Rapid Near-Infrared Spectroscopic Method for the Determination of Free Fatty Acid in Fish and Its Application in Fish Quality Assessment

Abstract

A rapid, simple, and environmentally friendly near-infrared (near-IR) spectroscopic method has been developed to directly determine free fatty acids (FFA) in fish oil and for the assessment of mackerel quality. The use of first derivative mathematical treatment for near-IR spectra of fish oil samples provides better results than N-point smoothing and second derivative. Both Multiple Linear Regression (MLR) and Partial Least Squares (PLS) regression are used for calibration. However, the calibration equation for FFA obtained from PLS gives higher correlation coefficients of calibration and prediction (r c and r p), and lower standard errors of calibration and prediction (SEC and SEP). The relative errors of prediction for FFA in mackerel fat are less than 8% using the calibration equation obtained from PLS. In this research, FFA change in mackerel has the same trend as hypoxanthine (Hx) change as a fish freshness index. Therefore, near-IR spectroscopy could be a useful technique to determine FFA contents in fish oil and for the assessment of mackerel quality. Keywords: Near-infrared; free fatty acid; mackerel; fish quality assessment

Predicting sensory score of cod (Gadus morhua) from visible spectroscopy

“…NIR has been used to assess quality parameters such as fat, water, and protein content (Downey, 1996;Wold, Jakobsen, & Krane, 1996;Nortvedt, Torrisen, & Tuene, 1998), and it has been reported to determine free fatty acid in mackerels (Zhang & Lee, 1997). In the work of Isaksson, Swensen, Taylor, Fjaera, and Skjervold (2001) it is shown how NIR spectroscopy can be applied to evaluate texture, and the method can also been used to predict the waterholding capacity of thawed fish muscle (Bechmann & Jørgensen, 1998).…”

Visible/Near‐Infrared Spectroscopy: A New Tool for the Evaluation of Fish Freshness?

“…As for the evaluation of quality parameters related to fish, NIR has been used for the determination of free fatty acids in mackerel (Zhang and Lee 1997), fat-, water-, and protein content in salmon and halibut (Downey 1995;Wold and others 1996;Wold and Isaksson 1997;Nortvedt and others 1998). The technique has also been used to estimate water-holding capacity of frozen and thawed cod ( Jørgensen and Jensen 1997;Bechmann and Jørgensen 1998).…”

A Review of Optical Nondestructive Visual and Near-Infrared Methods for Food Quality and Safety

“…Zhang and Lee [203] used near-infrared for determining free fatty acids content of fish oil and mackerel. Since the change in free fatty acids is related to hypoxanthine, they suggested it to be used as an indicator of freshness.…”