Studies On Application Of Non-destructive Test In Tea And Shrimp Based On Multispectral Imaging Technology

With the development of society and the improvement of the life quality, consumers pay attention not only on food safety, also more and more on the quality factors such as tasty, flavor, appearance, freshness, nutrition, etc. As a result, food quality and safety are gained great importance by human beings. Governments, international organizations and academic institutions across the world have been working on solving food quality and safety related problems for decades. Among these, food test is the key tools to ensure food quality and safety.At present, traditional test methods including sensory test, physical and chemical test and microbiological test are widely used for the evaluation of food quality and safety.However, these methods suffer certain disadvantages such as low efficiency, high destructiveness and high cost, but also cannot meet the needs of real-time monitor to ensure the safety and quality in the modern food industries. Hence, the new test method with high efficiency and low destructiveness is demanded urgently.Using multispectral imaging (MSI) system, the non-destructive test method was explored for tea and shrimp quality and safety characteristics by different chemometrics methods. Firstly, different storage periods of black tea, Iron Buddha tea and green tea were indentified, and the total polyphenols was determined in Iron Buddha tea;secondly, the mechanical properties and Irradiation doses of shrimps were investigated;lastly, used total polyphenols (TP) as the preservative coating, the difference of total viable count in shrimps was researched during diffent chill storage time, and also the visual dertimination was done by MSI.The main achievements of this work were summarized as follows:1. The classification accurate rate of storage time of the green tea, Irron Buddha tea and black tea is 100%, 95% and 94%, respectively; Optimized prediction models for total polyphenols in Iron Buddha tea was established by using PLS method. As a result,the model was obtained with Rp of 0.9092, SEC of 0.5239 and SEP of 0.5405.2. The performance of determining the mechanical properties and discriminating the irradiated shrimp samples at various doses were investigated by different chemometrics. Of which, the acceptable model was built for hardness, springness,cohesive, gumminess; For the irrdation doses prediction model, when irradiated doses up to 4 kGy, the classification accuracies with 90% were achieved, the performance with 100% were achieved when 10 kGy or above.3. The SPA-LS-SVM model was built up with Rp of 0.9587, SEP of 0.6148, RPD of 2.6726 for total viable count. Meanwhile,using TP from tea products as the preservative coating,the storage performance of shrimp at chill condition was researched. As a result, the 1.0% TP was the best method to keep shrimp with adding 4 days shelf life.This work suggested that tea and shrimp test by MSI technique could benefit food quality and safety control. Our results could provide a theory reference for applying MSI technology, and also reflect the important research value.