Determination of the Effect of Different Energy Classes of Household Refrigerators on the Freezing Process and the Quality Characteristics of Beef

The household refrigerator model used for freezing processes in this study was produced in the factory in different energy classes (C, D, and E). Equal amounts of beef (10 × 10 × 2 cm; 2 × 2 × 2 cm) and minced beef (10 × 10 × 2 cm) were placed in refrigerator bags before freezing. The freezing processes were carried out by placing beef samples on the top shelf where the radial fan was located in the freezer compartment of the refrigerators. After the frozen samples were thawed at +4°C, they were cooked in a water bath at 85°C. It was determined that the samples frozen in the refrigerator belonging to the D energy class at −24°C had shorter freezing times and therefore higher freezing rates. It was observed that pH (5.54–5.72) values of samples frozen in the D energy class were higher due to lower weight loss (0.32%–6.80%) values. When their color values were examined, the redness (a^∗) values (15.09–17.61) were the highest, while the yellowness (b^∗) values (10.31–13.29) were the lowest in these samples. In addition, the hardness (49.00–182.74) and chewiness (16.35–71.80) values of samples frozen in Energy Class D were found to be lower, while their protein denaturation temperatures were higher due to shorter freezing times. Consequently, in this study, the effects of the difference in energy classes of refrigerators on the quality characteristics of beef samples were examined, and the refrigerator belonging to the energy class (D) that gave the best quality properties was found to be the most suitable one for freezing the beef.