Recombinant DNA in meat additives: Specific detection of Roundup Ready™ soybean by nested PCR

Soybean proteins are widely used by the meat industry as technological coadjutor when producing processed products such as emulsified and ground meat products. Since regulations for the use and labeling of GMOs and derived ingredients are in force in Brazil, a PCR‐based method capable of detecting Roundup Ready^? (RR) soybean was employed for meat additives. Thirty‐two samples of meat additives containing soy proteins were tested for the presence of soybean amplifiable DNA and RR soybean DNA. Twenty‐five samples gave a positive signal for the lectin gene, confirming the presence of soybean amplifiable DNA and 15 samples returned a positive signal for specific RR detection confirming the presence of genetically modified soy. These results demonstrate for the first time the presence of RR soybean in meat additives. This method may be useful for meat industries interested in controlling the presence of RR soybean in additives used for meat products manufacture. Copyright © 2007 Society of Chemical Industry     

A survey of the use of soy in processed Turkish meat products and detection of genetic modification

To screen for possible illegal use of soybeans in meat products, the performance characteristics of a commercial polymer chain reaction (PCR) kit for detection of soybean DNA in raw and cooked meat products were established. Minced chicken and beef products containing soybean at levels from 0.1% to 10.0% were analysed by real-time PCR to amplify the soybean lectin gene. The PCR method could reliably detect the addition of soybean at a level of 0.1%. A survey of 38 Turkish processed meat products found only six samples to be negative for the presence of soybean. In 32 (84%) positive samples, 13 (34%) contained levels of soy above 0.1%. Of soybean positive samples, further DNA analysis was conducted by real-time PCR to detect whether genetically modified (GM) soybean had been used. Of 32 meat samples containing soybean, two samples were positive for GM modification.     

Monitoring genetically modified soybean along the industrial soybean oil extraction and refining processes by polymerase chain reaction techniques

In the present work, the extraction and detection of DNA along a complete industrial soybean oil processing chain was described to monitor the presence of Roundup Ready^® (RR) soybean. The analysed samples comprised all the steps prior to industrial oil extraction, namely, raw, cracked, laminated and expanded seeds, and the defatted flour as a sub-product. The samples collected at the refining unit included the crude oil, degummed/neutralised, washed, bleached and deodorised oil, as final product. The amplification of soybean lectin gene by end-point polymerase chain reaction (PCR) was successfully achieved in all the steps of extraction and refining processes, until the fully refined soybean oil. The amplification of RR soybean by PCR assays using event-specific primers was also achieved for all the extraction and refining steps, except for the intermediate steps of refining (neutralisation, washing and bleaching) possibly due to sample instability. The real-time PCR assays using specific probes confirmed all the results and proved that it is possible to detect and quantify genetically modified organisms in the fully refined soybean oil. To our knowledge, this has never been reported before and represents an important accomplishment regarding the traceability of genetically modified organisms in refined oils.     

Monitoring of Bt11 and Bt176 genetically modified maize in food sold commercially in Brazil from 2005 to 2007

BACKGROUND: The first genetically modified (GM) maize lines were approved for trading in Brazil after December 2007 and they were T25, MON810, Bt11, NK603 and GA21. The polymerase chain reaction (PCR) method was employed to monitor the presence of Bt11 and nested PCR was used to detect the presence of Bt176 in 81 maize‐derived products (maize flour, corn meal, maize flour flakes and polenta) that were sold in Brazilian market from 2005 to 2007, before the release of GM maize in Brazil. RESULTS: The PCR detection limit for Bt11 was 10 g kg^?1 and for nested PCR of Bt176 it was 1 g kg^?1. All Brazilian samples analyzed showed no positive signal for these GM maize events. CONCLUSION: Bt11 and Bt176 GM maize lines were not detected by specific PCR in 81 maize‐derived food samples sold in Brazil from 2005 to 2007, before the commercial release of GM maize in Brazil. These Brazilian food industries were in compliance with the rules stipulated by the current legislation with respect to consumer requirements about GMO labeling. Copyright © 2010 Society of Chemical Industry     

Analysis of Lunasin in Commercial and Pilot Plant Produced Soybean Products and an Improved Method of Lunasin Purification

