The effects of reheating methods on the quality characteristics of precooked ground pork patties with various salt and phosphate levels

The objective of this study was to determine the effect of reheating methods on the quality characteristics of precooked ground pork patties with various salt and phosphate levels. Cooking and reheating methods used were the electric grill cooking and microwave oven cooking. All treatments were composed by 80% pork ham and 20% pork fat. Salt and phosphate level about each treatment are as follows; S1 1% salt, S1+P 1% salt and 0.3% phosphate, S2 2% salt, S2+P 2% salt and 0.3% phosphate. The pH value reheated during storage was affected by phosphate, but water content was influenced by reheating method and phosphate. Reheating time and rate were affected by phosphate and reheating method, and there was a highly negative relationship between reheating time and rate (p<0.05). Reheating methods had a more effect on reheating loss and reduction in diameter, compared with the addition of phosphate. Hardness was affected by reheating methods and phosphate, and there was a negative relationship between water content and hardness in reheating (p<0.05). Therefore, reheating methods were more influential on the reheating properties of ground pork patties than the salt and phosphate level. Introduction Commercial precooked meat products may be frozen uncooked, frozen cooked, or cooked and stored at refrigerator temperature. Consumers use many cooking methods for eating pre-cooked meat products such as patty and sausage. Studies about reheating have mostly reported the problem such as an off-flavor called “warmed-over flavor”. But several studies have also been studied on the tenderness of whole meat (Obuz et al., 2003) and sausage (Egelandsdal et al., 2007). In order to minimize the change of qualities by reheating, it is necessary to make a basic study on adequate reheating temperature and time for various cooking methods such as conventional and microwave cooking. The objective of this study, therefore, was to determine the effect of reheating methods on the quality characteristics of precooked ground pork patties with various salt and phosphate levels. Materials and methods The fresh pork hams (M. biceps femoris, M. semitendinosus, and M. semimembranosus) were purchased from a local processor at 48 h postmortem. Lean muscles were initially ground through Φ-13 mm plate and the pork back fat was ground through Φ-8 mm plate using a meat grinder (PM-70, Mainca, Barcelona, Spain). All treatments were composed by 80% pork ham and 20% pork fat. Salt and phosphate level about each treatment are as follows; S1 1% salt, S1+P 1% salt and 0.3% phosphate, S2 2% salt, S2+P 2% salt and 0.3% phosphate. The mixtures from each batch were mixed for 30 min at 4 °C using a meat mixer (RM-90, Mainca, Barcelona, Spain). Patty was formed into 120±1 g weight, 100 mm diameter, and 15 mm thickness using patty presses and then stored at 4 °C. The cooking methods used were electric grill cooking and microwave cooking. In the electric grill cooking method, patties were cooked by electric grill. Patties were cooked for 3 min on one side and for 3 min on the opposite side, and thereafter flipped over every 2 min until the targeted center temperature reached to 76.5 °C (Zimmermann, 1984) using a digital thermometer. In the microwave cooking method, patties were cooked in a household-type microwave oven with medium-high power (750 W). The center temperature of the patties was measured using a fiber optic system until reached to 76.5 °C. The precooked patties were stored at 4 °C for 3, 6, and 10 days, then were reheated. Electric grill and microwave oven reheating was conducted identically according to each cooking method. The precooked patties were reheated only until the internal temperature of patty reached to 74 °C (Cremer & Hartley, 1988). The pH value was measured with a pH meter (Model 340, Mettler-Toledo GmbH, Schwerzenbach, Switzerland). The moisture content was determined by weight loss after 12 h of drying at 105 °C in a drying