健康月报

咖啡因降低皮肤癌风险哈佛公共卫生学院的研究显示,摄入咖啡因最多的女性患皮肤基底细胞癌的风险比极少摄入咖啡的女性低18%。在男性人群中也有类似效果——基底细胞癌变的风险可因摄入咖啡因而降低13%。动物实验表明,咖啡因可以帮助修复清除被紫外线损伤的皮肤细胞,从而阻止其发展为肿瘤。     

果蔬中外泌体样纳米颗粒的分离、表征和应用研究进展

果蔬中的外泌体样纳米颗粒（exosome-like nanoparticles，ELNs）是由果蔬细胞释放的纳米级囊泡结构，与动物的外泌体具有类似的超微结构，但其脂质、蛋白质及核酸等化学成分具有显著差异，并具有独特的生物学功能。本文综述了2013年以来数十种果蔬中ELNs的相关研究进展，对其提取方法和表征手段进行了分析，重点分析了不同植物来源的ELNs中脂质、蛋白质和核酸类化学成分的组成差异，并对ELNs的潜在生理活性和载体功能进行了探讨，可为果蔬中ELNs的相关研究提供借鉴和启示。     

高档烹调油应大力推广

油脂是人类生存必需的三大营养物质之一,对人体健康有着十分重要的作用,它不仅为人体提供热量,供给必需脂肪酸和油溶性维生素,而且赋予食物特有的风味,增进人们的食欲。膳食中缺乏油脂,尤其是亚油酸等必需脂肪酸,会产生生长停滞、生殖障碍、抵抗力减弱等生理性病症,还会出现脱毛、皮炎、湿疹、皮肤坏死、体内脂质代谢紊乱等症状,因此,在人类的膳食中,必需保证一定数量的     

某保健酒免疫调节和延缓衰老作用的研究

为研究天赐精元宝药酒的免疫调节和延缓衰老作用，进行了该酒对小鼠特异性和非特异性免疫功能的作用，对大鼠血、肝脂质过氧化水平和ＳＯＤ活性影响的以及对果蝇寿命的影响的试验。实验结果表明，在１５～５０ｍＬ／ｋｇ剂量下，经二周时间，该受试物具有提高小鼠特异性和非特异性免疫功能的作用，具有延缓衰老和抗脂质过氧化的作用     

鳀鱼抗菌肽脂质体的制备与抗单增李斯特菌生物被膜活性研究

本文采用薄膜蒸发法制备得到鳀鱼抗菌肽AAP脂质体,分析了脂质体的平均粒径、形态结构、包封率和贮存稳定性,研究了其对单增李斯特菌及其生物被膜的抑制活性。结果表明制备得到的AAP脂质体平均粒径为(131.65±1.63)nm,包封率为69.75%,AAP有效载量为4.17%,为内部呈环形层状分布的近球形。脂质体在4℃下的贮存稳定性高于其在25℃下的稳定性。脂质体型AAP和未包封AAP均能抑制单增李斯特菌的生长,但因脂质体的控释作用,两者对指示菌生长曲线的改变历程略有差异。脂质体型AAP抗单增李斯特菌生物被膜活性高于未包封AAP。结晶紫染色和银染实验结果表明AAP脂质体能抑制单增李斯特菌生物被膜的形成。扫描电镜和激光共聚焦显微镜形态观察表明AAP脂质体可引起细菌细胞结构的明显坍塌、细胞膜破损和胞内物质外溢,从而抑制生物被膜的形成。     

蜂花粉活性成分、生物活性及破壁技术研究进展

蜂花粉作为一种天然食品,富含大量的生物活性物质,包括多糖、蛋白质、脂质、多酚等。体内外研究表明,蜂花粉具有抗氧化、抗炎、降血糖、降血脂、保肝、治疗前列腺疾病、减肥、抗癌、抗动脉粥硬化和免疫调节等生物活性。但花粉壁结构复杂,在一定程度上限制了蜂花粉的生物活性物质释放和开发利用,因此,破壁技术的研究可以解决这些问题,进而提高蜂花粉的生物活性。本文综述了近年来蜂花粉的主要活性成分、生物活性和蜂花粉破壁处理技术的研究进展,为蜂花粉高附加值产品的开发提供借鉴。     

