化对褶皱臂尾轮虫脂类和脂肪酸组成的影响

试验采用30%鱼油+70%酵母(A组),20%鱼油+80%酵母(B组),10%鱼油+10%磷脂+80%酵母(C组),100%酵母(D组)、等鞭金藻(E组)五种方式培养褶皱臂尾轮虫.结果表明:轮虫的总脂含量和脂肪酸组成与培养方式密切相关,与其它方式强化的轮虫相比,鱼油强化组都含有较高的总脂含量.其中B组轮虫的二十碳五烯酸(EPA)含量最高,占其总脂肪酸的12.72%;E组轮虫的二十二碳六烯酸(DHA)含量最高,占其总脂肪酸的9.80%;D组轮虫的二十二碳六烯酸(DHA)含量最低,占其总脂肪酸的2.55%.     

Effect of exogenous long-chain fatty acids on individual fatty acid synthesis by dispersed ruminant mammary gland cells

We investigated the effect of exogenously added fatty acids on de novo synthesis of individual fatty acids and their incorporation into triacylglycerols by dispersed lactating ruminant mammary gland epithelial cells. Palmitate addition strongly stimulated synthesis and incorporation of butyrate and, to a smaller extent, palmitate synthesis and incorporation. Oleic acid strongly inhibited synthesis of all fatty acids except butyrate, whereas the effect of lauric acid was nearly neutral. Free fatty acid depletion of the mammary gland cells potentiated the effect of palmitate and made oleate less inhibitory.     

Effect of exogenous long-chain fatty acids on lipid biosynthesis in dispersed ruminant mammary gland epithelial cells: esterification of long-chain exogenous fatty acids

Dispersed epithelial cells from lactating bovine and goat mammary glands incorporated acetate into all fatty acids (C4 to C16) that were incorporated into mainly triacylglycerols. The cells secreted free fatty acids only into the incubation medium, and this secretion was dependent on the concentration of albumin and the type and amount of exogenous fatty acid added to the medium. Addition of palmitic acid to the incubation medium stimulated synthesis and incorporation of fatty acids synthesized de novo into triacylglycerols, whereas stearic and linoleic acid were inhibitory.     

Effect of heat processing on the fatty acid composition of lipids in meat-fish products

The content of fatty acids was studied in combined meat-fish foods. It was established that at a ratio of meat and fish being 1:1, the proportion of fatty acids C16:0/C:16:1 would be within the range of 1:4. A shift in this proportion towards an increase in the C16:1 content would indicate the presence of a large amount of fish. The results obtained can be used for the control of the content of meat and fish in the manufacturing of combined foods.     

进出口工业脂肪酸及其制品的属性鉴定

采用红外光谱法、气相色谱-质谱联用法、气相色谱法、X射线荧光光谱法、滴点测定法和黏度测定法等多种定性定量及理化参数测定技术,对不同种类和含量的进出口工业脂肪酸及其制品进行属性鉴定研究。讨论了样品不同的检测结果在《进出口税则》商品归类中的应用,并结合工业脂肪酸及其制品的报关商品实例,阐述了该类商品的海关化验步骤和归类过程,可为工业脂肪酸及其制品的定性鉴别、定量分析以及进出口商品归类提供技术参考。     

Effect of different types of feeding on the fatty acid makeup of the blood serum in premature infants

The composition of fatty acids and the content of total serum lipids were studied in 65 virtually healthy premature infants on varying types of feeding, natural and mixed ones (supplemented with kefir and a mixture of the "Similak" type). It was established that the composition of blood serum fatty acids in premature infants on natural feeding is marked by age-specific features. The differences in the content of blood serum fatty acids among children on natural feeding and those whose food was supplemented by kefir and a mixture of the "Similak" type were consequent on the specificity of lipid fatty acids from the food given. Good tolerance, adequate weight gain and a high content of indispensable fatty acids in blood serum were attained as a result of the research described. Therefore it is recommended that whole kefir and the mixture of the "Similak" type may be used for feeding premature infants.     

