NONDESTRUCTIVE DETERMINATION OF FAT, MOISTURE AND PROTEIN IN SALMON FILLETS BY USE OF NEAR-INFRARED DIFFUSE SPECTROSCOPY

Near infrared (NIR) diffuse spectroscopy was used to determine the fat , moisture and protein contents in whole and ground farmed atlantic sa lmon fillets. A remote fibre-optic probe was used for NIR measurements on 50 whole salmon fillets. The constituent ranges were: 91-205 g kg( -1) fat, 599-709 g kg(-1) moisture and 186-209 g kg(-1) protein. Princ ipal component regression resulted in the following prediction errors for ground salmon fillets, expressed as root mean square error of cros s validation: 6.6 g kg(-1) fat, 3.8 g kg(-1) moisture and 2.0 g kg(-1) protein. The corresponding prediction errors for non-destructive meas urements on whole salmon fillets were 10.8 g kg(-1) fat, 8.5 g kg(-1) moisture and 3.7 g kg(-1) protein. Regression models using the 760-110 0 m range gave lower prediction errors than models using the 1100-2500 nm or 760-2500 nm ranges. The results show that fibre-optic probe NIR instruments are suited to determine fat and moisture in whole salmon fillets non-destructively.