小麦储藏水分、温度和真菌生长危害进程预测的研究

对小麦储藏水分、温度、真菌最初生长时间和危害进程进行了初步探索性研究。采用喷雾着水方法将样品水分调至13.2%、13.6%、14.0%、14.5%、15.1%、15.5%、16.9%,分别于10、15、20、25、30、35℃恒温箱模拟储藏,定期检测各样品真菌生长变化情况,周期为120 d。结果表明,小麦在不同温度储藏,随着温度增加,真菌生长速度加快,30℃时达到最高,35℃时生长速度降低。在6个试验温度中,从安全和经济角度评价,最佳储藏温度为20℃;16.9%水分的小麦,由于出现一些青霉生长,即使低温储藏,这个水分仍存在着较大风险;根据上述研究结果,研究首次提出了小麦储藏水分、温度和真菌最初生长关系曲线,小麦在不同温度下储藏,真菌危害进程所需的时间。由于储粮真菌生长影响因素的复杂性,本试验数据仅供参考。     

高温储藏条件下不同水分含量小麦品质变化研究

以开麦21为原料,对其进行鼓风干燥和调质处理,使其水分含量分别为12.5%,9.5%,7.7%和5.9%,在35℃下密封储藏,研究其储藏过程中生活力、电导率、过氧化氢酶活动度、湿面筋含量、干面筋含量和面筋吸水率的变化,探讨高温密闭储藏下小麦的水分含量与其储藏品质变化的规律。结果表明:35℃条件下,水分含量高的小麦其生活力、过氧化氢酶活动度、湿面筋含量和面筋吸水率降幅大;水分含量为7.7%的小麦电导率增幅最小。     

稻谷储存水分和温度对真菌生长和稻谷主要品质的影响

研究水分、温度对稻谷储存过程中真菌生长和主要储存品质的影响。将稻谷设为含水量分别为12.1%、13.1%、14.0%、15.1%、16.0%的样品,分别置于10、15、20、25、30、35℃温度条件下模拟储存180 d后,检测稻谷样品中真菌生长、发芽率和脂肪酸值的变化。结果表明,水分是真菌生长的决定因素,13.1%水分处于真菌生长临界水分以下,即使温度适宜真菌也不生长;14.0%处于真菌生长临界水分以上,水分越高越利于真菌孢子萌发生长,温度越高真菌生长速度越快;脂肪酸值受真菌生长的影响程度要大于水分和温度,13.1%以下水分稻谷,没有真菌生长,脂肪酸值上升缓慢。14.0%以上水分稻谷,一旦真菌生长,就会加速脂肪酸值的升高;发芽率受温度影响程度最大,高温储存半年,无论是否有真菌生长,发芽率基本降为0,低温储存不仅能抑制真菌生长还利于保持种子发芽率。     

淀粉对高水分挤压组织化小麦蛋白产品特性的影响

研究小麦淀粉、马铃薯淀粉、玉米淀粉的添加量对高水分挤压组织化小麦蛋白产品特性的影响。以小麦蛋白为主要原料,采用高扭矩双螺杆挤压装备开发高水分组织化小麦蛋白,并分析了组织化蛋白色泽品质(L~*、a~*、b~*、ΔE)、质构特性(组织化度、硬度、黏着性、弹性、聚结性、咀嚼度)以及感官评价。结果表明:小麦淀粉、玉米淀粉的添加均可显著提高组织化蛋白产品的色泽品质,马铃薯淀粉的添加对组织化蛋白色泽品质影响不显著。淀粉的添加可显著提高组织化蛋白的组织化度。随着淀粉添加量的增加,组织化蛋白质构特性(硬度、弹性、聚结性、咀嚼度)均逐渐降低。添加适量小麦淀粉(5%)、玉米淀粉(5%)均可提高组织化蛋白感官品质,马铃薯淀粉的添加会降低感官品质。综合考虑组织化蛋白色泽品质、组织化度、质构特性和感官品质,添加小麦淀粉(5%)或玉米淀粉(5%)较合适,不仅达到了降低生产成本的目的,而且提高了组织化蛋白色泽品质、组织化度和感官品质。     

A comparison of the functional characteristics of wheat stored as grain with wheat stored in spike form

