臭氧水协同超声波处理对小麦中DON降解效果的研究

为了研究臭氧水协同超声波处理对赤霉病小麦中DON降解效果的影响,采用不同协同方式对赤霉病小麦进行处理,并筛选出臭氧水和超声波协同的最佳方式。随后在最佳联合方式下进行单因素和正交实验来探讨臭氧水浓度、超声振幅和处理时间对赤霉病小麦籽粒中DON降解效果的影响。结果表明:臭氧水和超声波最佳联合处理方式为T5,即先超声波处理5 min再臭氧水处理5 min,此时赤霉病小麦中DON降解率最高(46.99%)。经单因素和正交实验得出,在此联合方式下臭氧水浓度为58.32 mg/L,超声振幅为60%,处理时间比为9:1时赤霉病小麦中DON降解率最高(51.02%)。     

臭氧对不同基质中呕吐毒素的降解效果研究

为了研究臭氧对不同基质中呕吐毒素（DON）的降解效果及其规律，本研究采用臭氧来处理不同状态下DON纯品和赤霉病小麦，并初步探究了小麦组分对臭氧降解DON效果的影响。结果表明，臭氧可以在短时间内降解水溶液中的DON纯品和固态DON纯品，在处理浓度为10 mg/L、处理时间为60 s时，DON的降解率可达90%；臭氧可以有效降解小麦中的DON，料液比对小麦中DON的降解效果具有显著影响，当小麦粉与水的料液比为1:6时，臭氧可将初始含量为1.82 mg/kg的全麦粉中DON含量降解至国家标准限量 (1 mg/kg)以下。此外，在臭氧降解小麦中的DON时，小麦麸皮、淀粉和蛋白均对其降解效果有着明显的阻碍作用，且蛋白的阻碍作用最大。由此可知，臭氧可以显著降解不同状态下的DON纯品，对小麦各组分中的DON有较好的降解效果，并且臭氧对DON纯品的降解效率要显著高于赤霉病小麦，说明小麦各组分对臭氧降解DON有一定影响，其中蛋白的影响效果最为明显。不同基质中的DON的臭氧降解效果不同，且该降解效果受臭氧处理浓度和处理时间、样品与臭氧接触面积、样品水分含量等因素的影响。     

60Co-γ辐照对赤霉病小麦中DON的降解效果

采用60Co-γ射线辐照技术处理赤霉病小麦,结果表明:此技术可以降解赤霉病小麦中一定量的DON,降解率随辐照剂量的增加而逐渐升高。当辐照达到安全剂量10 k Gy时,赤霉病小麦籽粒中DON的降解率超过20%,若不结合其他小麦加工工艺,该技术可将DON含量低于1.25 mg/kg的赤霉病小麦降低到安全范围之内(DON含量≤1 mg/kg);小麦的物理形态、籽粒含水量及赤霉病感染程度对DON的辐照降解无显著影响(P0.05);此外,赤霉病麦粒经水浸泡后再辐照可以在很大程度上促进DON的降解,在安全剂量10 k Gy时降解率最高可达到55.76%。     

过热蒸汽处理对赤霉病小麦麸皮中脱氧雪腐镰刀菌烯醇降解效果研究

为提高赤霉病小麦麸皮利用率,使用过热蒸汽技术对赤霉病小麦麸皮进行处理。研究过热蒸汽温度、处理时间、蒸汽流速、麸皮水分含量4个因素对过热蒸汽降解麸皮中脱氧雪腐镰刀菌烯醇(deoxynivalenol, DON)的影响。结果表明,过热蒸汽处理可以显著降低赤霉病小麦麸皮中的DON含量,蒸汽温度240℃、处理时间10 min、蒸汽流速3 m/s、麸皮水分含量10%时,DON降解率达到最高值91.12%;在一定范围内提高蒸汽温度、延长处理时间、增大蒸汽流速均可以显著提高DON降解率(P<0.05),而水分含量升高则会显著降低降解率。     

电化学氧化降解湿态玉米酒精糟中脱氧雪腐镰刀菌烯醇

脱氧雪腐镰刀菌烯醇(deoxynivalenol, DON)是粮食中常见的一种次生代谢产物,对人类和牲畜的健康有许多不良影响。该实验采用高效液相色谱法(high performance liquid chromatography, HPLC)检测DON的含量变化,探究了电化学氧化法(electrochemical oxidation,EO)对DON纯品以及玉米酒精糟(wet distillers grains with solubles broths,WDGS)中DON的降解效果。结果表明,DON降解率与处理时间及电压呈正相关,1.2 V电压处理DON溶液60 min,降解率可达76.4%,且反应遵从一级动力学反应过程。当NaCl添加量为0.2 mol/L时,可达最佳降解效果。此外,处理60 min后受污染的WDGS中DON的降解率为43.28%,加入电解质有利于提高降解率。玉米酒精糟中粗蛋白质和脂质含量在电解前后没有显著变化。因此,电化学氧化可作为发酵工业中去除发酵残渣中DON的有效方法。     

