Detection of genetically modified rice: a construct-specific real-time PCR method based on DNA sequences from transgenic Bt rice

Genetically modified rice varieties developed in China are close to approval for agricultural cultivation and production. However, so far no method has been reported for specific detection of transgenic varieties of this crop. In the present study, rice seeds assumed to consist of field-tested Bt rice (‘Anti-pest Shanyou 63’ and ‘Anti-pest Jinyou 63’) were used as reference material to determine transgenic DNA sequences. The transition between the cryIA(b) and cryIA(c) fusion gene and the nopaline synthase terminator (nos) sequence was used to develop a construct-specific real-time PCR based detection method. This Bt rice specific detection system was combined with a recently published quantitative real-time PCR method for the rice-specific (Oryza sativa L.) reference gene gos9. The complete PCR assay for detection of transgenic Bt rice was in-house validated and the limit of quantification was found to be below 0.1% Bt rice relative to the rice content. Application of the PCR assay should allow more precise detection of transgenic rice varieties in imported food products which are so far not approved in the EU.     

Properties and qualities of rice flours and gluten-free cupcakes made with higher-yield rice varieties in Korea

Korean rice varieties, ‘Druryechanbyeo’ and ‘Boramchanbyeo’, were developed to get higher yields and to be used in rice products. The rice grains were dried and milled into rice flours after first going through the soaking process. The properties and qualities of cupcakes made with dry-milled rice flours were compared with cupcakes made with commercial dry-milled rice flours (CDRF). The newly developed rice flours (NDRF) had higher apparent amylose content, water binding capacity, swelling power, and peak viscosities, but had lower damaged-starch content, gelatinization temperature, and final and setback viscosities than CDRF. The specific gravity of batter, and hardness and springiness of cupcakes were lower in NDRF than in CDRF. The cake textures from ‘Boramchan’ NDRF were more preferable than those from ‘Druyechan’ NDRF. The specific volume and overall quality of cupcake were correlated positively with amylose content and water binding capacity, but negatively with damaged starch of rice flours.     

四川地方大米品种特性对方便米粉品质的影响

以四川省农业科学研究院试验区筛选出的7种优质杂交水稻为研究对象,米粉工业常用大米作对照,通过测定原料基本成分、米粉感官品质、蒸煮品质和质构特性等指标,研究不同品种四川地方大米原料对方便米粉品质的影响,通过相关分析建立大米原料品种指标与米粉品质间的相关性。结果表明:原料米品种对方便米粉感官品质、蒸煮品质、质构特性的均有显著影响。米粉的劲道、爽滑、风味等感官指标及其综合评分,质构特性与大米直链淀粉含量均呈显著的正相关性。米粉的断条率、复水时间与大米的直链淀粉含量、蛋白质含量呈显著的负相关性,与大米的支链淀粉含量、粗脂肪含量呈显著的正相关性(P0.05或P0.01)。当大米直链淀粉含量在21.40%～25.61%时,米粉感官品质、硬度、拉伸长度和断条率均最优。采用本实验方法制作米粉时,4#、5#、6#这3种大米加工的米粉品质较好,为进一步确定四川方便米粉原料标准化提供了参考依据。     

Impact of brown foxtail millet (Setaria italica) flour on thermo-mechanical properties of flours from different rice varieties

The physical, functional and thermo-mechanical properties of rice flours prepared from long, round and medium rice grain and of foxtail millet (Setaria italica) flour were investigated. The impact of foxtail millet flour addition on the thermo-mechanical properties to the rice flours was also explored. Rice flour from long grain had higher amylose content (26.37%), while the rice flour from round grain had better hydration properties compared to the other rice flours. The dough from long grain rice flour exhibited higher starch gelatinisation temperature and cooking stability and lower starch retrogradation compared to the other investigated rice flours. Foxtail millet flour addition to the rice flours exerted a lower impact on the thermo-mechanical properties of the dough based on rice flour from long grain compared to the other investigated rice flours. These differences might be due to the differences in terms of starch properties and proximate composition of the flour samples.     

