The Hydrogen Ion Titration Curves of Native, Heat‐Coagulated and Frozen‐Stored Myofibrils of Cod and Beef

摘要

SUMMARYBetween pH 2 and pH 10.5 the titration curve of washed native cod myofibrils can he accounted for solely on the basis of the probable dissociation constants of the carboxyl, histidyl, lysyl, and tyrosyl groups of the constituent proteins. On heat coagulation of washed cod myofibrils, a slight shift in the titration curve toward more alkaline pH's occurs, particularly between pH 4.5 and 7.0, but no evidence was obtained for experimentally significant changes in the numbers of titratable acid or basic groups. The titration curves of cod myofibrils prepared from fish stored at −14° for periods from 1 week up to 2 yr are very similar, and no evidence was obtained for loss of titratable acid or basic groups during frozen storage. The changes that occur in the titration curve of beef myofibrils on heat coagulation are similar to those occurring in the titration curve of cod myofibri