Detection of DNA in soybean oil

 The presence of DNA in foodstuffs which are, or contain, genetically modified organisms (GMO) is the basic requirement for labelling of GMO food in Switzerland and is also being discussed as a requirement for labelling in the European Union. The present work presents data indicating that no genetic material can be recovered after the first processing steps of soybean oil, i.e. when crude soybean oil is simply centrifuged. This fact is of some relevance because centrifugation is one of the first steps in industrial oil processing. A nested PCR system utilising a single copy gene (lectin 1) showed that centrifugation purified the oil from the genetic material by at least a factor of 10 000. The same results were observed when industrially processed oil fractions were analysed. Thus, with respect to the presence of DNA, soybean oil from GMO soybeans is identical to traditional oil and does not need to be labelled as a GMO product in Switzerland. Received: 21 January 1998 / Revised version: 30 March 1998     

Triacylglycerols composition of oil in OS soybean cultivars

Oil content in grain and triacylglycerol composition of several Croatian soybean cultivars (Glycine max (L) Merrill) was investigated. Trials were conducted at two localities during three years and involved seven soybean cultivars. All investigated cultivars were created in soybean breeding program at the Agricultural Institute Osijek in Croatia. Oil content in grain was determined by NMR method. Triacylglycerols were analyzed by reversed phase high performance liquid chromatography with refractive index detector and identified by comparing their retention time to standards.Oil content was similar in soybean cultivars within year and localities but varied significantly among years. Chromatograms of every injected sample showed 15 individual triacylglycerol peaks, and the main components are trilinolein, dilinoleoolein, and dilinoleopalmitin. A small difference of triacylglycerol composition was noticed among soybean cultivars whereas larger one was noticed among the investigated years. The obtained results will be able to use in further breeding work for soybean cultivars grain quality improvement.     

PCR法定性检测大豆食用油中转基因成分

针对大豆食用油中核酸含量低且被严重破坏、DNA难以提取的问题,对CTAB法进行优化,有效从食用油中提取到可用于PCR扩增反应的DNA模板。同时定性检测出大豆内源基因lectin,外源调控序列启动子CaMV35S、终止子Nos及目的基因CP4-EPSPS序列,成功建立了基于PCR技术在大豆食用油中快速检测转基因成分的方法。     

Detection of adulteration of pumpkin seed oil by analysis of content and composition of specific Δ7-phytosterols

 A simple and accurate method for the determination of phytosterols by capillary gas chromatography was developed for the analysis of the seeds and oil of the pumpkin Cucurbita pepo L., the naked seed variety growing in the southern Styrian parts of Austria. After extraction of the oil and saponification, the remaining unsaponifiable material was isolated and purified using silica gel columns. For greater volatility, the sterols were derivatised to trimethylsilylethers, and gas chromatography was performed on a column of high polarity, allowing separation of the Δ5-sterols from the Δ7-sterols and thus yielding a typical chromatographical pattern. Quantification of the phytosterols using 5α-cholestan or cholesterol as internal standards led to a method of high accuracy. Comparison of the chromatographic pattern of the phytosterol fraction of pumpkin seed oil with those of other vegetable oil samples permitted the use of this method to detect adulteration of pumpkin seed oil. Received: 20 April 1998     

脂酶催化下大豆粉末磷脂与全氢化大豆油酯交换反应的研究

本文利用脂酶的特异性催化作用,研究了正己烷体系中,大豆粉末磷脂与全氢化大豆油的酯交换反应。利用碘值和产率为指标,考察了酶的种类及用量、底物摩尔比、温度、时间等因素对酯交换反应的影响,通过单因素和正交试验优化了大豆粉末磷脂与全氢化大豆油酯交换反应条件。发现在25%磷脂酶A1(以磷脂质量为基准)催化下,摩尔比4:1的全氢化大豆油和大豆粉末磷脂的正己烷溶液(磷脂浓度为0.20 g/mL),在50 ℃下反应24 h,得到产率为72.9%的改性磷脂。与原料磷脂相比,改性磷脂的碘值由89 g /100 g降至52 g /100 g,脂肪酸组成变化较大,硬脂酸含量约为原料磷脂的9倍,不饱和脂肪酸亚麻酸和亚油酸含量降低了约一半,实现了大豆粉末磷脂的结构修饰。     

