Maize unsound kernel content is one of the limited items in maize trade, and generally determined by sensory detection. A certified reference material (CRM) for visual inspection of maize unsound kernels was developed according to a national standard of China, GB 1353-2018, and five items, such as insect-damaged kernels, spotted kernels, broken kernels, sprouted kernels and moldy kernels, were included. Unsound maize kernels were collected from fields or prepared in a laboratory, then screened, and ten kernels demonstrating varying levels of unsoundness or damage for each item were embedded in epoxy resin. The CRM showed excellent homogeneity and stability, which was stable for 14 days at the temperature from -20℃ to 45℃ and for at least 18 months at room temperature out of direct sunlight and strong light. Co-laboratory confirmation showed the CRM conformed to the morphological characteristics described in GB 1353-2018. The research filled the gap of unsound maize kernel CRM in maize detection.

Timely and accurate forecasting of crop grain protein content (GPC) is helpful in planning to acquire the desired target protein levels. A geographically weighted regression (GWR) model was estimated based on meteorological factors to predict the winter wheat GPC at the county level. In the Huang-Huai-Hai region, the grain protein content of winter wheat increased by 0.29% for every 1° increase in latitude. GPC prediction with this model was more precise than that of the multiple linear regressions (MLR) model. The correlation coefficient (R) and Akaike information criterion (AIC) value ranges were 0.26 ~ 0.66 and 1573.86 ~ 1710.70 for the GWR, and 0.06 ~ 0.46 and 1670.18 ~ 1939.76 for the MLR, respectively. Except for radiation in March (RAD03), radiation in April (RAD04) and radiation in May (RAD05), the sensitivity index of other monthly weather indicators to GPC had a high correlation with latitude. With 36° north latitude (L) as the limit, the correlation between RAD03 (RL<36 ° = 0.36, RL>36 ° = −0.29), RAD04 (RL<36 ° = 0.31, RL>36 ° = −0.35) and RAD05 (RL<36 ° = 0.20, RL>36 ° = −0.20) with latitude all showed an opposite trend. We highlight that spatial information needs to be considered when predicting county-level winter wheat GPC.

分析不同粒径大小分布对不同淀粉含量全籽粒玉米粉糊化特性的影响,选取淀粉质量分数66％～77％的玉米,通过小型实验磨研磨得到不同粒径的全籽粒玉米粉,研究粒径大小分布、主要成分、损伤淀粉等指标对糊化特性的影响.结果表明,玉米粉的粒径大小和分布对其糊化能力、凝胶特性影响明显,特别是小颗粒粒径大小影响明显,但对回生老化特性影响不显著.平均粒径和小颗粒粒径越小、颗粒表面积越大时,越容易糊化,峰值黏度也越大,玉米粉间糊化能力差异越显著,总淀粉越多、脂肪和蛋白越少也越容易糊化,峰值黏度也越大;小颗粒粒径越小、比表面积越大,凝胶抗剪切能力越差,玉米粉间凝胶特性差异越明显,总淀粉和损伤淀粉含量升高、脂肪和蛋白质降低,也降低凝胶抗剪切能力;粒径大小与分布对玉米粉回生老化特性影响不显著,总淀粉和直链淀粉增加、脂肪减少,提高凝胶回生能力.

为调查分析我国的常规大豆育种材料中是否混入转基因大豆品系,选取706份大豆品系,对可能含有的外源转基因调控元件(CaMV35S启动子、FMV35S启动子和NOS终止子)以及针对我国批准进口的主要耐除草剂转基因大豆转化体(GTS40-3-2和MON89788)成分进行PCR扩增,同时根据MON89788转化体侧翼序列和目的基因设计引物做特异性检测,为其定性检测提供技术支撑.结果表明,在选取的所有样品中,最终测得含有CaMV35S启动子的转基因成分所占比例为1％,含有FMV35S启动子的转基因成分所占比例为0.85％,含有NOS终止子的转基因成分所占比例为0.71％,耐除草剂转基因品系MON89788所占比例为0.85％,以此评估转基因大豆所占比例,为农业转基因监管部门开展转基因大豆监管工作提供数据支持.