Effects of different levels of trans fatty acids and oxidised lipids in diet on cholesterol and cholesterol oxidation products formation in rabbit

The objective was to assess the effects of trans fatty acids and oxidised lipids, present in dietary fat by-products used in feeds, on cholesterol and oxycholesterols in meat, liver and plasma of rabbits. A palm fatty acid distillate, before and after hydrogenation (trans fatty acid trial), and a sunflower–olive oil blend (70/30, v/v), before and after use in a commercial frying process (oxidised lipid trial), were used in experimental feeds (at 3%, w/w). High trans fatty acid and oxidised lipid diets caused significantly higher cholesterol and oxycholesterol levels in all tissues of rabbit (0.01 < p ? 0.05). The content of oxycholesterols in rabbit meat, liver and plasma obtained from trans fatty acid experiments varied from 9 to 34 μg/100 g, 24 to 61 μg/100 g and 60 to 138 μg/dl, respectively, from low to high levels. In the oxidised lipid experiments, content of oxycholesterols varied from 16 to 52 μg/100 g, 14 to 108 μg/100 g and 52 to 269 μg/dl in meat, liver and plasma, respectively. As a consequence, meat products from rabbits fed a diet containing higher levels of trans fatty acids or oxidised lipids may result in higher intakes of cholesterol and oxycholesterols by humans.     

Menhaden body lipids: Details of fatty acids in lipids from an untapped food resource

Menhaden are utilised almost exclusively for fish meal production. The depot fat is concentrated in the bodies. In anticipation of developments in deboned or minced fishery products menhaden body lipids have been recovered and separated into polar and triglyceride fractions for detailed fatty acid study. The original lipid contains about 30% long-chain polyunsaturated fatty acids and could be nutritionally beneficial if protected from autoxidation. A simple petroleum ether extraction removes essentially the same material as found in oil from reduction of whole fish but leaves half the original lipid in the fish.     

Influence of vacuum filtration of Viura must on the concentration of fatty acids and their utilization in fermentation

Fatty acids such as palmitoleic, oleic, linoleic and linolenic along with sterols constitute growth or survival factors for yeast. The objective of this work was to study the influence of vacuum filtration of Viura must on fatty acid contents and their use during fermentation. The results were compared with unclarified must, the control. Filtration drastically reduced the total fatty acid concentration (81.5%) and especially unsaturated fatty acids (97.1% of linoleic, and 100% of linolenic), as well as the minor saturated acids, arachidic and behenic. In the first half of fermentation, fatty acids were excreted in the filtered must (76.8%) whereas they were consumed in the control (46.8%). In the second half of fermentation, there was greater consumption in the control sample (74.5%) than in the filtered sample (37.4%).     

Effect of dietary unsaturated fatty acids in various forms on the de novo synthesis of fatty acids in the bovine mammary gland

Free and protected soya oil and soya oil fatty acids were included in the rations of dairy cows and from outputs in the milk of 18:1 trans and of polyunsaturated acids conditions in the rumen have been deduced. Similarly, the content of citrate in the milk has been used to evaluate changes occurring in the synthesis of fatty acids in the mammary gland.     

不同品种黄瓜中脂肪酸的研究

采用索氏提取法对不同品种黄瓜中脂肪酸进行了提取,以气相色谱-质谱联用仪进行了分析,由水黄瓜﹑旱黄瓜和水果黄瓜中分别分离鉴定出11种﹑5种和11种脂肪酸,并对其主要成分进行了鉴定,主要化学成分均为:9,12-十八碳二烯酸和9,12,15-十八碳三烯酸。     

多不饱和脂肪酸对大鼠大脑细胞膜脂肪酸组成的影响

研究多不饱和脂肪酸(PUFAs)对发育期大鼠大脑细胞膜脂肪酸类别与含量的变化。将56只初断乳雄性SD大鼠随机分为阴性组、必需脂肪酸(EFA)缺乏组、鱼油组[300mg/(kg·d)]、紫苏组[2.45mL/(kg·d)]、α-亚油酸组[1.32g/(kg·d)]、核桃组[2.45mL/(kg·d)]与红花组[1.65g/(kg·d)]。连续饲养8周,提取大脑组织总细胞膜,并使用气相色谱-质谱联用技术检测其脂肪酸的种类与含量。结果表明,各组大鼠脂肪酸组成无差别;与阴性组比较,各组均能显著提高n-3PUFAs的含量;紫苏组、核桃组和红花组能显著降低n-6PUFAs的含量,增加饱和脂肪酸的含量;紫苏组、核桃组、红花组和鱼油组能显著降低单不饱和脂肪酸的含量。说明PUFAs能改变大鼠大脑细胞膜的含量,但对其类别影响不大;短期缺乏EFA对细胞膜脂肪酸的类别与含量无影响。     

Mammary gland metabolite utilization in response to exogenous glucose or long-chain fatty acids at low and high metabolizable protein levels

