食品添加剂不饱和脂肪酸单甘酯的测定与表征

建立了食品添加剂不饱和脂肪酸单甘酯定性表征和定量分析方法。采用气相色谱-质谱法对不饱和脂肪酸单甘酯和甘油进行定性、定量分析,结果表明:不饱和脂肪酸单甘酯主要含有5种脂肪酸,即十六烷酸(棕榈酸)、十八碳二烯酸(亚油酸)、十八碳烯酸(油酸)、十八烷酸(硬脂酸)、二十二烷酸(山嵛酸)。     

反相高效液相色谱-大气压化学电离质谱分析猪脂甘油酯及调控氧化猪脂中极性非（难）挥发性物质

采用固相萃取-反相高效液相色谱-大气压化学电离质谱分析猪脂的甘油酯组成以及调控氧化工艺制备的氧化猪脂的极性非（难）挥发性物质组成。从猪脂中鉴定出33 种甘油酯,包括7 种甘二酯和26 种甘三酯,按总离子流色谱图中的相对峰面积,含量高的为1-棕榈酸-2-亚油酸-3-油酸甘三酯（16.13%）、1,3-二油酸-2-亚油酸甘三酯（15.25%）、1,3-二油酸-2-棕榈酸甘三酯（12.96%）、1-油酸-2,3-二亚油酸甘三酯（8.05%）。从调控氧化猪脂中鉴定出5 种甘二酯和由10 种甘三酯氧化形成的22 种单氢过氧化物,按总离子流色谱图中的相对峰面积,含量高的为1-硬脂酸-2-亚油酸-3-油酸甘三酯单氢过氧化物（18.44%）、1-棕榈酸-2-亚油酸-3-油酸甘三酯单氢过氧化物（16.03%）、1,3-二油酸-2-棕榈酸甘三酯单氢过氧化物（9.42%）、1,3-二油酸-2-亚油酸甘三酯单氢过氧化物（8.71%）、三油酸甘三酯单氢过氧化物（7.63%）、1-棕榈酸-2,3-二亚油酸甘三酯单氢过氧化物（7.53%）。结果表明,猪脂调控氧化主要对猪脂中含不饱和脂肪酸的甘三酯进行氧化,因形成的极性非（难）挥发性氧化产物仅检测到甘三酯单氢过氧化物。     

浅析上海单甘油酯发展前景

<正>一、前言 单脂肪酸甘油酯（简称单甘酯）属于非离子型的表面活性剂,广泛地应用于食品、日化、医药、塑料等工业。单甘酯分子结构中具有亲水基和亲油基,它是一个传统的乳化剂,不同碳链的脂肪酸如月桂酸、豆蔻酸、棕榈酸、硬脂酸、油酸等制取的单甘酯,由于不同的亲油亲水平衡值（简称HLB值）,性能和用途有所不同,其中单硬脂酸甘油酯所用原料的不同,又有硬脂酸含量≥90％的纯酸单甘酯及棕榈酸和硬脂酸为主（工业硬脂酸的组成）的混酸单甘酯二类产品,性能和用途亦有所差异。     

常用商品表面活性剂

化学名称咪唑啉季铵盐柔软剂棕榈酰胺基咪唑啉阳离子聚丙烯酰胺脂肪酚聚氧乙烯(2)醚C12脂醇聚氧乙烯(3,4,7,8,9)醚C12-18脂肪醇聚氧乙烯(10,20)醚烷基酚聚氧乙烯(7,9,10,2,14,15)醚壬基酚聚氧乙烯(4,7,9,10,15,40)醚山梨醇酐单月桂酸酯山梨醇酐单棕桐酸脂山梨醇酐单硬脂酸酯山梨醇酐三硬脂酸酯山梨醇酐单油酸酯山梨醇酐三油酸酯聚氧乙烯(20)山梨醇酐单月桂酸酯聚氧乙烯山梨醇酐单棕榈酸酯聚氧乙烯山梨醇酐单油酸酯山梨醇酐单硬脂酸酯聚氧乙烯(20)醚椰子油烷醇酰胺蓖麻油聚氧乙烯(10,30,40,80,90)醚聚丙烯酰胺十二烷基二甲基甜菜碱磺酸盐型…     

