Evaluation of dry-cured ham pastiness through rheological measurements of aqueous extracts obtained in vitro mimicking the mastication process

Abstract

Pastiness is a dry-cured ham defect that can be determined by sensory and chemical analysis. Since pastiness produces an increase of saliva viscosity, rheology might be useful to instrumentally evaluate this defect. The aim of this study was to evaluate the rheological behaviour of water extracts obtained in vitro mimicking the mastication of dry-cured ham samples with different pastiness intensities. Commercial samples from different groups (non-pastiness (NPG), medium pastiness (MPG) and high pastiness (HPG) groups) were sensorially and rheologically analysed. Effect of temperatures and HPP treatments at 7 °C, 20 °C and 35 °C were also evaluated. Results showed that apparent viscosity of the water extracts increased with the increase of pastiness and decreased with temperature. Significant differences (p < 0.05) were observed between NPG/MPG and HPG samples and between 25 °C and 37 °C in HPG. After HPP, sensory pastiness disappeared in samples from MPG at any temperature and decreased from 6.8 to 0.2 in samples from HPG only when HPP35 was used. Although the increase on viscosity of oral fluid is related to the sensory pastiness, other factors seem to be involved in the mechanism of pastiness perception. Despite this, HPG samples can be distinguished from MPG and NPG samples.