以巴西大豆为试验材料,模拟海上货轮舱内环境,对大豆热损伤粒率、霉变粒率、粗蛋白质含量、粗脂肪含量、蛋白质溶解度和脂肪酸值进行测定,监测不同水分含量大豆在50 d模拟储运期间的品质变化.结果表明,大豆水分含量越高,对豆堆温度的影响越大,进而对大豆的品质影响越大.当大豆水分含量小于等于12％时,各项指标均未发生明显变化,可长期安全储存;当水分含量为13％时,储存时间超过20 d后品质指标开始发生较明显变化;大豆水分含量大于等于14％时,短期内大豆各项指标发生显著变化,不耐储存.高水分导致豆堆温度升高,进而引起大豆霉菌滋生,热损伤粒率、霉变粒率、脂肪酸值增加,蛋白质溶解度降低,粗蛋白质和粗脂肪含量轻微下降.研究结果可为科学阐述进口大豆海上运输过程中品质变化和客观评估经济损失提供理论依据.

Abstract To investigate the fractioning of chlorpyrifos, omethoate, cypermethrin, and deltamethrin during wheat milling and the fate of four pesticides during Chinese steamed bread (CSB) processing, wheat samples, which were sprayed twice with chlorpyrifos, omethoate, cypermethrin, and deltamethrin at three levels of concentrations during the grain‐filling stage, were milled, and wheat flour was processed to CSB. The residues of four pesticides in the milling products, kneaded dough, fermented dough, and CSB were determined with GC‐MS/MS. The concentrations of chlorpyrifos, omethoate, cypermethrin, and deltamethrin in bran were 1.46–1.57, 1.85–2.13, 1.27–1.86, and 1.63–2.33 times higher than those in wheat, respectively, while the residues of the four pesticides in shorts decreased approximately 27.97% to 57.02% for chlorpyrifos, 6.22% to 44.77% for cypermethrin, and 13.13% to 61.15% for deltamethrin compared with the residues in wheat (p < .05); however, omethoate levels approximately doubled in the ten‐fold treatment group in shorts compared with those in wheat (p < .05). The residues of the four pesticides in flour were significantly lower than those in wheat, ranging from 38.68% to 98.04%. Chlorpyrifos and omethoate levels showed a slight decrease during the kneading and fermentation process, and further decreases of 2.46%–29.51% for chlorpyrifos and 14.22%–71.11% for omethoate were found in CSB; however, most of the groups of cypermethrin and deltamethrin showed various degrees of increases in kneaded and fermented dough and steamed bread compared with flour. The mechanism of this increase is unknown and needs further research.

为了解不同杀菌剂及施药次数对小麦赤霉病所造成的真菌毒素防控效果及所用杀菌剂带来的潜在安全问题,对信阳、襄阳两地区小麦主栽品种连续两年分别喷施不同种类、不同次数的杀菌剂,通过LC-MS/MS测定小麦中真菌毒素脱氧雪腐镰刀菌烯醇(DON)及各杀菌剂残留量,分析不同杀菌剂对小麦中DON累积量的影响,并对小麦籽粒中杀菌剂的残留量进行风险评估.结果 表明,4种杀菌剂(50％多菌灵WP、25％氰烯菌酯SC、25％咪鲜胺EC、70％甲基托布津WP)均能不同程度降低小麦中DON含量.随着施药次数的增加小麦中DON含量呈下降趋势(除多菌灵外).喷施50％多菌灵1次小麦籽粒中DON含量明显增加,较对照增加7％(信阳)、18％(襄阳),当喷施次数增加至2、3、4次,籽粒中DON累积量分别降至对照的55％～65％、24％～39％及20％～27％.25％咪鲜胺EC喷施3次后籽粒中DON含量较对照显著降低(P＜0.05),继续增加喷施次数,DON含量并未显著降低.25％氰烯菌酯SC对DON防控效果最佳,喷施1、2、3、4次小麦籽粒中DON毒素降至对照的42％～58％、29％～49％、12％～21％及6％～10％.喷施70％甲基托布津WP对籽粒中DON的影响与25％氰烯菌酯SC效果相差不大,喷施4次可使DON降至6％～12％.4种杀菌剂在小麦籽粒中的残留量均随施药次数的增加而增加.其中多菌灵的残留量最大,当施药4次后,信阳、襄阳两地小麦中多菌灵残留量分别为502.54μg·kg-1、547.38 μg·kg-1,均超过国家粮食安全限量水平,而其余三种农药残留量较低,均在安全限量范围内.研究结果还发现,小麦籽粒中的杀菌剂残留量与毒素DON的累积水平呈现一定程度的负相关性,施药次数与其残留量成正相关关系.因而,长江流域及江淮地区等小麦赤霉病易流行地区,建议于小麦扬花期及时喷施2～3次防控效果良好的杀菌剂,既能达到防控真菌毒素污染又可避免杀菌剂残留过高带来的安全隐患,以保证小麦安全生产.

