Effect of Konjac Glucomannan (KGM) and Carboxymethylcellulose (CMC) on some Physico-Chemical and Mechanical Properties of Restructured Gilthead Sea Bream (Sparus aurata) Products

Abstract

The development of restructured fish products and the application of new food ingredients have been used to create attractive new products and also to upgrade low-value species. The aim of this study was to evaluate the effect of konjac gum (KGM) and carboxymethylcellulose (CMC) fibres on the mechanical and physico-chemical properties of microbial transglutaminase treated restructured fish products from gilthead sea bream as well as to evaluate the effect of heat treatment and storage time. Water holding capacity, mechanical properties and colour attributes in fresh and heat-treated samples after 15 days of cold storage were measured. Results showed that these edible gums could be appropriate for making restructured products obtained from gilthead sea bream. In fresh formulations the addition of 10 g kg−1 of KGM or 10 g kg−1 of CMC presented a significant effect (p ≤ 0.05) on water activity for fresh samples and the lowest value was obtained for 10 g kg−1 of KGM (0.975 ± 0.002). Water holding capacity and adhesiveness increased due to the presence of these gums in fresh and heat-treated samples. For heat-treated samples, KGM significantly reduced (p < 0.05) hardness, cohesiveness and chewiness. Cryo-scanning electron microscopy revealed different structures for gels containing fibres. The use of these fibres did not induce significant changes in colour parameters. Fresh or heat-treated samples stored for 15 days at 4°C showed changes in relation to the parameters investigated.