In this study, wheat grain and wheat spike with 12%, 14% and 16% moisture content were stored at 10, 20 and 30 °C for 0, 3, 6 and 9 months. After storage, wheat samples were investigated for hectolitre weight, gluten content, Zeleny sedimentation volume, enzyme activity, acidity, phytic acid and L colour value. Storage of wheat at different storage forms (spike and grain) and storage conditions showed considerable changes in grain quality. In general, the storage period of 3 months positively affected wheat quality. However, hectolitre weight, gluten, Zeleny sedimentation, enzyme activity, acidity and colour of wheat got worse at storage periods beyond 3 months. Hectolitre weight, wet and dry gluten, Zeleny sedimentation, phytic acid content and L Colour value of wheat stored in both spike and grain form significantly decreased during storage. However, the increase in grain moisture content, storage time and temperature resulted in significant increase in total titratable acidity and falling number values of wheat. Falling Number and phytic acid values of wheat stored in spike form were generally lower than wheat stored in grain form. Storage in spike form had a positive effect on especially wet gluten content of wheat stored at non-optimal storage conditions such as high grain moisture content and high temperature. Wet gluten of wheat stored in spike form was higher than that of wheat stored grain form after storage at 30 °C for 6 and 9 months. Wheat stored in spike form is more resistant than wheat stored in grain form against adverse storage conditions such as high moisture content and temperature and longer storage time.     

Effect of gamma-ray irradiation on modeling equilibrium moisture content of wheat

ABSTRACT:  The experimental research found that gamma irradiation dose affected the equilibrium moisture content of wheat at the same relative humidity and temperature of ambient. Values of the equilibrium moisture content decreased with an increasing dose of γ-ray irradiation during both adsorption and desorption. These were due to the changes of wheat starch granules and their water bound ability caused by different irradiation doses. Factor of irradiation dose was added in 3 widely used models for modeling the equilibrium moisture content of irradiated wheat, and the parameters in models were estimated based on the experimental data. Based on the study of correlation coefficient, mean relative error, and standard error the modified Chung–Pfost equation and the modified Henderson equation were found to fit the desorption and adsorption isotherms for wheat, respectively, in the range of experiment at conditions studied.     

Effect of fungicides on the development of Fusarium head blight,yield and deoxynivalenol accumulation in wheat inoculated under field conditions with Fusarium graminearum and Fusarium culmorum

The effect of different fungicide treatments on Fusarium head blight (FHB) development, grain yields and deoxynivalenol (DON) accumulation in wheat was evaluated after artificial inoculation under field conditions with a mixture of Fusarium graminearum and F culmorum. The trials were carried out using commercially available products on five different cultivars of soft and durum wheat (Serio, Genio, Bracco, Duilio and Orobel) in two separate experimental fields located in the North of Italy. Treatments with Tiptor^® S (cyproconazole plus prochloraz) and a mixture of Horizon^® 250 EW (tebuconazole) plus Amistar^® 250 SC (azoxystrobin) significantly reduced the FHB disease severity (by between 25 and 77%) and DON content (by between 32 and 89%) in the grain as compared with the inoculated control. Yields (tonne ha^?1) and thousand grain weight (TGW) were higher in plots subjected to fungicide treatments. Tetraconazole (Eminent^® 40 EW) showed a markedly reduced effectiveness compared with the other treatments. Regression analysis showed a strong correlation of disease severity with DON levels (positive correlation) and with yields or TGW (negative correlation) for individual cultivars and locations. Fusarium graminearum, F culmorum and F poae were the species most commonly isolated from all trials, including inoculated and non‐inoculated control plots. Copyright © 2004 Society of Chemical Industry     

微波干燥对高水分稻谷中优势霉菌致死率的研究

研究了高水分稻谷中分离纯化的优势霉菌,以及探讨了微波工艺对染单一优势霉菌稻谷的菌落活性及后期储藏期间菌落数的影响。研究发现,从高水分稻谷中分离纯化分析得出优势霉菌是:链格孢霉、雪腐镰刀菌、白曲霉、灰绿曲霉、产黄青霉。然后在微波功率485、927和1349 W对染单一优势菌稻谷进行灭菌处理,发现稻谷表面霉菌降低约3 lg CFU/g,内部霉菌致死率约95%,同时随着微波时间的延长,受优势菌侵染的稻谷表面及内部霉菌数量均降低,致死率上升。此外通过微波工艺对杀菌后的稻谷侵染单一优势菌,以常规热风处理为对照组进行储藏,发现微波处理后稻谷霉菌生长量明显低于常规热风储藏的稻谷,有益于粮食长时间储藏。因此本文研究了微波工艺对高水分稻谷优势霉菌致死率及后期储藏的影响,为高水分粮食安全储藏提供一定的理论基础。     