二氧化氯对玉米乙醇发酵糟液中脱氧雪腐镰刀菌烯醇的降解

脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON)是造成粮食污染的主要原因之一。采用高效液相色谱-质谱联用(HPLC-MS)对DON含量进行检测分析,通过液体浸泡法,探究了ClO_2对DON纯品以及玉米乙醇发酵糟液中DON的降解效果。结果显示:DON降解率随ClO_2溶液浓度的增大以及处理时间的延长而提高,且pH值对DON降解有影响。当pH值为4. 5～5. 5时,600 mg/L ClO_2溶液对DON纯品处理12 h,降解率为28. 23%,并产生了2种降解产物;该方法同样适用于玉米乙醇发酵糟液中DON降解,600 mg/L的ClO_2溶液对玉米发酵糟液处理12 h,降解率达40. 70%,降解效果较好,对处理乙醇发酵工艺中的DON或其他真菌毒素具有一定的指导意义,为大规模生产中对DON的去除提供了新的思路。     

挤压降解赤霉病小麦麸皮中DON

挤压赤霉病小麦麸皮,采用高效液相色谱法检测挤压前后麸皮中脱氧雪腐镰刀菌烯醇(DON)含量,研究机筒温度、麸皮水分含量、主机频率和喂料机频率对DON降解率的影响。结果表明:当试验机筒温度170℃时,DON降解率最高为11.96%;当水分含量为24%时,DON降解率最高为14.21%;当主机频率为10 Hz时,DON降解率最高为12.47%;当喂料机频率为8 Hz时,DON降解率最高为14.56%。提高机筒温度,降低麸皮水分含量、主机机频率和喂料频率,可以提高麸皮中DON降解率。     

响应面法优化多聚原飞燕草素超声波降解工艺及其抗氧化性的研究

研究从杨梅叶中提取制备多聚原飞燕草素,并采用HPLC-DAD-ESIMS等方法对其结构进行了表征。利用单因素实验分析了超声时间、温度等超声波处理条件对多聚体的降解规律。在此基础之上,通过Box-Behnken响应面试验研究了超声波降解多聚原飞燕草素的条件,并采用DPPH·法和ABTS·+法比较了降解前后的抗氧化活性。结果表明制备的多聚原飞燕草素提取率为5.96%,平均聚合度为27.8,其结构组成主要为EGCG。超声波处理不同条件均对多聚体的降解有影响作用,其中主要影响因素为时间、温度、功率与占空比（P<0.05）。通过Box-Behnken响应面试验确定的最优降解条件为超声时间74 min,温度44 ℃,超声功率361 W,脉冲占空比67%,对应小分子的低聚原花色素得率为17.31%。超声波处理后多聚原飞燕草素相比处理前抗氧化活性显著提高（P<0.01）。     

赤霉病对小麦品质影响的研究

选取2012年江苏产硬质白小麦,制备不同赤霉病含量的小麦样品,探讨不同赤霉病含量对小麦籽粒品质、小麦粉品质影响程度,以及由小麦赤霉病病原菌分泌产生的脱氧雪腐镰刀菌烯醇(DON毒素)在小麦籽粒中积累分布情况。实验结果表明,随着小麦样品中赤霉病麦含量的升高,涉及小麦籽粒品质、小麦粉品质的主要指标明显下降;同时DON毒素在小麦籽粒中积累分布,皮层中含量明显高于胚乳(小麦粉)中的含量。     

清理和制粉工艺对去除污染小麦中DON效果及其小麦粉品质的影响

通过检测小麦清理工艺中各步骤的小麦和6种污染程度不同的小麦实验制粉后各粉路的DON含量,研究清理和制粉对小麦中DON的去除效果;通过检测污染前后小麦籽粒及其小麦粉的品质指标的变化,研究赤霉病对小麦及小麦粉食用和加工品质的影响。结果表明:清理和制粉均对DON有很好的去除效果,赤霉病感染小麦的加工和食用品质均下降,并随着污染程度的加深,品质越来越差。经过清理后,小麦中的DON含量由初始的1.56mg/kg下降到1.18mg/kg,DON去除率达24.36%,其中擦皮除菌机和色选机的清理效果最佳。6种污染程度不同的小麦实验制粉后,DON均有不同程度的去除,最高可达46.96%,轻度污染的小麦制粉后可达到国家产品安全标准要求。小麦中DON主要集中在小麦皮层部分,从外到内依次降低,小麦中心胚乳的DON含量最低;赤霉病对小麦及小麦粉的品质有较大影响,使小麦籽粒内部结构疏松,小麦粉烘焙品质和流变学特性也逐渐下降。     

