For those that harvest and process their own meats, here are some interesting things to consider....
Chapter 1 - Principles of Meat Science
Meat is composed of: water - 75%
protein - 20%
fat (varies greatly) - 3%
sugar (glycogen, glucose) - 1%
vitamins and minerals - 1%
Different animals or even meat cuts from the same animal exhibit different proportions of above components and this depends on the animal’s physical activity and type of diet. Those factors not only affect animal meat’s components, but the color of the meat as well.
Meat contains about 75% of water but fat contains only 10-15%.
This implies that a fatty meat will lose moisture faster as it has less moisture to begin with, the fact which is important when making air dried or slow fermented products. As the animal matures, it usually increases in fatness, which causes a proportional loss of water.
Meat Aging
When an animal dies, the oxygen stops flowing and many reactions take place inside. For a few hours the meat remains relaxed and may still be processed or cooked. Then muscles contract and the meat stiffens which is known as the “rigor mortis” stage. During that stage, which lasts differently for different animals, the meat should not be processed or cooked as the resulting product will be tough. Meat stock prepared from meats still in the rigor mortis stage is cloudy and has poor flavor. When this stage ends, the meat enters rigor stage and is kept in a cooler. In time it becomes tender again and is ready for processing. It is widely accepted that this happens due to the changes in the protein structure.
The length of rigor mortis or rigor stage directly depends on temperature. The higher the temperature, the shorter the stages and vice versa. Make note that aging meat at high temperature will help bacteria to grow and will adversely affect meat’s shelf keeping qualities.
mortis.
Times for onset and resolution of rigor
Cattle 12 - 24 hours 2 - 10 days
Pigs 6 - 12 hours 1 - 2 days
Lamb 7 - 8 hours 1 day
Turkey ½ - 2 hours 6 - 24 hours
Chicken ½ - 1 hour 4 - 6 hours
Rabbit 12 - 20 hours 2 - 7 days
Venison 24 - 36 hours 6 - 14 days
Looking at the above data, it becomes conclusive that the aging process is more important for animals which are older at the slaughter time (cattle, venison). Warm meat of a freshly slaughtered animal exhibits the highest quality and juiciness. Unfortunately there is a very narrow window of opportunity for processing it. The slaughter house and the meat plant must be located within the same building to be effective.
Meat that we buy in a supermarket has already been aged by a packing house. If an animal carcass is cooled too rapidly (below 50° F, 10° C) before the onset of the rigor (within 10 hours), the muscles may contract which results in tough meat when cooked. This is known as “cold shortening.” To prevent this the carcass is kept at room temperature for some hours to accelerate rigor and then aged at between 30-41° F, (-1 - 5° C).
pH of the meat
When an animal is alive the pH (acidity) value of its meat is around 7.0 (neutral point). After the slaughter and bleeding, the oxygen supply is interrupted and enzymes start converting glycogen (meat sugar) into lactic acid. This lowers the pH (increases acidity) of the meat and the process is known as glycolysis. This drop is as follows:
Beef - pH of 5.4 to 5.7 at 18-24 hours after slaughter.
Pork - pH of 5.4 to 5.8 at 6-10 hours after slaughter.
The concept of pH is also covered in Chapter 20 - Fermented Sausages. Understanding pH of meat is quite important as it allows us to classify meats by the pH and to predict how much water a particular type can hold. If you drink lemon juice or vinegar you know the acidic taste of it. Gentle foods such as milk will be found on the opposite end of the scale.
Marianski, Stanley. Home Production of Quality Meats and Sausages (Kindle Locations 87-91). Bookmagic LLC. Kindle Edition.
Chapter 1 - Principles of Meat Science
Meat is composed of: water - 75%
protein - 20%
fat (varies greatly) - 3%
sugar (glycogen, glucose) - 1%
vitamins and minerals - 1%
Different animals or even meat cuts from the same animal exhibit different proportions of above components and this depends on the animal’s physical activity and type of diet. Those factors not only affect animal meat’s components, but the color of the meat as well.
Meat contains about 75% of water but fat contains only 10-15%.
This implies that a fatty meat will lose moisture faster as it has less moisture to begin with, the fact which is important when making air dried or slow fermented products. As the animal matures, it usually increases in fatness, which causes a proportional loss of water.
Meat Aging
When an animal dies, the oxygen stops flowing and many reactions take place inside. For a few hours the meat remains relaxed and may still be processed or cooked. Then muscles contract and the meat stiffens which is known as the “rigor mortis” stage. During that stage, which lasts differently for different animals, the meat should not be processed or cooked as the resulting product will be tough. Meat stock prepared from meats still in the rigor mortis stage is cloudy and has poor flavor. When this stage ends, the meat enters rigor stage and is kept in a cooler. In time it becomes tender again and is ready for processing. It is widely accepted that this happens due to the changes in the protein structure.
The length of rigor mortis or rigor stage directly depends on temperature. The higher the temperature, the shorter the stages and vice versa. Make note that aging meat at high temperature will help bacteria to grow and will adversely affect meat’s shelf keeping qualities.
mortis.
Times for onset and resolution of rigor
Cattle 12 - 24 hours 2 - 10 days
Pigs 6 - 12 hours 1 - 2 days
Lamb 7 - 8 hours 1 day
Turkey ½ - 2 hours 6 - 24 hours
Chicken ½ - 1 hour 4 - 6 hours
Rabbit 12 - 20 hours 2 - 7 days
Venison 24 - 36 hours 6 - 14 days
Looking at the above data, it becomes conclusive that the aging process is more important for animals which are older at the slaughter time (cattle, venison). Warm meat of a freshly slaughtered animal exhibits the highest quality and juiciness. Unfortunately there is a very narrow window of opportunity for processing it. The slaughter house and the meat plant must be located within the same building to be effective.
Meat that we buy in a supermarket has already been aged by a packing house. If an animal carcass is cooled too rapidly (below 50° F, 10° C) before the onset of the rigor (within 10 hours), the muscles may contract which results in tough meat when cooked. This is known as “cold shortening.” To prevent this the carcass is kept at room temperature for some hours to accelerate rigor and then aged at between 30-41° F, (-1 - 5° C).
pH of the meat
When an animal is alive the pH (acidity) value of its meat is around 7.0 (neutral point). After the slaughter and bleeding, the oxygen supply is interrupted and enzymes start converting glycogen (meat sugar) into lactic acid. This lowers the pH (increases acidity) of the meat and the process is known as glycolysis. This drop is as follows:
Beef - pH of 5.4 to 5.7 at 18-24 hours after slaughter.
Pork - pH of 5.4 to 5.8 at 6-10 hours after slaughter.
The concept of pH is also covered in Chapter 20 - Fermented Sausages. Understanding pH of meat is quite important as it allows us to classify meats by the pH and to predict how much water a particular type can hold. If you drink lemon juice or vinegar you know the acidic taste of it. Gentle foods such as milk will be found on the opposite end of the scale.
Marianski, Stanley. Home Production of Quality Meats and Sausages (Kindle Locations 87-91). Bookmagic LLC. Kindle Edition.
