超临界条件下油脂氢化研究进展

近年来,反式脂肪酸带来健康问题日益引起人们关注,过多摄入反式脂肪酸将会引发心血管等多种疾病,而油脂氢化过程是产生反式脂肪酸主要来源之一;在超临界条件下进行油脂氢化可大大减少反式脂肪酸形成,已成为当前研究热点。该文主要介绍超临界流体特性及其在油脂氢化工艺中应用。     

如何限制油脂反式脂肪酸含量和摄入量

反式脂肪酸对人体有一定的负面作用,如引发冠心病、导致乳腺癌、影响必需脂肪酸的消化吸收等.反式脂肪酸存在于精炼油脂和氢化油脂中,为了减少油脂中反式脂肪酸的含量,应采用合适的设备、并控制油脂精炼过程中的脱臭条件,对于氢化油脂还需要控制氢化条件、选择合适的氢化油原料.通过低温、短时间的脱臭可以使精炼油脂中反式脂肪酸含量降到最低.另外,建议我国有关食品立法部门规定对反式脂肪酸加以标识,以正确引导消费.     

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.     

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。     

不饱和脂肪酸自动氧化形成反式脂肪酸机理研究进展

食用油热加工过程中由其不饱和脂肪酸异构化产生的反式脂肪酸 (TFAs) 对人体健康存在风险,有效控制TFAs的形成,对提升食品安全水平具有重要意义。以前研究者们重点关注的是油脂不完全氢化形成TFAs机理研究,而无需催化剂条件下油脂中不饱和脂肪酸热致异构化机理和氢化机理完全不同。而近年来油脂热处理过程中关注最多的顺反异构主要集中在C=C上的异构现象,因此,本文将着重总结不饱和脂肪酸自动氧化形成反式脂肪酸机理,旨在为为高脂食品中反式脂肪酸形成抑制作用研究提供理论基础和科学依据。     

食用油加氢过程催化剂对反式脂肪酸影响的研究进展

油脂氢化是油脂工业重要的反应过程,在此过程中油脂的结构和组成发生改变,在部分氢化过程中不可避免地产生反式脂肪酸.鉴于反式脂肪酸对人体健康有害,目前关于催化剂的研究大多集中在如何控制反式脂肪酸的生成量方面.就各种催化剂对食用油氢化反应的异构化影响进行讨论,重点介绍食品工业中使用的镍及其他诸如铜、金和铂族金属等非均相催化剂对反式脂肪酸生成量的影响,对非均相催化剂及与催化剂相关的载体、处理方法等诸种因素对顺式选择性的影响进行了简单阐述.     

利用气相色谱法测定焙烤食品中反式脂肪酸含量

反式脂肪酸是一种具有反式构型的不饱和脂肪酸。其中通过植物油或动物油脂的氢化过程中发生部分异构化形成的反式脂肪酸,通常为反油酸（C18：19t）。此类反式脂肪酸因具有可使食品酥软可口、延长保质期,比天然黄油成本低等特性,所以被广泛应用于烘烤食品中。     

低反式脂肪酸氢化油脂研究进展

综述了油脂氢化制备低反式脂肪酸氢化油脂工艺的最新研究进展.介绍了电化学催化氢化和超临界氢化的反应原理、反应器构造及工艺参数对氢化反应的影响,并分别阐述了其与传统油脂氢化、贵金属催化氢化相比在制备低反式脂肪酸氢化油脂方面的优缺点.     

低反式脂肪酸油脂替换高反式脂肪酸油脂的研究

我们日常食用的很多食品中存在不同程度的反式脂肪酸.一些焙烤和油炸食品如油饼、丹麦馅饼,深度油炸食品如炸鸡、炸土豆条等,以及假奶酪、人造奶油、冰淇淋、糖果中的反式脂肪酸含量可能较高,其中有很大部分是由于加工时使用了部分氢化油脂所致,也有的是加工过程中由于热作用产生的,它们的反式脂肪酸含量大都随加入的氢化油量的不同而存在较大差异.当煎炸油或加工原料中含有较多的反式脂肪酸时,产品中便会有较多的反式脂肪酸存在.传统的油脂氢化方法是在镍催化下,将氢气直接加成到脂肪酸不饱和位点处,对植物油脂或动物油脂进行部分氢化,高温、高压的催化条件能导致TFA的大量产生.传统的氢化工艺产生的反式脂肪酸较多,但通过控制工艺参数可一定程度上降低反式脂肪酸的形成量. 现在许多国家都已经将食品中的反式脂肪酸含量写入食品标签,美国FDA的规定已于2005年1月正式启用,即每份食品中的反式脂肪酸含量大于5％时,须在标签中标明.而我国在反式脂肪酸的研究方面还远远落后于国际,还没有关于反式脂肪酸含量的相应标准.     

