超高压及加热处理对羊乳脂肪酸组成的影响

为了研究超高压处理及加热处理对羊乳中脂肪酸组成的影响,该文以崂山奶山羊乳为研究对象,通过氯仿-甲醇法和碱催化法分别对乳脂肪进行提取和甲酯化,采用气相色谱-质谱（gas chromatography-Mass Spectrometry,GC-MS）方法分析在100、200、300、400 MPa超高压条件和65℃/30 min、75℃/15 min、90℃/1 min、煮沸加热条件下羊乳中各脂肪酸组成的变化,结果显示：经超高压处理,羊乳中的短链脂肪酸、饱和脂肪酸和不饱和脂肪酸含量的变化均不显著（P>0.05),而经加热处理羊乳中的短链脂肪酸和饱和脂肪酸含量均显著升高（P<0.01）,不饱和脂肪酸的含量显著降低（P<0.001）。经超高压处理羊乳中C6:0、C8:0和C10:0含量的变化均不显著（P>0.05）;C12:0、C14:0含量显著增加（P<0.01）,C16:0变化不显著（P<0.05）,C18:0含量显著降低（P<0.05）;C18:1含量的变化不显著（P>0.05）,C18:2和C18:3含量显著降低（P<0.01,P<0.05）,C20:4含量变化不显著（P>0.05）。而经加热处理羊乳中C10:0含量显著升高（P<0.01）;C12:0、C14:0和C16:0含量也均显著升高（P<0.05）,C18:0含量的变化不显著（P>0.05）;C18:1、C18:2、C18:3含量均显著降低（P<0.001,P<0.05,P<0.001）,而C20:4为检测出来。研究结果表明超高压处理能够更好的保持羊乳中脂肪酸的含量及组成,进而为超高压技术和加热处理在乳品中的应用及羊乳资源的开发提供了理论依据。     

Isolation of two anti-inflammatory and one pro-inflammatory polyunsaturated fatty acids from the brown seaweed Undaria pinnatifida

Two anti-inflammatory omega-3 polyunsaturated fatty acids (PUFAs) of stearidonic acid (SA) and eicosapentaenoic acid (EPA) and one pro-inflammatory omega-6 PUFA of arachidonic acid (AA) were isolated from the edible brown seaweed Undaria pinnatifida. SA was active against mouse ear inflammation induced by phorbol myristate acetate, with IC50 values of 160, 314, and 235 microg per ear for edema, erythema, and blood flow, respectively. EPA was also active against edema, erythema, and blood flow, with IC50 values of 230, 462, and 236 microg per ear, respectively. Although AA at low concentrations showed anti-inflammatory activities when measured 10 h later, AA doses of more than 243 microg per ear induced inflammatory symptoms 1 h later. Mature thalli generally had larger amounts of PUFAs than young thalli. The algal blade contained more omega-3 PUFAs than were found in other parts, while the holdfast contained extremely high amounts of AA. Late-season thalli showed increased amounts of PUFAs, especially AA.     

Comparison of lipid content and fatty acid composition between Tuber fermentation mycelia and natural fruiting bodies

A comparison of lipid content and fatty acid (FA) composition between Tuber fermentation mycelia and natural fruiting bodies indicates that the lipid content in Tuber fermentation mycelia is higher than that in fruiting bodies. Unsaturated FAs (particularly linoleic acid and oleic acid) were the predominant constituents in total FAs in both Tuber fermentation mycelia and fruiting bodies. A total of 23 FAs, including arachidonic, eicosapentaenoic, docosahexaenoic, and γ-linolenic acids, were first identified in the Tuber species. A hierarchical clustering analysis showed that the FA profile of fermentation mycelia was quite similar, regardless of Tuber species. However, the FA profile of the fruiting bodies was significantly influenced by its species and habitat environments. Interestingly, the FA profile of the Tuber indicum and Tuber aestivum fruiting bodies was nearly identical to that of the Tuber fermentation mycelia, which partially confirms the similarity between the Tuber fermentation mycelia and the fruiting bodies.     

