Rapid Quantification of Carotenoids and Fat in Atlantic Salmon ( Salmo Salar L.) by Raman Spectroscopy and Chemometrics

• Published in: Applied Spectroscopy
• Main Authors: Wold, Jens Petter, Marquardt, Brian J., Dable, Brian K., Robb, Dave, Hatlen, Bjarne
• Format: Article in Journal/Newspaper
• Language: English
• Published: SAGE Publications 2004
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1366/000370204773580220; http://journals.sagepub.com/doi/pdf/10.1366/000370204773580220

Raman spectroscopy (785 nm excitation) was used to determine the overall carotenoid (astaxanthin and cantaxanthin) and fat content in 49 samples of ground muscle tissue from farmed Atlantic salmon ( Salmo salar L.). Chemically determined contents ranged from 1.0 to 6.8 mg/kg carotenoids and 36 to 205 g/kg fat. In addition to the raw Raman spectra, three types of spectral preprocessing were evaluated: the first derivative, subtraction of the fitted fourth-order polynomial (POLY), and the intensity normalized versions of POLY (POLY-SNV). Further, variable selection based on significance testing by use of jack-knifing was performed on each spectral data set. Partial least-squares regression resulted in a root mean square error of prediction of 0.33 mg/kg ( R = 0.97) for carotenoids for the variable selected versions of all the preprocessed spectral data sets. The fat content was best estimated by the variable selected POLY-SNV, resulting in a root mean square error of prediction of 15.5 g/kg ( R = 0.95). Both preprocessing and variable selection improved the regression models significantly. The results demonstrate that Raman spectroscopy is a suitable method for simultaneous, rapid, and nondestructive quantification of both pigments and fat in ground salmon muscle tissue.