粗脂肪的快速分析

以等分配比两次萃取分析原理为基础,以饼干、火腿肠为样品,建立了粗脂肪快速分析法。与标准方法索氏提取法GB/T5009.6-1996相比,这种方法的测定结果令人满意,大大缩短了测定时间,分析结果的准确性与索氏提取法相同,有望代替索氏提取法。由此也说明等分配比两次萃取分析在实践上的正确性。      

索氏煮沸抽提法快速测定粮食油料粗脂肪含量

<正> 一、试验目的粮食油料粗脂肪含量的测定,多年来,一直采用索氏抽提的标准方法。此法经过长期操作实践,存在一定的弊端。主要是操作时间长工作人员劳动强度大、能源(电、水消耗大。索氏抽提法做一个测定结果仅抽提时间一般需八小时以上,工作效率低。     

索氏煮沸抽提法快速测定粮食、油料中粗脂肪含量的试验

介绍了一种新的用于粮食、油料中粗脂肪含量测定的操作方法——索氏煮沸抽提法，通过与国家标准方法比较，认为其测定结果同样准确、可靠，而且省时、省力、省能源。     

索氏煮沸抽提法快速测定粮食、油料中粗脂肪含量的试验

介绍了一种新的用于粮食、油料中粗脂肪含量测定的操作方法——索氏煮沸抽提法,通过与国家标准方法比较,认为其测定结果同样准确、可靠,而且省时、省力、省能源。     

烤烟粗脂肪提取工艺优化及光谱测定方法研究

为优化索氏提取法测定烤烟中粗脂肪的工艺条件,在单因素实验的基础上,通过Box-Behnken试验设计,研究称样量、回流时间、烘干时间对粗脂肪提取量的影响,并建立一种快速测量粗脂肪含量的紫外可见吸收光谱方法。结果表明,干燥温度为105 ℃时,预测最佳的粗脂肪提取条件为:称样量3.08 g,回流时间6 h,烘干时间1.5 h,粗脂肪含量为6.27%。在0.276~2.211 g/L(λ=326 nm)或 0.276~2.763 g/L(λ=415 nm)范围内,烟叶粗脂肪溶液的浓度与吸光度有较好的线性关系(R²_{326 nm}=0.9982,R²_{415 nm}=0.9993),检出限分别为0.128和0.093 g/L,定量限分别为0.387和0.281 g/L。利用响应面优化的索氏提取工艺及建立的粗脂肪紫外分光光度测定法,简便省时,且重复性和精密度较好,适合批量烟叶粗脂肪的分析测定。     

超声波辅助提取大豆粗脂肪技术用于大豆粗脂肪酸值测定的可行性研究

国标法检测大豆粗脂肪酸值时,索氏抽提法提取大豆粗脂肪耗时长、操作繁琐。本实验论证了超声波辅助技术替代索氏抽提法提取大豆粗脂肪,可以大大缩短大豆粗脂肪酸值检测时间。通过比对,两种方法测得的酸值的线性相关系数达到0.995 9,且两种方法制取的大豆油脂肪酸组成种类和含量均无显著差异。因此,可以利用超声波辅助提取大豆脂肪快速检测大豆粗脂肪酸值。     

索氏法提取植物种子粗脂肪的实验方法改进

索氏法是测定植物种子中粗脂肪的常用方法,对其实验操作方法进行改进,使其更方便、更快捷地应用于相关专业的学生实验操作。以芝麻为例,通过对芝麻研磨与称重、滤纸、石油醚添加方式、粗脂肪含量计算方法、石油醚的回收等5个方面进行改进,经具体实验验证,达到了减少操作步骤、节约时间、回收溶剂方便、提取完全、准确度高、重复性好的效果。     

肉与肉制品中粗脂肪含量的快速测定

<正>在食品分析中,脂肪含量的测定是很重要的项目之一.测定方法通常用索氏抽提方法,该方法消耗大量的有机溶剂和电能,费工费时,整个实验过程至少要用10小时才能完成.从1991年开始研究摸索快速测定方法,即用高氯酸处理样品,加热离心使脂肪游离,测定其体积,计算脂肪含量.实验过程不超过30分钟,获得较好的结果.本方法快速、灵敏、准确度高.分别对脂肪含量高的和脂肪含量低的样品进行测试,绘制标准曲线,相关系数是0.9332和0.9981.     