Cholesterol oxides,cholesterol, total lipid,and fatty acid composition in turkey meat

The contents of cholesterol oxides, cholesterol, and total lipid, and the fatty acid composition were determined in frozen turkey meat. The 7-ketocholesterol content varied from 33 microg/100 g in the breast to 765 microg/100 g in the skin, and the levels of 7 beta-hydroxycholesterol varied from not detected in the leg, breast, and skin to 370 microg/100 g in the skin. The values for total lipid (g/100 g) in the wings, legs, breast, and skin were 0.9 +/- 0.4, 1.1 +/- 0.2, 0.5 +/- 0.1, and 12 +/- 3, respectively. The contents for cholesterol (mg/100 g) were 46 +/- 5, 35 +/- 2, 27 +/- 3, and 81 +/- 6 in the wing, legs, breast, and skin, respectively. The main fatty acids identified in all cuts were C18:2n6, C18:1n9, C16:0, C18:0, and C20:4n6.     

Effect of lipid composition on meat-like model systems containing cysteine, ribose, and polyunsaturated fatty acids

This paper compares the volatile constituents of model systems containing the important meat aroma precursors cysteine and ribose, with and without either methyl linoleate, an n-6 fatty acid, or methyl alpha-linolenate, an n-3 acid, both of which are present in meat. Many of the volatile compounds formed from the reaction between cysteine and ribose were not formed, or formed in lower amounts, when lipid was present. This may be due to the reaction between hydrogen sulfide, formed from the breakdown of cysteine, and lipid degradation products. In addition, cysteine and ribose modified lipid oxidation pathways, so that alcohols and alkylfurans were formed rather than saturated and unsaturated aldehydes. Several volatile compounds, which have been found at elevated levels in cooked meat from animals fed supplements high in n-3 acids, were formed when methyl alpha-linolenate reacted with cysteine and ribose. The possible effects of increasing the n-3 content of meat upon flavor formation during cooking are discussed.     

Effect of the polyunsaturated fatty acid composition of beef muscle on the profile of aroma volatiles

The effect of n-3 polyunsaturated fatty acids (PUFAs) in beef muscle on the composition of the aroma volatiles produced during cooking was measured. The meat was obtained from groups of steers fed different supplementary fats: (i) a palm-oil-based control; (ii) bruised whole linseed, which increased muscle levels of alpha-linolenic (C18:3 n-3) and eicosapentaenoic acid (EPA, C20:5 n-3); (iii) fish oil, which increased EPA and docosahexaenoic acid (C22:6 n-3); (iv) equal quantities of linseed and fish oil. Higher levels of lipid oxidation products were found in the aroma extracts of all of the steaks with increased PUFA content, after cooking. In particular, n-alkanals, 2-alkenals, 1-alkanols, and alkylfurans were increased up to 4-fold. Most of these compounds were derived from the autoxidation of the more abundant mono- and di-unsaturated fatty acids during cooking, and such autoxidation appeared to be promoted by increased levels of PUFAs.     

Effect of dietary conjugated linoleic acid on lipid peroxidation and histological change in rat liver tissues

The effect of dietary conjugated linoleic acid (CLA) on hepatic lipid parameters in Sprague-Dawley rats was examined. When rats were fed a diet containing CLA at 0 (control), 1, or 2% of the weight of the amount of food given for 3 weeks, the liver weight exhibited a slight increase in the CLA-fed groups, although the difference was not significant. Lipid accumulation in the hepatocytes of CLA-fed rats was also demonstrated by electron microscopic observation. In addition, the liver thiobarbituric acid reactive substances levels were significantly higher in the 2 wt % CLA group than in the other two dietary groups, and the levels of phosphatidylcholine hydroperoxide were higher in CLA-fed groups when compared to that of the control group. On the other hand, the serum lipid peroxide levels were comparable among all three dietary groups. Levels of triglycerides in the white adipose tissue (WAT) and serum nonesterified fatty acid (NEFA) were reduced in a CLA-dose-dependent manner. CLA was shown to accumulate in the WAT much more than in the serum or liver. These results suggest that CLA accelerates the decomposition of storage lipids in WAT and the clearance of serum NEFA levels, resulting in lipid peroxidation and a morphological change in the liver.     

