Search

Formation of thaw loss cannot generally be avoided when meat is frozen and then thawed. Explanations have mainly focused on the damage to muscle fibers resulting from ice crystallization and the freezing-induced denaturation of myofibrillar proteins, the latter of which has, however, not received much research focus. This review discusses the relationship between myofibrillar protein denaturation and water-holding capacity of meat in freezing-thawing with the aim to improve the understanding the relative importance of protein denaturation in the formation of thaw loss. The contribution of decreased pH and high ionic strength in the unfrozen water in freezing is emphasized and we hypothesize that these two factors are causing protein denaturation and conformational changes within muscle fibers, and consequently loss of water-holding capacity. Slow freezing produces more thaw loss than fast freezing, and this is discussed here in relation to the impacts on myofibrillar protein denaturation induced by the freezing rate.

Dans le cadre du consortium européen Gemqual, 436 jeunes bovins issus de 15 races bovines différentes ont été conduits dans des systèmes d'élevage similaires afin d'évaluer l'impact de la race sur la qualité organoleptique de la viande déterminée par analyse sensorielle. Une comparaison de deux méthodes statistiques pour traiter les données de l'analyse sensorielle a tout d'abord été réalisée. L'analyse de variance avec ou sans effet dégustateur a abouti à des résultats similaires indiquant que ce choix méthodologique n'est pas décisif pour l'interprétation des résultats. Une classification non supervisée (classification ascendante hiérarchique) a ensuite permis de classer les races en fonction de trois profils sensoriels sur la base de 4 descripteurs (tendreté, jutosité, intensité de flaveur et flaveur anormale). Elle permet de mettre en évidence 5 associations de races. : Les races Aberdeen Angus, Highland et Jersey, qui ont une teneur élevée en lipides dans le muscle étudié (Longissimus thoracis), se sont distinguées des autres races par une flaveur de bœuf plus élevée. Les races mixtes et rustiques, Simmental, Casina et Marchigiana, ont produit une viande significativement moins juteuse et moins tendre que celle des races sélectionnées pour la production de viande. Les trois autres associations suivantes rassemblent les races Limousine et Charolaise dont le profil semble assez proche, les races Pirenaica et Avilena tendres et fortement appréciées par les panélistes, les races Asturiana de los Valles et Piemontaise caractérisées par une flaveur anormale plus intense. Dans l'ensemble, malgré des différences significatives de caractéristiques de l'animal, de la carcasse et du muscle, les différences de qualité sensorielle entre la plupart des races étaient faibles, avec seulement des différences significatives entre les quelques races qui présentaient des profils sensoriels extrêmes (comme la Simmental et la Pirenaica). Published Cet article correspond à une étude publiée dans Livestock Science 250 (2021) 104548. Elle démontre qu’il existe peu de différences de qualité sensorielle entre races bovines bien que les races rustiques ou mixtes tendent à produire une viande légèrement moins tendre et moins juteuse et les races les plus grasses une viande avec plus de goût

Publisher Copyright: © 2021 Institute of Food Technologists® Over the recent decades,protein oxidation in muscle foods has gained increasing research interests as it is known that protein oxidation can affect eating quality and nutritional value of meat and aquatic products. Protein oxidation occurs during freezing/thawing and frozen storage of muscle foods, leading to irreversible physicochemical changes and impaired quality traits. Controlling oxidative damage to muscle foods during such technological processes requires a deeper understanding of the mechanisms of freezing-induced protein oxidation. This review focus on key physicochemical factors in freezing/thawing and frozen storage of muscle foods, such as formation of ice crystals, freeze concentrating and macromolecular crowding effect, instability of proteins at the ice–water interface, freezer burn, lipid oxidation, and so on. Possible relationships between these physicochemical factors and protein oxidation are thoroughly discussed. In addition, the occurrence of protein oxidation, the impact on eating quality and nutrition, and controlling methods are also briefly reviewed. This review will shed light on the complicated mechanism of protein oxidation in frozen muscle foods.

In the past decades, metabolomics has been used to comprehensively understand a variety of food materials for improvement and assessment of food quality. Farm animal skeletal muscles and meat are one of the major targets of metabolomics for the characterization of meat and the exploration of biomarkers in the production system. For identification of potential biomarkers to control meat quality, studies of animal muscles and meat with metabolomics (MEATabolomics) has been conducted in combination with analyses of meat quality traits, focusing on specific factors associated with animal genetic background and sensory scores, or conditions in feeding system and treatments of meat in the processes such as postmortem storage, processing, and hygiene control. Currently, most of MEATabolomics approaches combine separation techniques (gas or liquid chromatography, and capillary electrophoresis)-mass spectrometry (MS) or nuclear magnetic resonance (NMR) approaches with the downstream multivariate analyses, depending on the polarity and/or hydrophobicity of the targeted metabolites. Studies employing these approaches provide useful information to monitor meat quality traits efficiently and to understand the genetic background and production system of animals behind the meat quality. MEATabolomics is expected to improve the knowledge and methodologies in animal breeding and feeding, meat storage and processing, and prediction of meat quality.

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.

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.

International audience; Cattle meat provides essential nutrients necessary for a balanced diet and health preservation. Besides nutritional quality, consumers' preferences are related to specific attributes such as tenderness, taste and flavour. The present study characterizes the fatty acid composition of beef, which is an important factor in both nutritional and quality values, in 15 European cattle breeds fed a similar diet and reared in five countries (United Kingdom, Denmark, France, Italy and Spain). The effect of possible slight differences on diet composition which might have occurred between countries were included in the breed effect which confounds country, diet, slaughter house and slaughter day as all individuals of a same breed were managed simultaneously. The wide range of breeds studied and the significant differences on lipid profile described here provide a broad characterization of beef meat, which allows giving a better response to the variety of consumers' preferences. Regarding meat health benefits, the groups that stand out are: the double-muscled animals, which displayed lower total fat, lower proportion of saturated (SFA) and monounsaturated (MUFA) fatty acids, and a higher proportion of polyunsaturated (PUFA) fatty acids; and Limousin and Charolais breeds with a significantly higher conversion of 18:3n-3 PUFA to the long chain 22:6n-3 PUFA.