大豆储藏真菌危害早期预测的研究

对大豆储藏中水分和温度的变化,与真菌生长关系进行了研究,建立了一种大豆真菌危害早期预测方法。将样品含水量分别调至11.4%、12.1%、13.0%、13.9%、14.3%和14.7%,经低温平衡后,于10、15、20、25、30、35℃温箱中储藏,每隔10 d取样1次,检测样品中真菌生长变化情况,试验周期为180 d。结果表明,11.4%水分大豆在6个试验温度下储藏均是安全的,12.1%水分样品在20℃以上储藏,检出有真菌生长,随着水分增加,真菌生长逐渐加快,大豆储藏水分与真菌生长速度具有良好的相关性。大豆在15℃以下储藏,低温对真菌生长有明显的抑制作用。超过20℃时这种影响会随着温度上升逐步变小。本试验对不同水分大豆储藏温度与真菌生长起始时间进行了幂函数拟合,得到了大豆储藏水分、温度,及真菌起始生长时间预测关系曲线,通过本曲线,可对高水分大豆短期储藏安全性进行早期预测。     

片烟贮藏期霉菌的分子鉴定及杀菌剂的室内毒力测定

对108个霉变烟叶样品进行霉菌分离、纯化、保存,获得5种病原真菌的纯培养,通过病原菌的显微镜检鉴定,观察霉菌形态特征、测定孢子大小,并提取真菌DNA,对18S rDNA的ITs进行PCR扩增并克隆产物,测定序列后,通过BLAST搜索比对,确定5种霉菌为镰刀菌(Fusarium sp.)、米曲霉(Aspergillus oryzae)、土生曲霉(Aspergillus terreus)、黑曲霉(Aspergillus niger)、桔青霉(Penicillium citrinum)。在药剂试验中,选用75%达科宁、40%核星、10%世高、100%富马酸二甲酯等药剂测试对烟草霉菌的抑制效果。通过室内生物测定,40%核星的抑菌谱和抑菌效果最好,在浓度为130.32 mg/kg时,对5种霉变微生物的抑制率均达95%以上。     

Evaluation of postharvest preservation strategies for stored wheat seed in Ethiopia

Limited information exists on postharvest preservation strategies of stored wheat in Ethiopia. The present study was conducted to evaluate the effectiveness of on-the shelf postharvest storage strategies of stored wheat in the country. The experiment consisted of eight treatments; (1) metal silos, (2) Purdue Improved Crop Storage (PICS) bags, (3) Super GrainPro bags, (4) industrial filter cake dust applied to wheat in polypropylene bag, (5) plastic drums, 6) Triplex applied to wheat in polypropylene bag, 7) Triplex applied to wheat in plastic drum, and 8) polypropylene bag as control. Measurements of oxygen and carbon dioxide levels, live adults of insects per kg, percentage seed damage, and percentage of weight loss, germination and seedling vigor were determined every two months for six months. Results indicated that storage strategies such as PICS and Super GrainPro bags, filter cake, Triplex, and plastic drums led to a significantly lower live insect density compared to the control. Besides, Triplex and filter cake dust or use of hermetic bags also resulted in a significantly lower rate of seed weight loss (%) compared to the control. After six months of storage, means ± SD germination of seed from the polypropylene bag (control) had decreased to 68.0 ± 6.1% while wheat in all other storage strategies exhibited means ± SD germination capacity ranging from 92.0 ± 3.6% to 98.0 ± 1.0%. The present results demonstrate the potential of preserving stored wheat without relying on synthetic insecticides by using hermetic bags, filter cake, and Triplex, with advantages over traditional strategies used by smallholder farmers in Ethiopia. We recommend that hermetic bags, filter cake dust, and Triplex powder should be promoted for use by farmers for the postharvest preservation of their stored wheat.     