Effect of sesame seeds rich in sesamin and sesamolin on fatty acid oxidation in rat liver

Activities of enzymes involved in hepatic fatty acid oxidation and synthesis among rats fed sesame (Sesamum indicum L.) differing in lignan content (sesamin and sesamolin) were compared. Sesame seeds rich in lignans from two lines, 0730 and 0732, lines established in this laborary, and those from a conventional cultivar (Masekin) were employed. Seeds from the 0730 and 0732 lines contained sesamin and sesamolin at amounts twice those from Masekin. Sesame seeds were added at levels of 200 g/kg to the experimental diets. Sesame increased both the hepatic mitochondrial and the peroxisomal fatty acid oxidation rate. Increases were greater with sesame rich in lignans than with Maskin. Noticeably, peroxisomal activity levels were >3 times higher in rats fed diets containing sesame seeds from the 0730 and 0732 lines than in those fed a control diet without sesame. The diet containing Masekin seed caused only a 50% increase in the value, however. Diets containing seeds from the 0730 and 0732 lines, compared to the control and Masekin diets, also significantly increased the activity of hepatic fatty acid oxidation enzymes including acyl-CoA oxidase, carnitine palmitoyltranferase, 3-hydroxyacyl-CoA dehydrogenase, and 3-ketoacyl-CoA thiolase. In contrast, diets containing sesame lowered the activity of enzymes involved in fatty acid synthesis including fatty acid synthase, glucose-6-phosphate dehydrogenase, ATP-citrate lyase, and pyruvate kinase. No significant differences in enzyme activities were, however, seen among diets containing sesame from Masekin cultivar and lines 0730 and 0732. Serum triacylglycerol concentrations were lower in rats fed diets containing sesame from lines 0730 and 0732 than in those fed the control or Masekin diet. It is apparent that sesame rich in lignans more profoundly affects hepatic fatty acid oxidation and serum triacylglycerol levels. Therefore, consumption of sesame rich in lignans results in physiological activity to alter lipid metabolism in a potentially beneficial manner.     

饲粮油脂对蛋鸡生产性能、血清脂质含量和蛋黄脂肪酸组成的影响

选用90只50周龄海蓝褐壳蛋鸡,随机分成5组。5组饲粮中分别添加使用2%棕榈油(对照组,2%PO)、2%亚麻油(2%LO)、4%亚麻油(4%LO)、4%鱼油(4%FO)、4%火麻仁油(4%HO),研究不同油脂对蛋鸡生产性能、蛋黄中脂肪酸组成和血清胆固醇等脂质含量的影响。结果表明:(1)4%亚麻油组鸡产蛋率较对照组提高,差异显著(P<0.05),4%鱼油组和2%亚麻油组产蛋率与对照组差异不显著(P>0.05)。(2)与对照组比较,随着饲粮亚麻油用量的增加,蛋黄中α亚麻酸(ALA)、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)的含量增加(P<0.05);4%鱼油组蛋黄中EPA和DHA含量增加(P<0.05);4%火麻仁油组蛋黄中亚油酸(LA)和ALA的含量增加(P<0.05)。(3)饲粮中不同油脂影响蛋黄中n6/n3多不饱和脂肪酸(PUFA)比值,亚麻油、鱼油、火麻仁油能降低n6/n3PUFA比值(P<0.05)。(4)不同油脂对血清脂质含量无显著的影响(P>0.05),但亚麻油、鱼油、火麻仁油有降低血清总胆固醇、低密度脂蛋白胆固醇和甘油三酯的含量,提高高密度脂蛋白胆固醇浓度的趋势。     

Effects of temperature and life stage on the fatty acid composition of Collembola

