小麦受蛀蚀性害虫侵害后品质变化机理及危害度预测研究

The FAO survey data indicate that the post-harvest losses of grain is about 10%, and the loss caused by pests is over 50% of total loss during grain storage. The existed researching results showed that decay pests not only result in the grain quantity loss, but also cause the deterioration of grain quality, furthermore, the fumigant-abusing and improper fumigation time lead to a serious problems such as the resource wasting, ecological environment pollution and harmful to human health as well. This project is based on the previous researches, and took decay pests as the research object, the effects of the pests growing stages and its metabolite changes on wheat end-use quality will be analyzed according to the biological characteristics of decay pests. Using detection technology such as chromatography, electrophoresis, mass spectrometry, Raman spectrum, scanning electron microscope, the changes of cells structure, nutrition composition, physiological metabolizing of wheat after pests damaging will be investigated to explore the internal mechanism of wheat quality variation after pests damaged based on the molecular and cellular levels. Combined with the concept of green ecological civilization, and exploring the correlation of wheat quality variation after pests damaged and wheat storage security, the hazardous prediction model of pests damage degree of wheat will established based on above to search the critical point that have a significant impact on wheat quality caused by pests, to guide the ways of the scientific pests prevention and control, and to improve on the earlier prediction theory of stored grain pest activity, finally to realize the subjective of the scientific green storage and construction of ecological civilization society in China.

世界粮农组织调查显示粮食收获后的损失约为10%，其中储粮害虫造成的损失约占储粮损失的50%。已有研究表明：蛀蚀性害虫不仅造成粮食数量损失，而且还可引起粮食品质的劣变，同时滥用熏蒸剂及熏蒸时机不当又会带来资源浪费、生态环境污染以及危害人体健康等问题。本项目在前期研究的基础上，以蛀蚀性害虫为研究对象，根据害虫的生物学特性，分析蛀蚀性害虫不同生长发育阶段与代谢产物的变化对小麦最终使用品质的影响。利用色谱、电泳、质谱、拉曼光谱、电镜扫描等检测技术，研究害虫蛀食后小麦细胞结构、营养组分、生理代谢等变化，从分子和细胞水平探索虫蚀小麦品质变化的内在机理。结合绿色生态文明理念，探索虫蚀小麦品质变化与小麦储藏安全的相关性，据此建立虫蚀小麦危害度预测模型，找出由害虫侵害引起小麦品质产生显著影响的临界点，指导科学防治害虫，完善储粮虫害活动早期预测理论，实现我国绿色科学储粮和建设生态文明社会的目标。

蛀蚀性害虫是造成粮食产后损失的主要原因，其危害不仅造成粮食数量损失，还可导致品质的劣变，同时滥用熏蒸剂及熏蒸时机不当又会带来资源浪费、环境污染和健康危害等问题。课题在建立的害虫侵害实验平台上，以正常小麦为对照，研究蛀蚀性害虫（米象、玉米象和谷蠹）不同生长发育阶段的侵害，对小麦籽粒的微观结构、研磨特性、理化特性及小麦粉的流变学、凝胶质构及糊化特性、馒头和面条加工品质的影响；对小麦蛋白、淀粉及脂质代谢和酶促防御系统的破坏；从分子水平揭示虫蚀小麦品质变化机理，建立小麦品质危害度预测模型，找到害虫侵害显著影响小麦品质的临界点。其结果如下：.利用响应面法确定了3种蛀蚀性害虫的最佳接种条件和取样时间；研究发现随着害虫的生长发育，小麦硬度、出粉率、粗淀粉含量、小麦粉白度均下降，破损淀粉含量、溶解度、膨胀势、析水率、透光率和吸水率均增大，小麦淀粉颗粒表面出现凹痕，蛋白结构的完整性受到破坏；小麦淀粉及全麦粉的糊化特性、小麦的氨基酸、脂肪酸的组成、-SH和-S-S-含量及蛋白、淀粉的二级结构受到影响；高分子量蛋白质明显减少，快消化淀粉增加，抗性淀粉、支链淀粉的重均分子量含量减少，直链淀粉的重均分子量先增后减；馒头的比容升高，色泽、粘性、韧性、气味和食味评分均呈下降趋势。全麦粉面条的蒸煮损失率和断条率升高，质构特性变劣，各品质变化表明3种害虫在蛹期对小麦品质影响最大。蛀蚀小麦品质变化的敏感指标为脂肪酸值和降落数值，建立的不同蛀蚀性害虫对小麦危害度预测模型表明：感染10头/kg害虫（米象、玉米象和谷蠹）在28℃±1℃、70%±5%RH的条件时，小麦品质分别在90d、90d和105d时达到重度不宜存。.课题提示了虫蚀小麦品质变化规律及其机理，筛选的敏感指标和建立的危害度预测模型，可准确地判断储粮害虫对小麦的危害度，实现了对储粮的安全性评价，完善了储粮虫害活动早期预测理论，达到了减少粮食产后损失，实现绿色储粮和保护生态的战略目标。