Analysis of volatile compounds in Polished-graded wheat flours using headspace sorptive extraction

Headspace sorptive extraction method was used to determine the volatile flavor compounds of the Polished-graded wheat flours and commonly milled wheat flour (CW). The Polished-graded wheat flours of three fractions, C-1 (100-90%), C-5 (60-50%) and C-8 (30–0%), and CW obtained from a hard-type wheat cultivar ‘1CW’ (No. 1 Canada Western Red Spring) were used in the present study. A total of 48 volatile flavor compounds determined in all samples were common as in the wheat grain or flour. The major volatile compounds in C-1 included methoxybenzene (i.e. 1,4-dimethoxybenzene, 1,2,4-trimethoxybenzene, 1,2-dimethoxybenzene) associated with musty odors, and nitrogen compounds (i.e. trimethylamine, 3(4)-methyl pyridine, and 3-methoxy pyridine). The volatile flavor compounds identified in C-5 and C-8 were similar to those in CW. But, some compounds that have a connection with both oxidation products from unsaturated fatty acids and metabolites of a number of species associated with moldy grains, were more abundant in C-5 and C-8 than in CW. Furthermore, hexanal, methanol, ethanol, hexanol, 1-octen-3-ol, 3-octen-2-one, (E,Z)-3,5-octadien-2-one, (E,E)-3,5-octadien-2-one were considerably abundant in C-5 and C-8.     

Evaluation of the performance of flours from cross- and self-pollinating Canadian common buckwheat (Fagopyrum esculentum Moench) cultivars in soba noodles

Two Canadian cross-pollinating common buckwheat (Fagopyrum esculentum Moench) varieties, Koban and Koto, and two self-pollinating lines, BR01 and BR06, were dehulled and roller milled on a pilot mill to produce three distinct milled products, white flour, dark flour and whole groat flour. The white flours contained mostly starch (79.2–87.2%), whereas the dark flours were rich in proteins (37.1–38.7%), dietary fibre (15.2–22.0%), ash (5.49–5.99%), and fagopyritols (1420–2220 mg/100 g). The buckwheat flours were blended with wheat flour (Canada Western Red Spring straight grade flour) at 60:40 ratios and evaluated for soba noodle properties. Significant differences in milling properties, and in raw noodle colour and texture were detected among cultivars, although the impact of flour type on noodle properties was far greater. The self-pollinating lines exhibited comparable milling and soba noodle properties to Koban. Koto exhibited slightly higher white flour yield and generally firmer noodle texture compared to the other lines. White flours produced the brightest noodles, followed by whole groat and dark flours. Dark flours yielded the thickest cooked noodles with the largest maximum cutting stress and greatest resistance to compression. Noodles prepared with white flour offered the best chewiness, springiness and recovery parameters. Soba noodles prepared with dark flours contained considerably higher amounts of minerals, proteins, dietary fibre, and fagopyritols than noodles prepared with white flour.     

Physicochemical properties of flour recovered from broken rice noodles during production

Flour recovered from broken rice noodles was evaluated by microscopy, X‐ray diffractometry, differential scanning calorimetry, in vitro starch digestibility, pasting and gel texture analyses. Rice noodle making processes destroyed the granular and crystalline structures of rice flour (RF), but the process‐induced recrystallised amylopectin and amylose‐lipid complexes were observed. Higher level of resistant starch in broken rice noodle flour (BRNF) was due to the retrograded amylose, which formed during noodle making. The absence of pasting temperature and low pasting viscosity of BRNF were distinct from those of RF, whereas gel textures of both flours were similar. BRNF‐added rice noodles showed lower hardness, but the other cooking and texture qualities were close to the one without BRNF. Up to 17% of BRNF could be incorporated into composite rice noodle making. This study thus provided an approach to the management and utilisation of food processing wastes.     

Effect of heat-moisture treatment for utilization of germinated brown rice in wheat noodle

Effect of heat-moisture treatment of germinated brown rice (GBR) on the texture and cooking quality of the noodles containing mixtures of wheat and GBR flours was investigated. With the increase in GBR content, hardness and tensile strength of the composite noodles decreased and cooking loss and water absorption increased. Pasting viscosity of the flour mixtures was significantly decreased by increasing the amount of GBR. Heat-moisture treatment of GBR (17 or 20 g/100 g moisture at 100 °C for 4 h), however, apparently increased the pasting viscosity and improved the texture and cooking quality of the composite noodles. The mixture of wheat and a treated GBR (1:1 weight ratio) showed a pasting viscosity similar to pure wheat flour. The noodle containing the heat-moisture treated GBR flours showed the lower cooking loss, and higher hardness and tensile strength than the noodle containing untreated counterparts. Among the treated GBR flours tested, the GBR treated at 100 °C for 4 h at a moisture level of 17 g/100 g was the most acceptable in terms of cooking quality and textural property, close to those of the noodle of pure wheat flour. Substitution with the heat-moisture treated GBR, however, made the noodle darker because of thermal discoloration of GBR.     