Fatty acid (FA) analysis is used as a promising tool to investigate trophic interactions in soil food webs. The FA profile of neutral lipids in consumers is affected by the diet, and the occurrence and amount of certain FAs can reflect feeding strategies. We investigated the lipid composition of the Collembola Folsomia candida, Heteromurus nitidus and Protaphorura fimata with the fungus Chaetomium globosum as food source. The impact of environmental temperature and life stage was assessed, with special respect to linoleic acid (18:2ω6,9) as a marker FA for fungal feeding. In all Collembola species the ratio of C16/C18 in neutral lipid fatty acids (NLFAs) increased with decreasing temperature. In the NLFAs of F. candida and H. nitidus the Unsaturation Index and the amount of 18:2ω6,9 decreased with temperature, whereas in P. fimata effects were the opposite. The composition of phospholipid fatty acids (PLFAs) differed between species, but was little affected by temperature. The degree of unsaturation in NLFAs increased with the age of Collembola, mainly due to higher amounts of 18:2ω6,9 and a lower proportion of 18:1ω9. The biomarker linoleic acid represented over 20% of FAs in all fungal feeding Collembola. Despite considerable influence of temperature and life stage on its proportion, the amount was always higher than in individuals reared on other diets. This suggests that linoleic acid can serve as marker for fungal feeding independent of such physiological variations in Collembola.     

土壤中木质素磺酸盐对土壤溶液化学和磷脂脂肪酸组成的影响

An incubation experiment （Exp. 1） with three soils, two from Australia and one from Norway, was carried out to investigate the fate of dissolved BorreGro （a lignosulfonate, produced by Borregaard LignoTech Company, Norway） at different concentrations （0, 10 and 100 mg C L-1） in soil solutions. A rhizobox experiment （Exp. 2） was also done in a Norwegian clay soil, mixed with four levels of BorreGro-carbon （BG-C） added （0, 2, 20 and 200 mg BG-C kg-1） to test the impact of BorreGro on root growth, rhizosphere chemistry （pH, metals and dissolved organic carbon （DOC）） and the composition of phospholipid fatty acids （PLFAs）. The BorreGro addition increased the concentration of Mn due to the high concentrations in BorreGro. The BorreGro addition to soil had an indirect but significant impact on the rhizosphere chemistry and PLFAs. The lowest amounts of added BorreGro facilitated the DOC excretion at plant roots, and thereby increased the bacterial and fungal biomass, likely as an effect of increased Mn solubility from BorreGro in the root zone.     

氮素对两种玉米脂肪及其组分含量的影响

选取两种玉米研究了施氮对玉米不同器官脂肪积累及子粒脂肪组分含量变化的影响。结果表明,两种玉米叶片、茎秆脂肪含量在灌浆过程中均呈逐渐下降趋势,品种间子粒粗脂肪含量存在差异;两种玉米叶片、茎秆中脂肪含量对氮素的反应不同,子粒中脂肪含量品种间均随氮素供应水平提高而增加;氮素供应主要影响子粒中油酸和亚油酸含量,对硬脂酸、棕榈酸和亚麻酸含量的影响不显著。     

Effect of additions of brown coal and peat on soil solution composition and root growth in acid soil from wheatbelt of western Australia

Abstract

Additions of several categories of organic materials including fresh plant materials, compost, manure, coal derived products, and peat have been shown to ameliorate soil acidity. The main effect is increased soil pH and the corresponding decrease in soil solution and exchangeable aluminum (Al). The organic matter addition is expected to decrease the solubility of soil aluminum so that lower activities are maintained at a given pH value, but this effect has not been tested. Aluminum solubility was investigated after addition of brown coal and peat to an acid soil. Root length was used as a bioassay for the acid ameliorating properties of the organic materials. Addition to soil of brown coal and peat resulted in changes in Al activity in the soil solution. The negative log of Al activity (pAl) was directly proportional to the soil solution pH. A single pAl‐pH line could describe the control, calcium chloride and organically treated soil samples. This line was parallel to that of gibbsite. The intercept was greater suggesting undersaturation with respect to that mineral. The coal and peat applied at the rate of 1 and 2% had little effect on the solubility of soil Al. Any decrease in Al activity was solely dependent on increased soil pH. Relative root length was inversely related to Al activity. This relationship was improved by including base cations in the index of Al phytotoxicity. This index could provide the basis for evaluating the value of brown coal and peat in ameliorating soil acidity.     