膳食脂质肠道消化及吸收的研究进展

膳食脂质作为人类生活中一种必不可少的营养物质来源，为机体提供所需的必需脂肪酸和能量，维持人体正常的生理活动，其中肠道作为脂质最主要的消化场所及特定吸收场所，发挥了重要的作用。该研究在基于脂质肠道消化途径的基础上，从脂质自身形态、蛋白质与脂质相互作用下的形态、脂质构型变化、胆汁盐分泌、胰脂肪酶以及共脂肪酶等多角度论述了影响脂质肠道消化的主要因素，分析了影响脂质消化关键行为的界面作用，从转运因子调节、分子吸收路径以及肠道微生物间接调控吸收三个方面阐述了膳食脂质的肠道吸收机制，为深入开展膳食脂质的功能化修饰、高值化利用、创新性研发提供了理论依据。     

加氏乳杆菌的降脂活性研究

目的:探究加氏乳杆菌是否具有降脂活性,并验证其对HepG2细胞脂质堆积和高脂血症小鼠脂质代谢活性的影响.方法:利用油酸诱导建立HepG2细胞脂质堆积模型,通过多次油红O染色定量对166株加氏乳杆菌进行降脂活性筛选,选择活性最强的一株菌通过Bodipy染色、甘油三酯含量测定进行验证.利用C57BL/6J小鼠喂食高脂饲料建...     

The global research progress of enzymatic processing of oils with Omega 3 polyunsaturated fatty acids（网络首发、推荐阅读）

综述ω-3多不饱和脂肪酸（polyunsaturated fatty acids,PUFA）作为一类必需脂肪酸（essential fatty acids,EFAs）,主要来源为海产品中的鱼油,对多种人体疾病治疗和/或预防具有的积极作用。梳理了酶法制备富含ω-3多不饱和脂肪酸油脂的研究最新进展（截至2019年）,讨论很多不同产品的营养功效、不同脂肪酸组成的结构脂质、ω-3多不饱和脂肪酸浓缩液、磷脂的酶促酯交换制备技术及应用,历年研究发现,可以通过改善油脂中ω-3多不饱和脂肪酸含量的方式提高其在饮食中的摄入量。由于酶法反应条件温和,尤其是脂肪酶特异性强,且从生物利用度角度ω-3多不饱和脂肪酸在脂质分子上的位置与其含量同等重要,因此相对于化学法,酶法制备含ω-3多不饱和脂肪酸的油脂因安全高效而更受青睐。     

桦褐孔菌乙酸乙酯萃取物对朊病毒复制的抑制作用

探究桦褐孔菌乙酸乙酯萃取物对朊病毒复制的影响及潜在作用机制。采用Cell Counting Kit-8（CCK-8）方法对桦褐孔菌二氯甲烷萃取物、乙酸乙酯萃取物和正丁醇萃取物进行细胞毒性评价，得到最大作用浓度；应用三种萃取物的安全浓度（0.1×2?14~0.1×2?8 mg/mL）处理SMB-S15细胞，通过PrP特异性蛋白质免疫印迹（Western blot）试验检测不同萃取物对朊病毒复制的影响；对乙酸乙酯萃取物处理细胞后的活性氧、过氧化氢及相关抗氧化因子水平进行测定。结果显示，桦褐孔菌二氯甲烷萃取物、乙酸乙酯萃取物和正丁醇萃取物的最大作用浓度为0.1×2?8 mg/mL，在该浓度下处理细胞3 d，发现乙酸乙酯萃取物可抑制朊病毒复制（P< 0.01），而二氯甲烷萃取物及正丁醇萃取物对朊病毒复制没有影响。进一步发现，乙酸乙酯萃取物可降低活性氧和过氧化氢水平，增加HO-1、GCLC蛋白表达，升高SOD活性和总谷胱甘肽水平，以上均具有统计学意义。本研究表明桦褐孔菌乙酸乙酯萃取物具有抑制朊病毒复制作用，且此抑制作用可能与激活Nrf2信号通路相关。     

