Sensory evaluation and instrumental measurements to determine tactile properties of wool fabrics

Abstract

Fabrics manufactured in Italy with 100% Sardinian sheep breed wool, traditionally named ‘Orbace’, and with local Tuscan wool from 50% Sardinian and 50% Comisana sheep breeds wool (Tuscan Cloth), were subjected to sensory evaluation, through descriptive analysis performed by a trained panel, and to an instrumental evaluation method, through FAST – Fabric Assurance by Simple Testing. The correlation between instrumental data and sensory attributes was investigated. Sensory evaluation indicated that Orbace fabrics, originated from 100% Sardinian wool, had higher grittiness, stiffness, force of compression and hand friction and lower softness and tensile stretch, as compared to the fabrics obtained from mixed wool. Principal component analysis (PCA) indicated a high correlation for grittiness, stiffness and force of compression in one direction, tensile stretch, softness, warmth and fullness in the opposite, clearly discriminating in this dimension Orbaces from Tuscan fabrics. This discrimination appears to be an effect of the wool used for the different fabrics. Differences in key sensory traits were also recorded among fabrics derived from the same raw material, but differing in weave. Thickness, as the key attribute of the second PCA dimension, provided discriminations within groups and is reasonably perceived as an effect of different weaves. Canonical Correlation Analysis indicated that measurements performed with FAST were correlated with a number of basic touch traits, including softness, stiffness, force of compression and tensile stretch. Orbace and Tuscan Cloth handle definition, on the basis of sensory and instrumental measures, will be of use to describe and protect original products.