食用油脂中3-MCPD脂肪酸酯和缩水甘油脂肪酸酯分析方法研究进展

随着对油脂中3–MCPD脂肪酸酯(ME)和缩水甘油脂肪酸酯(GE)研究和检测技术的不断更新,在精炼棕榈油中发现了ME存在,且在大多数食用油脂中发现了GE存在。ME和GE作为两类食用油脂加工过程中产生的污染物,对人体可能存在致癌性。目前对ME和GE的检测有直接方法和间接方法 2种,直接方法主要是对油样处理或不处理后直接用LC–MS、LC–MS/MS、LC–TOF–MS、GC–MS等进行检测;间接方法是将ME和GE醇解为3–MCPD和缩水甘油酯,苯硼酸或七氟丁酰咪唑衍生化后用GC–MS或GC–MS/MS检测。该文对现有的ME和GE检测方法的样品处理过程、仪器条件、结果等加以比较和分析探讨。     

废弃油脂脂肪酸甲酯制备二聚酸甲酯聚合工艺研究

以废弃油脂制备的脂肪酸甲酯为原料进行聚合反应,产物经分子蒸馏后得到单体酸甲酯(生物柴油)和二聚酸甲酯.研究了催化剂加入量、反应温度和反应时间等因素对聚合反应产品收率和质量的影响.结果表明,聚合反应适宜的工艺条件为:催化剂加入量为脂肪酸甲酯质量的10%,反应温度240℃,反应时间8 h.在此条件下,二聚酸甲酯产率达到74.0%,粗产品经提纯后二聚酸甲酯含量为90.7%.自制片状活性白土催化剂活性好,催化剂与产品容易分离,产品夹带损失少.     

食用油脂中反式脂肪酸研究进展

反式脂肪酸(Trans fatty acids,简称TFA)是含有反式构型双键的一类不饱和脂肪酸的总称,可以导致多种人类疾病的发生.本文对反式脂肪酸的来源、危害、各国限量标准、检测方法等方面做了综述,并对其以后研究方向作了展望.     

食用植物油中氯丙醇酯检测方法研究进展

脂肪酸氯丙醇酯是食用植物油加工过程中形成的一类污染物,进入人体胃肠道后在脂酶作用下可水解释放出具有潜在致癌性的氯丙醇类物质,食用油中氯丙醇酯污染已成为新出现的热点食品安全问题之一。建立准确、可靠、高灵敏的检测食用油中氯丙醇酯含量的方法具有重要的现实意义。目前氯丙醇酯的检测方法有直接法和间接法两种,直接法不破坏氯丙醇酯结构直接检测,间接法将氯丙醇酯转化为游离氯丙醇,以测得的氯丙醇含量反推计算出样品中氯丙醇酯的含量。本文综述了近年来国内外氯丙醇酯检测技术的研究概况,对各种检测方法的基本原理、操作步骤、仪器条件及各自的优缺点进行了比较分析,最后展望了氯丙醇酯检测方法的发展趋势和检测结果的应用。     

特征脂肪酸鉴别餐厨废弃油脂方法有效性评估

目的建立食用油脂中特征脂肪酸的气相色谱-质谱联用检测方法并评估特征脂肪酸鉴别餐厨废弃油脂的有效性。方法采集植物油混合地沟油22份、煎炸老油20份、纯精炼地沟油7份、植物原油9份、精炼植物油48份、棕榈油6份、正常食用油加香精5份,油样经甲酯化处理后,采用UF-m FFAP毛细管气相色谱柱(30 m×0.25mm,0.25μm),经气相色谱-质谱法检测样品中十一烷酸甲酯和13-甲基十四烷酸甲酯的含量,对检测结果以样品类别进行统计学检验,评估特征脂肪酸鉴别废弃油脂的有效性。结果通过特征脂肪酸指标鉴别地沟油的方法是有效的。13-甲基十四烷酸可选为是否含有动物源性油脂的指标物,十一烷酸可选为反复煎炸油脂的指标物。两者结合可为鉴别正常植物油和餐厨废弃油提供有利依据。结论特征脂肪酸检测灵敏度高,特异性较强,但由于地沟油基本都是勾兑正常植物油出售,判定结果会出现假阴性,需结合其他指标进行研判,以提高鉴别的有效性。     