为科学判定我国进口巴西大豆在储存期间的品质变化,采用模拟储存试验的方式,对不同水分含量巴西大豆在储存过程中粗脂肪、脂肪酸值和脂肪酸相对含量的变化进行监测.结果表明,巴西大豆在储存6周后,营养指标会出现不同程度的变化,储存28周时粗脂肪含量下降0.52～1.76个百分点,脂肪酸值(KOH)升高3.38～105.48 mg/100 g,亚油酸和亚麻酸的相对含量均呈现不同程度的下降.超过安全水分值(12％)越高,大豆品质下降越明显.低于安全水分值的大豆在储存18周后,品质开始发生较明显变化.因此,认为低水分含量(≤12％)大豆最佳储存期在18周内,高水分含量(>12％)大豆最佳储存期在6周内.通过试验不仅能够准确判定巴西大豆储存过程中的品质随时间的变化,也可以指导国家和地方大豆储备库对大豆的管理,保证大豆安全储存.

除了水分和温度是影响进口大豆货损的重要原因之外,海上运输期间船舱通风也是争论的焦点.对运输大豆的船舱构造进行模拟,通过持续通风储存和不通风储存的对比,考察通风对进口大豆货损的影响.结果表明:水分含量为9.9％的大豆,无论通风与否,在储存期间均不会发生霉变;水分含量为14％ ～16％的大豆,即使储存期间不间断通风,也会在短时间内迅速发生霉变,与不通风条件下储存相比大豆霉变速度和程度相同.因此,通风与否和大豆货损无直接关系.

小麦品种品质分类标准对规范我国小麦品种品质分类,促进小麦品种改良起到了重要作用.本文对历年来国家小麦品种试验品质分类标准进行了分析,讨论了当前小麦品种品质分类标准存在的问题,根据近10多年国内外小麦质量数据,提出了针对性的修改建议,为小麦品种试验品质分类标准的进一步完善提供参考.

To fill the gap of matrix reference material of fumonisins in our country, we developed a reference material of Fumonisins FB1 in corn flour. The homogeneity and stability of corn samples were tested by UPLC-MS/MS after screening, labeling, freeze-drying, grinding, mixing and sealing it. The content of Fumonisins FB1 in corn flour was determined by several laboratories, and the uncertainty of samples was analyzed. The homogeneity of the sample was calculated, with 1.42 of F which was less than the critical F0.05, and there was no significant change in the content of Fumonisins FB1 within the limited time for six months. The results showed that the uniformity and stability fulfill the requirements of reference material. The determined value of the sample was 1475.56 µg kg–1, and the uncertainty was 169.98 µg kg–1. The reference material can be used to calibrate the instrument, control laboratory quality and evaluate the testing quality of operators during the testing process of Fumonisins.

