食品工业专用油脂中反式酸的控制

含有反式酸的油脂因其独特的物理化学特性多年来一直被用于食品工业生产.然而,近年来的临床试验和流行病学研究表明,反式酸是对人体健康有害的脂肪酸.出于对公众健康负责的考虑,一些食品公司正寻找低反式或零反式的工业专用油脂用于生产.综述了反式酸的定义、主要来源、各国政府对反式酸的态度以及在食品工业专用油脂(烘焙油脂、糖果油脂以及煎炸油脂)加工中降低反式酸的措施.     

食品工业专用油脂中的反式脂肪酸

本文综述了反式脂肪酸的定义,主要的来源,分析检测方法以及反式酸对人体的危害与在食品工业专用油脂加工中降低反式脂肪酸的措施.     

食品工业专用油脂中的反式脂肪酸

本文综述了反式脂肪酸的定义,主要的来源,分析检测方法以及反式酸对人体的危害与在食品工业专用油脂加工中降低反式脂肪酸的措施.     

微波辅助合成/萃取-气相色谱法测定植物黄油中反式脂肪酸

建立了微波辅助合成/萃取-气相色谱测定植物黄油中反式脂肪酸的分析方法,优化了萃取溶剂、萃取温度和萃取时间等条件。反式脂肪酸甲酯以气相色谱FID检测,通过单标甲酯的保留时间和脂肪酸的出峰规律定性,以十三烷酸为内标,定量测定目标反式脂肪酸的含量。该方法使样品脂肪的提取、甲酯化及萃取同步完成,顺反式脂肪酸甲酯得到有效分离,前处理简单、快速,内标法定量准确,最小检出量低,可用于实验室检测食品中油脂的微量反式脂肪酸含量。     

油脂中反式脂肪酸的危害及检测方法

反式脂肪酸对人体的危害是饱和脂肪酸的10倍，食品安全与人类生存、繁衍息息相关，为解决反式脂肪酸检测问题，给国人提供食品生产和检测方法的借鉴，通过石英毛细色谱柱GC检测，对反式脂肪酸进行准确的定量，为食品特别是油脂、煎炸食品企业的生产提供危害源控制和检测保证。     

植物油的营养和如何在加工中减少反式酸

介绍了油脂脂肪酸对人体的关系及反式脂肪酸对人体的负面作用。在油脂加工过程中,反式酸含量的增加主要在脱臭工段和氢化工段,为了降低油脂中反式脂肪酸含量,在脱臭段设计填料和板式相结合的脱臭塔,要控制操作条件。在我国间歇氢化过程中,反式酸增加量超过20%,要总结影响因素并加以控制反式酸的含量。超声波氢化、电化学催化氢化和生物酶技术可以减少油脂中反式酸含量。     

食用油脂中的反式脂肪酸

综述了反式脂肪酸的定义、主要的来源、分析检测方法以及反式酸对人体的危害以及在油脂加工中降低反式酸的措施     

食用油脂中的反式脂肪酸

综述了反式脂肪酸的定义、主要的来源、分析检测方法以及反式酸对人体的危害以及在油脂加工中降低反式酸的措施。     

反式脂肪酸的控制与检测技术

近年来反式脂肪酸对人体健康尤其是心脑血管的危害,引起了世界各国重视.阐述了反式脂肪酸的产生、安全性及对人体危害的临床研究进展,分析了国内外在油脂制备和加工过程中反式脂肪酸控制技术的研究现状.介绍了反式脂肪酸检测方法的国内外标准和研究进展,并进行对比分析,最后提出了目前反式脂肪酸研究中存在的问题和发展方向.     

油脂食品中反式脂肪酸危害问题探讨

随着科学的进步和人们生活水平的提高,以往传统的食品加工方法以及由此而产生的一些食品安全问题,不断引起人们的疑虑。其中,在油脂食品加工中,有关油脂食品中的反式脂肪酸(Trans Fatty Acids)对人健康产生危害即是一个颇为敏感的问题。经过近10余年来人们对油脂食品中的反式脂肪酸的深入研究,有关反式脂肪酸对人体的影响,如何在油脂加工中控制和减少反式脂肪酸的含量,以及当前油脂食品中反式脂肪酸应控制的最低限量范围,学术界和产业界及消费者不断有了新认识。目前,美国食品药物局(FDA)已做出提案,将要求对油脂食品中反式脂肪酸的含量…     

