Quality Characteristics of Vacuum-Packaged Pork Patties Irradiated and Stored in Refrigerated or Frozen Conditions
Pork loins were ground twice through a 9-mm plate and patties (approximately 80 g each) were made. Patties were individually vacuum-packaged in oxygen impermeable plastic bags and stored either in a cooler (4°C) or a freezer (-40°C). Refrigerated patties were irradiated 0, 1.5, 3.0, or 4.5 kGy and stored at 4°C for 2 weeks, and frozen ones were irradiated at 0, 2.5, 5.0, or 7.5 kGy and stored at - 40°C for 3 months. Samples were analyzed for lipid oxidation, volatile production, and off-odor during refrigerated or frozen storage. The 2-thiobarbituric acid reactive substances (TABRS) values of both refrigerated and frozen patties were not changed during storage. Irradiation dose had no effect on the TBARS of refrigerated patties, but patties irradiated at 7.5 kGy had higher TBARS value than the nonirradiated control. With refrigerated storage, panels could detect irradiation odor at day 0, but could not detect after 1 week of storage at 4°C. With frozen storage, however, irradiation odor was detected even after 3 months of storage. No difference in odor preference was found between irradiated and nonirradiated samples. Vacuum packaging was better than aerobic packaging for irradiation and subsequent storage of meat because it could minimize oxidative changes in patties during storage and produced minimal amount of volatile compounds responsible for irradiation odor.