Application Of Near-infrared And Raman Spectroscopy Rapid Nondestructive Testing Technology In Sericulture Products

Sericulture is a characteristic and advantageous industry in China.Promoting the vigorous development of the sericulture industry is of great significance for improving the employment rate of rural labor,increasing the national fiscal revenue,expanding the export of foreign exchange,and the national economic construction.In recent years,the nondestructive testing technology of near-infrared and Raman spectroscopy has developed rapidly and has been used in research and analysis in many fields due to its advantages,such as no sample pretreatment,fast detection speed,green and pollution-free,and real-time online analysis.In this paper,a fast and efficient method for the separation of male and female silkworm pupae,a method for the determination of the oil content in silkworm pupae,and a method for the detection of the nutrient substance of mulberry leaves were developed based on the near-infrared spectroscopy.Methods for the determination of the peroxidation value and the adulteration of silkworm pupae oil by a portable near-infrared and Raman spectrometer developed,respectively.The test results are as follows:?1?Separation models for male and female silkworm pupae were established based on near-infrared spectroscopy.A self-made automatic sorting system for male and female silkworm pupae was used to collect the near-infrared spectra of 8 silkworm pupae varieties.Then the models of principal component analysis?PCA?,Linear Discriminant Analysis?LDA?,and Partial least squares discrimination Analysis?PLSDA?were established respectively.PLSDA model has the best identification effect,and the identification accuracy is over 97.5%.?2?The oil content of silkworm pupae was determined by near-infrared spectroscopy.The near-infrared spectra of silkworm pupae powder was collected by two portable spectrometers of DLP NIRscan Nano and Micro NIR 1700.The combination of synergy interval partial least squares?Si PLS?and Random Frog?RF?algorithm was used for the wavelength optimization.A model of silkworm pupae oil content was established based on the partial least square method?PLS?.For the DLP NIRscan Nano spectrometer,the Si PLS was used to optimize the model,and the root mean square error of calibration set?RMSEC?and coefficient of determination for calibration?R_C²?were 1.535%and 0.843,respectively.The root mean square error of the cross-validation set?RMSECV?and coefficient of determination for the cross-validation(R²_CV)were 1.775%and 0.791,respectively.The root mean square error of the prediction set?RMSEP?and coefficient of determination for prediction set?R_P²?were 1.682%and 0.779,respectively.The ratio of performance to the standard deviation?RPD?and the ratio of the range to the RMSEP?RER?were 2.164 and9.281,respectively.For the silkworm pupa oil,the near-infrared spectra were collected by Micro NIR 1700 spectrometer,and the RF was used for the wavelength optimization.The root mean square errors of the established model correction set,cross-validation,and prediction set were 1.512%,1.700%,and 1.697%,respectively.The determination coefficients were 0.846,0.808,and 0.780,RPD was 2.144,and RER was 9.199.The results show that the prediction accuracy of the regression model for silkworm pupa oil content obtained by the DLP NIRscan Nano spectrometer is higher than that of Micro NIR 1700spectrometer.?3?The peroxidation model of silkworm pupae oil was established based on the near-infrared and Raman spectroscopy.The near-infrared and Raman spectra of silkworm pupae oil were collected,and the PLS regression model of peroxide value was established.The modeling effects of feature wavelengths extracted by competitive adaptive reweighted sampling?CARS?,genetic algorithms?GA?,and Random Frog were compared.Among them,the CARS algorithm is the best,and the RMSEC and R_C²were 0.759 mmol/kg and0.923,the RMSECV and R²_CVwere 0.984 mmol/kg and 0.875,and the RMSEP and R_P²were0.950 mmol/kg and 0.867,respectively.The Raman spectra modeling of silkworm pupae oil optimized by the GA algorithm was the best.The RMSEC,RMSECV and RMSEP of the model were 0.931 mmol/kg,0.983 mmol/kg and 0.965 mmol/kg,respectively,and the R_C²,R²_CVand R_P²were 0.879,0.868 and 0.869,respectively.?4?The identification model of silkworm pupae oil adulteration was established based on Raman spectroscopy.The PCA,LDA,and soft independent modeling of class analogy?SIMCA?were applied to analyze the adulteration of silkworm pupae oil.Among them,the correct identification rates of the PCA for the correction set and unknown sample set were96.43%and 92.86%,respectively.The identification accuracy of the LDA model for the correction set and unknown sample set was 100%and 96.43%,respectively.For the SIMCA model,all the samples in the correction set were classified correctly,and the recognition rate of silkworm pupae oil and edible oil in the unknown sample set was 100%.The rejection rate was 100%and 94.74%,respectively.The PLS was used to analyze the adulteration of silkworm pupae oil quantitatively.Results showed that the RMSEC,RMSECV,and RMSEP were 3.360%,4.525%,and 4.023%,and the determination coefficients were 0.994,0.989,and 0.992,respectively.?5?The models of water content,crude protein,and soluble sugar in mulberry leaves were established based on near-infrared spectroscopy.The characteristic wavelength variables were extracted from the original near-infrared spectroscopy,and the RMSEP of the established prediction models of water content,crude protein and soluble sugar content of mulberry leaves were 1.185%,0.608%,and 2.361%,respectively,and R_P²were 0.914,0.924 and 0.714,respectively.Among them,the water content and crude protein content model had higher prediction performance,and the soluble sugar content had slightly lower prediction ability.In summary,the near-infrared spectra technology can be used for the identification of the sex of silkworm pupae and the determination of oil content in silkworm pupa,peroxide value of silkworm pupa oil,and quality parameters of mulberry leaves.The high-precision model for oil peroxide value of silkworm pupa oil and identification model for the adulteration of silkworm pupa oil were obtained by the Raman spectroscopy.Therefore,it is feasible that the near-infrared spectra and Raman technology can be use in the area of sericulture industry.