Bioactive lipids naturally occurring in bovine milk

Bioactive properties of food components increasingly gain in importance in the modern diet. Bovine milk fat (BMF) exhibits bioactive substances mainly in the class of fatty acids. Currently, most interest is addressed to trans fatty acids (TFA) and particularly conjugated linoleic acids (CLA) with BMF being the main source of CLA in food. Whereas saturated fatty acids (C12–C16) and TFA are reported to be positively correlated (negatively for oleic acid) with atherosclerosis and coronary heart disease, CLA are regarded as potent anticarcinogens. Also butyric acid (C4) as well as some phospholipids and ether lipids present in BMF are thought to have anticarcinogenic properties. Furthermore, BMF contains the essential fatty acids C18 : 2 n-6 and C18 : 3 n-3 that have many and diverse functions in human metabolism and, thus, control a variety of biochemical and physiological processes. Altogether, BMF contains approximately 75 wt% of bioactive substances. However, the overall impact on human health can hardly be assessed.     

转录组学在乳酸菌研究中的应用

转录组学是一门从RNA水平上研究基因表达情况的学科,是一种重要的生命科学研究手段,被广泛应用到多个物种的研究中。乳酸菌作为一类公认安全的食品工业微生物,在发酵食品工业中发挥着重要作用。随着乳酸菌分子水平研究的快速发展,乳酸菌转录组学日益成为研究热点。本文对转录组学及其研究技术进行综述,阐述了转录组学在研究乳酸菌生长代谢调控机制、环境胁迫应激反应、发酵及益生功能中的应用,并对乳酸菌转录组学研究存在的问题及发展趋势进行了讨论,期望为乳酸菌转录组学研究提供参考。     

Decomposition of environmentally persistent trifluoroacetic acid to fluoride ions by a homogeneous photocatalyst in water

Decomposition of trifluoroacetic acid (TFA) was achieved with a tungstic heteropolyacid photocatalyst H3PW12O40*6H2O in order to develop a technique for measures against TFA stationary sources. This is the first example of C-F bond cleavage in an environmentally harmful perfluoromethyl-group-containing compound using a homogeneous photocatalyst. The catalytic reaction proceeds in water at room temperature under UV-visible light irradiation in the presence of oxygen. The system produces only F- ions and CO2; the (mole of formed F-)/(mole of decomposed TFA) and (mole of formed CO2)/(mole of decomposed TFA) ratios were 2.91 and 2.09, respectively. GC/MS measurements showed no trace of other species such as environmentally undesirable CF4, which is the most stable perfluorocarbon and has a very high global warming potential. When the (initial TFA)/(initial catalyst) molar ratio was 20:1, the turnover number of TFA decomposition reached 5.58 by 72 h of irradiation, accompanying with no catalyst degradation. The catalytic reaction mechanism can be explained by a redox reaction between the catalyst and TFA, involving a photo-Kolbe process.     

Trans fatty acid content in Malaysian supermarket foods: a field-to-laboratory approach in assessing food risk

The extent of industrial trans fatty acids (TFA) in the food supply is unknown in Malaysia, whilst TFA disclosure on food labels is not mandatory by Malaysian food standards. Supermarket foods such as dairy products, fats and oils, meat products, snack foods, soups, and confectionery are commonly cited to be major contributors of TFA in the diet. A consumer survey (n = 622) was used to develop a food listing of these ‘high risk’ foods. TFA content of high-risk foods were analysed by gas chromatography. Food samples (n = 158) were analysed and their total TFA content were compared with Malaysian Food Standards. A wide variation in TFA content within food categories was indicated. Of the foods containing TFA, many food labels did not cite TFA content or the use of partially hydrogenated vegetable oils (PHVO) as an ingredient. Hypothesised estimates of TFA intake from these supermarket foods in a sample day’s menu providing 2000 kcal projected a minimum intake of 0.5 g and a maximum intake of 5.2 g TFA. This study found there was no voluntary disclosure of TFA content on food labels or identifying PHVO as an ingredient. It appears that health education targeting consumers to minimise TFA consumption is required supported by mandatory PHVO disclosure on the food label.     