Abstract: Lunasin is a bioactive peptide present in soybean. It is important to quantify lunasin concentration in soy products to assess its potential impact as functional food. The objectives of this study were to analyze lunasin in commercial soymilk products and implement an efficient method to isolate and purify it from defatted soybean flour. Defatted soybean flour was suspended in water, and the extract was loaded in a pre‐equilibrated diethylaminoethyl column and bound proteins eluted using a step gradient of salt. Most lunasin was eluted from the column at 0.2 to 0.4M NaCl as quantified by immunoassays and purified using ultracentrifugation and ultrafiltration techniques. Lunasin purity was ≥90% and a standard curve was used to quantify its concentration in soymilk products. Concentration of lunasin in soy products, including organic soymilk, soy protein shakes, and soy infant formulas, ranged from 1.78 to 9.26 mg lunasin/100 g product. The concentration per serving ranged from 1.59 ± 0.01 to 22.23 ± 0.74 mg lunasin with variability depending on brand and size per serving. Steam‐ground‐cooked soy had the highest concentration of lunasin (22.23 ± 0.74 mg/serving), similar to some commercial products. Ground‐cooked soymilk contained roughly half the concentration of lunasin (14.39 ± 1.4 mg/serving). Soy infant formulas that used soy protein isolate revealed lower concentrations of lunasin (P < 0.05). It was concluded that all soymilk products analyzed contained lunasin, and a more efficient method to isolate lunasin with higher purity was developed. Practical Application: Soy foods have shown to play a role in cardiovascular health prevention. The quantification of lunasin in commercially available soy products can add to the already existing health claim for soy foods and encourage consumers to include soy products in their diets.     

Effect of lipoxygenase activity in defatted soybean flour on the gelling properties of soybean protein isolate

Soybean lipoxygenase was inactivated to different degrees by dry heating of defatted soybean flour for 0, 5, 10, 15, 20 and 25 min and soy protein isolates were prepared thereof by isoelectric precipitation of the water extract of the defatted soybean flour. The fluorescence emission intensity at 420 nm of the chloroform–methanol extract of soy protein isolates, which was indicator of the existence of peroxidized lipid, varied in parallel with the lipoxygenase residual activity in defatted soybean flours. The dispersion of soy protein isolate showed an increasing turbidity with the increase of lipoxygenase residual activity in the starting defatted soybean flour, suggesting an elevated tendency to form insoluble aggregates during the preparation of soy protein isolate. Small deformation rheological test revealed that the gelling times were shorter for those soy protein isolates derived from low lipoxygenase activity defatted soybean flours than that of high lipoxygenase activity. Frequency sweep showed that G′ of soy protein isolate derived from low lipoxygenase defatted soybean flour was independent of oscillation frequency in contrast to that of derived from non dry-heated defatted soybean flour, the latter showed a marked frequency dependence. Large deformation test revealed that the gel hardness increased about 10 times after dry heating of defatted soybean flour for 20 min. As the increase of the lipoxygenase residual activity, the gel permeability increased markedly, suggesting that soy protein isolate from high lipoxygenase defatted soybean flour produced coarser textured gel, which corresponded well with the results of scanning electron microscopy.     

Purification, Thermal Stability, and Antigenicity of the Immunodominant Soybean Allergen P34 in Soy Cultivars, Ingredients, and Products

ABSTRACT:  Protein P34 ( Gly m Bd 30K) is the immunodominant allergen in soybean ( Glycine max L.). The objectives of this study were (1) to study the effect of thermal treatment on P34 antigenicity and secondary structure after isolation and purification of P34 from soybean by chromatographic techniques; (2) to identify the variability of P34 allergen within 138 accessions from a diverse USDA soybean germplasm collection by ELISA; and (3) to quantify P34 immunoreactivity in various commercial soy ingredients and products. Thermal processing decreased P34 antigenicity. Soybean accessions with the highest P34 content were ancestral (12 mg/g defatted flour) followed by modern (10 mg/g defatted flour) and exotic (8 mg/g defatted flour). The cultivar that emerged as the lowest-expressing P34 accession was PI548657 (2.3 mg/g defatted flour). Among commercial soy ingredients, soy flour yielded the highest P34 antigenicity (32 mg/g extracted protein) followed by soy protein isolate (29 mg/g extracted protein) and soy protein concentrate (24 mg/g extracted protein). Among soy consumer products, soymilk presented the highest P34 antigenicity, ranging from 7 to 23 mg/g extracted protein, followed by tempeh (8 mg/g extracted protein), soy infant formula (3.4 mg/g extracted protein), soy powder (2 mg/g extracted protein), and soy cheese products (0.50 mg/g extracted protein). Korean miso, soy sauce, soy chili mix, soy nuts, soy cream cheese, soy meat patty, texturized soy protein, and soy cereal exhibited undetectable P34 antigenicity (detection limit = 0.45 ng). Selecting soybean varieties with low levels of this allergen, or via processing, could potentially make soybean products less antigenic.     

