Comparison of smartphone and lab-grade NIR spectrometers to measure chemical composition of lamb and beef

Context. Near-infrared reflectance spectroscopy (NIRS) has been extensively investigated for non-destructive and rapid determination of pH and chemical composition of meat including water, crude protein, intramuscular fat (IMF) and stable isotopes. Smaller, cheaper NIRS sensors that connect to a smartphone could enhance the accessibility and uptake of this technology by consumers. However, the limited wavelength range of these sensors could restrict the accuracy of predictions compared with benchtop laboratory NIRS models. Aims. To compare the precision and accuracy metrics of predicting pH, water, crude protein and IMF of three sample presentations and two sensors. Methods. Fresh intact (FI) store-bought beef and lamb steak samples (n = 43) were ground and freeze-dried (FD), and then oven-dried to create freeze-dried oven-dried (FDOD) samples. All three forms of sample presentation (FT, FD, FDOD) were scanned using the smartphone and benchtop MRS sensors. Key results. The IMF was the best predicted trait in FD and FDOD forms by the smartphone MRS (R-2 >0.75; RPD >1.40) with limited differences between the two sensors. However, predictions on FI meat were poorer for all traits regardless of the NIRS scanner used (R-2 <= 0.67; RPD <= 1.58) and not suitable for use in research or industry. Conclusion. The smartphone NIRS sensor showed accuracy and precision comparable to benchtop MRS to predict meat composition. However, these preliminary results found that neither of the two sensors reliably predicted quality attributes for industry or consumer applications.

Automated summary

The study compared the precision and accuracy of predicting pH, water, crude protein, and IMF of different sample presentations using smartphone and benchtop MRS sensors. While the smartphone sensor showed comparable accuracy and precision in predicting meat composition as the benchtop MRS, neither sensor reliably predicted quality attributes for industry or consumer applications.