Exploration of microwave dielectric and near infrared spectroscopy with multivariate data analysis for fat content determination in ground beef

• Merits of microwave and NIR spectroscopy for ground beef quality control have been evaluated.
• PLS models were developed to explore dielectric properties in different frequency ranges for fat content prediction.
• PLS modelling was used to examine the potential influence of water on fat content prediction using microwave spectroscopy.

This study investigated using microwave dielectric and near infrared (NIR) spectroscopy for the determination of fat content in ground beef samples (n = 69) in a designed experiment. Multivariate data analysis (principal component analysis (PCA) and partial least squares (PLS) regression modelling) was used to explore the potential of these spectroscopic techniques over selected multiple frequency or wavelength ranges. Chemical reference data for fat and water content in ground beef were obtained using a nuclear magnetic resonance-based SMART Trac analyser. Best performance of PLS prediction models for fat content revealed a coefficient of determination in prediction (R2P) of 0.87 and a root mean square error of prediction (RMSEP) of 2.71% w/w for microwave spectroscopy; in a similar manner, R2P of 0.99 and RMSEP of 0.71% w/w were obtained for NIR spectroscopy. The influence of water content on fat content prediction by microwave spectroscopy was investigated by comparing the prediction performance of PLS regression models developed using a single Y-variable (PLS1; fat or water content) and using both Y-variables (PLS2; fat and water contents).