Mainz. Professor Thomas Vilgis, Project Leader at the Max Planck Institute for Polymer Research in Mainz, and his team look into protein denaturation of meat using a sous-vide technique. Their results have now been published in Food Biophysics and should help you prepare delicious pork filets.
This study systematically investigates the impact of time (10 minutes – 48 hours) at different cooking temperatures (45 – 74°C) on the state of protein denaturation and water content of a cooked piece of meat. The scientists used the so-called DSC (Differential Scanning Calorimetry) method in order to perform the measurements. This is the first study to address such a broad range of times and such well-defined temperatures. This is particularly important since every muscle protein denatures at a precisely defined temperature.
“This study has important gastronomical implications: it discredits a common belief. Cooked meat had long been held warm until serving. It was thought that maintaining meat at a constant temperature was better than reheat it. This study now shows that the ongoing protein denaturation over a long period of time might lead to undesired properties such as a lack of tenderness or juiciness”, explains Thomas Vilgis.
Upon heating muscle and connective tissue lose their native molecular shape or conformation. It causes a change in the texture. Above 60°C, muscle meat loses the bigger part of its water. It gets hard, tough and fibrous. Between 48°C and 71°C, different proteins gradually change shape. They shrink, form close meshed networks or coagulate. Factors such as juiciness or tenderness change to the same extend. Sous-vide cooking enables to best control the exact temperature and thus the associated properties.
The sous-vide technique is a common cooking method used in the gastronomy. Food is sealed in an airtight plastic bag then placed in a water bath at a well-defined temperature. The aim is to cook the item evenly, ensuring that the inside is properly cooked without overcooking the outside, and to retain moisture. Fresh meat contains about 75% of water. Yet cooking meat is a complex process. The water holding capacity of meat as well as the water loss changes at high cooking temperature. By controlling the denaturation state of meat proteins using sous-vide cooking, the meat will remain tender and juicy. Selective denaturation of meat proteins is essential to reach the desired textures. Please remember: the loss of meat juices increases with time and temperature. The main water loss, for its part, occurs during the first 20 minutes and at temperatures above 60°C. In the end, to obtain the best pork filet (average sized), cook it sous-vide for 20 minutes at 55°C.