PCR detection of soy ingredients in bread

Bread may contain soy ingredients to variable extends. The nature of this soy may be genetically modified, or the ingredient may cause allergic reactions in sensitive patients. PCR is a powerful tool to detect the presence of soy in food products. Major prerequisite for a PCR analysis is DNA of good quality and quantity. The persistence of soy DNA during bread making was evaluated using different amounts of different soy ingredients. Agarose gel electrophoresis of the samples taken during the baking process reveal that DNA is degraded, but subsequent PCR detection remains possible. Results, however, greatly depend on the type of ingredient and the amount present. Lower detection limits were obtained for full-fat and defatted soybean flours than those for toasted soybean flour and soy fibre samples. Samples taken at different places in the bread, however, reveal that sampling strategy may influence the PCR results.     

2012~2015年深圳市售转基因大豆及其产品的监测结果分析

目的 了解2012~2015年深圳市售转基因大豆及其制品的市场占有率、标识情况及发展态势。方法 在深圳各大连锁超市随机抽取大豆及其制品, 采用试剂盒法提取样品DNA, 采用实时荧光PCR的方法扩增大豆内源基因Lectin, 并扩增外源基因CaMV35S启动子和NOS终止子对样品进行定性筛查, 分析不同类别、不同年份样品的阳性率差异及变化趋势。结果 4年监测大豆及豆制品共283份, 检出阳性样品19份,总体阳性率为6.71%; 大豆样品的转基因阳性率为0; 不同年份的豆制品转基因阳性率之间存在显著性差异且有逐年上升的趋势; 所有检出的阳性样品均未按照规定标识。结论 目前深圳市场转基因大豆及其制品(大豆油除外)的市场占有率还很低, 但豆制品转基因阳性率有逐年上升的趋势。政府应该加强转基因产品的标识管理, 并加强转基因农产品的监管。     

Antioxidant capacity,phenolics and isoflavones in soybean by-products

This study aimed to determine proximate composition, antioxidant capacity, total phenolic content, isoflavones and free phenolic compounds in soy by-products. High carbohydrate and protein contents were found in grade A soymilk powder (GASP) compared to grade B soymilk powder (GBSP) and soy husk powder (SHP). Ash, moisture and total dietary fibre contents were reported to be the highest in soy husk, while GBSP had the highest fat content. Antioxidant capacity as assessed using β-carotene bleaching assay was in the order of SHP ≈ GBSP > GASP, and the ranking order of the Trolox Equivalent Antioxidant Capacity (TEAC) value was GASP ≈ GBSP > SHP, while the Ferric Reducing Antioxidant Power (FRAP) value was GASP > GBSP > SHP. The total phenolic content was in the range of 62.44–103.86 mg GAE/100 g wet weight, and the major phenolic compounds in free form were ferulic, vanilic as well as gallic acids. Acid hydrolysis increased the amount of total extractable isoflavone in all soy samples.     

转基因大豆Roundup Ready调控元件在食品加工过程中降解变化的研究

35S启动子可能会通过基因的水平转移插入到某一致癌基因上游，活化并导致癌症的发生。为了解转基因植物中调控元件的安全性问题，以转基因大豆Roundup Ready为实验材料，针对Roundup reaqdy转基因大豆中CaMV35S启动子及NOS终止子的序列，设计了不同长度片段的引物，通过对CaMV35S启动子和NOS终止子的PCR扩增，研究了豆腐、豆奶、豆粉3种大豆加工食品中磨浆、煮浆、调配、均质、杀菌、喷雾干燥等关键工艺对Roundup Reaqly大豆中调控元件的影响。结果表明调控原件在食品加工过程中的降解变化与其所处位置有较大关系。扩增长度相近的2个片段，包含大豆基因组。DNA序列的片段受加工过程的影响较小，在3种豆制品的所有加工过程中均能检测到。而只包含CaMV35S启动子序列的片段仅能在原料中检测到，原料经过磨浆后。片段大小降至200bp以下。NOS终止子受食品加工工艺的破坏和影响较小，在被检测食品的每一个加工过程中都能够检测到NOS终止子片段。     

我国豆粉与豆奶生产现状、问题及对策

根据国内外有关信息资料及实际研发生产情况,对我国的冲调豆粉与液体豆奶在产品分类、功能特性、产业建设、市场营销等方面作了较为全面地叙述.并对技术应用、产品研发和应用领域作了说明,指出了豆粉与豆奶目前存在的共性问题,表明了创新技术的应用和产业发展方向.     

