Use of Konjac glucomannan as additive to reinforce the gels from low-quality squid surimi

This paper reports a study of the influence of a Konjac glucomannan aqueous dispersion (KAD) as ingredient, at different alkalinity levels, on the thermal stability of low-quality squid surimi (Dosidicus gigas) and the viscoelastic properties of its gel. An increase in elastic (G') and viscous (G '') moduli at T < 50 degrees C, reflecting protein aggregation, and a strong decrease at T > 50 degrees C, reflecting structural damage, were observed in thermal gelation profiles of low-quality squid surimi. The contribution of 1% KAD (10%) to enhancement of gelation ability was assessed by evaluating the viscoelastic properties of the gels, with and without KAD, at increasing alkalinity levels. Gels with KAD at high-pH had the best rheological properties. Small amplitude oscillatory shear (SAOS) tests showed a significant decrease in rigidity, an increase in strain amplitude and a decrease in the frequency-dependence of G' and G ''. These results were in agreement with instrumental texture analyses, meaning that KAD may be used to overcome the negative effect of the poor protein functionality of low-quality squid surimi and achieve better gels from them. (c) 2010 Elsevier Ltd. All rights reserved.