不同链长单甘酯-籼米淀粉复合物结构及体外消化特性

研究不同链长脂肪酸单甘酯添加量变化时,单甘酯-籼米淀粉复合指数和糊化性质双变量相关性,通过傅里叶变换红外光谱仪、差示扫描量热仪、X-射线衍射分析仪和扫描电镜,研究单甘酯链长、添加量及温度对籼米淀粉-单甘酯复合物结构和体外消化特性的影响。研究结果表明:单甘酯碳链越长,与籼米淀粉的复合程度越高,且越易在冷却过程中形成黏度峰。相比于月桂酸单甘酯和硬脂酸单甘酯,棕榈酸单甘酯与籼米淀粉形成的复合物具有更高的焓变值、结晶度。硬脂酸单甘酯-籼米淀粉复合指数和糊化特性显著相关(除最低黏度值外);不同链长脂肪酸单甘酯-籼米淀粉复合指数与快消化淀粉含量显著负相关。     

油脂

甘油酯的不饱和脂肪酸的位置 对三甘酯氧化速率的影响 本文探讨了在50℃下,甘油酯的不饱和脂肪酸位置对三甘酯氧化速率的影响。将饱和的与不饱和的单种脂肪酸的甘油酯,用甲醇钠作催化剂,进行不规则的交酯化而得到不规则的甘油酯。所用的单种甘油酯为三棕榈酸甘油酯、三硬脂酸甘油酯、三油酸甘油酯和三亚油酸甘油酯。应用高效液相结合气相色谱法和酶水解,可分析不规则三甘油酯的分子结构。用气相色谱法测定氧吸收量,结果发现     

三酰甘油Sn-2位上棕榈酸生理功能及研究概况

棕榈酸的代谢及生理功能与在三酰甘油上结合的位置有关。在代谢过程中通常是1,3位的脂肪酸首先被胃酶和胰酯酶水解下来形成2-棕榈酸单甘酯和游离脂肪酸,2-棕榈酸单甘酯可以直接被人体吸收。母乳脂肪酸的20%～25%是棕榈酸,而且70%的棕榈酸在Sn-2位置上被脂化;相反,存于植物油和非牛奶脂肪内的棕榈酸主要在Sn-1和Sn-3的位置上脂化,而结合在1,3位置上的棕榈酸不易被机体吸收,容易形成不溶性的皂化钙随粪便排出体外,导致能量和钙的流失。     

分子蒸馏单甘酯的分子结构对低脂冰淇淋质构的影响

研究了分子蒸馏单甘酯的碘值、总单酯含量、总双酯含量等反映的内部分子结构对低脂冰淇淋质构的影响。通过测定发现:采用总单酯含量在70%左右(单硬脂酸甘油酯含量高于单棕榈酸甘油酯含量),总双酯含量在20%左右,碘值在20.0gI/100g左右的分子蒸馏单甘酯,开发的低脂冰淇淋,在口感、硬度、抗融性等方面完全可以达到甚至超过普通全脂冰淇淋的效果。     

单甘酯对棉籽油和棕榈硬脂酯交换体系结晶性质的影响

研究不同油酸单甘酯添加量对棉籽油和棕榈硬脂(质量比50:50)酶催化酯交换产物结晶性质的影响。结果表明:添加2%和5%的油酸甘油酯,酯交换产物的固体脂肪含量(SFC)与熔点基本不发生变化,添加量增大到10%,体系的SFC与熔点略有下降;添加不同量的油酸甘油酯,均使酯交换产物结晶温度发生变化,其中低熔点组分对应的峰温度随添加量增加而增大,高熔点组分对应的峰温度随添加量增大而下降;添加2%的油酸单甘酯对酯交换产物的成核速率和结晶速率不存在影响;添加不同量的油酸单甘酯后,酯交换产物中β′晶形比例下降,下降程度与添加量成负相关。     

