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Ligand binding to recombinant bovine acyl-CoA-binding protein (rACBP) was examined using a Lipidex 1000 competition assay and an e.p.r. spectroscopy displacement assay. Of all putative ligands tested, rACBP exhibited a high binding affinity only for acyl-CoA esters. No alternative ligands could be found in rat liver fractions purified on an affinity of column on which ACBP was coupled to Sepharose 4B. E.p.r. data indicate that both the acyl chain and the CoA head group of acyl-CoA are involved in binding and that the 3'-phosphate group on the ribose moiety of acyl-CoA esters plays a crucial role in the binding of acyl-CoA to ACBP. E.p.r. competition binding studies show that the binding affinity of acyl-CoA esters for rACBP is strongly dependent on the length of the acyl chain with a clear preference for acyl-CoA esters with 14-22 carbon atoms in the acyl chain. No correlation between the number of double bonds in the acyl chain and the binding affinity was observed. The experimental results strongly indicate that ACBP specifically binds long-chain acyl-CoA esters with a very high affinity, results that indicate that ACBP is likely to be involved in the intracellular transport and pool formation of these compounds.

The basic contractile unit of muscle, the sarcomere, will contract as the muscle goes into rigor post-mortem. Depending on the conditions, such as the rate of pH decline, the cooling rate and the mechanical restraints on the muscles, this longitudinal shortening will result in various post-mortem sarcomere lengths as well as lateral differences in the distances between the myosin and actin filaments. This shortening is underlying the phenomena described as rigor contraction, thaw rigor, cold shortening and heat shortening. The shortening in combination with the molecular architecture of the sarcomere as defined by the myosin filaments and their S-1 and S-2 units, the interaction with the actin filaments, and the boundaries formed by the Z-disks will subsequently influence basic meat quality traits including tenderness and water-holding capacity. Biochemical reactions from proteolysis and glycogen metabolism interrelate with the sarcomere length in a complex manner. The sarcomere length is also influencing the eating quality of cooked meat and the water-holding in meat products.

Heat treatment of meat at temperatures between 50 and 65 °C, for extended periods of time, is known as low-temperature long-time (LTLT) cooking. This cooking method produces meat that has increased tenderness and better appearance than when cooked at higher temperatures. Public concerns regarding this method have focused on the ability to design heat treatments that can reach microbiological safety. The heat treatment induces modification of the meat structure and its constituents, which can explain the desirable eating quality traits obtained. Denaturation, aggregation, and degradation of myofibrillar, sarcoplasmic and connective tissue proteins occur depending on the combination of time and temperature during the heat treatment. The protein changes, especially in relation to collagen denaturation, along with proteolytic activity, have often been regarded to be the main contributors to the increased meat tenderness. The mechanisms involved and the possible contribution of other factors are reviewed and discussed.

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Protein oxidation readily occurs in postmortem muscle during storage and processing. Over the past decade new analytical methods have been developed and new aspects of protein oxidation in meat have been studied, such as the reaction mechanism, and impacts on eating quality and nutritional value. It is now evident that amino acid side chains in myofibrillar proteins undergoes modifications due to oxidative stress. In turn this will lead to formation of new protein-protein cross-links in structural proteins, however, also the overall level of fixed-charge groups attached to the peptide backbones is modified. Meat texture and water-holding are important quality attributes and they are affected by the oxidation of structural proteins. Different mechanisms have been suggested to explain the oxidation-induced quality changes, focusing mainly on reduced proteolysis and formation of cross-links. This review explores the current understanding of protein oxidation in fresh meat in relation to texture and water-holding. The consequences of protein oxidation at molecular level in relation to oxidation-induced cross-linking and changes in net charges of myofibrillar proteins, and the impacts on texture and water-holding are discussed.