Effect of Storage on the Physicochemical and Textural Quality of Pork Chops and Chicken Breast

Abstract

Meat is an essential source of amino acids and micronutrients in the human diet, and its consumption is increasing worldwide. Chicken and pork meat currently dominate the global market due to their affordability and availability. Nevertheless, meat is a highly perishable food with a short shelf life; due to its greater water activity and can be prone to the growth of microorganisms leading to accelerated deterioration. For the meat industry, extending the shelf life of products while maintaining wholesome quality is essential. Therefore, cold storage methods such as refrigeration and freezing, along with vacuum packaging, can help extend the shelf life of meat. To understand the impact of storage on physical, chemical and textural characteristics, two studies were conducted under cold storage conditions. In the first study, the impact of 120 days of frozen storage on the characteristics of vacuum-packed chicken breasts was evaluated. Chicken breasts (N = 25 per sampling day) were analyzed on days 0, 30, 60, 90 and 120 of storage, for cooked color, cooking loss, Warner-Bratzler shear force, and texture profile. Chicken breast fillets were darker (p < 0.0001) after 30 days, as well the surface was more yellow (p < 0.0005) and also further from the red axis and greater vividness on day 120. Cooking losses increased with increased storage time (p < 0.0074) and Warner-Bratzler shear force decreased (p < 0.0002) during storage. Texture profile analysis decreased until day 60 and then an increase in hardness (p < 0.0003) and chewiness (p < 0.0001) occurred through day 120 of storage. Frozen storage at -20°C effectively preserved the quality of the chicken breast in the short term, but after 2 months there was a noticeable deterioration in chicken characteristics. A second study analyzed the impact of 60-day refrigerated (Treatment 1) and frozen (Treatment 2) storage on the quality characteristics of pork chops. Pork chops were analyzed every 10 days during storage (as described) and evaluated for cooking loss, Warner- Bratzler shear force, texture profile, internal cooked color, and pH values. Cooking loss increased (p < 0.0001) while shear force decreased (p < 0.0001) throughout storage and treatment 2 resulted in greater shear force (p < 0.0001) compared to treatment 1. For texture profile analysis, both treatments decreased in hardness, but Treatment 2 was harder (p < 0.0001) than Treatment 1. Similarly, chewability and resilience decreased over time (p < 0.0001). Cooked internal color decreased (p < 0.0001) for L*, a*, b* values, and the red-to-brown color transition during storage for both treatments. Finally, pH values decreased (p < 0.0001) over the days of refrigerated storage. These findings from study two demonstrate that preservation methods are essential to extending shelf life and maintain the quality of a retail pork product. Regardless of the storage treatment, prolonged storage had the greatest impact on pork quality causing gradual changes, while storage temperature only modulates the speed at which these changes occur.