反式脂肪酸的安全问题及最新研究进展

反式脂肪酸（TFAs）的安全问题近年来得到越来越多国家的密切关注，各国对TFAs严厉措施的出台将促进油脂食品工业的发展和科技水平的提高。本文综述了这方面研究的最新进展和研究动态。     

3种淡水鱼油脂肪酸的含量分析

运用气相色谱质谱联用方法,分析了鲢鱼、罗非鱼和草鱼3种淡水鱼脂肪的脂肪酸组成。淡水鱼脂肪经氯仿/甲醇(体积比=2∶1)提取后,用三氟化硼甲醇溶液衍生,衍生物用气相色谱质谱法分析。结果显示,3种淡水鱼脂肪多不饱和脂脂酸(PUFA)含量为29.26%～41.49%,主要有亚油酸(C18∶2)、亚麻酸(C18∶3)、花生四烯酸(C20∶4)、二十二碳五烯酸(C20∶5,EPA)和二十二碳六烯酸(C22∶6,DHA);单不饱和脂肪酸(MUFA)的含量为26.46%～39.60%,主要有棕榈油酸(C16∶1)和油酸(C18∶1);饱和脂肪酸(SFA)的含量为23.35%～37.05%,主要有肉豆蔻酸(C14∶0)、棕榈酸(C16∶0)和硬脂酸(C18∶0)。3种淡水鱼脂肪SFA∶MUFA∶PUFA的比值,鲢鱼为0.56∶0.84∶1;罗非鱼为1.07∶1.35∶1;草鱼为1.02∶0.72∶1。鲢鱼、罗非鱼和草鱼脂肪的n-6/n-3脂肪酸比值分别为1.16,2.46和1.98。3种淡水鱼脂肪具有较高的营养和开发价值。     

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。     

鄱阳湖野生鱼类脂肪酸含量的比较研究

通过研究鄱阳湖野生淡水鱼类脂肪酸的含量,了解鄱阳湖鱼类中饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸(PUFA)的含量和构成比。鱼肌肉用氯仿甲醇溶液提取脂肪,碱法甲酯化后用气相色谱分析。结果显示:鱼肌肉中的PUFA的含量随鱼类品种的不同有较大的差别,范围为18.65%～43.07%;二十二碳六烯酸(DHA)和二十碳五烯酸(EPA)的含量也变化较大,其中黄颡鱼的DHA含量最高,可达10.72%,而鲹鲦的EPA含量则是所测鱼类中最高的,达4.61%。其中n-3系不饱和脂肪酸与n-6系不饱和脂肪酸的比例也相差悬殊,从1:0.7到1:2.5不等。不同科目的鱼,在C22:4n-6、C22:5n-3(DPA)含量上有显著性差异。不同生活习性的鱼,其共轭亚油酸(CLA)、C20:4n-6、C22:2n-6、C22:4n-6、C22:5n-3、C22:6n-3(DHA)均存在显著性差异。研究结果表明鄱阳湖水域中,鱼肌肉的多不饱和脂肪酸与鱼的生活习性如生活在不同的水层和食性等有较大关系,鱼的遗传因素与脂肪酸比例和含量也有一定关系。     

分子蒸馏法制备鱼油多不饱和脂肪酸

研究了多级分子蒸馏法提取深海鱼油中多不饱和脂肪酸的工艺方法,通过对压力和温度的控制得到不同多不饱和脂肪酸含量的各级鱼油产品,当蒸馏温度为110℃以上,蒸馏压力为20Pa以下时,经过三级串联分子蒸馏,得到高碳链不饱和脂肪酸质量分数为90.96%的鱼油产品,并用气相色谱法测定了产品的脂肪酸组成,分析了产品的理化指标.     

传统熏鱼中反式脂肪酸的形成机理及控制措施

传统熏鱼常采用油炸方式进行加工,油炸是反式脂肪酸的形成途径之一.本文介绍了反式脂肪酸的危害,讨论了传统熏鱼油炸工艺对反式脂肪酸形成的影响,及控制熏鱼油炸过程中反式脂肪酸形成的相应措施,最后介绍了非油炸的熏鱼绿色制造新技术.利用该技术可替代传统油炸工艺,实现产品的工业化安全化生产.     

Storage Quality of Fresh and Frozen-thawed Fish in Ice

The objective was to determine whether traditional quality indexes of fresh (unfrozen) fish like sensory analysis, bacterial counts and trimethylamine content could be applied to thawed whole cod, cod fillets and ocean perch fillets kept in ice. Freezing and short-term freezer storage (≤5 wk at ?25°C) had very little effect on bacterial counts. During long-term freezer storage (≥14 wk at ?25°C) total counts were reduced as well as counts of trimethylamine oxide-reducing bacteria in cod fillets but not in ocean perch fillets. When the thawed fish was unacceptable the trimethylamine was <1 mgN/100g. Trimethylamine as a spoilage indicator was of no value when evaluating spoilage of thawed whole cod, cod fillets and ocean perch fillets kept in ice.     

