Total volatile basic nitrogen content in duck meat of different varieties based on calibration maintenance and transfer by use of a near-infrared spectrometric model

Total volatile basic nitrogen (TVB-N) content is an important indicator for evaluation of duck-meat freshness. The accuracy of the existing near-infrared spectrometric model is affected by sample characteristics of different varieties. Hence, improvement in the model is needed. In order to improve the applicability of the model for TVB-N content in duck meat with different varieties, calibration maintenance methods were done, based on different principles including model updating (MU), direct standardization (DS), and slope/bias correction (SBC). The numbers of samples in the standardization sets were investigated for transfer effects. The results showed that the univariate SBC method exhibited a more significant transfer effect than multivariate DS transfer or complete recalibration of MU. The best results were obtained by the SBC method with 20 standard samples, for which the root mean square error of prediction and mean bias were 0.930 and -0.130. The calibration maintenance and transfer study done will likely provide reference for model maintenance between samples with different varieties and lay a foundation for industrial application.