Rapid compositional analysis of Atlantic salmon ( Salmo salar ) using visible‐near infrared reflectance spectroscopy

Rapid measurement of salmon flesh quality parameters (>400 samples day −1 ) was demonstrated in the laboratory and remotely at industrial sites. Visible‐near infrared spectroscopy ( VNIRS ) was applied to predict astaxanthin ( AX ) and fat content in farmed Atlantic salmon. Fish were sampled from thirteen batches (1–6 kg whole weight, containing 2.3–16.3% fat and 1.2–12.5 μg g −1 AX ), and models validated on small (average ± SD : 1.4 ± 0.4 kg) and large fish (4.2 ± 0.9 kg). Both constituents were well predicted in minced Norwegian Quality Cutlet ( NQC ) samples (r 2  ≥ 0.86; standard error of prediction ( SEP ) ≤0.7% for fat and ≤0.7 μg g −1 for AX ). Comparable metrics were observed for AX prediction in whole NQC s (r 2  = 0.80–0.88; SEP 0.7 μg g −1 ). Fat was better predicted in small fish than large fish for whole NQC s (r 2  = 0.82, SEP 1.0% cf r 2  = 0.59, SEP  = 0.59%) and non‐destructive scanning through the skin of whole, gutted fish (r 2  = 0.77, SEP  = 1.2% cf r 2  = 0.49, SEP  = 1.5%). Models were also developed for screening polyunsaturated fatty acid ( PUFA ) concentrations, e.g. in NQC s for docosahexaenoic acid (r 2  = 0.73) and n‐3:n‐6 PUFA (r 2  = 0.89).