The use of dielectric properties and other physical analyses for assessing protein denaturation in beef biceps femoris muscle during cooking from 5 to 85°C

Dielectric properties of beef biceps femoris muscle were recorded during heating (5-85 degrees C) to assess their linkage to phase changes monitored by differential scanning calorimetry (DSC) and rheology. DSC indicated endotherms between 56 and 81 degrees C corresponding to denaturation of actin, collagen and myosin. Matching changes in dielectric properties (dielectric constant (epsilon') and loss factor (epsilon")) were noted at radio and/or microwave frequencies though the nature of the change differed depending upon frequency. The main observation in was an increase above 65-66 degrees C, most likely due to fluid release on collagen denaturation. This fluid plus liquid from myosin denaturation most likely solvated ions freed during myosin denaturation which manifested as an epsilon" increase. However, it must be noted that meat structural protein denaturation is compounded with physical shrinkage which can also influence dielectric properties. Rheological parameters of beef muscle heated from 5 to 85 degrees C also displayed marked changes relating to structural protein denaturation. (c) 2005 Elsevier Ltd. All rights reserved.