Non-Destructive Quantification of Lipid and Water in Fresh Tuna Meat by a Single-Sided Nuclear Magnetic Resonance Scanner

Yoshito Nakashima

doi:10.1080/10498850.2019.1569742

Abstract

ABSTRACTA portable single-sided nuclear magnetic resonance (NMR) surface scanner was applied to the non-destructive quantification of lipid and water in meat block samples of farmed bluefin tuna (Thunnus thynnus). Proton NMR relaxation measurements of the fresh meat block samples were performed at room temperature in a laboratory. Totally, 34 tuna meat block samples were measured; the required measurement time was approximately 70 s for each sample. The results yielded estimation errors of 3.7 and 2.7 g/100 g for the lipid and water weight fractions, respectively. The investigation depth of the sensor was as deep as 3 cm, which enables the non-destructive quantification of the meat of the intact whole tuna beneath the thick scales, skin, and subcutaneous fat in markets and seafood factories.

Highlights

The lipid content of fresh tuna is an important factor for determining meat quality and price (Shimose et al, 2018)
A portable single-sided nuclear magnetic resonance (NMR) surface scanner was applied to the non-destructive quantification of lipid and water in meat block samples of farmed bluefin tuna (Thunnus thynnus)
The fact that the slope of the regression line for the lipid content is as steep as – 1.4 suggests that the protein content increases with water content, which was confirmed by the above-mentioned positive correlation between the protein and water contents

Summary

Introduction

The lipid content of fresh tuna is an important factor for determining meat quality and price (Shimose et al, 2018). There is a high demand for non-destructive, rapid, portable, and precise measurement systems to enable buyers to more precisely evaluate the meat quality of tuna Such measurement systems of the lipid content are needed for the quality control of aquatic food products at factories (Marcone et al, 2013; Tao and Ngadi, 2018). NMR surface scanners allow the water and lipid contents to be quantified separately by taking advantage of the difference between the proton spin-spin relaxation times (T2 values) of the water molecules in the muscle and the lipid molecules This NMR method is advantageous over other methods employing near infrared, microwaves, and electrical current (Tao and Ngadi, 2018; Willis and Hobday, 2008; Xiaobo et al, 2016) in that the sensed region can lie completely in the meat portion, and the undesirable effects of the backbone and skin (Kent, 1990; Koyama et al, 2018; Nielsen et al, 2005; Shimamoto et al, 2003) can be neglected

Methods

Results

Discussion

Conclusion