Characteristics of carbon dioxide sorption by stored wheat

The sorption of carbon dioxide gas (CO₂) by wheat was determined in glass flasks at four temperatures (0, 10, 20 and 30 °C) and four moisture contents (m.c.) (12, 14, 16 and 18% wet basis). The gaseous concentrations were analyzed by gas chromatography and the vacuum developed from the sorption of CO₂ by wheat was measured with a mercury manometer. The calculated amount of CO₂ sorted at equilibrium was a non-linear function of both temperature and moisture content. Sorption of CO₂ by wheat decreased with increasing temperature from 0 to 30 °C at 14% m.c., and the initial rate of sorption increased with increasing m.c. from 12 to 18% at a temperature of 20 °C. Sorption was modelled using non-linear regression at two conditions (0–30 °C at 14% moisture content and 12–18% moisture content at 20 °C). The maximum mass of CO₂ sorbed in 60 h was 0.510 g/kg of wheat at 18% m.c. and 0 °C and the lowest was 0.224 g/kg at 18% m.c. and 30 °C. A linear relationship existed between the initial CO₂ concentration and the concentration after 60 h when 250 g of wheat of 14% m.c. at 20 °C was exposed in 500 ml flasks.     

储存水分、温度和真菌生长对大豆品质的影响

研究大豆储存过程中水分、温度和真菌生长对其品质的影响。采用11.2%、11.8%、12.7%、13.9%和14.7%水分的大豆,分别置于10、15、20、25、30、35℃下模拟储存,周期180 d,检测储存真菌、发芽率和脂肪酸值的变化情况。结果表明,大豆储存中,真菌生长受储存水分和温度的影响,水分是决定真菌生长的主要因素,而温度影响真菌生长速度。真菌生长临界水分(11.8%左右)以下储存,种子发芽率和脂肪酸值主要受温度的影响,20℃以下低温储存能维持较高的发芽率,30℃以上储存会加剧脂肪酸值升高。真菌生长临界水分以上储存,种子发芽率和脂肪酸值受真菌生长和温度协同作用的影响,大豆储存水分越高,真菌生长越快,即使低温也会在一定程度上导致大豆品质劣变。     

Dough characteristics of wheat flour milled from wheat grains stored in spike form

This study compares the effects of storage form (grain and spike) of wheat as well as grain moisture content (12%, 14% and 16%), storage time (0, 3, 6 and 9 months) and temperature (10, 20 and 30 °C) on rheological (farinograph and extensograph) characteristics of dough obtained from stored wheat. While water absorption, stability and degree of softening of wheat stored in spike form were 61.2%, 15.8 min and 25.9 Brabender unit (BU), these values of wheat stored in grain form were 60.8%, 14.1 and 29.1 BU, respectively. Resistance to extension and dough energy of wheat stored in grain form were significantly higher than those of wheat stored in spike form, while extensibility was significantly lower. Storage in spike form had a positive effect on all farinograph and extensograph characteristics of wheat stored under nonoptimal storage conditions such as high grain moisture content, high temperature and long storage time.     

The effects of grasshopper carcasses as dockage in stored wheat

In years of high grasshopper field populations, large numbers may be collected with harvested grain and deposited into storage. Little is known about the impact of grasshopper carcasses on stored-wheat quality; therefore, this study was conducted to determine such effects. Ninety-six glass bottles (237 mL capacity) were filled with 120 g of clean No. 1 wheat conditioned to 14.5% or 15.5% moisture content. Two-striped grasshoppers, Melanoplus bivittatus were collected in the summer of 2004 near Elie, MB, Canada and euthanized. Six grams of whole grasshoppers were mixed into half the bottles of each moisture content. All bottles were sealed and 12 bottles with and without grasshoppers were incubated at 25 °C and 50% relative humidity (r.h.), 25 °C and 75% r.h. 30 °C and 50% r.h. and 30 °C and 75% r.h. for 24 wk. Four bottles with and without insects were assessed every 4 wk for fat acidity value, seed microfloral infection and germination. The experiment was repeated and data pooled for statistical analysis (ANOVA). Significant differences (P < 0.05) arose between grasshopper and control treatments. Mean fat acidity values for wheat reached 32.99 mg KOH/100 g with grasshoppers compared to 25.23 mg KOH/100 g without carcasses. Initial seed germination of 98% rapidly declined to below 20% with grasshoppers between 4 wk and 8 wk; the majority of seeds were dead in the 75% r.h. treatments by 12 wk. Mean infection by the post-harvest fungi, Aspergillus glaucus group with grasshoppers ranged from 80.5 to 92% compared to 25–79.8% in controls. Penicillium spp. infection at 25 °C and 75% r.h. was 16.8% with grasshoppers and 4.2% without. Results from this experiment clearly demonstrate that the presence of grasshopper carcasses in stored wheat has negative consequences on grain quality. The implications of our research are discussed with respect to harvest practices and climate change.     