We reported the conversion of deoxynivalenol-3-glucoside (D3G) to deoxynivalenol (DON) during Chinese steamed bread (CSB) processing by artificial D3G contamination. Meanwhile, the effects of enzymes in wheat flour and those produced from yeast, along with the two main components in wheat flour—wheat starch and wheat gluten—on the conversion profiles of D3G were evaluated. The results showed D3G could convert to DON during CSB processing, and the conversion began with dough making and decreased slightly after fermentation and steaming. However, there was no significant difference in three stages. When yeast was not added, or enzyme-deactivated wheat flour was used to simulate CSB process, and whether yeast was added or not, D3G conversion could be observed, and the conversion was significantly higher after dough making. Likewise, D3G converted to DON when wheat starch and wheat gluten were processed to CSB, and the conversion in wheat starch was higher.

为研究不同油爆条件对不同类型爆裂玉米爆花特性影响,选取蝶型和球型两类爆裂玉米,分析不同加油量和处理温度对其特性的影响.研究表明,对于膨爆倍数,加油量和处理温度对不同类型爆裂玉米的影响不显著,而膨爆倍数在40％～50％的加油量时为最佳,等体积下的蝶型需油量更多,蝶型的适宜处理温度低于球型.爆花温度受加油量影响明显且呈显著正相关,而处理温度影响不明显,不同加油量和处理温度下,蝶型平均爆花温度高于球型.爆花起始和总时间受加油量影响并呈显著负相关,处理温度影响不显著,但随处理温度增加呈下降趋势.由此可见,油爆时爆花温度和时间主要受加油量影响,而蝶型和球型爆裂玉米适宜处理温度不同.

目的 为提高农业转基因成分检测能力和水平,保证检测质量,更好地发挥检测机构在转基因生物安全管理中的技术支撑作用.方法 根据农业农村部公告的转基因检测方法的要求,分别对编号为YZ180011、YZ180012、YZ180013和YZ180014样品进行检测.结果 检测到所有样品外源基因CaMV35S启动子均为阳性;YZ180012和YZ180014样品中,外源基因bar均为阳性;YZ180011、YZ180012和YZ180013号样品中,外源基因NOS终止子为阳性;而YZ180012号样品,外源基因pat为阳性;YZ180012和YZ180013号样品中,外源基因FMV35S启动子和NPTⅡ均为阳性;YZ180011和YZ180012号样品中,外源基因HPT为阳性.结论 本次能力验证获得结果为满意.

大米原料的质量是影响米粉加工性能、烹煮性能和感官品质的重要因素.影响米粉品质的大米原料质量指标主要有直链淀粉含量、胶稠度、糊化温度、蛋白质含量和储藏时间等,本文对近年来有关这些指标的研究进行了归纳总结,对各项指标对米粉品质的影响进行了逐一评述.通过总结分析可以得出,直链淀粉含量较高的籼米适宜于生产米粉;胶稠度与稻米其他各项指标有显著的相关性,可以作为选取米粉原料的主要指标;不同种类大米的糊化温度是不同的,可以根据糊化温度来指导米粉生产,避免淀粉过度糊化和米粉品质降低;蛋白质含量不仅决定大米的营养品质,也影响大米制品外观、加工和食用品质;使用陈化一段时间的大米制作米粉能够提升米粉品质.

目的 对比国标法、整粒烘ASAE法和快速水分法3种不同水分检测方法测定大豆水分含量的结果差异.方法 取自3种不同产地的大豆,包括巴西大豆、美国大豆和国产大豆,进行大豆整籽粒和粉碎后的水分测定实验来比较大豆水分含量差异.同时对2种谷物粉碎仪差异进行了比较.结果 以进口巴西大豆为例,用国标法测定水分平均值为7.76％,其中谷物磨测量值为7.75％,万用粉碎仪测量值为7.78％;ASAE法测得水分值为10.39％,快速水分仪测定值为10.7％.国标法水分测量值低于用ASAE法和快速水分仪法,且不同的粉碎磨粉碎后的水分测量值无明显差异(P>0.05).通过对比,ASAE法和快速水分法测定的大豆整籽粒水分含量比较接近真实值,而粉碎后测得的水分含量比真实值低.结果表明,国标法中将大豆粉碎后水分测量值低于用ASAE法和快速水分仪法整籽粒法水分测量值(P<0.05),且不同的粉碎磨粉碎后的水分测量值无明显差异.结论 结合实际现场测量的实验环境、实验周期和成本等因素考虑,推荐谷物快速水分法为最佳检测方法.

