| Paddy is one of the main grain varieties in China,while the paddy suffering from harmful fungal infection will seriously affect the health of human beings and animals.However,many problems exist in traditional detection methods for grain mold such as complex operation,time-consuming and imprecise.In this paper,the paddy infected by harmful fungal will be researched,qualitative and quantitative detection model established for the paddy suffering from harmful fungal infection through near/mid infrared spectroscopy and electronic nose technology will be explored and used based on the characteristics information of physical,chemical changes and smell,etc.produced during the paddy storage.Furthermore,electronic nose combined with GC-MS technology will be used to determine the chemical composition and content of volatile substances in harmful fungal infected paddy,rules of change in the chemical composition of volatile substances over time will be analyzed,difference between volatile substances in the paddy suffering from different harmful fungal infection will be compared.The main conclusions of this study are as follows:1.A qualitative detection model for the rice suffering from harmful fungal infection was established based on near/mid infrared spectroscopy and electronic nose technology.The results of principal component analysis(PCA)and linear discriminant analysis(LDA)showed that the rice samples suffering from different fungal infection can be effectively distinguished through the three kinds of technology,with the average accuracy rate of 86%,86%and 92%,respectively.The rate accuracy rate to discriminate the state of moldy rice samples suffering from single fungal infection was 97.5%,98.75%and 100%,respectively.The accuracy rate to discriminate the state of moldy rice samples suffering from multiple fungal infections was 80%,87.5%and 95%,respectively.The results showed that rice fungal can be discriminated quickly through these three technologies,with the model performance:electronic nose signal>mid infrared spectroscopy>near infrared spectroscopy.2.Qualitative and quantitative detection models for the paddy suffering from harmful fungal infection was established based on near infrared spectroscopy and electronic nose technology.(1)NIR results showed that rapid discrimination of paddy samples suffering from different fungal infection based on near infrared spectroscopy should be further optimized,with an average accuracy rate of 94%to discriminate the paddy samples subject to different moldy conditions and 88%to discriminate the different storage time of all samples.The quantitative results of the PLSR model for the total number of colonies in paddy were as follows:the effective determination coefficient(Rp2)was 0.7482,the root mean square error(RMSEP)was 0.585 Lg CFU/g,and the relative percent deviation(RPD)was 1.94.(2)The results of electronic nose technology showed that electronic nose technology can effectively discriminate the paddy samples infected with different fungal,with an average accuracy rate of up to 100%.The average accuracy rate was 98%to discriminate the paddy suffering from single fungal infection,and was up to 96%to discriminate the paddy suffering from multiple fungal infections.The quantitative results of the PLSR model for the total number of colonies in paddy were as follows:Rp2 was 0.804,RMSEP was 0.505 Lg CFU/g and RPD was 2.154.(3)The results of electronic nose load analysis and GC-MS showed that with the increase of time,siloxane and phenols in the volatile substances of the paddy appeared and their contents increased gradually.Differences existed in the volatile components of the paddy suffering from different fungal infections,embodied in the ethers,aldehydes,ketones and other oxygen containing compounds.Their contents were different in the paddy suffering from different strains as well as the paddy suffering from the same strain in different storage stages.The results showed that the infrared spectroscopy and the electronic nose method could be used as a rapid and non-destructive method to determine the infection status of moldy paddy,so as to ensure the safety of paddy storage and transportation. |
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