2011~2019年吉林省米面制品中食源性致病菌监测分析

目的 了解米面制品中食源性致病菌的污染情况,为米面制品食物中毒的原因和影响因素提供线索。方法 根据《国家食源性疾病监测工作手册》对2011—2019年吉林省九个地(市)级所采集到的米面制品食品样本中蜡样芽孢杆菌、金黄色葡萄球菌、单增李斯特菌进行检测。结果 2011—2019年共检测米面制品3967份,其中阳性菌株313株,总检出率为7.89%,2015年检出率最高(14.68%)；蜡样芽孢杆菌在白山市检出率最高(44.44%),金黄色葡萄球菌在白城市检出率最高(44.44%),单增李斯特菌在白山市检出率最高(6.21%)；餐饮服务环节总阳性检出率为9.72%,流通环节总阳性检出率为5.38%；蜡样芽孢杆菌在炒的米面制品中检出率最高(43.42%),金黄色葡萄球菌在速冻面米生制中检出率最高,单增李斯特菌也是在速冻面米制品中检出率最高(14.29%)。结论 吉林省各地市米面食品污染的情况普遍存在,白山市最严重,但是近年来污染情况正在逐步好转速,餐饮服务环节需加强管理,小吃店,零售加工店和百货商场应该给予更严格的把控,速冻米面制品生制污染相对严重,需给予重视。     

Physicochemical,antioxidant properties and in vitro digestibility of wheat–purple rice flour mixtures

The physicochemical characteristics, antioxidant properties and in vitro digestibility of high‐antioxidant content flours made from different combinations of Thai purple rice flour and refined wheat flour from 25%, 50% to 75% (w/w) were investigated and these were compared with whole flour from purple rice and refined wheat flour. The increase in substitution levels of purple rice flour affected all the functional properties of flours, at the same time the levels of dietary fibre, protein digestibility and antioxidant compositions were also changed. The purple rice flour exerted a particularly strong effect on starch digestibility as the purple rice increased to 50% in the mixture. Moreover, purple rice flour showed lower amounts of rapidly digested starch (RDS), whereas slowly digested starch (SDS) of whole flour from purple rice and 75% substitution purple rice flour was found to be the highest for all samples. The in vitro starch digestibility of all samples also showed a positive correlation between dietary fibre and antioxidant compounds. Overall, the addition of purple rice flour improved the final nutritional properties, notably a lower predicted glycaemic index, and a higher antioxidant potential, which are two important nutritional properties for human health.     

Determination of Tinopal CBS-X in rice papers and rice noodles using HPLC with fluorescence detection and LC-MS/MS

To date there have been no reports of methods to determine Tinopal CBS-X. We developed a rapid and simple method to determine the Tinopal CBS-X content in rice noodles and rice papers using HPLC equipped with fluorescence detection. Heating the rice noodles and rice papers to 80°C after adding 75% methanol solution induced the release of Tinopal CBS-X from processed rice products. Tinopal CBS-X was separated using an isocratic mobile phase comprising 50% acetonitrile/water containing 0.4% tetrabutyl ammonium hydrogen sulphate at pH 8.0. The samples suspected to be positive by HPLC analysis were then confirmed by LC-MS/MS analysis. This study also investigated the Tinopal CBS-X content of three rice noodle products and two rice papers. The limits of quantification for rice papers and rice noodles were 1.58 and 1.51 µg kg^–1, respectively, and their correlation curves showed good linearity with r² ≥ 0.9997 and ≥ 0.9998, respectively. Moreover, rice papers had recoveries of 70.3–83.3% with precision ranging from 5.0% to 7.9%, whereas rice noodles had slightly lower recoveries of 63.4–78.7% and precisions of 8.5–11.5%. Only one rice noodle product contained Tinopal CBS-X, at around 2.1 mg kg^–1, whereas it was not detected in four other samples. Consequently, Tinopal CBS-X from rice noodles and rice papers can be successfully detected using the developed pre-treatment and ion-pairing HPLC system coupled with fluorescence detection.     

