title: Endogenous proteolytic enzymes--a study of their impact on cod (Gadus morhua) muscle proteins and textural properties in a fermented product.
abstract: The aim of this study was to investigate endogenous proteolytic activities in a cod product and their impact on muscle proteins and textural properties during fermentation and storage. The result of specific proteolytic activities showed that cathepsins, especially cathepsin B, had the highest activities during fermentation and storage. SDS-PAGE indicated more degradation of myofibrillar proteins by cathepsin L than other proteases and that the hydrolysis by cathepsins was pronounced in the last stage of fermentation. Texture analysis showed that cathepsins had a negative impact on gel strength and this impact increased in the last stage of fermentation. However the product still had a firm texture. During storage (4 °C) for one week, no significant changes were seen in the gel strength. In conclusion, cathepsins had more impact on muscle proteins and textural properties than other proteases during fermentation but had little impact on gel strength during storage at 4 °C.
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Biotechnology, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
authors.forename: Turid
authors.initials: T
authors.lastname: Rustad
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
authors.forename: Yanshun
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
authors.forename: Qixing
authors.initials: Q
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China. Electronic address: xiaws@jiangnan.edu.cn.
authors.forename: Wenshui
authors.initials: W
authors.lastname: Xia
mesh_terms: D000818:Animals; D002401:Cathepsin B / Q000378:metabolism; D056668:Cathepsin L / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005285:Fermentation; D061353:Food Storage; D048389:Gadus morhua / Q000378:metabolism*; D005782:Gels / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009124:Muscle Proteins / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D059748:Proteolysis; D013696:Temperature
chemical_list: D005782:Gels; D009124:Muscle Proteins; D010447:Peptide Hydrolases; D002401:Cathepsin B; D056668:Cathepsin L
keywords: Fermentation; Fish muscle proteins; Gel strength; Specific proteolytic activities