Detection of genetically modified organisms in processed meat products on the Serbian food market

The addition of soybean proteins to processed meat products has significantly increased in recent years due to the interesting functional and nutritional properties of these vegetable proteins. Since the Roundup Ready (RR) soybean is the only transgenic soybean line approved for market in EU this work was aimed at monitoring its presence in meat products on the Serbian food market. The extracted DNA was analyzed using duplex polymerase chain reaction (PCR) with primer pairs aimed at the lectin gene and 35S promoter. Samples positive for the presence of GM soybean were subjected to a real-time quantification of the percentage of RR soya. The results indicated that out of fifty processed meat products examined, twelve gave positive results with 35S promoter and all contained RR soya below 0.1%.     

Selected odor compounds in cooked soymilk as affected by soybean materials and direct steam injection

ABSTRACT:  Soy odor is a major concern in the consumption of soymilk by Western consumers. The objectives of this study were to determine selected soy odor compounds as affected by soybean materials and direct steam injection and to determine if the steam-injection method affected overall cooked soy aroma of the soymilk and compared to the soymilk cooked by a traditional indirect method. Five varieties of soybeans with or without lipoxygenases were processed by direct-steam injection for up to 20 min at 100 °C. Eight selected odor compounds were analyzed by gas chromatography after extraction using a solid-phase micro-extraction (SPME) method. Hexanal, hexanol, 1-octen-3-ol, 1-octen-3-one, and trans-2-nonenal decreased whereas 2-pentylfuran and trans-2, trans-4-decadienal increased by boiling up to 20 min. The results showed that soybean variety was a significant factor to affect odor compositions. Direct steam injection cooked soymilk resulted in lower odor contents than a traditional indirect cooking method. The advantage of having a low odor composition in the heated soymilk products made from lipoxygenases-null soybean varieties could be attained by using normal soybean materials with direct steam injection.     

Detection of genetically modified organisms obtained from food samples

Genetially modified organisms (GMOs) were explored in food samples obtained from November 2000 to March 2003 in the Tokyo area by using PCR and real-time PCR techniques. The existence of Roundup Ready Soybean (RRS) was surveyed in processed foods derived from soybeans, such as tofu, boiled soybean, kinako, nama-age, abura-age, natto, miso, soymilk and yuba. RRS was detected in 3 of 37 tofu, 2 of 3 nama-age, 2 of 3 yuba and 3 of 3 abura-age samples. The CBH351 in 70 processed corn foods, NewLeaf Plus and NewLeaf Y in 50 processed potato foods, and 55-1 papaya in 16 papayas were surveyed. These GMOs were not detected among the samples. Qualitative and quantitative analyses of RRS and genetically modified (GM) corn were performed in soybean, corn and semi-processed corn products such as corn meal, corn flour and corn grits. RRS was detected in 42 of 178 soybean samples, and the amount of RRS in RRS-positive samples was determined. The content was in the range of 0.1-1.4% in identity-preserved soybeans (non-GMO), and 49.8-78.8% in non-segregated soybeans. On the other hand, GM corns were detected in 8 of 26 samples. The amount of GM corn in GM corn-positive samples was in the range of 0.1-2.0%.     

Quantification of Human IgE Immunoreactive Soybean Proteins in Commercial Soy Ingredients and Products

ABSTRACT:  The objective of this study was the detection and quantification of human IgE immunoreactive soybean proteins in commercially available soy ingredients and products. Optimum dilutions of primary antibody and antigens as well as detection sensitivity were determined for the implementation of a sandwich ELISA method using plasma from soy sensitive subjects (IgE ranging from 0.35 to 98.7 IU/mL). Human IgE immunoreactivity of commercial soybean ingredients showed that the plasma of subjects with strong allergic reaction to soybean presented proportionally higher immunoreactive response. Soy protein isolate and soy protein concentrate contained less immunoreactive proteins than soy flour and grits. As expected, a hypoallergenic soybean product presented the lowest IgE immunoreactivity. Hydrolyzed and fermented soy ingredients showed negligible human IgE immunoreactivity when proteins and peptides were < 20 kDa. The IgE immunoreactivity of soymilk samples ranged from 3.4 to 68.9 ng IgE/mg extracted protein. Tofu contained about 20-fold higher IgE immunoreactivity than soymilk products (median 171 ng IgE/mg extracted protein). Furthermore, soy cheese products presented twice the IgE immunoreactivity than tofu products (median 359 ng IgE/mg protein). Meat analogues presented considerably high extracted protein concentration (median 67.9 mg/g product). The findings of the current investigation demonstrate sandwich ELISA as a reliable immunochemical method with good repeatability, sensitivity, and low detection limit to quantify IgE immunoreactive proteins in soy ingredients and products. Quantitative measurement of specific IgE is likely to become an increasingly valuable tool for soybean industry to comply with food labeling for manufacturers, thus protecting soy-sensitive consumers.     