超声波处理提高谷朊粉溶解度的工艺条件

以谷朊粉为原料,研究了利用超声波处理对谷朊粉溶解度的改善作用,通过pH值、离子强度、脉冲振幅、超声时间、脉冲on值和off值对谷朊粉溶解度的影响,确立了四因素三水平的正交试验,探讨了超声波处理提高谷朊粉溶解度的最佳条件。结果表明：各因素对提高谷朊粉溶解度的明显程度依次为脉冲振幅＞脉冲on值和off值＞超声时间＞pH值。正交试验分析表明,超声波处理提高溶解度的最佳作用条件为pH4.5、脉冲振幅60%、超声时间为120s、脉冲on值和off值分别为40s和20s。在最佳条件下,谷朊粉的溶解度为51.12mg/ml,与未处理时相比,溶解性提高到18.4倍,拓宽了谷朊粉的应用范围。     

TiO2-超声协同降解水中乙酰甲胺磷的研究

采用自制的TiO2为催化剂,探讨TiO2-超声协同降解水中低质量浓度乙酰甲胺磷的作用。考察处理温度、pH值、超声声强、TiO2加入量及TiO2-超声协同作用对乙酰甲胺磷降解率的影响。结果表明:在5～20℃之间、超声1h以内,温度越高,超声时间越长,乙酰甲胺磷的降解率越高;pH值为3.0的偏酸环境有利于乙酰甲胺磷的降解;在一定范围内,TiO2加入量与乙酰甲胺磷降解率呈正相关;当超声功率为40W/cm2时,有利于乙酰甲胺磷降解率的提高;且超声与TiO2对于乙酰甲胺磷的降解有一定的协同作用,当温度20℃、pH值3.0、超声频率25kHz、声强40W/cm2、TiO2加入量0.6g/L时,经过50min超声降解,质量浓度为2mg/L的乙酰甲胺磷降解率可达78.3%。     

Immunoassay based on monoclonal antibodies versus LC-MS: deoxynivalenol in wheat and flour in Southern Brazil

An indirect competitive enzyme-linked immunosorbent assay (ELISA) method using a monoclonal antibody for deoxynivalenol (DON) detection in wheat and flour was standardised and validated (detection limit?=?177.1?μg?kg(-1)) and its performance was compared with LC-MS, quantification limit?=140?μg?kg(-1)). DON recovery ranged from 88.7% to 122.6% for wheat grain and from 70.6% to 139.3% for flour. Among the 38 wheat samples evaluated, DON was detected in 29 samples (76.3%) by ic-ELISA (281.6-12?291.4?μg?kg(-1)) and in 22 samples (57.9%) by LC-MS (155.3-9906.9?μg?kg(-1)). The 0.93 correlation coefficient between ic-ELISA and LC-MS data in 19 positive DON wheat samples demonstrated the reliability and efficiency of ic-ELISA. Results indicated that standardised ic-ELISA was suitable for DON screening in wheat samples and the need for continuous monitoring of mycotoxin levels in foodstuffs.     

小麦麸皮总黄酮超声提取工艺研究

以小麦麸皮为原料,乙醇为提取溶剂,对超声波辅助提取小麦麸皮总黄酮工艺进行研究。考察了超声功率、提取时间、乙醇浓度、料液比、提取次数等因素对小麦麸皮总黄酮得率的影响,并通过正交试验对总黄酮的提取工艺进行优化。结果表明,小麦麸皮总黄酮最佳提取工艺为:超声功率600 W,提取时间30 min,乙醇浓度60%,料液比1∶20,提取两次,在最佳条件下总黄酮得率为2.29%。     

Immunoassay based on monoclonal antibodies versus LC-MS: deoxynivalenol in wheat and flour in Southern Brazil

An indirect competitive enzyme-linked immunosorbent assay (ELISA) method using a monoclonal antibody for deoxynivalenol (DON) detection in wheat and flour was standardised and validated (detection limit?=?177.1?µg?kg^?1) and its performance was compared with LC-MS, quantification limit?=140?µg?kg^?1). DON recovery ranged from 88.7% to 122.6% for wheat grain and from 70.6% to 139.3% for flour. Among the 38 wheat samples evaluated, DON was detected in 29 samples (76.3%) by ic-ELISA (281.6–12?291.4?µg?kg^?1) and in 22 samples (57.9%) by LC-MS (155.3–9906.9?µg?kg^?1). The 0.93 correlation coefficient between ic-ELISA and LC-MS data in 19 positive DON wheat samples demonstrated the reliability and efficiency of ic-ELISA. Results indicated that standardised ic-ELISA was suitable for DON screening in wheat samples and the need for continuous monitoring of mycotoxin levels in foodstuffs.     

