Rapid and non-destructive quantification of meat content in the legs of live red king crab (Camtschaticus paralithodes) by near-infrared spectroscopy

Abstract

Red king crab (RKC) is one of the most widely distributed and well-known of all king crabs. The edible meat of the RKC is in the legs and claws and is considered a delicacy. Occasionally, the content of meat is low, and this is regarded as the single most negative quality attribute. In this study, we elucidated how rapid and non-destructive near-infrared spectroscopy (NIRS) on live RKCs can be used to predict the meat content in the cooked legs. A NIRS prototype (wavelength range 760-1080 nm) was used to obtain spectra from the interior tissue of the crab legs. 99 live crabs (380 legs) were measured over a 10-month period. Calibration models were developed with a prediction error for meat content of 6.4 %-points, which is accurate enough to classify the crabs into low (< 80 %) and high meat content. The amount of cooked meat is proportional to the amount protein in the muscle. A limitation with the method is that it may overestimate the meat content if the legs have lost free water due to e.g. injuries in the exoskeleton. The technology described can facilitate a more sustainable RKC fishery and improve the subsequent trade and processing.