Integrated structure and event-specific real-time detection of transgenic <Emphasis Type="Italic">cry1Ac/SCK</Emphasis> rice Kefeng 6

Transgenic rice Kefeng 6 is a transformation event containing two insect-resistant genes, cry1Ac and SCK (modified CpTI gene) in China. In order to monitor the probable release of Kefeng 6 in the future and execute the labeling requirements, it is necessary to develop a rapid and reliable detection method. In this study, both the 5′ and 3′-junction sequences spanning the plant DNA and the integrated gene construct of the rice event Kefeng 6 were isolated by genome walking and long-distance PCR (LD-PCR), successively. Multiple copies of truncated SCK gene and cry1Ac gene were found to integrate into the host rice genome. The event-specific real-time detection method for Kefeng 6 event based on its 5′-junction sequence was established using one plasmid molecule pMD-KF6 containing both 5′-junction sequence and rice endogenous gene gos9 sequence as the reference material (RM) with an absolute limit of quantification (LOQa) around 10 template copies. Thereafter, three different transgenic amounts of w/w mixed samples (5, 1, and 0.5%, respectively) were quantified to assess the performance characteristics of the established real-time PCR method. The accuracy expressed as bias deviated from the 4.00–26.00%, the precision expressed as standard deviation (SD) and relative standard deviation (RSD) deviated from 0.03–0.19 and 3.42–4.76%, respectively. Based on the earlier results, we concluded that the qualitative and quantitative PCR assays were reliable and accurate for Kefeng 6 measurement, and the reference plasmid pMD-KF6 could be a good substitute for the reference material for Kefeng 6 quantification.     

高纯度大米蛋白和淀粉的分离提取

高纯度的大米蛋白和大米淀粉可以作为大米综合利用的两个主产品，本研究采用碱法将大米蛋白和淀粉分离，研究表明最适提取条件是：NaOH求度0．05N，提取2h此条件下分离体系不受破坏，且大米蛋白的蛋白含量可达94.03％(干基)，蛋白得率63．37％；大米淀粉中蛋白含量0．39％(干基)，淀粉得率47．87%。     

Quality and safety of a new rapeseed ‘Kangyu’ cultivated at different regions in Korea

The quality and safety of rapeseed are greatly affected by glucosinolate and erucic acid. To determine the quality of a new variety, ‘Kangyu’ was cultivated at 3 different regions and analyzed to evaluate oil quality and glucosinolates contents. The new cultivar accumulated 38–43%(w/w) of oil and 5–14 μmol/g of glucosinolates, whereas the local race contained 43% and 52 μmol/g, respectively. The total glucosinolates in ‘Sunmang’ was above the permissible limit. All ‘Kangyu’ samples had safe fatty acid compositions but the local race contained 43% of erucic acid (C22:1) that is far from the International Standard. The contents of oleic (C18:1), linoleic (C18:2), and linolenic acid (C18:3) in ‘Kangyu’ were 61–65, 21–23, and 9–10%, respectively. Consequently, ‘Kangyu’ was good oil source in Korea in terms of erucic acid (C22:1) and total glucosinolates for human health.     

Toxicological evaluation of transgenic rice flour with a synthetic cry1Ab gene from Bacillus thuringiensis

Bacillus thuringiensis (Bt) transgenic (KMD1) and non‐transgenic (KMD1′s parental variety Xiushui 11) rice flours were assessed in a 90 day feeding test with rats. KMD1 contained a synthetic cry1Ab gene from Bt, and selection marker genes nptII and hpt linked in tandem. In the≤64 g kg^?1 body weight (BW) dosage range (Bt transgenic rice flour composed 64% of the ingredients of the diet), no adverse effects of Bt rice on rats were observed in terms of animal behaviour, weight gain and feed utilisation rate. Necropsy at the end of the experiment indicated that neither pathological lesions nor histopathological abnormalities were present in organs such as liver, kidneys, intestines and testes of rats in both test and control groups by macroscopic and microscopic pathology. In addition, no significant differences (P > 0.05) were observed in relative organ weights, haemograms and blood indices of rats between test and control groups. Several serum parameters of female rats were found to be significantly different between Bt and non‐Bt diets, but the values of these parameters were still within the normal ranges of values for rats of this age and sex. These results demonstrated that Bt rice flour at a dosage of 64 g kg^?1 BW, Bt toxin and NPTII and HPT proteins have no toxic effects on rats. © 2002 Society of Chemical Industry     

Hydrothermal treatments of rice starch for improvement of rice noodle quality

Two types of hydrothermal treated rice starches were prepared by annealing and heat-moisture treatment (HMT). Annealing of starch slurry was conducted at 55 °C for 24 h and HMT was applied in starch with 20 g/100 g moisture at 110 °C for 1.5 h, based on the optimization of the treatment conditions. The apparent changes on gelatinization, swelling, RVA paste viscosities and gel hardness of starch were observed. The study on 50% substitution of rice flour with untreated (UR), annealed (AR) or heat-moisture treated (HR) rice starches proved that the cooking and texture quality of rice noodle was substantially affected by the treatments. The composite noodles of flour and hydrothermal treated rice starches exhibited quality parameters which were closer to those of commercial noodles. The results revealed the possibility of utilizing these starches with low quality rice flour so as to produce noodles of acceptable quality. The study also inferred that characterization of RVA paste viscosities and gel texture of flour could become a practical method for predicting the quality of the derived noodle.     

