我国主要食用植物油中反式脂肪酸的研究

以GB/T 22110-2008为检测方法,对我国市场上销售的主要食用植物油(调和油、大豆油、花生油、芝麻油)中反式脂肪酸含量进行测定.结果显示:十八碳类反式脂肪酸有6种检出,同一油种具有相同种类的反式脂肪酸,各种类反式脂肪酸含量变化具有同步性,并呈显著性相关,各类反式脂肪酸在产生时具有相同的异构几率;当一种食用植物油的某类反式脂肪酸总含量接近或超过相应脂肪酸组成含量时,这份油样肯定不是单一品种的油样;反式脂肪酸主要来源于食用植物油的精炼过程,尤其是脱臭过程;我国存在因为反式脂肪酸摄入量过高而影响健康的情况,消费者、企业及政府部门应对食用植物油中反式脂肪酸的含量引起足够的重视.     

Trans fatty acids content and fatty acid profiles in the selected food products from Korea between 2005 and 2008

Since a high intake of trans fatty acids (TFA) has been associated with the increased risk of developing cardiovascular disease, food regulation worldwide has been amended with respect to nutrition labeling and health claims on TFA. In the present study, the TFA levels of Korean food products were investigated to assess the regulation effect of TFA labeling. Same Korean food products within 7 different categories were purchased in years 2005 and 2008, and the contents of TFA and lipid and fatty acid composition were investigated. Lipid and TFA contents decreased in all food products manufactured in 2008. TFA levels were 0.01 to 6.88 g/100 g food in 2005, but the levels remarkably decreased to nondetectable level or up to 0.5 g TFA/100 g food in 2008. The foods from 2005 contained a various level of TFA ranging 0.6% to 44.6% of total fatty acids; however, the TFA level significantly decreased in most foods up to 3.8% from year 2008. For TFAs, trans C18:1 levels were greater than trans isomers of C18:2, and the levels in 2005 were significantly reduced in 2008 (P < 0.05). TFA levels at the sn-2 position were up to 48.3% of total fatty acids in 2005, but the level considerably decreased up to 5.4% in 2008. The considerably decreased content of TFA in 2008 suggested that food manufacturers recognized the adverse effect of TFA on human health and followed the compulsory trans fat labeling rule by Korean Food and Drug Administration (KFDA), which started December 2007.     

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.     

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.     

中国市场食品中反式脂肪酸含量现状调研

比较了中国市售食品中的反式脂肪酸(TFA)含量调研数据,包括家用烹调油、餐饮用油和常见含油食品产品.从市场购买样品,然后测定TFA含量并进行分析和比较.对133个品牌的581个家用烹调油样品进行了测定,包括调和油、大豆油、玉米油、葵花籽油、菜籽油、橄榄油、花生油、芝麻油、茶籽油等15个油种.结果发现87.52％的烹调油样品中TFA质量分数在2％以下.收集并测定了5个油种74个样品的餐饮用油,结果表明各油种的TFA质量分数为0.45％～ 1.68％,可见调查范围内餐饮用油的TFA维持在一个较低水平.而对蛋糕、面包、饼干、炸薯条、冰激凌、巧克力、爆米花、方便面、植脂末、植物奶油等各类常见含油食品共计9大类76个主要品牌的257个样品进行分析的结果则表明,其TFA含量与2005～2010年公开发表的市场调研数据相比有了大幅度的下降.蛋糕面包派、饼干两类产品的TFA质量分数高于1％(油基),其他产品中TFA的质量分数较低.对各类主要产品间TFA含量和种类的差异原因也进行了深入分析.     

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。     

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.     

Trans fatty acids in margarines and shortenings marketed in Austria

Margarines and shortenings available in Austria were repeatedly sampled in 1991/1992 and the content oftrans fatty acids (TFA) determined by using capillary GLC. Wide variations of the TFA contents with respect to intra- and inter-brand differences were observed. Diet margarines contained up to 1% TFA, while TFA concentrations in tub or stick margarines were much higher (15.7±5.8% and 21.3±5.3%, respectively). A sub-set of samples was also purchased in 1995 and a general reduction of the TFA content was noticed. Taking into account different market shares of certain margarine types, a weighted average of 15.7% TFA and 6.5% TFA was calculated for the 1991/1992 and the 1995 samples. Based on availability data the amount of TFA supplied with margarines was estimated to be 3.7 g per person per day, while a more accurate method of measuring dietary intakes, i.e. diet history and food frequency data, approximates the amount of TFA supplied with margarines to be 1.5 g per person per day for the 1991/1992 samples and 0.6 g for the 1995 samples.     

油脂中的反式酸及其检测方法

油脂是人们摄取能量和必需脂肪酸的主要来源,对人体的健康起着至关重要的作用.油脂中的反式脂肪酸(TFA)是人们研究和争论的话题,但是经过长时间的研究,表明过多的摄入反式酸对人体有害.最近美国食品药品管理局(FDA)通过法案,强制性标注食品中反式酸的含量.为了控制油脂加工过程中反式脂肪酸的形成,对其影响因素及其定性、定量检测进行了论述.红外检测(IR)和Ag 薄层色谱可用来定性检测反式酸的存在,气相色谱可用来定量检测反式酸.     

