肠衣是香肠的外包装，其基本的功能就是保证香肠在一定条件及时间内不变质，以满足贮存及流通的需要。这种功能由肠衣的阻隔性指标所提供的，即：氧气阻隔性、水汽阻隔性、香味阻隔性。
Sausage coat is the outer packaging of sausage, its basic function is to ensure that the sausage does not deteriorate in certain conditions and time to meet the needs of storage and circulation. This function is provided by the intestinal barrier indicators, namely: oxygen barrier, water vapor barrier, aroma barrier.