Rapid real-time PCR detection of transgenic cry1C rice using plasmid molecule as calibrator

Transgenic Bacillus thuringiensis (Bt) rice expressing cry1C gene showed a high level of resistance to leaffolders (Cnaphalocrocis medinalis) and stemborers. Till now, no detection method based on the plasmid molecule as the calibrator has been reported. In this study, one plasmid molecule containing the rice root-specific gene (gos9) endogenous sequence and the cry1C rice 5′ event-specific sequence was developed. Real-time polymerase chain reaction (PCR) method was established using the developed plasmid molecule as the calibrator. Two standard curves for gos9 and the cry1C rice 5′ event-specific sequence showed high PCR efficiency and good linear regression. Limit of quantification of the plasmid molecule in quantitative PCR assays was 40 copies. Biases for 5 and 0.25 % content samples’ quantification were ?6.01 and ?3.55 % with acceptable standard deviation and repeatability standard deviation, respectively. Comparing with genomic DNA, the plasmid molecule was suitable for cry1C rice quantification as the calibrator. Furthermore, the present study provided a reliable and stable identification and quantification system for monitoring cry1C rice.     

Extrudate gluten-free breakfast cereals from rice and corn flours with different amylose content: technological and sensory properties

The objective of this study was to evaluate the effects of different amylose content and conditioning moisture on the technological and sensorial properties of extrudate gluten-free breakfast cereals from rice and corn flours. Extrusion was applied to develop breakfast cereals from low-, medium- and high-amylose rice flours combined with corn flour (70:30 w/w), and different conditioning moisture (15% and 17%). When the conditioning moisture was 15%, the extrudates presented lower expansion, hardness and fracturability, when compared to 17% moisture. Extrudates obtained from the combination of rice and corn flours provided light and slightly yellow products, with low values of hardness and fracturability. The micrographs showed the presence of pores, air bubbles and an uneven surface. For industry application, the extrudate with low-amylose rice flour and conditioning moisture of 15% is recommended due to greater expansion and less retrogradation, features that extend shelf life. This cereal was best accepted sensorially.     

Effects of processing conditions and the use of modified starch and monoglyceride on some properties of extruded rice vermicelli

Pasting profile and gel appearance of rice flour, rice flour mixed with the modified starch, MYK-500T and monoglyceride, Monomul 90-35P were examined. The optimum conditions for the extrusion of rice vermicelli obtained were: screw speed 30 rpm; feeder speed, 50 rpm; temperature of three zones, 90 °C:100 °C:100 °C. The rice noodle had white color, good retention of shape but stuck together after cooking. The use of modified starch, and monoglyceride could reduce the stickiness of the product. The noodle extruded from rice flour added with MYK-500T (4 g/100 g blend), and Monomul 90-35P (1 g/100 g blend) was firm and not sticky, showing cooking time at 2 min, cooking weight 315 g/100 g dry noodle, cooking loss 11.1 g/100 g dry noodle and degree of gelatinization 88.9%. The hardness of the product was 1230 g and tensile strength 9.5 g. Sensory evaluation showed that the acceptance of the extruded rice vermicelli was not significantly different from other 3 commercial products prepared by conventional method.     

Effect of γ-irradiation on phenolic compounds in rice grain

Whole grain rice is rich in phenolic compounds. The effect of γ-irradiation on the main phenolic compounds in the rice grains of three genotypes (black, red, and white) was investigated. Three phenolic acids (p-coumaric acid, ferulic acid, and sinapinic acid) were identified as major phenolic compounds in all rice samples, while two anthocyanins (cyanidin-3-glucoside and peonidin-3-glucoside) were identified in pigmented grain samples. In general, γ-irradiation at most of doses could significantly (p < 0.05) decrease total phenolic acid contents in all samples and total anthocyanins contents in the black rice, but their decreases were not completely in a dose-dependent manner. Unexpectedly, 6 and 8 kGy significantly (p < 0.05) increased total contents of anthocyanins and phenolic acids in black rice. This study suggested that suitable doses of irradiation might be carefully selected and used to minimise the loss of antioxidant phenolic compounds in whole grain rice during storage.