Muscle glycogen and collagen solubility in final pH ranges, with an approach to technical-scientific dissemination of the impacts of natural acidification on beef quality.

• Grant number: 22/12972-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2022
• End date: August 31, 2023
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Science
• Principal Investigator: Carmen Josefina Contreras Castillo
• Grantee: Gabriele de Fátima Marchezin Baccarin
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 17/26667-2 - Beef quality in Bos indicus cattle: biological markers for meat attributes in different ultimate pH ranges, AP.TEM

Abstract

Muscle glycogen is one of the main compounds involved in post-mortem energy metabolism, and its concentration at the time of slaughter is a factor that alters the natural acidification of meat (drop in pH). The determination of its concentration is a fundamental data to compose the studies related to obtaining carcasses that present different ranges of final pH (< 5.7 = normal; > 5.8 and < 6.1 = intermediate; > 6.2 = high). Among the meat quality attributes, water retention capacity and color stability in meat are affected by the final pH. In addition, the rate of proteolysis can also be impacted by the final pH, influencing proteases responsible for meat tenderization. Although post-mortem proteolysis of stromal proteins is considered to have little impact, metalloproteinases can act on the collagenous matrix, and in any case, total collagen and its solubility are important factors in defining softness, therefore, other fundamental parameters for verification in the study of collagen. impact of final pH ranges on meat tenderness. All the biophysical and chemical aspects involved in the project are of great importance for meat science, and the numerous determinations, in addition to the proposals in this project, that make up the research of the associated thematic project, involving determination of instrumental tenderness, coloring parameters, water retention (which were and will be obtained by other fellows in collaboration, and whose steps will be monitored at some point by the fellow) are valuable information that will benefit from technical-scientific dissemination in digital media. The aim of the project is to study the impact of the initial concentration of muscle glycogen on the definition of the three pH ranges and its relationship with softening, collagen solubility and instrumental softness. A total of 80 ringed, uncastrated male bovines (Bos indicus), with up to 35 months of age, will be used, in whose carcasses the final pH (42-46 hours) will be determined. Glycogen concentrations in samples of Longissimus thoracis et lumborum muscle taken approximately 30 minutes after slaughter and 24 hours post mortem, as well as the concentration of total and soluble collagen in samples obtained 72 hours post mortem, will be determined by the scholarship holder. All samples were or will be frozen in liquid nitrogen for further analysis. The carcass samples will have physicochemical quality determined by collaborators, including biochemical characterization related to myofibrils, myofibrillar proteolytic systems and instrumental softness. During the process, posts will be made on the Instagram platform in order to disseminate the methodologies and analyzes carried out in the laboratory with research projects linked to the theme, postgraduate research, within public-private partnerships and research funding agencies; in addition to reaching a greater number of people and presenting the project in question in a didactic and visual way to the scientific community, consumer public and all those interested in the meat chain.