食品中反式脂肪酸的监测与评估研究进展

随着西式快餐的兴起和经济的发展,食品种类和数量越来越丰富,我国居民的饮食习惯在逐步发生改变,反式脂肪酸的摄入逐年增加。目前我国对反式脂肪酸健康影响认识的模糊、食品中反式脂肪酸含量基础有效数据缺乏、食品中反式脂肪酸的风险监测与评估研究经验不足等原因,已在社会造成一定的消费恐惧。目前,我国需借鉴国际食品中反式脂肪酸含量的风险监测和摄入风险评估研究经验,为建立食品中反式脂肪酸的法定限量、加强对食品中反式脂肪酸有效监管和建立合理的安全预警体系提供支持。本文综述了国际相关研究进展,并提出开展我国食品中反式脂肪酸监测与评估的建议。     

不饱和脂肪酸与人体健康关系探讨

本文系统的介绍了各种不饱和脂肪酸对人体健康的有利和不利影响,为人们合理的摄取油脂提供了科学依据.     

Microbiological and Sensorial Quality Assessment of Ready-to-Cook Seafood Products Packaged under Modified Atmosphere

ABSTRACT:  The effects of modified atmosphere packaging (MAP) (30:40:30 O₂:CO₂:N₂ and 5:95 O₂:CO₂) on the quality of 4 ready-to-cook seafood products were studied. In particular, the investigation was carried out on hake fillets, yellow gurnard fillets, chub mackerel fillets, and entire eviscerated cuttlefish. Quality assessment was based on microbiological and sensorial indices determination. Both packaging gas mixtures contributed to a considerable slowing down of the microbial and sensorial quality loss of the investigated seafood products. Results showed that sensorial quality was the subindex that limited their shelf life. In fact, based primarily on microbiological results, samples under MAP remained acceptable up to the end of storage (that is, 14 d), regardless of fish specie. On the other hand, results from sensory analyses showed that chub mackerel fillets in MAP were acceptable up to the 6th storage d, whilst hake fillets, yellow gurnard fillets, and entire cuttlefish became unacceptable after 10 to 11 d. However, compared to control samples, an increase in the sensorial shelf life of MAP samples (ranging from about 95% to 250%) was always recorded.
Practical Application: Modified atmosphere packaging (MAP) is an inexpensive and uncomplicated method of extending shelf life of packed seafood. It could gain great attention from the fish industrial sector due to the fact that MAP is a practical and economic technique, realizable by small technical expedients. Moreover, there is great attention from the food industry and retailers to react to the growing demand for convenience food, thus promoting an increase in the assortments of ready-to-cook seafood products.     

Production of Biogenic Amines and Their Potential Use as Quality Control Indices for Hake (Merluccius merluccius, L.) Stored in Ice

ABSTRACT: The production of tyramine, histamine, putrescine, cadaverine, agmatine, and spermidine was studied for use as quality indices in muscle of gutted hake stored in ice for 25 d. The changes in biogenic amine concentrations were correlated with trimethylamine nitrogen levels. All concentrations except for spermidine, increased progressively throughout storage. During storage, cadaverine reached 72.14 mg/kg while there were no significant increases in histamine and tyramine. The levels of free amino acids, which may be metabolized into biogenic amines, were not correlated to respective biogenic amines levels. The production of cadaverine and agmatine occurred prior to spoilage and these biogenic amines may indicate freshness of hake stored in ice.     

脂肪酸营养与功能的最新研究

概述了脂肪酸的种类以及与胆固醇和动脉硬化的相关研究,同时综述了各类脂肪酸营养与功能的最新研究,包括有n-6系多价不饱和脂肪酸、n-3系多不饱和脂肪酸、饱和脂肪酸、一价不饱和脂肪酸,以及一些微量脂肪酸如共轭脂肪酸、中短边脂肪酸等等。     