高油大豆与低油大豆油脂体组成及其稳定性的研究

为研究高油大豆和低油大豆油脂体组成及乳化稳定性和氧化稳定性差异,本试验分析了高油大豆和低油大豆油脂体基本组成、脂肪酸组成、磷脂组成、生育酚组成,同时比较了高油大豆油脂体与低油大豆油脂体乳化性及乳化稳定性、过氧化值及TBARS值。研究表明,高油大豆油脂体蛋白质含量显著低于低油大豆油脂体(P0.05),而高油大豆油脂体的脂肪含量显著高于低油大豆油脂体(P0.05);高油大豆油脂体的棕榈酸和亚油酸含量显著低于低油大豆油脂体(P0.05),而十七碳酸、油酸、二十碳一烯酸和α-亚麻酸含量显著高于低油大豆油脂体(P0.05),高油大豆油脂体的总不饱和脂肪酸质量分数(83.08±0.05)%显著高于低油大豆油脂体(81.86±0.12)%(P0.05);高油和低油大豆油脂体中脑磷脂、卵磷脂和溶血磷脂酰胆碱含量无显著差异(P0.05);高油大豆油脂体中DL-α-生育酚和γ-生育酚含量显著高于低油大豆油脂体(P0.05);高油大豆油脂体和低油大豆油脂体的乳化性无显著差异(P0.05),而高油大豆油脂体的乳化稳定性显著高于低油大豆油脂体(P0.05);14 d热处理条件下,高油大豆油脂体的过氧化值和TBARS值均高于低油大豆油脂体。上述研究表明,高油大豆和低油大豆的油脂体之间的组成和稳定性都存在差异。     

食用植物油转基因成分检测技术的研究进展

目前在世界范围内对转基因食品的安全性存在争议,食用植物油转基因成分的定性检测是当前食品检验工作中的一个重要方向。就食用植物油中转基因成分的核酸提取和检测技术的最新进展进行了综述,为后续的检测及研究提供参考,同时指出转基因成分的定量检测将是检验的另一个方向。     

东北地区大豆主栽品种油份蛋白含量的关联分析

为探寻与大豆油份含量、蛋白含量相关的关键位点,本研究选取中国东北地区92份大豆主栽品种及常用种质资源品种群体基于蛋白含量和油份含量的Meta分析,进行基于数学模型的类群划分评价,估测样本群体的结构,应用简单线性模型分析与大豆油份含量、蛋白含量相关的的位点。结果表明,通过多次迭代测试,当K=5时,即该资源群体可以分为5个亚群时,为最稳定的分类结果,并在显著水平下（p〈0.05）贡献率大于1%的标记中,得到与大豆油份含量相关标记有Sat_412,Sat_195,Satt317,Sat_187,Sat_195,Satt255,Satt713,Satt468,Satt267,Satt686,Sat_294和AZ302047,对油分含量的总贡献率为39.54%。蛋白质含量相关标记有Satt683,Sat_311,Satt578,Satt181,Satt317,Satt700,Satt713,Satt255,Sat_242和Satt720对蛋白质含量总贡献率为48.39%。这些重要的标记位点为大豆油份含量和蛋白含量的分子辅助育种提供重要基础。     

氨基化二氧化硅颗粒应用于大豆油DNA提取研究

建立了以氨基化二氧化硅为载体提取大豆油DNA并进行转基因成分检测的方法。结果表明：利用氨基化二氧化硅法富集提取大豆毛油中的DNA质量浓度高于国标法;以氨基化二氧化硅法提取的大豆毛油DNA为模板成功扩增出了大豆内源基因、外源基因片段和转基因调控元件,而精炼油DNA未扩增出。氨基化二氧化硅法只适用于大豆毛油DNA的提取,而不适用于精炼油。     