不同品种核桃仁中脂肪酸含量及组成分析

以国内外不同品种的核桃仁为材料,采用酸水解法和气相色谱法,测定不同品种核桃仁中脂肪酸含量及组成,结果表明核桃仁中脂肪含量在65%左右,其中脂肪酸分别由棕榈酸、珠光酯酸、硬脂酸、油酸、亚油酸、α-亚麻酸、花生酸、花生一烯酸等8种脂肪酸组成。其中棕榈酸、珠光酯酸、硬脂酸、花生酸属于饱和脂肪酸,其含量在50～70g/kg左右,油酸、花生一烯酸属于单不饱和脂肪酸,含量在100～150g/kg之间,亚油酸、α-亚麻酸属于多不饱和脂肪酸,含量达到了410～490g/kg。     

High correlation of methylglyoxal with acrylamide formation in glucose/asparagine Maillard reaction model

α-Dicarbonyl compounds were highly reactive intermediates formed in Maillard reaction (MR), and o-phenylenediamine (OPD) was widely used as a trapping agent for α-dicarbonyl compounds. Both aqueous glucose/asparagine (Glc/Asn) and glucose/asparagine/o-phenylenediamine (Glc/Asn/OPD) model systems were heated at 150 °C for up to 30 min. The α-dicarbonyl compounds formed in MR were identified by HPLC/MS in our particular model system, indicating that 3-deoxy-2-hexosulose, 2,3-butanedione and methylglyoxal (MG) were three main α-dicarbonyl compounds. In this work, MG was chosen as a representative of α-dicarbonyl compound in MR to investigate the influence on the formation of acrylamide (AA). The concentrations of AA, MG and Asn were detected during MR by HPLC method. The results indicated that the formation of AA increased with the heating time, and nearly 80% of AA formed through participation of α-dicarbonyl compounds. These results were consistent with the changes of amounts of MG. The amounts of formation and consumption of MG increased with heating time, and from 9 min of reaction, the consumed amounts of MG accounted for 73–88% on basis of total amounts of MG formed in MR, suggesting that most of MG take part in the next reaction steps. Meanwhile, the Asn concentration decreased with heating time in both models. The formation of AA and consumption of Asn were highly correlated with MG. Indeed, as MG concentration in MG/Asn model system decreased during heating at 150 °C, the concentration of AA significantly increased. The coefficient of correlation between consumed amounts of MG and the formed amounts of AA is 0.931, again demonstrating that MG does play a role in AA formation.     

分子印迹固相萃取—高效液相色谱法检测鱼肉中的孔雀石绿和结晶紫

将分子印迹固相萃取和高效液相色谱法联用,建立一种检测鱼肉中孔雀石绿和结晶紫及其代谢产物残留的新方法。以孔雀石绿为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,本体聚合法合成分子印迹聚合物。并制成分子印迹固相萃取柱,优化分子印迹固相萃取的实验条件。鱼肉样品经过超声提取后,采用分子印迹固相萃取富集净化,用高...     

市售淡水鱼中孔雀石绿及其代谢物残留量的调查研究

目的 了解福建省餐饮环节淡水鱼孔雀石绿(MG)及其代谢物无色孔雀石绿(LMG)的残留情况.方法207份样品来自福建省6个市有关餐饮场所,共28个品种,制作为鱼肉浆,经前处理后,采用高效液相色谱/荧光法对鱼内浆中孔雀石绿及其代谢物的残留总量进行检测,阳性样品再用高效液相色谱/质谱法确证.结果 15个品种的48份样品检出孔雀石绿及其代谢物,检出率为23.2％,总MG含量在0.54～8 099μg/kg之间.桂花鱼检出率最高,达到92.9％ (26/28),草鱼检出率较低,为2.38％ (2/84).结论 餐饮环节销售的淡水鱼孔雀石绿及其代谢物的检出率相对较高,在某些品种淡水鱼供应链中滥用MG的现象较为突出,需要有关监管部门加大打击滥用MG的力度,确保淡水鱼的消费安全.     