Muscle lipids, vitamins E and A, and lipid oxidation as affected by diet and RN genotype in female and castrated male Hampshire crossbreed pigs

The objectives of this study were to investigate the polar and neutral lipid fatty acid composition, content of retinol, -tocopherol, γ-tocopherol and level of oxidation of the pig muscle (M. longissimus dorsi). Female and castrated male Hampshire crossbreeds were produced in two systems. One group was raised indoors with a more polyunsaturated diet and the other raised outdoors with a more saturated diet. The level of polyunsaturated fatty acids in muscle was higher in the indoor females compared with the outdoor females, indoor castrated males and outdoor castrated males. The increased level of polyunsaturated fatty acids in the muscle, which was accompanied by a relatively low content of -tocopherol, increased the susceptibility to lipid oxidation in the form of MDA (malondialdehyde) in the indoor female pigs. Finally, the level of polyunsaturated fatty acids in the polar lipids was affected by the RN genotype, and this difference was dependent on sex. In conclusion, diet has a major effect on the fatty acid composition and oxidation stability in pork muscle, but additional factors such as sex and RN genotype might also contribute.     

Fatty acids, cholesterol and protein content of nutria (Myocastor coypus) meat from an intensive production system in Uruguay

This study describes the total lipids, protein and fatty acids in the meat, liver, brain and adipose tissue of five male and five female nutria (Myocastor coypus). The animals were reared on a specialized farm in Uruguay. Total lipid content was between 1.41% and 1.84% in males and females. Total cholesterol content was between 70.1 mg and 72.7 mg/100 g of wet tissue. The protein content was between 19.56% and 22.34% in males and females. No significant differences (P > 0.05) were detected between males and females for total lipid, cholesterol or protein. Total, saturated, monounsaturated and polyunsaturated fatty acid values were higher (P < 0.001) in female than in male thigh muscle. Pectoral muscle had more (P < 0.05) saturated and monounsaturated fatty acids in females than in males. Subcutaneous adipose tissue from females had the highest (P < 0.01) total, saturated and monounsaturated but not polyunsaturated fatty acids while abdominal adipose tissue from males had more polyunsaturated fatty.     

Quality control method based on quartz crystal microbalance and WGA for flour milled from germinated wheat

Plasma membrane is the initial sensor of different stress conditions and its composition is modified with response to environmental changes. In the present study, we have modified the lipid composition of the membrane by growing Saccharomyces cerevisiae in the presence of different fatty acids and ergosterol. All supplemented fatty acids were incorporated into the cell and this incorporation produced significant changes in the lipid composition. The incubation with ergosterol also modified the lipid composition of the cells; however, these cells presented a strong reduction in the content of this sterol. The different cellular lipid composition has been related to viability and fermentation performance at low temperature (13 °C). The cells incubated with palmitoleic acid (C16:1) showed higher viability and significant reduction in the fermentation length. These cells presented higher C16:1 and ergosterol content, shorter chain length of the fatty acids and higher ratio of sterols/phospholipids. Therefore redesigning the composition of cellular membranes during industrial yeast propagation seems to be a promising strategy for improving fermentation performance in the winery.     

雌雄灰海马和三斑海马营养价值与功能性成分对比分析

分析海马营养价值与功能性成分含量,探究因性别不同而产生主要成分的差异,对雌雄灰海马（Hippocampus erectus）和三斑海马（H. trimaculatus）营养及功能成分的含量进行测定,并评价其营养价值。结果表明：1）海马粗蛋白含量（干质量）较高,平均高达（60.61±2.83）%,粗脂肪含量（干质量）较低,平均为（3.04±0.26）%。雌雄海马的基本营养成分无显著差异。2）雌雄海马氨基酸组成一致,含量相差不大。海马的7种必需氨基酸略低于FAO/WHO建议的氨基酸需求,限制氨基酸包括缬氨酸、异亮氨酸、蛋氨酸和胱氨酸。雌海马的氨基酸评分、化学评分和必需氨基酸指数均高于雄性。3）雌雄海马脂肪酸组成一致,雌海马的饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸（polyunsaturated fatty acids,PUFA）总量均显著高于雄性。海马n-3 PUFA含量相对较高,n-6/n-3值介于0.14～0.18之间,动脉粥样硬化指数和血栓形成指数明显高于低冠心病发病率的爱斯基摩人饮食。4）雌海马胆甾醇和次黄嘌呤含量显著高于雄性,尿苷含量低于雄性。综上所述,灰海马和三斑海马可作为较优的蛋白质和n-3 PUFA来源。此外,除尿苷含量低于雄性,同种雌海马的营养成分和主要功能性成分（胆甾醇和次黄嘌呤）含量均高于雄性。研究结果为特异性开发海马产品提供了科学依据。     

