Profiles of water content, water activity and texture in crusted dry-cured loin and in non-crusted dry-cured loin

Abstract

This study compares the profiles of water activity (aw), water content (X) and texture in loin with crusted surface versus those profiles in loin without crust, and establishes a mathematical model able to describe hardness based on aw and/or X. Two loins (m. longissimus dorsi) were dry-cured, aged and then each one was divided into four pieces. Two of them were dried at 15±2 °C, 50±3% RH (CL treatment) and the other two were dried at 2±2 °C, 80±3% RH (NCL treatment). The pieces of CL were dried under more severe conditions in order to develop a crust on the surface. Three-millimetre thick slices were taken from the most external part towards the inner part. The slices were prepared (10×10×3 mm) for texture profile analysis (TPA). Measurements of aw and X were carried out on each slice. Variance analyses and non-linear regression analyses were performed to create a model for loin hardness prediction through X and/or aw and a linear regression model for cohesiveness and springiness. CL loins showed a higher hardness and chewiness and lower cohesiveness at the surface (3-mm thickness) than the NCL loins. Hardness and chewiness, fitted with a non-linear model, were better described by X than by aw. Springiness showed a low relationship with X and aw. The on-line monitoring of X and aw at the surface of the product would enable an estimation of the profiles of water content, aw and texture and it could be, therefore, a useful tool to avoid crusting.