Research On Detection For Freshness Of Wheat Based On Delayed Luminescence

Grain security which related to the national economy development and the overall integration of social stability, has laid the foundation for building a harmonious society. Safe store of grain is a vital part of grain security.Inner physiological activities and storage environment have great influence on the grain during storage, with the aging degree of grain rises, the edible quality decreased. Freshness is an important index for detection of grain storage quality, the present freshness detection methods have a series of problems, such as long detection time, poor repeatability and destructive testing. It was time to find a quicker,convenient and non-invasive method for detecting the freshness of wheat.The delayed luminescence from grain is external representation of its inner physiological activity and change of quality which is directly related to grain’s quality and its final utilization. The delayed luminescence detection technology is an advanced green detection technology which not only has the advantages of the sensory evaluation method and biochemical methods, but also has quantifiable objective criteria and belonged to non-destructive testing. The characteristics of the delayed luminescence from wheat during storage are studied, a system based on delayed luminescence was designed for detecting freshness of wheat. Making appropriate arrangements of white LED in order to form a uniform illumination on the test sample surface. Taking STM32 as the core of system, based on the precise control of illumination time,delayed time and acquisition time, the biophoton emission from wheat can be absolutely detected with a high precision single photon counting module. Based on the tool of Visual Basic 6.0, the delayed luminescence test interface has been designed for displaying,processing and storing data.The test wheat sample equaled natural storage years can be obtained by rapid artificial aging. The delayed luminescence of wheat from various breed, different illumination intensity,different illumination time, different temperature and different aging time were detected and analyzed, the results showed that:(1) Cultivar has slightly effect on the delayed luminescence intensity, and the delayed luminescence intensity curves of wheat follow a hyperbolicattenuation trend.(2) The delayed luminescence intensity affected by illumination intensity is extremely significant, with the increasing intensity of illumination,the delayed luminescence intensity gradually increased; To further fitting the test data, the delayed luminescence decay time lasts for consistence at different illumination.(3) For a given illumination intensity,the delayed luminescence of wheat has a corresponding illuminating saturation time. The illumination intensity is stronger, the delayed luminescence of wheat illuminating saturation time is shorter.(4) The influence of temperature on the delayed luminescence is obvious,as the temperature rises, the intensity of the delayed luminescence biophoton emission decreases gradually.(5) It was demonstrated that the difference of the delayed luminescence ability for different aged with the same breed wheat is significant, as the aging degree of wheat rises,the ability of the delayed luminescence increases correspondingly. The research demonstrates that it offers a new way to detect freshness of wheat based on the delayed luminescence. It provides the theory foundation and technical guidance for the improvement of grain storage technology in China.