TEXTURE AND COLOUR CHANGES IN MEAT DURING COOKING RELATED TO THERMAL DENATURATION OF MUSCLE PROTEINS1

Abstract

ABSTRACT Differential scanning calorimetry was used to select temperatures that diferentiated between thermal denaturation of the three major structural protein species in bovine muscle: myosin, collagen and actin. Samples of m. semimembranosus, m. semitendinosus and m. psoas major were heated to those different temperatures and evaluated sensorially. Three groups of sensory properties were needed to describe the main texture changes observed in the meat: 1. Firmness 2. Fiber cohesivity, bite‐off force, residual bolus 3. Juiciness Firmness increased with thermal denaturation of the myofibrillar proteins (myosin; 40‐60d̀C and actin; 66‐73d̀C). Fiber cohesivity etc. decreased with collagen denaturation (56‐62d̀C). Reduction in juiciness was primarily associated with actin denaturation, while cooking loss increased over the whole temperature range. The property “total chewing work”, a composite of the first two texture groups mentioned, yielded like the judges' “total texture preference”, optimal texture in the 60‐67d̀C temperature region, implying denatured myosin and collagen but native actin. This meat was light pink‐gray in colour, while the cooking juice released was dark red.