反式脂肪酸的产生及降低措施

反式脂肪酸能增加患心脏病、冠心病、乳腺癌的几率,同时还有抑制幼儿生长发育的负面作用.对反式脂肪酸的来源、各国的限制性规定,以及油脂加工过程中采用何种措施降低反式脂肪酸含量进行了论述.通过降低油脂脱臭温度和时间,选用填料脱臭塔可有效降低油脂脱臭过程中产生的反式脂肪酸;通过控制油脂氢化反应条件,选择Pt作催化剂或选择超临界流体反应器可降低油脂部分氢化产生的反式脂肪酸.另外,通过基因改良生产多不饱和脂肪含量低的油料,或采用交酯化反应也可生产低或零反式脂肪酸含量的产品.     

Accumulation of trifluoroacetate in seasonal wetlands in California

Trifluoroacetate (TFA, CF3COO-) is a stable and mildly phytotoxic breakdown product of several fluorinated organic compounds including the hydro(chloro)fluorocarbons (HFC/HCFCs) that have largely replaced the stratospheric ozone-depleting chlorofluorocarbons (CFCs). TFA enters aquatic ecosystems primarily through precipitation and has the potential to accumulate in water bodies with little or no outflow to the point where toxic concentrations could be achieved. This study demonstrated that seasonal wetlands lacking outflow concentrated TFA as they evaporated during the dry season. In addition, the TFA within the pools was retained between years, which may result in long-term TFA accumulation. Since plants acquire TFA from their growing media, the plants exposed to high aqueous concentrations of TFA within the pools had elevated TFA concentrations with a median concentration of 279 ng/g dry weight in their tissues as compared to 33 ng/g for species growing outside the pools. The highest TFA concentrations in water, which occurred just prior to the pools drying up, were in the 2-10 micrograms/L range. These concentrations are approximately 190 or less than reported toxic concentrations for the most sensitive species tested, but our evidence suggests that these concentrations will increase with continued TFA deposition into the pools.     

从感性与理性的对峙看夏娃的叛逆与堕落

弥尔顿的史诗《失乐园》中最为重要也最为复杂的主题就是亚当和夏娃的堕落。撒旦的引诱可以视为《失乐园》中亚当和夏娃堕落的外因。鉴于上帝的警告以及创造亚当夏娃时的纯洁性,要促成堕落还需要内因配合外因起作用。内心的堕落应当从夏娃身上找寻,因为是她最先受到诱惑,并且堕落也主要由其完成。从感性与理性对峙的角度,看《失乐园》中夏娃的叛逆,对于全面理解这一作品,是一条有价值的线索。     

Effects of Processing and Storage on the Folate Content of Spinach and Broccoli

Free and total folate activities (FFA and TFA) in spinach and broccoli were determined at various processing stages. In most cases FFA was significantly lower than TFA (P < 0.05). Steam-blanching resulted in greater TFA retention than water-blanching. Spinach lost 50% of the TFA during canning and another 10% after storage for 3 months. Storage at - 32.2°C of water blanched spinach resulted in 27% TFA loss after 3 months and 17% TFA loss for water-blanched broccoli after 8 months. For spinach and broccoli, 40% and 68%, respectively, of the TFA was in the blanch water but only 1% and 4% TFA, respectively, were in the steam-blanch condensate. When canned, 14% of the TFA in spinach immediately after processing was in the liquid in the can. This amount increased to 18% after 3 months storage.     

油炸与油炸食品中的反式脂肪酸产生、危害及消减

反式脂肪酸(trans fatty acids,TFA)一般天然存在于反刍动物体内,或在油脂精炼、加热、氢化加工过程中产生。不恰当的加工方式,如高温加热或油炸等,也会产生一定量的TFA,且不同加工条件对TFA生成量的影响程度不同。TFA对人体健康的影响是多方面的,因此更需要在油脂烹调过程中对其加以控制。本文从TFA的结构、来源、不同加工条件对其形成的影响、危害和消减措施等方面做出阐述,对我国目前暴露量进行分析并提出相关的建议。     

快速检测技术构筑食品生产的安全防线

近年来食品安全事故频频发生,食品安全问题受到了广大人民群众的广泛关注。食品快速检测技术快速、简单、灵活,应用于食品生产的质量控制,有利于食品安全防线的构筑。