Thermal denaturation and aggregation of threadfin bream actomyosin

Threadfin bream (Nemipterus bleekeri) actomyosin formed insoluble aggregates at >40 degreesC. Conformational changes, as measured by surface hydrophobicity, began at >30degreesC and continued to increase with heating temperature. Reactive sulfhydryl groups increased as heating progressed and decreased at 50degreesC, indicating the formation of disulfide linkages of threadfin bream actomyosin at >50degreesC. Two distinct a-helical transition temperatures of actomyosin were found at 36.1 and 47.9degreesC, while major endothemic transitions were at 38.4, 51.0, and 80.7degreesC. Storage modulus (G) started to increase at 34.5degreesC, implying the simultaneous occurrence of denaturation and aggregation. Gel network formation began to develop at >41degreesC. (C) 2003 Elsevier Ltd. All rights reserved.