Correlation of methylglyoxal with acrylamide formation in fructose/asparagine Maillard reaction model system

α-Dicarbonyl compounds were highly reactive intermediates formed in Maillard reaction (MR), and o-phenylenediamine (OPD) was widely used as a trapping agent for α-dicarbonyl compounds. Both aqueous fructose/asparagine (Fru/Asn) and fructose/asparagine/o-phenylenediamine (Fru/Asn/OPD) model systems were heated at 150 °C for up to 30 min. Methylglyoxal (MG) was the main α-dicarbonyl compounds formed in MR, which was chosen as a representative of α-dicarbonyl compound to investigate the influence on acrylamide (AA) formation. The concentrations of AA, MG and Asn were detected during MR by HPLC method. The results indicated that the formation of AA increased with the heating time, and nearly 75% of AA was formed through the participation of α-dicarbonyl compounds. The amounts of formation and consumption of MG increased with heating time, and from 12 min of reaction, the consumed amounts of MG accounted for 62.1–90.3% on the basis of total amounts of MG formed in MR, suggesting that most of the MG took part in further reactions. Meanwhile, Asn concentration decreased with heating time in both models. The formation of AA and consumption of Asn were highly correlated with MG. Indeed, as MG concentration in MG/Asn model system decreased during heating at 150 °C, the concentration of AA significantly increased. The coefficient of correlation between consumed amounts of MG and the formed amounts of AA was 0.931, demonstrating that MG plays a role in AA formation.     

Development of a sensitive and group‐specific polyclonal antibody‐based enzyme‐linked immunosorbent assay (ELISA) for detection of malachite green and leucomalachite green in water and fish samples

BACKGROUND: Malachite green (MG) is widely used in fishery, since it is easily adsorbed by fish during waterborne exposure and is rapidly metabolised into leucomalachite green (LMG). However, both MG and LMG are potential carcinogens, teratogens and mutagens. In this study the LMG derivative bearing an amino group on the phenyl ring was synthesised and coupled to carrier proteins. An LMG polyclonal antibody‐based enzyme‐linked immunosorbent assay (ELISA) was developed and characterised. RESULTS: The ELISA standard curve was constructed with concentrations of 0.1–100 ng mL^?1. The IC₅₀ value for nine standard curves was in the range 0.9–2.6 ng mL^?1 and the limit of detection at a signal‐to‐noise ratio of 3 was 0.02–0.10 ng mL^?1. The cross‐reactivity values of the LMG antibody with MG, crystal violet and leucocrystal violet were 95.25, 29.07 and 212.38% respectively, while less than 0.2% cross‐reactivity was found with eight other compounds. For LMG‐spiked water and fish samples, recoveries were 76.2–95.0% and the correlation coefficient of ELISA with high‐performance liquid chromatography (HPLC) was 0.9752 (n = 7). For (LMG + MG)‐spiked fish samples the results of ELISA were similar to those of HPLC. CONCLUSION: The proposed ELISA can be utilised as an analytical tool for detecting the sum of MG and LMG in water and fish muscle samples. Copyright © 2009 Society of Chemical Industry     

Determination of malachite green and crystal violet in processed fish products

This paper presents analysis of malachite green (MG) and crystal violet (CV) residues in processed fish products. Samples were homogenized and extracted with ammonium acetate buffer and acetonitrile. The extracted residues were partitioned into dichloromethane, in situ oxidized to chromic forms with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, and cleaned up on neutral alumina and propylsulfonic acid cation-exchange solid-phase extraction (SPE) cartridges. MG and CV were determined at 618 and 588 nm using HPLC with a visible detector (LC–VIS) and confirmed by LC–electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS). The recoveries were as follows: MG (74.8–83.8%), LMG (80.0–88.4%), CV (68.6–73.9%), and LCV (85.5–90.0%). The method modified in this study has been evaluated by application in-house to a survey of 253 processed fish products. As a result of monitoring, MG and CV were positive in one shrimp and one eel sample, respectively. Our results showed that regular monitoring of these antibiotic residues is recommended for protection of public health.     