Trans fatty acids in margarines and shortenings marketed in Austria

Margarines and shortenings available in Austria were repeatedly sampled in 1991/1992 and the content oftrans fatty acids (TFA) determined by using capillary GLC. Wide variations of the TFA contents with respect to intra- and inter-brand differences were observed. Diet margarines contained up to 1% TFA, while TFA concentrations in tub or stick margarines were much higher (15.7±5.8% and 21.3±5.3%, respectively). A sub-set of samples was also purchased in 1995 and a general reduction of the TFA content was noticed. Taking into account different market shares of certain margarine types, a weighted average of 15.7% TFA and 6.5% TFA was calculated for the 1991/1992 and the 1995 samples. Based on availability data the amount of TFA supplied with margarines was estimated to be 3.7 g per person per day, while a more accurate method of measuring dietary intakes, i.e. diet history and food frequency data, approximates the amount of TFA supplied with margarines to be 1.5 g per person per day for the 1991/1992 samples and 0.6 g for the 1995 samples.     

Fatty Acid Composition Including Trans‐Fatty Acids in Edible Oils and Fats: Probable Intake in Indian Population

Abstract: The susceptibility of trans‐fat to the human health risk prompted the Food and Agriculture Organization (FAO) and World Health Organization (WHO) to prepare regulations or compulsory claims for trans‐fatty acids (TFA) in edible oils and fats. In this study, analysis of fatty acid composition and TFA content in edible oils and fats along with the possible intake of trans‐fat in Indian population was carried out. The analysis was carried out as per the Assn. of Official Analytical Chemists (AOAC) methodology and the results were statistically analyzed. The average TFA content in nonrefined mustard and refined soybean oils exceeded by 1.16‐ to 1.64‐fold as compared to the Denmark limit of 2% TFA in fats and oils destined for human consumption. In branded/nonbranded butter and butter oil samples, average TFA limit exceeded by 4.2‐ to 9.5‐fold whereas hydrogenated vegetable oil (HVO) samples exceeded the limit by 9.8‐fold, when compared to Denmark standards. The probable TFA intake per day through different oils in Indian population were found to be less than WHO recommendation. However Punjab having highest consumption of HVO (–15 g/d) showed 1.09‐fold higher TFA intake than the WHO recommendation, which is alarming and may be one of the factors for high cardiovascular disease mortality rate that needs further elucidation. Thus there is a need to prescribe TFA limit for edible oil, butter, and butter oil in India and to reduce the already proposed TFA levels in HVO to safeguard the health of consumers. Practical Application: The probable daily intake of trans‐fatty acid (TFA) especially through hydrogenated vegetable oil (HVO) was assessed. In absence of any specification for TFA and fatty acid composition for edible oils, butter, and butter samples, a pressing need was felt to prescribe TFA limit in India. The study indicates that TFA intake through HVO consumption is higher in States like Punjab than the recommended daily intake prescribed by WHO. Hence, strategies should be adopted to either decrease the consumption of HVO or to modify the industrial processing method of HVO with less content of TFA to safeguard the health of consumers.     

反式脂肪酸检测方法研究与应用

研究了甲醇钠-甲醇、氢氧化钾-甲醇、浓硫酸-甲醇和三氟化硼-甲醇4种甲酯化试剂的浓度、用量及甲酯化时间和温度对反式脂肪酸检测的影响,优化了色谱条件,建立了以三氟化硼-甲醇法甲酯化,RT-2560（100m×0．25mm×0．2μm）毛细管柱为基础的反式脂肪酸气相色谱检测方法,C18：1—9t,C18：1—11t,C18：2—9t,12t和C22：1—13t 4种反式脂肪酸的最小检出浓度在0．77—4．08mg／kg之间。4种反式脂肪酸不同添标浓度回收率为98．44％-101．23％,重复测定的相对标准差在0．22％-1．31％之间,有较好的准确度和重现性。应用该方法检测了武汉部分小型市场散装食用植物油和-些餐馆的废弃油脂,以所含脂肪为基准,其反式脂肪酸含量分别为：0．12％-0．25％、3．63％-6．58％。表明天然食用植物油中反式脂肪酸含量较低,但油脂在高温加工过程中会产生反式脂肪酸。     

