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Keywords:

  • Astaxanthin;
  • Atlantic salmon;
  • chemical analysis;
  • fat;
  • rapid prediction;
  • near infrared reflectance spectroscopy

Abstract

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 (r2 ≥ 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 NQCs (r2 = 0.80–0.88; SEP 0.7 μg g−1). Fat was better predicted in small fish than large fish for whole NQCs (r2 = 0.82, SEP 1.0% cf r2 = 0.59, SEP = 0.59%) and non-destructive scanning through the skin of whole, gutted fish (r2 = 0.77, SEP = 1.2% cf r2 = 0.49, SEP = 1.5%). Models were also developed for screening polyunsaturated fatty acid (PUFA) concentrations, e.g. in NQCs for docosahexaenoic acid (r2 = 0.73) and n-3:n-6 PUFA (r2 = 0.89).