Reasons for the loss of nutritional value of casings
Oxygen entering causes oxidation browning
This change occurs from the outside in. First, turn the outer layer of the sausage from pink to light, white, and then gradually turn grayish brown. Cut the sausage horizontally to see an oxidation circle, and the longer the time, the deeper the oxidation circle.
Bacterial reproduction causes meat spoilage
Under the protective effect of the casing, bacteria outside the sausage will not enter the interior. The bacteria mentioned here refer to the bacteria in the raw meat of sausages, which cannot be completely killed by the pasteurization method at 80-90 ℃ after filling. This sterilization process can only kill most pathogenic bacteria, but cannot kill heat-resistant Bacillus and other bacteria. These bacteria reproduce slowly under conditions of 0-4 ℃, but if the oxygen resistance of the casing is poor or over time, it can cause sausage spoilage and deterioration. As a result, it loses its edible value.
The loss of moisture in sausages results in a loss of elasticity, a decrease in freshness, and a decrease in taste. This requires the casing to have excellent water resistance.
The loss of sausage aroma requires the casing to have excellent air resistance.