The impact of choline availability on muscle lipid metabolism

Consumption of choline-rich foods is essential to ensure membrane integrity, neurotransmission and genomic methylation pathways. Insufficient dietary choline supply can cause choline deficiency (CD) which manifests in the development of non-alcoholic fatty liver disease. There is very limited information regarding the effect of CD on non-hepatic tissues such as muscle. In this study, we induced CD in muscle cells and investigated the effect on choline transport, phosphatidylcholine (PC), fatty acid and triacylglycerol (TAG, fat) metabolism. Choline transport was stable across the plasma membrane of CD cells but significantly impaired in mitochondria. The main choline-transporter SLC44A1 was down-regulated by CD at the mRNA level, and SLC44A1 protein was reduced in total cell lysates and isolated mitochondria. CD significantly reduced PC synthesis but PC degradation was unaffected. PC from CD muscle was modified and contained more monounsaturated fatty acids at the expense of saturated fatty acids. Surprisingly, CD muscle cells also accumulated TAG in the form of large lipid droplets. Those droplets were formed from endogenous fatty acids and by slower TAG metabolism. This study established for the first time that choline availability affects muscle membrane lipid composition and intracellular lipid metabolism, and underlines the significance of choline-rich foods for proper muscle function.     

Lipid and antioxidant blood levels in vegetarians

Parameters of lipid metabolism (triacylglycerols TG, cholesterol CH, HDL-CH, LDL-CH, atherogenic index AI, profile of fatty acids) were measured in blood samples of 81 healthy lacto and lacto-ovo vegetarians (42 males, 39 females; age range 19–39 years). The average period of being on a vegetarian diet was 6.2 years. Low levels of TG, CH, LDL-CH, AI and HDL-CH values on the borderline between standard and reduced risk (1.4 mmol middot; 1^?1) can be considered as favourable from the atherosclerosis prevention aspect. Compared with non-vegetarians (n = 62), the levels of TG, CH, LDL—CH, and AI are significantly reduced in the vegetarian group. As opposed to non-vegetarians, vegetarians showed a higher total sum of polyunsaturated fatty acids, a significantly higher content of linoleic acid (C 18:2) and linolenic acid (C 18:3), unchanged content of oleic acid (C 18:1), stearic acid (C 18:0) and other polyunsaturated fatty acids. The process of lipoperoxidation (with polyunsaturated fatty acids as substrate) is involved in the etiology of cardiovascular and oncological diseases. Favourable values of prooxidative-antioxidative parameters demonstrated a reduced risk of lipoperoxidation in vegetarians, compared to non-vegetarians (significantly reduced content of conjugated dienes of fatty acids in plasma, significantly higher plasma levels of vitamin C, β-carotene, vitamin E/cholesterol ratio — an indicator of LDL protection, vitamin E/triacylglycerols ratio — an indicator of fatty acid protection —, selenium and glutathione-peroxidase activity).     