索氏抽提法测定粗脂肪含量的改进

将粮食、油料脂肪测定方法的抽提过程和抽提前后采用的处理手段进行改进，并将热浸提-油重法、残余法和国标法进行多方面比较对照试验。结果表明，3种方法测定的结果无显著性差异，在一定条件下3种方法可以相互代替使用。     

响应面法优化南极磷虾粗脂肪索氏提取工艺

采用索氏提取法从南极磷虾中提取粗脂肪,分别考察提取溶剂、提取温度、提取时间和提取溶剂体积比对南极磷虾粗脂肪得率的影响。在单因素试验的基础上,采用响应面法进行工艺优化,确定最佳提取条件为提取溶剂正己烷-无水乙醇(3.5∶1,V/V)、提取温度80℃、提取时间5.4 h。在此条件下,南极磷虾粗脂肪得率为12.32%。采用气相色谱法分析南极磷虾粗脂肪的脂肪酸组成,结果表明,粗脂肪中主要含有棕榈酸(C16:0,28.86%)、EPA(C20:5n3,15.48%)、油酸(C18:1n9c,12.71%)和二十二碳六烯酸(C22:6,12.22%)。不饱和脂肪酸的相对含量高达57.47%,其中单不饱和脂肪酸相对含量19.82%,多不饱和脂肪酸相对含量37.65%。因此,南极磷虾是多不饱和脂肪酸的新来源,具有较高的营养价值,可作为膳食营养补充剂广泛应用。     

Fast method for capsaicinoids analysis from Capsicum chinense fruits

Chili peppers are widely utilized in the world as savory food additives due the pungency induced by the capsaicinoids. Also, these compounds have functional properties as antimutagenic, antitumoral, antioxidant and analgesic. These characteristics increase the interest in this compound class, hence the capsaicinoid analysis must be reproducible and accurate. This study aimed to develop and validate a fast, efficient and reproducible method to analyze capsaicinoids in Brazilian Capsicum chinense fruits. The extracts were obtained after an optimization step that indicated the condition 100% of methanol and 10 min on ultrasound assisted extraction. The analyses were carried out in an ultra high performance liquid chromatographic system with detection by a photo diode array and mass spectrometer. The analytical method developed permits the separation of 8 capsaicinoids in 4 min of time analysis expending only 2 mL of solvent as mobile phase. The validation parameters evaluated for the method show the effectiveness and satisfactory performance to answer the analytical needs of this research area, presenting low values to relative standard deviation in repeatability and reproducibility and recoveries ranged from 88 to 112% for capsaicin and 89 to 109% for dihydrocapsaicin. In the extracts from different accessions of C. chinense fruits analyzed, the contents of capsaicin and dihydrocapsaicin were in the range of 156–1442 μg g^− 1 and 26–478 μg g^− 1 of fresh fruit, respectively, showing the large application of this method for quantification of the two major capsaicinoids in fast routine analysis and may be used to determine the concentrations of other minor capsaicinoids once appropriate standards are available.     

从酱渣中制取粗脂肪的研究进展

酱渣具有较高的利用价值,但当前对其开发利用进行得很不够。文中在前期研究开发的基础上,结合酱渣的性质特点,对已报道的酱渣中制取粗脂肪的方法,包括压榨法、单一溶剂萃取、混合溶剂萃取以及超声强化萃取等进行了较深入的理论分析与实际操作可行性评述。指出当前研究开发中的瓶颈问题是快速、高效地去除新鲜酱渣中的水分与盐分,且提出以丙酮为溶剂的萃取法是值得深入研究的较为理想的方法。     

从微藻中提取粗脂的方法比较

采用改良的酸水解法、异丙醇法、乙醇法、乙醚-石油醚法、索氏抽提法5种方法对3株微藻的粗脂含量进行测定。结果表明,改良的酸水解法与索氏抽提法提取效果稳定、粗脂提取程度高。与索氏抽提法相比,改良的酸水解法大大节省了测定时间,且可以同时对多个样品进行测定,是实验室中对多个微藻样品粗脂含量快速测定的首选方法。     

Carcass characteristics of feedlot lambs fed crude glycerin contaminated with high concentrations of crude fat

Thirty non-castrated male lambs with 20 ± 2.3 kg average body weight (BW) were randomly assigned to five treatments consisted of different dietary concentrations of crude glycerin (CG; 0, 3, 6, 9 and 12% on DM basis) to evaluate the effects on performance, carcass and meat quality traits. A quadratic effect was observed for performance (P = 0.04), final BW (P < 0.01) and hot carcass weight (P < 0.01). No effects of CG were observed (P > 0.05) on carcass pH neither on shear-force, cooking loss and ether extract content in longissimus. The inclusion of CG tended to reduce the Zn content in meat (P = 0.09). The data suggests that CG (36.2% of glycerol and 46.5% of crude fat) may be used in diets of finishing lambs with concentrations up to 3% without negative effects on performance and main carcass traits. Moreover, inclusion of CG seems to not affect quality and safety of meat for human consumption.     

A method for reconstituting fat extracted flour

Summary. A low temperature technique is described for the reconstitution of fat extracted wheat flour which allows the return of lipid material with the minimum alteration of flour properties. A study of the effect of moisture level on lipid binding in reconstituted flour is compared with a similar study of the original flour. Flours with augmented lipid contents were produced and confirmation that the method avoided the introduction of mechanical work obtained.     