食用油脂生产过程中邻苯二甲酸酯类的迁移规律及其脱除方法的研究进展

邻苯二甲酸酯(PAEs)是一类类激素污染物,在污染的食用油脂中均有存在。PAEs具有致畸、致突变、致癌以及生殖毒性,对食品安全带来高风险。目前,PAEs已被美国、日本、中国先后列入"优先控制污染物名单",也成为我国食品安全领域重点监控对象。对食用油脂加工过程中PAEs的迁移规律和脱除方法进行了综述及展望,以期为食用油脂生产企业预防塑化剂对产品造成二次污染提供帮助。     

食用油中脂肪酸检测方法的比较研究

使用气相色谱—质谱(GC-MS)联用技术对油脂中的脂肪酸进行检测,比较三种甲酯化方法,并对比了DB-5 ms,VF-23 ms两种毛细管色谱柱对37种脂肪酸甲酯的分离效果.结果表明VF-23 ms色谱柱具有更好的分离效果,4％盐酸甲醇法具有最好的甲酯化效果.研究为油脂中脂肪酸的气相色谱—质谱检测提供了依据.     

全自动样品处理平台在食用油脂中氯丙醇酯和缩水甘油酯测定的应用研究

目的 建立一种在线全自动快速测定食用油脂中氯丙醇酯（MCPDE）和缩水甘油酯（GE）含量的分析方法,并考察植物油种类、温度等因素对GE转化为3-氯-1,2-丙二醇（3-MCPD）的影响。方法 参考AOCS Cd 29c-13基本原理,将样品置于全自动样品前处理平台进行水解、氯代、液-液萃取和衍生,采用毛细管柱（DB-5MS柱）分离,多反应监测模式（MRM）采集,内标法定量。结果 5种植物油中GE的转化率差异不明显,但温度的影响略大,当10℃下水解7 min时,MCPDE和GE水解基本完成。3-氯-1,2-丙二醇酯（3-MCPDE）、2-氯-1,3-丙二醇二酯（2-MCPDE）和GE的检出限均为5μg/kg（以醇计）,在0～0.4μg/mL范围内浓度与峰面积比值呈良好的线性关系（决定系数R2≥0.999）;在20～2 500μg/kg范围内加标,MCPDE和GE的回收率范围为90.3%～109.7%,相对标准偏差（n=6）为1.3%～7.7%,精密度上全自动方法优于手工前处理操作。与食品安全国家标准方法（送审稿）进行对比,方法间结果具有可比性,将该方法用于FAPAS考核样的测定,结果满足...     

三种食用植物油中不饱和脂肪酸含量调查

对市售大豆油、花生油、菜籽油等常见食用植物油中不饱和脂肪酸含量进行调查,调查结果表明:80个大豆油、花生油和菜籽油三种食用植物油样品中,不饱和脂肪酸的含量不符合相应国家标准规定的样品分别占相应品种调查数量的6.38%、7.14%和47.37%,部分食用植物油中存在掺杂现象。在符合国家标准规定的67个食用植物油样品中,含量较高的不饱和脂肪酸组成为大豆油中的亚油酸,花生油中的油酸和菜籽油中的油酸,平均含量分别为51.54%、42.20%、38.87%。     

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.     

Synthesis of aroma compounds by apples supplied with alcohols and methyl esters of fatty acids

Ester synthesis by apples supplied with alcohols (C2–C8) and methyl esters of short chain fatty acids (C4–C8) was studied using gas chromatographic analysis of the products. The substrates were supplied as vapours to whole fruits stored in 2% O₂ at 3°C. The alcohols were converted to the corresponding acetate ester; butanol, pentanol and hexanol were converted most rapidly. The methyl esters of short chain fatty acids (C_n) were converted to esters with an alkyl group (C_n-2, C_n-4) confirming the presence in whole fruits of an active β-oxidation pathway for fatty acids. Ester synthesis was stimulated when apples were supplied with methyl octanoate at different periods during long term storage in 2% O₂. Treatment of the fruit immediately postharvest did not enhance ethylene synthesis.     

