Changes in physical and microstructure attributes of surimi from black mouth croaker (Atrobucca nibe) during frozen storage (-18ºC)

Black mouth croaker (Atrobucca nibe) is considered as a new and valuable fish stock in the deep water of the Oman Sea. In this study, nonmarket sized of the fish was subjected to produce surimi and kamabako gel manually and changes in the physical and microstructure properties of them during 6 months at freezing conditions were investigated. With increasing storage time, whiteness index from 66.24±0.20% to 60.11±0.23% and gel strength from 583.53±56.583 to 303.60±31.518 cm g-1 reduced after six months at frozen storage. The maximum expressible moisture content of kamabako gel sample (7.42±0.26%) was obtained in six months storage (p<0.05). With increasing storage time, quality score of surimi gel decreased to 3.75±0.500 grade. Due to increase the shelf life, rough and irregular of protein structures were appeared in the protein network of the surimi. The average number of surimi polygonals were significantly decreased from 15038±280 to 10399±564 number per mm2 and their area were significantly increased from 27±0.9 to 84±4.5 μm2, with increasing storage time (p<0.05). The results indicated that in spite of relative decreasing in the functional properties of surimi proteins due to denaturation, produced surimi acceptable after six months at frozen storage.