代谢组学是继基因组学和蛋白质组学之后新发展的一门学科,真正反映在生物体内已经发生的生命活动,揭示生物体在特定时间、特定条件下的整体功能性状态,为生物体内在规律的研究提供信息,在植物学研究中得到广泛关注.本研究主要介绍了代谢组学常用的高通量检测技术(如核磁共振、气相色谱-质谱联用、超高压液相色谱-四极杆飞行时间质谱联用等)、数据分析方法、检索数据库等,对比了不同检测方法的优缺点.小麦作为世界上的主要的粮食作物之一,在代谢组学方面也有相关研究.本文重点概述了发芽小麦代谢组学的研究现状,通过分析代谢物及小麦理化性质,揭示了小麦萌发的主要能量来自糖酵解,同时增加有益活性成分,为了解在代谢水平上的谷物种子萌发的生化机制及代谢产物发生的系列变化提供了理论基础.

为探究不同提取方法对发芽小麦代谢物提取效果的影响,本研究建立了基于超高效液相色谱-四级杆飞行时间质谱(UPLC-QTOF/MS)的发芽小麦非靶向代谢组学样品前处理方法和分析方法,以发芽2 d周麦26籽粒为材料,设计提取溶剂、提取方式、提取时间3个因素在3个水平上L9(34)正交试验,并通过主成分分析和聚类分析确定提取效果最佳的组合.以80％乙腈(0.1％甲酸)震摇提取30 min可检测出1609个代谢峰,说明提取溶剂对代谢物提取效果起主要作用.共鉴定出92种小麦代谢物.

The contents of total arsenic and inorganic arsenic in 100 rice samples which were collected from 10 cities of Jiangxi were determined by inductively coupled plasma mass spectrometry ( ICP﹣MS) and high performance liquid chromatography﹣inductively coupled plasma mass spectrometry ( HPLC﹣ICP﹣MS) , respectively. The results showed that the method had good linear relationships with a correlation coefficient of more than 0. 999 3, and the determination of total arsenic and inorganic arsenic contents in reference material for rice flour also showed a better result. The total arsenic contents of 100 rice samples varied from 0. 045 to 0. 382 mg/kg, with an average of 0. 170 mg/kg; the inorganic arsenic content varied from 0. 000 to 0. 180 mg/kg, with an average of 0. 067 mg/kg. The results of SPSS analysis of variance showed that, there are significant differences in the contents of total arsenic and inorganic arsenic among various cities of Jiangxi. The results displayed that the content of As3+ in rice is relatively high, account﹣ing for about 90% of inorganic arsenic content. Results of USEPA health risk assessment showed that the exposure of inorganic arsenic content in rice in Jiangxi province has no risk to human health.

A study was carried out to evaluate the dissipation kinetics of field-applied omethoate during wheat storage. Both the identification and metabolic dynamics of omethoate metabolites were analyzed using UPLC-QTOF/MS. The presence of the metabolite dimethyl phosphate (DMP) was confirmed in wheat samples with applied omethoate. This might be because the group attached to the P atom of omethoate is replaced by a hydroxyl group through hydrolysis, thus leading to the formation of the specific metabolite DMP during wheat storage. Although the initial concentrations of DMP in different doses were considerably lower than those of omethoate, the half-life values of DMP were 11.87-31.50 days, which were close to the half-life of the parent omethoate (11.85-30.94 days). This indicates that potential health risks might be caused by dietary exposure to DMP and omethoate. Therefore, more importance should be given to the risk assessment for omethoate and its metabolite DMP in wheat.