高碘酸氧化法测定油脂中1-单甘酯的含量

对用高碘酸氧化法测定油脂中 1- 单甘酯含量的方法进行了研究,并对测定结果进行数理统计分析,重点讨论了影响 1- 单甘酯含量测定结果的一些因素.     

Determination of 3-monochloropropane-1,2-diol fatty acid esters in Brazilian vegetable oils and fats by an in-house validated method

An in-house validated GC-MS method preceded by acid-catalysed methanolysis was applied to 97 samples of vegetable oils and fats marketed in Brazil. The levels of the compounds ranged from not detected (limit of detection = 0.05 mg kg^?1) to 5.09 mg kg^?1, and the highest concentrations were observed in samples containing olive pomace oil and in products used for industrial applications, such as palm oil and its fractions (olein and stearin). The content of diesters and monoesters was also investigated by employing solid-phase extraction on silica cartridges, indicating that the majority of the compounds were present as diesters. This study provides the first occurrence data on these contaminants in Brazil and the results are comparable with those reported in other countries.     

几种脂肪酸甲酯的热解特性及动力学研究

采用热重分析法研究了硬脂酸甲酯、油酸甲酯和亚油酸甲酯在氮气气氛中的热分解特性,并采用Coats-Redfern积分法对硬脂酸甲酯、油酸甲酯和亚油酸甲酯的热分解过程进行动力学分析,建立热分解模型。结果表明:硬脂酸甲酯和油酸甲酯的热分解过程表现为简单的一步分解,而亚油酸甲酯则呈现出较复杂的两步分解过程;随着升温速率提高,热分解区间向高温区移动,热分解活化能和指前因子呈现出较好的动力学补偿效应,且在不同升温速率下具有不同的热分解反应机理函数;模拟计算的热分解率与实验数据误差基本在10%左右。动力学模型能够很好地预测各脂肪酸甲酯热分解过程,为进一步扩大试验和生物柴油应用中的高温热分解衰变模型提供理论依据。     

Fatty acid esters of 3-chloropropane-1,2-diol in edible oils.

A series of 25 virgin and refined edible oils, obtained from retailers, was analyzed for levels of free 3-chloropropane-1,2-diol (3-MCPD) and 3-MCPD released from esters with higher fatty acids (bound 3-MCPD). Oils containing free 3-MCPD ranging from <3 microg kg-1 (LOD) to 24 microg kg-1. Surprisingly, bound 3-MCPD levels were much higher and varied between <100 (LOD) and 2462 microg kg-1. On average, virgin oils had relatively low levels of bound 3-MCPD, ranging from <100 (LOD) to <300 microg kg-1 (LOQ). Higher levels of bound 3-MCPD were found in oils from roasted oilseeds (337 microg kg-1) and in the majority of refined oils (<300-2462 microg kg-1), including refined olive oils. In general, it appears that the formation of bound 3-MCPD in oils is linked to preliminary heat treatment of oilseeds and to the process of oil refining. Analysis of unrefined, de-gummed, bleached, and deodorized rapeseed oil showed that the level of bound MCPD decreased during the refining process. However, additional heating of seed oils for 30 min at temperatures ranging from 100 to 280 degrees C, and heating at 230 degrees C (260 degrees C) for up to 8 h, led to an increase in bound 3-MCPD levels. On the other hand, heating of olive oil resulted in a decrease in bound 3-MCPD levels. For comparison, fat isolated from salami was analyzed for intact fatty acid esters of 3-MCPD. This fat contained bound 3-MCPD at a level of 1670 microg kg-1 and the fatty acid esters of 3-MCPD mainly consisted of 3-MCPD diesters; monoesters of 3-MCPD were present in smaller amounts. The major types of 3-MCPD diesters (about 85%) were mixed diesters of palmitic acid with C18 fatty acids (stearic, oleic, linoleic acids). These diesters were followed by 3-MCPD distearate (11%) and 3-MCPD dipalmitate (4%). Generally, very little 3-MCPD existed as the free compound (31 microg kg-1).     