Degradation, under non-oxygen-mediated autooxidation, of carotenoid profile present in paprika oleoresins with lipid substrates of different fatty acid composition

A heat-induced degradation was carried out over two crude paprika oleoresins diluted with high oleic or high linoleic oil. Occurrence of oxygen was avoided, and changes in individual carotenoids were followed over time. Degradation rate constants were not significantly different, so that carotenoid stability was not linked with unsaturation degree of the oily system. A parallel reaction to degradation, trans to cis carotenoid isomer conversion, was also denoted during the thermal treatment, and it initially showed a higher rate than degradation of cis-isomers. Both processes (isomerization and cis-isomers degradation) were finally compensated, and their development was also unaffected by the nature of the lipid profile. Under the reaction conditions, oleic and linoleic fatty acids showed the same reactivity and induced degradative reactions, equally affecting the carotenoid profile. An enhanced stability of carotenoid content and provitamin A value was not achieved with a decrease in the unsaturation level of the oily system.     

Effects of nitric oxide on fatty acid composition in peach fruits during storage

Peach (Prunus persica (L.) Batsch., cv. Feicheng) fruits were fumigated with 0, 5, 10, and 15 microL/L nitric oxide (NO), and the effects of NO on rot index, ion leakage, and the lipid compositions in peach fruits were studied. The results showed that the treatment with 10 microL/L NO significantly increased the contents of the palmitoleic (16:1), oleic (18:1), and linolenic (18:3) acid in phospholipid (PL), while it decreased the contents of linoleic (18:2) acid in PL. The content of monoacylglycerol (MG) in fruit fumigated with 10 microL/L NO were higher than in the control but lower in fruit fumigated with 15 microL/L NO. The treatment with 10 microL/L NO increased the content of MG, decreased the contents of diacylglycerol (DG) and triacylglycerol (TG). However, there was no significant difference in the contents of free fatty acid (FFA). The compositions of MG, DG, TG, and FFA in peach fruit were also changed by the treatment with 10 microL/L NO. It could preserve the content of 18:3, maintain the integrity of membrane, and prevent the softening and rotting of peach fruit. The content of 18:1 was detected in PL and FFA but not in MG, DG, and TG. This might be due to the different compositions of MG, DG, and TG.     

Effects of dietary vitamin B6 supplementation on fillet fatty acid composition and fatty acid metabolism of rainbow trout fed vegetable oil based diets

Fish oil replacement in aquaculture feeds results in major modifications to the fatty acid makeup of cultured fish. Therefore, in vivo fatty acid biosynthesis has been a topic of considerable research interest. Evidence suggests that pyridoxine (vitamin B(6)) plays a role in fatty acid metabolism, and in particular, the biosynthesis of LC-PUFA has been demonstrated in mammals. However, there is little information on the effects of dietary pyridoxine availability in fish fed diets lacking LC-PUFA. This study demonstrates a relationship between dietary pyridoxine supplementation and fatty acid metabolism in rainbow trout. In particular, the dietary pyridoxine level was shown to modulate and positively stimulate the activity of the fatty acid elongase and Δ-6 and Δ-5 desaturase enzymes, deduced by the whole-body fatty acid balance method. This activity was insufficient to compensate for a diet lacking in LC-PUFA but does highlight potential strategies to maximize this activity in cultured fish, especially when fish oil is replaced with vegetable oils.     

外源腐殖酸对棕壤有机磷组分的影响

采用Bowman和Cole提出的有机磷分组方法，对施人外源腐殖酸条件下，不同时期棕壤有机磷的组成变化进行测定。结果表明，施入外源腐殖酸，在培养的各个时期，有机磷各组分所占比例的基本格局没有改变，依然是中等活性有机磷〉中等稳定性有机磷〉高稳性有机磷〉活性有机磷。施入外源腐殖酸后，在培养的30d，活性有机磷均下降；在培养的60d和90d，施入高量腐殖酸的土壤，活性有机磷升高。施入外源腐殖酸，在培养的各个时期均可明显增加中等活性有机磷的含量，特别是在施入高量腐殖酸时增加的最多；同时还可降低中等稳定性有机磷的含量，在施入高量腐殖酸时降低的最多。