Genetically modified maize and soybean on the Egyptian food market

The results of a survey study on food samples produced from genetically modified soybean and maize collected from the Egyptian market are presented. Forty samples of soybean and 40 samples of maize products have been gathered randomly from markets in Cairo and Giza. The genetic modification was detected by polymerase chain reaction (PCR) using official detection methods according to section 35 of the German Foodstuffs Act. Samples were investigated for the presence of material derived from the following genetically modified organisms (GMOs) all of which are approved for food use in Europe: Roundup Ready soybean (RRS) and maize lines Bt176, Bt11, T25 and MON810. In addition, samples were examined in qualitative and quantitative analysis for the presence of material derived from the transgenic maize line StarLink (Aventis) which was approved for animal feed use exclusively in the US. Twenty % of 40 investigated soy samples contained Roundup Ready soybean; 15% of 40 maize samples tested positive for Bt176 and 12.5% positive for Bt11 maize. Furthermore, the presence of StarLink maize could clearly be demonstrated in four samples mixed with Bt176 and Bt11. The percentage of StarLink was less than 1% in quantitative analysis. The maize lines T25 and MON810 were not detected.     

一种家庭豆浆机豆片原料的研制

为了制备专用于家庭豆浆机、不产生豆渣的大豆原料,利用干法粉碎制备脱皮大豆豆粉,然后利用单冲压片机压制成豆片。以豆片为原料利用家用豆浆机按照干豆豆浆程序制备豆浆,以残渣率、粗蛋白含量、蛋白体外消化率及感官评分为指标对豆浆品质进行评价,结果表明将豆粉压制成片可避免以豆粉直接制备豆浆产生的加热管焦糊现象;与脱皮豆相比,豆浆残渣率从8.51%降低到1.30%,感官试验表明,利用豆片制备豆浆,不分渣在口感上亦可完全接受;粗蛋白从2.26%提高到3.08%;体外消化率(氮释放量)从49.82%提高到64.35%;感官评分从82.3分提高到91.8分。因此,利用豆片作为家用豆浆机专用原料可以提高原料利用率、蛋白质消化率及感官品质,且不用分渣,可实现原料(大豆子叶)全利用。     

Functional attributes of soybean seeds and products,with reference to isoflavone content and antioxidant activity

The concentrations of isoflavones, especially daidzein and genistein, were determined by high performance liquid chromatography in 4 soybean cultivars and 26 soybean products. The total isoflavone content of the soybean cultivars was in the range of 525–986 mg per kg, and for soy products it was 32.9–795 mg per kg. Amongst the soybean products, the isoflavone content decreased in the order: soy sprouts, soy seeds, soy flour, soy milk, soy meals and soy sauce. Significant differences in the concentration of genistein and daidzein were observed between the commercial soy products and also within the soybean cultivars. The antioxidant activity of soybean and soy products correlated well with total phenolic content (TPC) and total isoflavones (TI), whereas TPC showed higher correlation with TI.     

转基因大豆DAS44406-6多重荧光定量PCR检测方法的建立

本文针对大豆内源基因Lectin和转基因大豆DAS44406-6品系的5’端插入位点序列,设计特异性引物及探针,建立同时检测转基因大豆DAS44406-6品系和大豆内源基因Lectin的多重荧光定量PCR方法,并运用15种转基因大豆、3种转基因玉米、1种转基因油菜、1种转基因水稻和非转基因大豆对该方法进行特异性评价,并分析该方法的灵敏度和稳定性。结果显示,该方法能准确从20种转基因样品和1种非转基因样品中检出靶目标,检测结果与待检样品信息一致,表明本方法具有良好的特异性;灵敏度高达0.01%;重复性实验表明DAS81419品系4种含量、9次重复反应Ct值的标准偏差介于0.050⁰.222,相对标准偏差介于0.169%⁰.677%,均在可接受范围内。该方法特异性强、灵敏度高、稳定性强,适用于各口岸实验室进行转基因大豆DAS44406-6的快速、准确的检测。