脂肪酸对米饭食味的影响

研究脂肪酸对米饭食味的作用,以垦育38号为原料,采用米饭硬度黏度仪、气相色谱-质谱联用仪及快速黏度分析仪等测定添加油酸、亚油酸对米饭的质构特性、挥发性风味化合物及淀粉糊化特性的影响。结果表明,在1%～3%添加量范围内,随脂肪酸添加量的增加,油酸、亚油酸与大米淀粉形成的淀粉-脂质复合物增多,米饭的硬度分别升高了9.02%～30.97%、12.45%～29.10%,黏度分别降低了23.28%～53.44%、11.64%～30.17%;与亚油酸相比,油酸分子更易与大米淀粉形成复合物,对米饭黏度的降低作用更显著。添加油酸和亚油酸可显著提高大米淀粉的最终黏度和回生值,使最终黏度由198.88 RVU分别升至232.21 RVU和237.96 RVU,回生值由59.04 RVU分别升至126.96 RVU和90.96 RVU。与亚油酸相比,油酸对大米淀粉糊化特性和米饭挥发性风味化合物的作用更显著。     

ω-3多不饱和脂肪酸在改善鸡蛋营养质量方面的研究

本文对ω-3多不饱和脂肪酸的化学结构、特性、作用及在改善鸡蛋营养质量等方面的研究进行了综述,讨论了如何通过饲喂对鸡蛋的脂肪组分加以调控,从而使其成为人类ω-3多不饱和脂肪酸的重要来源。     

Effect of Ice Storage on Fatty Acids Profile of Freshwater and Marine Fishes Available at Malaysia Wet Market

This study was conducted in the intention to identify and determine the fatty acid profile in freshwater fishes and marine fishes available at Malaysian wet market as well as its deterioration kept in ice storage up to 21 days. Three freshwater fishes： Oreochromis sp. commonly known as Tilapia, Monopterus alba commonly known as Belut, Pangasius hypothalamus commonly known as Patin and marine fish Rastrellinger kanagurta commonly known as Kembung, Thunnus tonggol commonly known as Tongkol and Epinephelus sp. commonly known as Kerapu with average weight of 500-600 g were tested with storage time of 1, 3, 6, 9, 12, 15. 18 and 21 days kept ice storage. The Fatty Acid Methyl Ester （FAMEs） were prepared using one step method and were identified by using gas chromatograph Agilent 6890N equipped with flame ionization detector. Separation was performed by injecting 1μL of a sample into the capillary column DB-225MS column （30 m length × 0.250 mm diameter × 0.25 μm film thickness）. The fatty acids peaks were indentified using Agilent Technologies software 5988-5871EN and comparing their retention time against the authentic standard Supelco 37 Component FAME Mix. Statistical results showed that palmitic acid （CI6：0） were the major fatty acids among the saturated fatty acids （SFA） while oleic acid （C 18：1 n9） were the major monounsaturated fatty acids （MUFA） detected in each sample studied. Both linoliec acid （C 18：2n6） and arachadonic acid （C20：4n6） were predominant in total omega-6 polyunsaturated fatty acids （PUFA）. The essential fatty acids show prominent in ecosapentanoic acid （C20：5n3） and docosahexanoic acid （C22：6n3）. During ice storage polyunsaturated fatty acids （PUFA） and monounsaturated fatty acids （MUFA） decrease as the time of storage increase. There is significant decrease in polyene index （PI） index of all the species throughout the storage time, The PI in freshwater fishes decrease by 70% in Tilapia, 90.1% in Belut and 90.9% in Patin, while for marine fishes, PI in Kembung decreases by 67.8%, 85.7% in Kerapu and 65.93% in Tongkol during kept in ice storage. During ice storage, the percentage of EPA, DHA and ALA decrease in Tilapia （55.36%, 13.86% and 75.41%）, Belut （78.55%, 87.74 % and 74.53%） and Patin （82.45%, 40.0% and 82.10%）, respectively. The same result were also observed in the marine fishes where the percentage ofEPA, DHA and ALA decrease in Kembung （94.27%, 49.03% and 88.52%）, in Kerapu （73.03%, 88.18% and 38.73%） and Tongkol （70.05%, 38.24% and 57.14%）, respectively.     

近红外光谱法快速检测婴儿配方奶粉中的脂肪酸含量

采用傅里叶近红外光谱结合偏最小二乘法(PLS)法建立了测定婴儿配方奶粉中的总脂肪酸、饱和脂肪酸和不饱和脂肪酸含量的近红外数学模型,并通过交互验证和外部检验两种方式考察了近红外数学模型的可靠性。通过选择不同的波长范围,采用平滑、矢量归一化、一阶求导、二阶求导和散射校正对近红外光谱进行处理,总脂肪酸、饱和脂肪酸和不饱和脂肪酸的校正模型相关系数(R2)分别为0.9337、0.9374、0.9020,RPD分别为3.63、3.65、2.90。结果表明近红外数学模型具有良好的预测性能。采用建立的模型对验证集中的20个婴儿配方奶粉样品进行预测,总脂肪酸含量、饱和脂肪酸和不饱和脂肪酸的预测值与化学测定值之间经配对t检验分析,与常规化学方法得到的检验结果无显著差异。