Electrical conductivity as a precise method for salt content estimation in raw and cooked tuna meat

Abstract

This study evaluates electrical conductivity (EC) for estimating salt content in raw and cooked Skipjack tuna (Katsuwonus pelamis) across various sizes and preparation methods. Tuna sizes ranged from 0.10 to 9.00 kg, and the analysis included moisture, fat, protein, ash, EC, and salt content. In raw tuna, EC exhibited a high correlation with salt content (R² = 0.84), with the prediction equation Y = 0.112X - 0.525. For cooked tuna, which had reduced moisture, fat, and salt compared to raw tuna, EC showed a strong relationship with salt content (R² = 0.89) and the prediction equation Y = 0.169X - 0.623. Canned tuna in brine demonstrated high EC effectiveness for predicting salt content (R² = 0.93 and 0.95 for with and without media, respectively). However, for tuna in oil, EC correlations were weak (R² = 0.06 and 0.01), indicating that oil interferes with ion movement. After validating the estimated salt content using EC against the actual salt content obtained by auto-titration, the results confirm that EC is a reliable and cost-effective tool for estimating salt content in raw, cooked, and brine tuna, although its applicability is limited for oil-based canned products.