We investigated mammary gland metabolism in lactating dairy cattle in response to energy from glucogenic (glucose; GG) or lipogenic (palm olein; LG) substrates at low (LMP) and high (HMP) metabolizable protein levels. According to a 6 × 6 Latin square design, 6 rumen-fistulated second-lactation Holstein-Friesian dairy cows (97 ± 13 d in milk) were abomasally infused with saline (LMP-C); isoenergetic infusions (digestible energy basis) of 1,319 g/d glucose (LMP-GG), 676 g/d palm olein (LMP-LG), or 844 g/d essential AA (EAA; HMP-C); or isoenergetic infusions of 1,319 g/d glucose + 844 g/d EAA (HMP-GG) or 676 g/d palm olein + 844 g/d EAA (HMP-LG). Each experimental period consisted of 5 d of continuous infusion followed by 2 d of rest. A total mixed ration (42% corn silage, 31% grass silage, and 27% concentrate on a dry matter basis) formulated to meet 100 and 83% of net energy and metabolizable protein requirements, respectively, was fed at 90% of ad libitum intake by individual cow. Arterial and venous blood samples were collected on d 5 of each period. Infusing GG or LG at the HMP level did not affect milk yield or composition differently than at the LMP level. Neither GG nor LG infusion stimulated milk protein or lactose yield, but fat yield tended to decrease with GG and tended to increase with LG. Infusion of GG increased arterial plasma concentrations of glucose and insulin and decreased concentrations of β-hydroxybutyrate (BHB), nonesterified fatty acids, long-chain fatty acids (LCFA), total AA, EAA, and group 2 AA. Infusion of LG increased arterial triacylglycerides (TAG) and LCFA but did not affect EAA concentrations. Compared with the LMP level, the HMP level increased arterial concentrations of BHB, urea, and all EAA groups and decreased the concentration of total non-EAA. Mammary plasma flow increased with GG and was not affected by LG or protein level. Uptake and clearance of total EAA and group 2 AA were affected or tended to be affected by GG × AA interactions, with their uptakes being lower and their clearances higher with GG, but only at the LMP level. Infusion of LG did not affect uptake or clearance of any AA group. The HMP level increased uptake and decreased clearance of all EAA groups and decreased non-EAA uptake. Infusion of GG tended to increase mammary glucose uptake, and tended to decrease BHB uptake only at the LMP level. Infusion of LG increased mammary uptake of TAG and LCFA and increased or tended to increase clearance of TAG and LCFA. We suspect GG increased mammary plasma flow to maintain intramammary energy and AA balance and stimulated lipogenesis in adipose, accounting for depressed arterial BHB and group 2 AA concentrations. Mammary glucose uptake did not cover estimated requirements for lactose and fat synthesis at the HMP level, except during HMP-GG infusion. Results of this study illustrate flexibility in mammary metabolite utilization when absorptive supply of glucogenic, lipogenic, and aminogenic substrate is increased.     

Effect of antioxidants on stabilization of meat products fortified with n-3 fatty acids

The effects of an n-3 oil emulsion, with and without added antioxidants, on lipid oxidation in n-3 polyunsaturated fatty acid (PUFA)-fortified meat products were studied. An emulsion of n-3 PUFAs was prepared (25% algal oil, 2.5% whey protein isolates, 10mM sodium citrate, 0.2% potassium sorbate, 500ppm of 70% mixed tocopherols, 100μM EDTA, pH 3, pasteurized at 75°C for 30min) and incorporated into fresh ground turkey, and fresh pork sausage (20% fat) to achieve a concentration of 500mg n-3 PUFA/110g meat. An antioxidant combination containing rosemary (0.2% w/w; radical quencher), citrate (0.5% w/w; sequestrant) and erythorbate (1g/kg product; reductant) was prepared and incorporated into ground turkey patties (5cm dia, 1.5cm thick) or fresh pork sausages (5cm dia, 1.5cm thick). Meat products were stored at 4°C or -18°C and analyzed for color (L*, a*, b* values), lipid oxidation (TBARS and lipid hydroperoxides) and n-3 PUFA profile. a* Values of refrigerated ground turkey patties decreased with storage, and an antioxidant combination effect was observed after 4 days (P<0.05). For fresh pork sausages at 4°C, control+antioxidant (CON+ANTI), and n-3+antioxidant (n-3+ANTI) groups showed greater a* values than controls (CON) indicating that the antioxidant combination stabilized meat color. TBARS and lipid hydroperoxides of both n-3 PUFA-enhanced meat products increased with storage (P<0.05); there were no significant changes in TBARS or lipid hydroperoxides for treatments containing the antioxidant combination (P<0.05). The actual level of n-3 PUFA incorporation in both meat products was greater than 87%; n-3 PUFA concentrations did not change within any treatment during storage (P>0.05). These results provide support for including antioxidant protection in n-3 PUFA fortified meat products.