The prevalence of deoxynivalenol and its derivatives in the spring wheat grain from different agricultural production systems in Lithuania

Deoxynivalenol (DON) together with two acetylated derivatives, 3-acetyldeoxynivalenol (3-ADON) and 15-acetyldeoxynivalenol (15-ADON) occurs in cereal grains and their products. Co-occurrence of DON and acetylated derivatives in cereal grain is detected worldwide. Until now, DON and its derivatives have been considered equally toxic by health authorities. In this study, we analysed 103 samples of spring wheat grain, originating from the fields of different production systems in Lithuania, for the co-occurrence of type-B trichothecenes (DON, 3-ADON, 15-ADON). The samples were classified according to the production system—organic, sustainable and intensive. Mycotoxin levels in the spring wheat grain samples were determined by the HPLC method with UV detection. The type-B trichothecenes were found to be present at higher concentrations in the grain from the intensive production system. Eighty-one percent of the spring wheat grain samples from the intensive production system were co-contaminated with a combination of DON+3-ADON+15-ADON, 1% with DON+3-ADON. Additionally, DON+15-ADON and DON were found in 5% and 10% of the tested samples, respectively. Two percent of the samples were free from mycotoxins. In the grain samples from the sustainable production system, DON and a combination of DON+3-ADON showed a higher incidence – 47% and 23%, respectively. The samples with a combination of DON+3-ADON+15-ADON accounted for 18%. Completely different results were obtained from the analyses of organic grain samples. A large number of the organic spring wheat grain samples were contaminated with DON+3-ADON (55%) or DON (36%). The combination of DON+3-ADON+15-ADON was not present, while DON+15-ADON was present in 9% of the samples tested. The production systems did not lead to significant differences in mycotoxin levels, although a trend toward higher incidence and higher contamination was observed for the samples from the intensive and sustainable production systems.     

Effect of gaseous ozone treatments on DON,microbial contaminants and technological parameters of wheat and semolina

Deoxynivalenol (DON) is an important mycotoxin produced by several species of Fusarium. It occurs often in wheat grain and is frequently associated with significant levels of its modified form DON-3-glucoside (DON-3-Glc). Ozone (O₃) is a powerful disinfectant and oxidant, classified as GRAS (Generally Recognised As Safe), that reacts easily with specific compounds including the mycotoxins aflatoxins, ochratoxin A, trichothecenes and zearalenone. It degrades DON in aqueous solution and can be effective for decontamination of grain. This study reports the efficacy of gaseous ozone treatments in reducing DON, DON-3-Glc, bacteria, fungi and yeasts in naturally contaminated durum wheat. A prototype was used to dispense ozone continuously and homogeneously at different concentrations and exposure time, in 2 kg aliquots of durum wheat. The optimal conditions, which do not affect chemical and rheological parameters of durum wheat, semolina and pasta, were identified (55 g O₃ h^?1 for 6 h). The measured mean reductions of DON and DON-3-Glc in ozonated wheat were 29% and 44%, respectively. Ozonation also produced a significant (p < 0.05) reduction of total count (CFU/g) of bacteria, fungi and yeasts in wheat grains.     

Fluorescence polarization as a tool for the determination of deoxynivalenol in wheat.

The mould Fusarium graminearum is found worldwide as a pathogen of cereal grains, in particular of wheat and maize, and it produces a mycotoxin known as deoxynivalenol (DON or vomitoxin). Each year, the presence of this compound and related trichothecenes causes substantial losses to agricultural productivity. Rapid methods for the measurement of the toxin in grains are required to monitor and divert effectively contaminated grain from the food supply. A fluorescence polarization (FP) immunoassay using a previously described monoclonal antibody for DON was developed. The assay was based on the competition of unlabeled DON from a sample with a fluorescently tagged DON, DON-fluorescein (DON-FL), for a DON-specific monoclonal antibody in solution. The FP of the tagged DON was increased upon binding with the antibody. In the presence of free toxin, less of the DON-FL was bound and the polarization signal was decreased. The assays were very simple to perform, requiring only mixing of an aqueous extract of wheat with the DON-FL and antibody. The sensitivity of the assay was strongly dependent upon the time between mixing of the sample with the tracer and measurement of the fluorescence polarization, with midpoints for the competition curves ranging from 0.03 microg ml(-1) with a 15-s incubation to >1 microg ml(-1) with a 12-min incubation. Samples of wheat naturally contaminated with DON were evaluated by FP and by an HPLC-UV method, with a good correlation (r2 = 0.97). Although the FP method tended to overestimate DON slightly in the wheat samples, by approxiamtely 20%, the assay was easy to use and very useful for the screening of wheat.