A Comparison of Selected Rapid Methods for Fat Measurement in Fresh Herring (Clupea harengus)

Several methods exist for the determination of fish-fat content. This study compares the accuracy of four of these methods against reference Soxhlet measurements, i.e., the Torry Fatmeter, a microwave method, near-infrared reflectance spectroscopy and a commercial modification of the Soxhlet procedure (the fexIKA control extraction method). Using 60 herring samples from a single 3-month period, the standard errors of prediction of these methods were 1.37, 0.79, 0.8 and 1.36%, respectively. Associated regression coefficients of 0.84, 0.95, 0.95 and 0.84, respectively were also obtained. Values predicted by Torry Fatmeter were unaffected by filleting or by previous freezing of the fish. However, icing and desiccation did affect the predictive accuracy for this instrument.