响应面法优化大豆油脂肪酸乙酯合成工艺

以大豆油为原料,KOH作催化剂,通过大豆油与乙醇的酯交换反应合成了大豆油脂肪酸乙酯。应用响应曲面分析法中的Box-behnken模型对影响大豆油脂肪酸乙酯转化率的四个主要因素（催化剂用量、醇油摩尔比、反应温度、反应时间）进行了优化。研究表明大豆油脂肪酸乙酯的最佳合成工艺条件为：KOH用量1.3%,醇油比8.3∶1,反应温度74.8℃,反应时间130min。在此条件下,酯转化率达98.93%。     

Quantitative competitive PCR for the detection of genetically modified soybean and maize

 The surveillance of food labelling concerning genetically modified organisms (GMOs) requires DNA-based analytical techniques. Present assay systems allow the detection of GMO in food; however, they do not permit their quantitation. In this study, we report the development of quantitative competitive polymerase chain reaction (QC-PCR) systems for the detection and quantitation of the Roundup Ready soybean (RRS) and the Maximizer maize (MM) in food samples. Three DNA fragments that differ from the GMO-specific sequences by an insertion were constructed and used as internal standards in the PCR. These standards were calibrated by co-amplifying with mixtures containing RRS DNA and MM DNA, respectively. The calibrated QC-PCR systems were applied to nine commercial food samples containing RRS DNA and to three certified RRS flour mixtures in order to elucidate whether these food samples contain more or less than 1% RRS DNA. Finally, the GMO contents of four samples that were found to contain more than 1% RRS were determined by QC-PCR using various amounts of standard DNA. Received: 13 January 1998 / Revised version: 4 March 1998     

食用大豆油中转基因成分的检测

食用油脂中转基因成分的检测是当前食品检验工作的一个主要方面。针对食用油脂中DNA含量极低、DNA序列片段短、破坏严重的特点,建立了食用油脂中DNA提取方法,通过实时荧光PCR可检测出大豆内源基因(Lectin)以及外源抗除草剂基因EPSPS,为食用油脂进行核酸类生物性检测提供了一种简捷有效的方法。     

PCR法检测大豆加工食品中的转基因成分

通过分子生物学手段,以聚合酶链式反应(PCR)技术为基础,建立了检测大豆加工食品中转基因成分的方法。实验分别采用CTAB法和试剂盒(Kit)法对大豆锅巴、豆浆、豆奶粉、豆腐、豆腐丝等五种大豆加工食品中的DNA进行了提取,用内标基因Lectin对此两种方法的提取效果进行了比较,并以提取的DNA为模板,利用不同的引物分别对目标基因35S和NOS进行了PCR扩增和琼脂糖凝胶电泳检测。结果表明:Kit法的DNA提取效果优于改良CTAB法,上述五种大豆加工食品中均检测出35S启动子和NOS终止子,且均含有转基因成分。     

模拟油罐储藏大豆油氧化稳定性研究

以过氧化值、酸值、p-茴香胺值和氧化稳定性指数(OSI)为评价指标,模拟油罐储藏,通过正交试验探讨了温度、含水量、氮气量、储油罐的表面积/体积关键影响因素,在储藏5个月内对成品大豆油储藏期氧化稳定性的影响.结果表明,在大豆油储藏过程中,温度对油脂的氧化稳定性的影响比较显著,其次是氮气量、含水量和储油罐的表面积/体积.由于受外界环境和自身结构的影响,大豆油氧化是一个复杂的过程,因此,为了控制成品大豆油具有较好的氧化稳定性,成品大豆油应在较低的温度(25℃)、适量的含水量(0.02％～0.05％)、充足的氮气(100％)和较大的表面积/体积条件下储藏.     