氢化制备低反式酸油脂的研究进展

在油脂氢化过程中会产生一些反式脂肪酸(Trans fatty acid,TFA),其对人体健康具有诸多负面影响,故在油脂氢化过程中,应最大限度降低氢化油脂中TFA的含量。本文重点对油脂氢化的各种技术进行综述,进一步阐明油脂氢化的原理,为以后的研究提供一定的经验。     

食用油氢化反应器

该文根据食用油氢化特征,扼要介绍最典型间歇式淤浆反应器和连续式反应器,介绍中试和实验室用不同类型氢化反应器,如喷淋床氢化反应器;等温并流流动反应器;超声波氢化反应器;磁场氢化反应器;电化学催化氢化反应器;超临界催化氢化反应装置;膜氢化反应器等反应器的结构、特点和实验结果。     

食用油脂及加工食品中反式脂肪酸的风险评价

目的 对我国标准人经食用油脂及加工食品摄入反式脂肪酸进行风险评价。方法 采用气相色谱法检测食用油脂及加工食品中反式脂肪酸的含量, 运用Crystal Ball软件对食用油脂和加工食品中反式脂肪酸的风险商(hazard quotient, HQ)进行分析和风险描述。结果 食用油脂的HQ平均值为1.21E-1, 90百分位概率下风险商为3.07E-1(HQ<1), 95百分位概率下风险商为3.33E-1(HQ<1); 含油脂高的加工食品HQ平均值为5.30E-1, 90百分位概率下风险商为9.59 E-1(HQ<1), 95百分位概率下风险商为1.92E 0(HQ>1)。结论 郑州市居民经食用油脂摄入反式脂肪酸的风险较低(HQ<1); 摄入含油脂高的加工食品的90百分位的概率下不存在风险(HQ<1), 95百分位暴露水平下存在一定的风险性(HQ>1)。     

Are Chinese edible oils safe? A survey of trans fatty acid contents in Chinese edible oils

Food Science and Biotechnology - Nine different edible oil types from 7 cities in China were analyzed. Trans fatty acid (TFA) contents in edible oils were determined, TFA distribution...     

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.     

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.     

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。     

食用氢化油的用途

对食用氢化油在糖果、焙烤食品、煎炸食品、冷饮，仿乳制品、预制产品中的应用进行了综述，并对不同用途的氢油的制备方法作了简单介绍。     

Polycyclic aromatic hydrocarbon content in commercial Spanish fatty foods

The levels of polycyclic aromatic hydrocarbons (PAHs) were determined by reversed-phase high-performance liquid chromatography with fluorescence detection in different fatty foods from a Spanish market. The average concentration of the sum of total PAHs in edible vegetable oils was below 25 ng/g, whereas the sum of heavy PAHs did not surpass 5 ng/g. Olive pomace oils obtained before the summer of 2001 were an exception because they were highly contaminated. The effects of different technological processes, such as bleaching, deodorization, and hydrogenation, on PAH concentration in edible oils have been studied. The PAH profiles, as well as the influence of cooking procedures, of other fatty foods (margarine, mayonnaise, and oils from canned fishes) have been examined.     

Impact of trans fatty acids of ruminant origin compared with those from partially hydrogenated vegetable oils on CHD risk

There is a considerable overlap of trans fatty acid (TFA) isomers in fats of ruminant origin and partially hydrogenated vegetable oils (PHVOs), with many isomers in common. However, there is a considerable difference in the amount of individual TFAs in both sources. At present it is uncertain as to which component(s) of TFAs created by chemical hydrogenation are responsible for their negative metabolic effects. There is evidence of unfavourable effects of TFAs from hydrogenated vegetable oils on LDL and other risk factors of atherosclerosis. There is no evidence that the predominant TFA in milk, vaccenic acid, exerts these unfavourable effects. Prospective studies addressing the effect of TFA intake on coronary heart disease risk, whose estimate of TFA intake was based on dietary protocols, were mostly carried out in populations with a relatively low intake of dairy or ruminant TFAs. Nevertheless, several of them showed a significantly or non-significantly decreased risk with increasing intake of animal TFAs, or at least no increased risk. Up to now there is no human study available that investigates the effect of different TFAs under “Ceteris paribus” conditions (isoenergetic diets with otherwise identical fatty acid profile). By now the production of milk fat samples differing mainly in TFA content is feasible and would allow such controlled intervention studies.