Protein oxidation induced by oxidizing systems in meat from grass-fed cattle and grain-finished cattle

• Grant number: 12/06099-6
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: November 15, 2012
• End date: February 14, 2013
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Science
• Principal Investigator: Mariza Pires de Melo
• Grantee: Alessandra Aparecida Silva
• Supervisor: Youling L. Xiong
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil
• Institution abroad: University of Kentucky (UK), United States
• Associated to the scholarship: 10/08565-9 - Impact of protein and lipidic oxidation on the quality attributes from aged beef., BP.DR

Abstract

The objective of this project is to investigate the protein oxidation in myofibrillar protein isolates from cattle fed to different diets through the use of three different oxidizing systems. For this, ten Longissimus dorsi muscles (from five grass-fed cattle and from five grain-finished cattle) will be used. The myofibrillar protein isolates (MPI) will be prepared and suspended (26 mg of protein/mL) in 15 mM piperazine-N,N bis (2-ethane sulfonic acid) buffer (pH 6.0) with 0.6 M of NaCl. Next, the protein suspension will incubated at 4ºC for 24 h with three different oxidizing systems: iron-catalyzed oxidizing system (IOS), lipid-oxidizing system (LOS, linoleic acid), and metmyoglobin oxidizing system (MOS). The protein oxidation of MPIs in muscles (from grass-fed cattle and from grain-finished cattle) will be evaluated through the increase of carbonyl content and decrease of thiol groups. Analysis of the protein cross-linking products will also be conducted. The data of the carbonyl content and thiol groups will be analyzed using a completely randomized design with split-splot, where feeding is the split and oxidizing system is the splot. (AU)