Investigation on the nutritive value and microbiological quality of wild quail carcasses

Quail meats have many advantages and superiority one the other species of poultry. This study was planned to throw plenty of light on gross chemical composition, lipid fractions, fatty acids composition, amino acids composition, of thigh and breast of male and female wild quail meat as well as the microbiological quality. The mean values of moisture, protein, fat, ash and energy contents ranged from 60.1 to 69.2%, 55.0 to 68.8%, 28.8 to 42.1%, 2.40 to 3.63% and 696 to 1000 kJ, respectively. Seven fractions of lipids (phospholipids, monoglycerides, cholesterol, diglycerides, free fatty acids, triglycerides and hydrocarbons) were estimated. The individual fatty acids were determined. The mean total unsaturated fatty acids represented 73.9, 66.8, 60.2 and 67.5% of the total fatty acids in thigh male, breast male, thigh female and breast female quail, while that of saturated fatty acids were 25.1, 30.1, 32.0 and 30.4%, respectively. The essential fatty acids in thigh and breast males were 34.8 and 29.0% against 25.7 and 28.1% in females. Amino acids composition were varied from 82.6 to 95.2 g/100 g protein in thigh, breast of male and female wild quails. The essential amino acids were illustrated. The mean values of psychotrophic, Pseudomonas, Enterobacteriaceae, coliforms, Streptococci and Staph. aureus were 4 x 10(4), 1 x 10(2), 4 x 10(3), 3 x 10(3), 6 x 10(2) and 1 x 10(3) cfu/g, respectively. E. coli, Enterobacter agglumerans, E. cloacae, Morganella morgani, Proteus mirabilis, and P. vulgaris could be isolated in varying percentages. Neither Salmonellae nor Clostridium perfringens could be isolated from the examined quails. The public health aspects for the estimated and isolated criteria were outlined.     

Effect of Phospholipid Hydrolysis on Lipid Oxidation in Flounder Muscle Microsomes

Endogenous phospholipase A activity was observed to be associated with the microsomal fraction of flounder muscle. Preincubation of microsomes with exogenous phospholipase A 2 resulted in an inhibition of both enzymic and nonenzymic lipid oxidation systems contrary to the generally accepted assumption that fatty acids are more susceptible to oxidation when free than when esterified. Removal of free fatty acids from the membrane led to a partial restoration of oxidative activity in both systems. Preincubation of microsomes with phospholipase C lowered enzymic oxidation but did not affect non-enzymic oxidation, whereas, preincubation with 1% sodium desoxycholate led to inhibition of both oxidation systems. This study suggests a direct role of phospholipid hydrolysis in the inhibition of lipid oxidation in an isolated membrane fraction of fish muscle and the possibility that such hydrolysis in situ may be a controlling factor in lipid oxidation and its subsequent effects.     

Nutritional and sensory evaluation of wheat breads supplemented with oleic-rich sunflower seed

Wholegrain and refined (white) wheat breads were prepared with the addition of high-oleic sunflower seed at various levels (8%, 12%, 16% flour basis). The nutritive value of breads was determined by measuring the chemical composition, including the mineral content, the fatty acid composition (saturated, monounsaturated, polyunsaturated, linoleic and linolenic acids) and the contents of tocopherols (α-, β-, γ-, δ-). The obtained data were used to estimate the intakes of nutrients and compare them to the dietary reference intakes (DRIs). The breads made with the addition of sunflower seed were sensorially acceptable, containing significantly more tocopherols, fat, essential fatty acids, crude fibre, copper and zinc. It was estimated that wholegrain supplemented breads would contribute to the corresponding DRIs in the range 33.7–40.8% (adults) for copper and 4.7–18.4% (males), i.e. 6.4–25.3% (females) for zinc, 18.3–26.8% (males), i.e. 25.9–37.9% (females) for linoleic (omega-6) acid, 7.4–7.6% (males), i.e. 10.7–11.0% (females) for alpha-linoleic (omega-3) acid.     

Subcellular Distribution and Composition of Lipids in Muscle and Adipose Tissues

Subcellular distribution of fatty acids in the membranes and cytoplasm of muscle and adipose tissues from USDA Select beef carcasses was determined. Cholesterol in subcellular fractions of intramuscular adipose tissue also was quantified. There was a greater percentage of saturated fatty acids in cytoplasmic, than in membrane, fractions of muscle. With the exception of intramuscular adipose tissue, monounsaturated fatty acids constituted a greater percentage of the total lipid in the cytoplasm than in membranes. There was a greater percentage of polyunsaturated fatty acids in the membrane, than in the cytoplasmic, fraction. Cholesterol averaged 118 mg per 100 g intramuscular adipose tissue with 54% in the cytoplasm and 46% in the membranes.