Characterization of chia seed oils obtained by pressing and solvent extraction

The oil yield, fatty acid composition and the physicochemical and quality characteristics of chia crude seed oils obtained by pressing and solvent extraction were determined. The extraction methods assayed influenced significantly the oil yield, obtaining about 30% more oil by solvent than by pressing. The main fatty acids ranked in the following order of abundance: α-linolenic acid (α Ln) > linoleic acid (L) > oleic acid (O) ≈ palmitic acid (P) > stearic acid (S) for both extraction systems. The n-3/n-6 FA ratio of chia oils ranged from 3.18 to 4.18, being markedly higher than that reported for other vegetable oils. The main triacylglycerols were: αLnαLnαLn > αLnαLnL > αLnLL > αLnαLnP > αLnLO ∼ αLnLP, which represent about 87-95% of the total content of these compounds. The quality and composition of some minor constituents of chia seed oils were influenced by the extraction process. Oils presented a moderate content of bioactive components, such as tocopherols, polyphenols, carotenoids and phospholipids; the high unsaturation level determined their low oxidative stability.     

Long-term intake of fish oil increases oxidative stress and decreases lifespan in senescence-accelerated mice

Objective

The effects of fish oil including ω-3 polyunsaturated fatty acids on aging and lifespan are not well understood. In this study, the influence of long-term ingestion of fish oil on lifespan was examined in senescence-accelerated (SAMP8) mice.

Methods

We investigated the effects of dietary fish oil on lifespan and on lipid composition and oxidative stress in plasma and liver in SAMP8 mice. Male mice were fed a fish oil diet (5% fish oil and 5% safflower oil) or a safflower oil diet (10% safflower oil) from 12 wk of age.

Results

The SAMP8 mice fed fish oil did not have a longer maximum lifespan and had a shorter average lifespan than mice fed safflower oil. To examine the mechanism underlying these results, the effects on oxidative stress of long-term ingestion of fish oil were also examined. SAMP8 mice fed fish oil for 28 wk showed strong oxidative stress that caused hyperoxidation of membrane phospholipids and a diminished antioxidant defense system due to a decrease in tocopherol compared with mice fed safflower oil.

Conclusion

These findings suggest that intake of fish oil increases oxidative stress, decreases cellular function, and causes organ dysfunction in SAMP8 mice, thereby promoting aging and shortening the lifespan of the mice.     

真菌产生多不饱和脂肪酸的研究

研究了温度、pH、时间以及碳源、氮源等因素对多不饱和脂肪酸产生菌A60细胞生长和产油脂的影响，确定了A60菌株摇瓶发酵培养基及其产生油脂的脂肪酸组分，其中花生四烯酸含量为10．04％，γ-亚麻酸含量为4．5％，二高γ-亚麻酸含量为6.27％。     

交酯化法制备鱼油多不饱和脂肪酸乙酯的研究

采用正交实验设计法，对交酯化法制备鱼油多不饱和脂肪酸乙酯的工艺条件进行研究，优选出提高乙酯转化率的最佳条件。鱼油：无水乙醇：Cat．1＝1：0．86：0．029。采用滴加乙醇－Cat．1溶液方式．在50℃反应3h，交酯化反应可较方便地制备鱼油多不饱和脂肪酸乙酯。重复3次实验，转化率均大于93％，稳定性良好。     

不饱和脂肪酸对枯否氏细胞膜磷脂的影响

本文研究了不饱和脂肪酸（鱼油）对脓毒症大鼠枯否氏细胞（KC）膜磷脂的影响,结果表明,脓毒症组大鼠KC膜磷脂酰肌醇（PI）、磷脂酰丝氨酸（PS）、磷脂酰乙醇胺（PE）、磷脂酰胆碱（PC）以及膜上花生四烯酸（AA）含量明显减少,KC培养液中AA代谢产物6-k-PGF_(1a)、TXB_2浓度明显升高。经鱼油治疗后,KC膜结构损伤程度减轻,AA代谢产物减少,提示不饱和脂肪酸有调节KC膜磷脂结构与功能,减少炎性介质产生的作用。     

Feeding a polyunsaturated fatty acid diet prevents the age-associated decline in glucose uptake observed in rats fed a saturated diet