大豆油酶法脱胶与吸附脱酸工艺的优化研究

本研究以大豆毛油为原料,采用酶法脱胶和物理脱酸法对其进行精炼处理。通过单因素实验和正交实验进行工艺优化,以获得合适的大豆油精炼条件。结果表明：采用磷脂酶C酶法脱胶的最佳工艺条件为pH 5.4,酶添加量10.0 μL/kg,酶解温度45.0 ℃。在此条件下,大豆毛油磷含量可降低至7.3 mg/kg;最佳的脱酸工艺条件为保温时间40.0 min、加水温度90.0 ℃、加水量3.5%、絮凝剂量0.7%,此条件下大豆油酸值为0.08 mg/g,磷含量为5.5 mg/kg。大豆毛油经酶法脱胶和物理脱酸处理后的磷含量和酸价显著降低,品质提高。实验结果为大豆油的非化学精炼提供了依据。     

Determination of DNA traces in rapeseed oil

 Today, genetically modified oilseeds are commercially available. Consumer protection as well as product safety demand analytical methods for the identification of products which have been genetically manipulated. By means of a technique which incorporates polymerase chain reactions, deoxyribose nucleic acid (DNA) fragments have been identified in oil samples from Brassicca napus. DNA fragments were successfully identified in samples of coldpressed oil, as well as in samples of refined oil. Detectable amounts of DNA were isolated and amplified. In contrast to other results from the literature, we were able to demonstrate that DNA fragments also occur in oil samples and that they can be used for the identification of the plant species from which the oils are derived, and for use in further analyses. The techniques developed not only permit the identification of genetically modified seeds, but can also be used to identify different types of oils which have been adulterated with genetically manipulated foodstuffs. Received: 11 August 1997 / Revised version: 3 November 1997     

水酶法提取大豆油与其他不同种大豆油品质差异研究

通过对大豆油的感官指标、理化指标及部分功能性成分的比较,研究不同种大豆油(水酶法提取大豆油、一级大豆油、三级大豆油、压榨大豆油、溶剂浸提大豆油)的品质差异。结果表明,水酶法大豆油的外观品质介于一级油与三级油之间;色泽处于二级油与三级油之间,折光率最高,密度处于一级油和三级油之间;水分及挥发物的含量和p-茴香值最高,碘价最低,酸价、过氧化值介于一级油和二级油之间;水酶法大豆油的亚麻酸未检出,其饱和脂肪酸含量最低,总不饱和脂肪酸含量最高,磷脂含量介于一级大豆油和三级大豆油之间。     

完备区间作图法定位大豆含油量QTL及标记辅助选择

以高油大豆吉农18和高蛋白大豆吉育47杂交后获得的F2及F2∶3衍生群体为材料,采用QTL Ici-Mapping v2.2完备区间作图法在F2及F3群体中共检测到7个高含油量QTL,分布于4个遗传连锁群,可解释3.60%~20.98%的遗传变异。Satt636在10份大豆材料中的标记辅助选择检测,发现其符合度最高为83.33%。     

食用精炼大豆油DNA提取及单管巢式PCR检测

设计了针对转基因Roundup Ready大豆外源基因扩增的内外2对引物,分别位于CaMV35s启动子,CTP基因,CP4EPSPS基因区域,并成功对精炼大豆油中的外源基因进行单管巢式PCR检测。结果表明,用改良试剂盒法和冷冻干燥法提取大豆油中的DNA均可以满足单管巢式PCR检测要求;单管巢式PCR扩增对内外引物的Tm值有特殊要求,外引物的退火温度高于内引物。本实验建立的精炼大豆油转基因成分的单管巢式PCR检测方法特异性强,灵敏度高且快速方便。      

大豆油生产加工中色泽控制措施

一些大豆油含特殊杂质和色素,在脱色过程中白土用量过高,成品油氧化稳定性差。为了防控大豆油制取和精炼过程中色泽加深,降低白土用量,可采取不同的措施:预处理过程中调整参数让部分色素固化,浸出过程中采取多级过滤,降低蒸发和汽提温度,改造汽提塔结构以减少加工色素;精炼过程依据小样实验取得毛油品质数据调整操作参数,对部分脱色设备进行改造。生产精炼包装油按酸价(KOH) 0. 05 mg/g,色泽Y5～6/R0. 5～0. 6;散装油酸价(KOH) 0. 07～0. 08 mg/g,色泽Y7/R0. 7。储备大豆油和酸价(KOH) 2～3 mg/g毛油的脱色白土消耗量在原17～24 kg/t的基础上平均降低30%,包装油的货架期也明显延长。