Abstract
Quick determination of fat content in frozen whole skipjack was studied by non-contact measurement of NIR reflectance spectra. NIR spectra of the center of frozen whole skipjack were measured at a distance of 10cm above by using grating type NIR instrument. Multiple linear regression was performed based on 2nd derivative spectra and fish fat laboratory measurements. The highest multiple correlation coefficient of 0.88 with a standard error of calibration (SEC) of 6.6% and validation (SEP) of 6.1% was obtained in case of calibration equation with tree optical terms including 1162nm as first wavelength. At distance of 10cm, the effective measuring area of the fish body was a circular area with a diameter of 5cm. The distance between the sensing head and the sample was one of the factors causing errors in NIR fat determination. The fish sample temperature affected the NlR spectra, but did not affect the NlR fat determination because sample temperature compensation was included in the calibration equation developed. It was concluded that non-contact measurement of NIR spectra of frozen whole skipjack was possible with on-1ine grating NlR instrument.HomePageKeywords: fat, near infrared spectroscopy, whole skipjack, non-contact determination