Effect of a new vacuum leaching technology on the textural characteristics of sardine mince

Abstract

In order to determine the effect of the vacuum level and leaching time used during the washing process on the gelation characteristics and water-holding capacity (WHC) of sardine mince, a Response Surface Methodology was used. The use of vacuum leaching for short time periods was highly efficient and produced a 50% decrease in the fat content of the washed mince. The leaching under atmospheric pressure produced minces characterised by a low water content and a high residual fat content. The minces' WHC was shown to be conditioned exclusively by the vacuum pressure produced during stirring, with the lowest WHC results corresponding to the highest fat contents in the minces, which result from the leaching at atmospheric pressure. The determination of gel strength showed that the highest values are obtained with intermediate values of air pressure, and correspond to minces with high protein contents. Harder gels were also obtained with intermediate levels of vacuum. In general, the gels tended to be more cohesive when medium levels of vacuum are used (200-300 mmHg, 26.7-40.0 kPa) for short periods (5 min), or low vacuum levels (550-650 mmHg, 73.2-86.5 kPa) for longer periods. Hardness, as well as gel strength and breaking force, presented a behaviour that followed the evolution of the protein content in the mince, i.e. higher values were measured at higher protein contents. © Springer-Verlag 1997.