R. Bras. Zootec.20/Mar/2026;55:e20250035.
Protein degradation, oxidation stability, microbiological quality and physicochemical properties in beef muscles subjected to freeze-thawing cycle
ABSTRACT
Freezing is one of the fundamental preservation techniques for increasing the shelf-life of meat. However, the quality of frozen meat is highly dependent on the thawing process. Thus, the current study sought to investigate the effects of freeze-thawing processing on protein degradation, lipid oxidation, microbiological spoilage, and qualitative parameters of two types of beef muscles: Longissimus lumborum and Semitendinosus. Beef muscles were collected from ten steer carcasses of at approximately 15 months of age with a mean body weight of 440 ± 50 kg, at 24 h post-mortem at a commercial slaughterhouse. The muscles were divided into two groups randomly: chilled or frozen-thawed. The freezing and thawing processes resulted in significantly higher degrees of protein and lipid oxidation in meat, resulting in reduced pH, moisture retention ability, and color stability. During the freeze-thawing process, there was a higher desmin degradation but no change in troponin T degradation. Frozen-thawed meat samples exhibited significantly increased growth of total aerobic count, Pseudomonas spp., Enterobacteriaceae, and coliform counts than those from chilled samples. Due to freezing-thawing, Longissimus lumborum muscle was more color-stable and had greater water holding capacity than Semitendinosus muscle (P≤0.05). The data indicate that freeze-thawing consistently caused protein degradation, fat oxidation, color deterioration, and reduced water holding capacity in both beef muscle types. Therefore, to avert quality deterioration during frozen storage, it is imperative to consider the characteristics of each beef muscle.
Keywords: beef muscle; freeze-thawing; meat quality; oxidative stability; proteolysis
