POLYACRYLAMIDE GELS AS ELASTIC MODELS FOR FOOD GELS

The physical properties of polyacrylamide gels (10% w/v) were evaluate d by dynamic oscillatory testing, stress relaxation and torsional frac ture analysis. Gels had a linear relationship between shear stress and strain when deformed to fracture; thus small strain (storage modulus, G;) and large strain (fracture modulus. Gf) moduli were equivalent, N on-fracture and fracture tests showed that gels maintained an entropy (rubber) elastic response over all testing temperatures (10-80-degrees -C). Shear stress at fracture was independent of temperature. whereas shear strain at fracture decreased as temperature increased. This was associated with increased thermal motion strains decreasing the amount of mechanically induced strain required for fracture. Our results hav e shown that polyacrylamide gels are a suitable elastic model tor unde rstanding the molecular mechanisms of food texture.