Discrimination of Bayberry Juice Varieties by Vis/NIR Spectroscopy Based on PLS Analysis and Bayesian-SDA

Abstract

Bayberry juice is a green beverage contained many different kinds of nutrition components. Visible and near infrared reflectance spectroscopy (Vis/NIRS) offers a promising means for the detection of bayberry juice varieties. A total of 60 bayberry juice samples (20 for each species) were investigated for Vis/NIRS on 325-1075 nm using a field spectroradiometer. Absorbance of 20 samples of each variety after pretreatment was exported and the lacked Y variables were assigned independent values for partial least squares (PLS) analysis. 8 principal components from PLS were used as 8 variables in Bayesian stepwise discriminant analysis (Bayesian-SDA). The full-cross validation results of PLS, i.e., standard error of prediction (SEV) 0.415, correlation coefficient (r) 0.865 and root mean square error of validation (RMSEV) 0.412, indicated an optimum model for bayberry juice identification. By handling these 8 principal components from PLS analysis with Bayesian-SDA, the results with deviation presented a 100% bayberry juice detection rate. Thus, it could be concluded that PLS analysis combined with Bayesian-SDA was an available alternative for species recognition based on Vis/NIR spectroscopy