The ability of the intestine to adapt to changes in environmental stimuli may be compromised with aging. Young animals fed saturated fatty acids (SFA) versus polyunsaturated fatty acids (PUFA) have an increased intestinal uptake of glucose. The objectives of this study were to determine (1) the effects of age on glucose uptake in rats; (2) the influence of feeding SFA versus PUFA; and (3) the mechanisms of these age- and diet-associated changes. Male Fischer 344 rats aged 1, 9 and 24 months received semi-purified isocaloric diets enriched with either SFA or PUFA. The uptake of 14C-labelled D-glucose was determined in vitro using the intestinal sheet method. Northern blotting, Western blotting and immunohistochemistry were used to determine the effects of age and diet on SGLT1, GLUT2 and Na(+)K(+)-ATPase. The mucosal surface area of the jejunum was reduced in 9 and 24 as compared with 1-month-old rats fed SFA. PUFA delayed this age-associated reduction in surface area. In SFA, the ileal uptake of glucose fell with age when expressed on the basis of intestinal or mucosal weight. Feeding PUFA prevented this decline. Alterations in glucose uptake were not paralleled by the changes in SGLT1, GLUT2 or Na(+)K(+)-ATPase abundance.     

幼年期多不饱和脂肪酸喂饲对高脂膳食大鼠胰岛素敏感性的影响

目的 研究幼年期多不饱和脂肪酸饲料对高脂膳食大鼠胰岛素敏感性的影响。方法 雄性Wistar大鼠出生后24天断乳，按体重随机分为A、B两组．给予相同能量、不同构成饲料，分别为高碳水化合物供能的基础饲料和高不饱和脂肪酸构成饲料。3周后均转为基础饲料。2周后再按体重将A组分为A1、A2两组．A1组继续基础饲料，A2和B组则转为猪油为主要脂肪来源的高脂膳食，6周后结束实验。分别在不同处理期末每组随机处死8只动物，称重，采血检测血糖和胰岛素水平。结果 幼年期喂饲多不饱和脂肪酸饲料组大鼠体重明显降低；胰岛素和血糖水平显著降低，胰岛素敏感指数明显升高，胰岛素敏感性升高。结论 幼年期给予多不饱和脂肪酸饲料可以显著增加高脂膳食大鼠的胰岛素敏感性。     

Relationship of serum polyunsaturated fatty acids with cytokines in colorectal cancer

AIM: To investigate the relationship of serum levels of polyunsaturated fatty acid(PUFA) with kinds of cytokines in colorectal cancer(CRC).METHODS: Serum samples of 100 CRC patients were collected. The concentration of total n-3 PUFA which included C18:3 n-3, C20:5 n-3, C22:5 n-3, C22:6 n-3 and the total n-6 PUFA included C18:2 n-6, C18:3 n-6, C20:3 n-6, C20:4 n-6, and C22:5 n-6 were detected onGC-2010 Plus Gas Chromatograph with a Omegawax TM 250 column. Cytokines were detected by Mag Plex TM-C microspheres. P values for the trend were estimated by creating a continuous variable using the median value within quartiles.RESULTS: Interleukin-6(IL-6) showed significantly positive association with the C20:4 n-6(P for trend = 0.004). Interferon gamma(IFN-γ) showed significant positive association with the C22:5 n-3(P for trend = 0.035). IL-8 and matrix metalloproteinase-9(MMP-9) showed significant inverse association with the C22:6 n-3(P for trend = 0.049, and 0.021). MMP-2 showed significant inverse association with the C20:5 n-3(P for trend = 0.008). MMP-7 showed significantly positive association with the ratio of n-6 PUFA and n-3 PUFA(P for trend = 0.008). MMP-7 also showed significantly inverse association with the ratio of C20:4 n-6 and(n-6 PUFA + n-3 PUFA)(P for trend = 0.024). IL-10(P for trend = 0.023) and IL-6(P for trend = 0.036) showed significantly positive association with the ratio of C20:4 n-6 and C20:5 n-3.CONCLUSION: Our data suggested that serum levels of PUFA is related to the inflammation of CRC, and also play different role in regulation of immune response.     

On the within-population relationship between dietary habits and serum lipid levels in Belgium

In a Belgian population group of 15 954 male and 2116 femalesubjects, an epidemiological survey has been conducted to investigatethe relationship between dietary fat intake and serum totaland HDL-cholesterol. The study has established, both in menand in women, a significant positive relationship between serumtotal cholesterol and the dietary intake of saturated fat anda significant positive relationship between serum total cholesteroland the dietary intake of saturated fat and a significant negativeone between serum total cholesterol and the intake of polyunsaturatedfat and the P/S-ration of the diet. At equal levels of consumption,polyunsaturated fat has a decreasing effect on serum total cholesterolwhich is about half the increasing effect due to saturated fat.Polyunsaturated fat and the P/S-ratio decrease the HDL-cholesterolvalue but only with borderline significance. The present studydemonstrates the importance of dietary fat as a determinantof the serum lipid level within a Population.