Infrared spectroscopy in the study of edible oils and fats

The use of infrared spectroscopy in the study of fats and oils is reviewed. The importance of the mid-infrared region in the study of lipids is shown. Differences between dispersive and Fourier-transform infrared techniques are commented on and the experimental methods used in the handling of oil and fat samples are reported. The assignment of oil and fat bands of mid-infrared spectra is made, and the usefulness of this technique to characterise oils and fats and to detect adulterations is reviewed. The application of spectroscopic data to determine the degree of unsaturation or iodine value, trans- double bonds content, free fatty acid content, average chain length or saponification number, solid fat content, as well as peroxide and anisidine values, is commented on. Also, the importance of this technique for monitoring oxidation processes is shown. © 1997 SCI.     

茶多酚棕榈酸酯在食用油脂中的应用

2014年6月,国家卫计委发布增补茶多酚棕榈酸酯等两种食品添加剂的公告。研究了不同添加量茶多酚棕榈酸酯在大豆油中的抗氧化效果,并与几种常见的脂溶性抗氧化剂在大豆油中的抗氧化性能进行比较,同时研究了茶多酚棕榈酸酯在猪油和人造奶油中的抗氧化效果。结果表明:0.03%的茶多酚棕榈酸酯添加量在大豆油中比较适宜;在几种常见的脂溶性抗氧化剂中,茶多酚棕榈酸酯的抗氧化效果和TBHQ相当;茶多酚棕榈酸酯在猪油和人造奶油中也有良好的抗氧化性。     

食用油脂中p-茴香胺值的测定

对ISO中食用油脂的p-茴香胺值测定方法进行了验证,并对影响茴香胺值测定的影响因素进行了探讨。对几种食用油脂茴香胺值的测定结果进行统计分析表明,ISO法准确性、重复性好。在茴香胺值测定过程中应注意取样量、样品、试剂含水率等因素。另外,对于低含氧酸油脂,可以用正己烷代替ISO方法中的异辛烷试剂。     

不同催化体系中脂肪酸甲酯环氧化反应研究

研究了甲酸、磷钨酸和磷钨杂多酸季铵盐3种催化剂对不饱和脂肪酸甲酯的环氧化.考察了氧源、溶剂和催化剂的不同组合、表面活性剂和工艺条件对不饱和脂肪酸甲酯环氧化的影响.结果表明,表面活性剂和适宜溶剂可缓解体系的非均相特性,显著加快受传质控制的脂肪酸甲酯环氧反应速率.对于碘值(I)为105 g/100 g的混合脂肪酸甲酯环氧化,磷钨杂多酸季铵盐催化体系所得产品环氧值最高,达5.78％,磷钨酸体系次之,为4.76％,甲酸体系仅为4.25％.     

Fatty acid esters of monochloropropanediol (MCPD) and glycidol in refined edible oils

Recently, fatty acid esters of monochloropropanediol (MCPD) and that of glycidol have been reported in refined edible oils. Since then a wealth of research has been published on the factors influencing the formation of these contaminants in foods. It can be noted that the predominant precursors in a given matrix will not necessarily be the same as in other matrices. Further, proven relationships in the past between precursors responsible for free MCPD or free glycidol formation will not necessarily be valid for their fatty acid-esterified counterparts. This review attempts to summarise the current status of the literature as it pertains to the reasons surrounding the manifestation of MCPD esters and glycidyl esters in oils and fats. Recent efforts to mitigate the levels of these contaminants were highlighted and put into the context of their respective reaction matrices. As more accurate occurrence data for MCPD esters and glycidyl esters in other foods are collected, more targeted mitigation experiments can be formulated with respect to the reaction matrices under investigation.