基于BP神经网络的仓储小麦的生理生化指标预测

BP神经网络算法在粮食仓储领域拥有巨大的应用价值和潜力。本研究尝试将BP神经网络引入仓储小麦品质预警模型,以天津储粮抽检数据为对象,通过对室内温度的记录,样品水分、淀粉、蛋白质等11项生理生化指标的定期检测,利用BP神经网络算法进行仓储小麦的品质预测与影响分析。仿真结果表明,基于BP神经网络的数据预测方法具有较小的过程误差和较高的结果准确性,为仓储小麦的品质预测提供了一种有效的研究方法。     

Effective nitrogen preservation during urine collection from Holstein heifers fed diets with high or low protein content

Six Holstein heifers (body weight = 535-625 kg) fed a total mixed ration containing either high protein (13.4%) or low protein (9.0%) were used to evaluate the effect of 3 urine collection methods (chilled, acidified before collection, or acidified after 6 h of collection) on urinary N preservation. In a 2-period crossover design, 16-d diet adjustment stages preceded five 24-h collections. Urinary catheters were inserted 1 d before the collection periods. Urine collection tubes were configured to split urine to 3 collection containers: 1 acidified with 6 N HCl before collection at a rate calculated to reduce pH to below 2, 1 acidified every 6 h during collection to pH below 2, and 1 located in a large cooler of ice. Collection method did not affect urinary concentration of N or urine urea-N (9.2 ± 0.9 g/L and 6.58 ± 0.9 g/L, respectively) or urinary excretion of N or urea-N (82 ± 3.8 g/d and 59.5 ± 3.8 g/d, respectively). These 3 collection methods are equally effective in preserving N during urine collection, but the “chilled immediately” approach may be useful for studies focused on ammonia emission. Urinary and fecal N excretion were significantly different across collection days; fecal N was more highly variable than urinary N. Intake and apparent N digestibility decreased during the collection week, and excretion of urinary and fecal N increased, particularly on d 5. (Stable rectal temperatures suggested no urinary infections.) Improvements in total collection methodology will support continued progress in the understanding of livestock N utilization and post-excretion changes in manure N.     

芝麻种子带菌检测及药剂消毒处理效果

采用吸水纸检测法对我国6个芝麻主产区的13个广泛栽培的芝麻品种进行了带菌检测,并测定了5种杀菌剂对芝麻种子的消毒效果。结果表明,芝麻种子外部携带的真菌主要类群包括镰孢属（Fusarium spp.）、棒孢属（Corynespora spp.）、长蠕孢属（Helminthosporium spp.）、壳球孢属（Macrophomina spp.）、链格孢属（Alternaria spp.）、曲霉属（Aspergillus spp.）和青霉属（Penicillium spp.）,其中引起芝麻茎点枯病的壳球孢属分离频率和带菌率最高。种子内部携带的真菌类群主要包括镰孢属、棒孢属、壳球孢属和曲霉属等,引起芝麻叶枯病的棒孢属真菌分离频率和带菌率最高。供试的5种杀菌剂对芝麻种子均有一定的消毒效果,其中50%扑海因和80%多菌灵处理对芝麻种子消毒效果最显著。     

农户小麦储藏品质评价指标研究

为了探讨农户储粮的品质评价指标,为农户储藏小麦的品质检验与控制提供指导,对取自河南省小麦主产区储藏的3个年份小麦样品质量指标以及储藏品质指标进行测定,筛选能够明显反映出农户小麦储藏品质变化的指标.结果表明,随着储藏时间的延长,发芽率、面筋吸水率作为快速判定农户小麦质量及品质变化的指标灵敏性不高,霉变粒、不完善粒和降落数值随时间变化较大,且与储藏时间呈极显著相关,相关系数分别为0.566、0.837和0.545,在各个指标中尤其是虫蚀率与储藏时间呈极显著相关(r=0.960),虫蚀率变化最为灵敏,且不受其他测定因素的影响,可操作性强,可以直接用来评价农户小麦储藏品质.     

高水分小麦通风干燥过程中加工品质变化规律研究

将刚收获的高水分小麦放置在就仓干燥模拟仓内进行通风干燥,测定小麦粮堆各层水分含量变化,及小麦粗蛋白含量、湿面筋含量、粉质特性、降落值等指标。结果表明：含水量超过20%的小麦在模拟仓中采用纵向通风技术可以在短期内将小麦水分含量降低至安全水分,对其加工品质没有显著不良影响。使用通风技术可有效降低小麦水分含量,但各粮层降水存在一定不均匀性,在实仓干燥中可辅以其他技术予以改善。