Effects of nitrite incorporated active films on quality of pork.

Nitrite (0.25-2%) incorporated thermoplastic starch (TPS) and linear low-density polyethylene (LLDPE) blend films were produced by the conventional blown-film extrusion process. Films were characterized and determined for efficacy as active packaging for pork steak. Scanning electron micrographs showed enhanced starch granule disruption due to melting. Increased nitrite contents enhanced the starch network and improved mechanical properties. Water vapor and barrier properties of blend films were improved by nitrite incorporation, with increased compatibility between TPS and LLDPE networks. Films containing 0.5% nitrite effectively improved redness and corresponded to 0.06 ppm residual nitrite and 75 ppm nitrosomyoglobin in packaged pork. Nitrite addition modified protein secondary conformation involving CO stretching bonds via H-bonding, while films with 1% and 2% nitrite significantly inhibited growth of lactic acid bacteria, yeast and mold, and retained softer texture during storage. Nitrite incorporated films were demonstrated as efficient active packaging to improve the quality of red meat products.