摄入反式脂肪对大鼠脂质代谢的影响

人群跟踪调查表明,反式脂肪酸(trans fatty acids,TFA)增加冠心病危险及死亡率,可能主要通过影响血脂和炎症反应引起某些慢性疾病。实验在脂肪供能33%(目前中国居民膳食供能比)的情况下,通过 90d 的大鼠饲养实验探讨以TFA 为主的脂肪摄入对大鼠体内脂质代谢的影响。结果表明：与基础饲料对比,以TFA 为主的脂肪摄入显著升高大鼠血液甘油三酯(TG)含量,显著降低大鼠高密度脂蛋白胆固醇(HDL-C)含量,显著降低血浆肝素前脂蛋白脂酶(LPL)和肝脂酶(HL)的活力,显示TFA 可能改变大鼠脂肪酸代谢,引起甘油三酯代谢异常;TFA 同时显著降低大鼠血液血清总胆固醇(TC)和低密度脂蛋白胆固醇(LDL-C)含量,且对C 反应蛋白(CRP)没有影响,显著升高HDL-C/ LDL-C,表明以TFA 为主的脂肪摄入可能并不引起大鼠胆固醇代谢异常,这可能是由于除基础饲料外,植物油的摄入没有引入外源胆固醇,且大鼠本身缺乏胆固醇转移蛋白(CETP)。     

食品中的反式脂肪酸与食品安全

反式脂肪酸是具有反式构型双键的一类不饱和脂肪酸的总称,其来源广泛,存在于大量的油脂及油脂食品中。近年流行病学调查研究表明,反式脂肪酸对人类健康有很大的危害,这引起了大众和科学家的广泛关注。本文综述了反式脂肪酸的存在现状、主要来源及对健康的主要危害,并从氢化技术、油脂精炼技术、交酯化反应及基因改良技术等方面介绍了减少油脂加工中反式脂肪酸产生的措施。     

反式脂肪酸与心血管疾病的研究进展

我国居民膳食中反式脂肪酸（TFA）含量呈逐年增高的趋势,而我国对Ⅱ认与人体健康关系的研究甚少。通过内皮细胞损伤来研究TFA对内皮细胞的作用机制,为研究TFA对血管壁细胞的影响及其与动脉粥样硬化的关系提供理论依据,为我国心血管疾病的预防提供科学数据,具有重要的理论和社会价值。     

反式脂肪酸与内皮细胞凋亡研究进展

鉴于我国居民膳食中反式脂肪酸(TFA)含量呈逐年增高的趋势和国内对TFA与人体健康关系的研究甚少的现状,通过内皮细胞凋亡信号转导来研究TFA对内皮细胞的作用机制,研究TFA对血管壁细胞的影响及其与动脉粥样硬化的关系,为心血管疾病的预防提供科学数据和理论依据。     

Fatty acid composition of grain from winter and spring sown oats, barley and wheat.

The fatty acid composition of grain has been studied in six varieties of oats, two of wheat and two of barley, sown in pots in an unheated glasshouse in winter and in spring. Differences were found between the species in composition and in their response to sowing date. Oats showed the greatest varietal variation in both total fatty acid (TFA) content and in the proportion of its component fatty acids. The content and degree of unsaturation of the oat TFA was higher in the winter sown than in the spring sown crop. Increases in the TFA content of oats, whether arising from differences in variety or sowing date, were generally followed by an increase in the proportion of oleic acid and a decrease in the proportions of palmitic and linoleic acid in the TFA. Winter sowing, as compared with spring, led to a small, but significant, decrease in the TFA content of barley and an increase in its degree of unsaturation. There were no significant changes in the content or composition of wheat TFA as a result of differences in sowing date. Factors influencing the differences in TFA content and composition between species, varieties and sowing dates are discussed.     

Trifluoroacetate profiles in the Arctic, Atlantic, and Pacific Oceans

A series of depth profiles was collected at 22 sites in the Arctic, North and South Atlantic, and Pacific Oceans to determine spatial patterns for trifluoroacetate (TFA) concentrations in the marine environment and to investigate possible natural sources of TFA. Profiles were also taken over underwater vents in the North and South Pacific and the Mediterranean Sea. At the profile sites, TFA values ranged from <10 ng/L in the Pacific Ocean to greater than 150 ng/L in the Atlantic Ocean. Samples from the Canada Basin of the Arctic Ocean exhibited variable TFA concentrations (60-160 ng/L) down to 700 m. Below this depth, in water having 14C ages exceeding 1000 years, the TFA concentrations were constant (150 ng/L). Water returning to the Atlantic through the Canadian Arctic Archipelago had constant high TFA values. Profiles from the Northern Atlantic exhibited high values at all depths but were more consistent in the Western Atlantic. The northwestern Pacific Ocean surface profile sites exhibited low TFA concentrations in the top 100 m increasing to a maximum of 60 ng/L with depth. Samples from the South Pacific Ocean site had generally low values with a few depths (>800 m) having concentrations of 50 ng/L or more. To determine if underwater vents could contribute to the TFA concentrations in the oceans, profiles were taken over three vents in the Pacific and Mediterranean Oceans. The results suggest that some deep-sea vents may be natural sources of TFA.     

巧克力样品中反式脂肪酸含量的测定

采用气相色谱内标法,对20个巧克力样品中的反式脂肪酸含量进行测定分析。试验结果表明,以代可可脂为主要原料的巧克力样品中,反式脂肪酸含量范围在未检出至4．96％之间。以可可脂为主要原料的巧克力样品中,反式脂肪酸含量范围在未检出至0．844％之间。所测定的巧克力样品中反式脂肪酸以反十八碳一烯酸为主。     

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.