To liquefy the collagen we need to cook the meat to 180F and hold it there for for long periods of time. Even meat cooked in liquid will dry out although not as quickly. A slab can lose 20% or more of its weight in cooking due to shrinkage. turning collagen into gelatin requires temperatures above 160F and for extended time periods. As moisture evaporates, the meat begins to shrink. To minimize moisture loss requires temperatures less than 130F, however. The reality is that these methods are contracdictory and hence the challenge or dilemma to cooking meats. We therefore want our meat to be cooked tender where tough collagen is converted to gelatin but with a minimum loss of moisture. We like our meat tender and juicy at the same time. Individual muscle fibres are bounded by a plasma membrene surrounded by connective tissue (endomysium) which consists of a basement membrane surrounded by a reticular later in which a meshwork of fine collage fibrils is embedded in a matrix. Source: Harold McGee - On Food and CookingĪ muscle is completely enclosed by a thick sheath of connective tissue (the epimysium) and is divided into bundles of fibres by a connective tissue network (perimysium).
The fibers are still stiff and dry but meat seems more tender. At 160 ☏/ 70 ☌ connective tissue collagen begins to dissolve to gelatin. Meat served at this temperature med-rare is changing from juicy to dry. NOTES: At 140 ☏ changes are caused by the denaturing of collagen in the cells. Although the fibers are still very stiff and dry the meat appears more tender since the gelatins provide succulence. With time muscle fibers that had been held tightly together begin to easily spread apart. The meat gets dryer, but at 160F the connective tissues containing collagen begins to dissolve into gelatin. Well Done Slow Cooked Meats: Falling apart tenderness collagen turns to gelatin at 160/70. Melting of collagen starts to accelerate at 160F and continues rapidly up to 180F. Meat served at this temperature is considered medium and begins to change from juicy to dry.ġ60☏/70☌ - Connective tissue collagen begins to dissolve to gelatin. At 140-150 the meat suddenly releases lots of juices, shrinks noticeably and becomes chewier as a result of collagen shrinkage.
Medium - Well Meats: Collagen shrinks as the meat tmeperature rises to 140/60 more of the protein coagulates and cells become more seggregated into a solid core and surrounding liquid as the meat gets progressively firmer and moister. Meat turns from pink to brown-grey color.ġ40☏/60☌ - Meat suddely releases lots of juice, shrinks noticebly, and becomes chewy as a result of collagen denaturing which squeezes out liquids. At this temperature meat is considered rare and when sliced juices will break through weak spots in the connective tissue.ġ40☏/60☌ - Red myoglobin begins to denature into tan colored hemichrome. Water then collects around the solidifyed protein core and is squeezed out of the cell by connective tissue. As the myosin molecules bond to each other they begin to squeeze out water molecules that separated them. This lends each cell some solidity and the meat some firmness. Rare Meats: 120☏/50☌ is the early stages of juiciness in meats as the the protein myosin, begins to coagulate. Coagulation produces large enough clumps to scatter light. Meat should however be quickly seared or blanched first to kill surface microbes.ġ20☏/50☌ - Meat develops a white opacity as heat sensitive myosin denatures. Since enzyme activity increases up to those temperatures, slow cooking can provide a significant aging effect during cooking. Cooking at low temperatures require long periods of time to liquify collagen.ġ05F/40C - 122F/50C-Calpains begin to denature and lose activity till around 105F, cathepsains at 122F. When cooking it is important to liquify collagen.ĭenatu ration of the collagen molecule is a kinetic process, and hence a function of both temperature and duration of heating. This gives meat a lot of flavor and a wonderful silky texture. When you cook, collagen begins to melt at about 160F and turns to a rich liquid, gelatin. These tough cuts of meat contain large amounts of collagen which require long cooking times to break down into a rich gelatin. Slow cooked meals are generally easier to make and very cost effective using cuts of meat that improve in texture and flavor when cooked for long periods of time at low temperatures. Of all the attributes of eating quality, tenderness is rated the most important factor affecting beef palatability.
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