Determination of glyoxal and methylglyoxal in Thai fish sauce and their changes during storage test

Recently more research attention has been given to glyoxal (GO) and methylglyoxal (MG) in relevant to their role in biological and food systems. In this study, pre-column derivatization using 5,6-diamino-2,4-hydroxypyrimidine sulfate (DDP) for fluorescence detection on HPLC was optimized for fish sauce matrix. DDP–GO and DDP–MG derivatives detected had fluorimetric wavelengths coincided with the spectral characteristics reported. Standard addition experiment showed that the detection method was free from interference and matrix effect with good recovery (90–115 %) and precision (less than 8 % RSD at 88–242 ng/mL). Limit of detection for GO and MG were 11.7 and 10.9 ng/mL respectively. Prolonged storage of the fish sauce sample under 4, 25, 40, and 60 °C showed that GO increased at 40 and 60 °C while MG increased at 25, 40, and 60 °C. The results also suggested possible role of molecular oxygen in these formations. Together with GO and MO, browning development and Strecker aldehydes were also monitored.     

水产品中残留孔雀石绿液质联用分析方法研究

研究了一种针对水产品中残留孔雀石绿和无色孔雀石绿的液质联用分析方法。采用固相萃取方法对样品中的目标物进行净化前处理,以乙腈- 醋酸铵缓冲液作流动相分析食品中的孔雀石绿和无色孔雀石绿,缩短了色谱分离时间,提高了检测灵敏度和分析结果的可靠性,并对柱后衍生化和非衍生化方法以及DAD 和MS 检测方法进行了比较。结果表明本方法具有准确、快速以及灵敏度高的特点,能够适应大规模样品的快速分析要求,目前此方法已经用于水产品中残留孔雀石绿的分析检测。     

高效液相色谱法同时测定葡萄酒中八种有机酸的研究

建立了同时检测葡萄酒中8种有机酸的高效液相色谱分析方法。采用日本资生堂CAPCELLPAKMGS5色谱柱(4.6mmi.d.×150mm,5μm),乙睛-磷酸溶液为流动相等度洗脱,流速为0.5mL/min,210nm和243nm下检测,外标定量法。结果显示:8种有机酸的线性关系良好,相关系数在0.9953~0.9999之间;精密度、稳定性的RSD都低于5%;平均回收率为85%~120%之间,检出限为0.0141~1.3427mg/L之间。     

Kinetic model for studying the conversion and degradation of isoflavones during heating

The conversion and degradation of isoflavones during dry or moist heating at 100, 150 and 200 °C, for varied lengths of time, were kinetically studied. Results showed that, at the early stage, all the reaction rates of malonylgenistin (MG), acetylgenistin (AG), genistin (G), and genistein (Ge) increased with increasing temperature and fitted a first-order model, when the concentration changes during heating were analyzed using HPLC. For dry heating, the conversion of MG to G exhibited the highest rate constant (h⁻¹), followed by MG to AG, AG to G, AG to Ge, G to Ge and MG to Ge. Moist heating showed the same phenomenon; however, the last three conversions were not observed. In addition, MG had the highest degradation rate, followed by G, Ge and AG during dry heating, while the reversed trend occurred for moist heating. Moist heating was more susceptible to conversion and degradation of isoflavones than dry heating. The correlation coefficients (r²) ranged from 0.664 to 0.987 for moist heating and 0.688–0.960 for dry heating. The kinetic model developed in this study can be used to predict the concentration changes of isoflavones during dry heating and moist heating.