Rehydration of Freeze‐Dried Pork as Related to pH and Protein Denaturationa

Abstract

SUMMARYIn order to determine the influence of pH on percentage rehydration and the degree of protein denaturation caused by freeze dehydration, 70 freeze‐dried fillets taken from the longissimus dorsi muscle of three hogs were utilized. Percentage rehydration of the freeze‐dried fillets ranged from 48.5 to 92.4%, with a mean of 73.8%, and was not influenced significantly by either pH of the rehydrating solution or pH of the rehydrated meat under the conditions of this trial. Fat content had little effect on percentage rehydration. An increase in pH was noted during the dehydration process, but trapping of the acidic volatiles and adding them hack during rehydration restored the original pH. The qualitative amino acid composition of the rehydration solution was not influenced by pH. However, a change in ionic strength varied the qualitative amino acid composition. The sarcoplasmic protein fraction noticeably decreased in nitrogen content on freeze‐dehydration and rehydration, indicating that some denaturation was occurring.