粗脂肪标准物质的制备及均匀性和稳定性研究

用全麦粉作为粗脂肪标准物质的基体,对粗脂肪标准物质的制备程序和工艺以及标准物质的均匀性和稳定性进行了研究。采用粉碎、混匀、干燥、分装、Co-60辐照灭活(辐照量为2.5Mrad)全麦粉粗脂肪标准物质的制备工艺。粗脂肪标准物质样品的均匀性检验结果经F检验以及14个月稳定性监测结果经t检验表明,单元内和单元间均匀程度以及标准物质样品的稳定性均达到国家一级标准物质的制备要求。     

Development of a sensitive heterologous ELISA method for analysis of acetylgestagen residues in animal fat

A new heterologous ELISA method for detecting acetylgestagen multi-residues in animal fat was developed. An antibody generated has high cross-reactivity with relative progestogens (up to 50%) and no cross-reactivity with other steroids (<0.1%) in homologous ELISA. Three heterologous immunoassay were developed and one of them improved not only sensitivity but also the class-selectivity compared with the homologous assay against these progestogens. The IC₅₀ for four acetylgestagens, chlormadinone acetate (CMA), 17α-hydroxyprogesterone acetate (HPA), megestrol acetate (MEGA) and medroxyprogesterone acetate (MPA) were, 4.5, 2.5, 2.9 and 1.8 μg/L, respectively. The cross-reactivity for CMA, HPA and MEGA were 40%, 72% and 62% when they were compared with MPA. Progestogens recoveries from spiked swine fat averaged between 61% and 78%. Results obtained from LC/MS/MS method showed the heterologous ELISA method developed was reliable and suitable for rapid screening the four progestogens residues in fat tissues.     

植酸酶对鲫鱼养殖中磷、粗蛋白质和粗脂肪的影响

通过设置5组不同水平无机磷和植酸酶添加量的饲料来喂养鲫鱼,探索鲫鱼饲料中植酸酶和无机磷之间的最佳配比。结果表明:用植酸酶替代无机磷能明显减少养殖水体中磷的排放,同时能满足鱼体对磷的需求,对鱼体粗蛋白质含量影响较小,并能降低鱼体粗脂肪的含量。最佳的无机磷盐和植酸酶配比是1 kg饲料中加9 g的Ca(H2PO4)2和1500 U的植酸酶,其磷的排放量减少了66.9%,粗脂肪含量降低17.65%。     

基于近红外透射光谱的大豆蛋白质和粗脂肪含量快速检测

该研究采用近红外光谱分析技术分别建立大豆蛋白质和粗脂肪含量的近红外检测模型,比较了不同数学处理方法和去散射校正方法及不同回归技术对模型准确性的影响,选出最佳的近红外检测模型,并通过内部验证和外部验证对模型的预测能力进行评价。结果表明:所建立的大豆蛋白质和粗脂肪含量的近红外检测模型的内部验证相关系数分别为0.947 1、0.889 0,外部验证相关系数分别为0.962 2、0.915 5。说明所建立的大豆蛋白质和粗脂肪含量的近红外检测模型具有很好的预测能力,近红外光谱技术可用于大豆成分含量的快速检测。     

Supercritical fluid extraction as a method for fat content determination and preparative technique for fatty acid analysis in mesh feed for pigs

Objective of this investigation was supercritical fluid extraction (SFE) with CO₂, as analytical technique for total fat extraction from food and feed samples. Most significant advantages of this technique, compared with the others, are safety, cleanness, and shorter analysis time. Its main limitation includes difficulty of extracting polar lipids, due to the non-polar character of the CO_2, which is used as a solvent. Influence of added absorbent and co-solvent on the SFE of mash pig feed was investigated in this paper. Total fat content was determined for ten commercially available mesh pig feeds. Optimization of absorbent weight and volume of added co-solvent showed that the maximum yield of extracted fat has been achieved at adsorbent mass of 1.8 g and ethanol volume of 0.54 ml. Yields of fat extracted with both Soxhlet method (AOCS Method Ba 3-38) and SFE were plotted one against the other. There were no significant (p > 0.05) differences between results of these two methods, which were confirmed by low value for standard deviation (SD). SFE appears to be reliable, faster, and less hazardous alternative for traditional extraction method. Fatty acid compositions from lipid extracts obtained by both methods were determined by gas chromatography—flame ionization detection (GC–FID). Results obtained by SFE were far more representative than results obtained by analyzing Soxhlet extracts, and in consistence with literature results. SFE method gave significantly higher (p < 0.001) contents of polyunsaturated fatty acids (PUFA) than Sohxlet method, especially of linoleic acid, C18:2 n-6.