Oxidative stability in fresh, aged and refrigerated beef meat from Aberdeen Angus steers produced in Uruguay

Doctoral thesis abstract

Abstract

This Doctoral thesis was divided in three parts. In the first one, the impact of the three feeding systems that take place in Uruguay (pasture, pasture plus grain supplementation and feedlot) on the oxidative stability of fresh and aged beef meat from Aberdeen Angus steers, was investigated. A feeding system effect was observed on lipid oxidation in the aged outside and the fresh blade bolar cuts, where pasture plus grain supplementation (P+S) system presented a higher oxidation, and on protein oxidation in the outside cut (Pasture>P+S, Feedlot) and in the blade bolar cut (P+S>Pasture). A higher catalase activity was found in the striploin of pasture system compared with the other two systems, and a higher superoxide dismutase activity in pasture and feedlot systems compared with P+S (striploin) and in pasture system compared with feedlot (blade bolar). Glutathione peroxidase (GPx) activity was higher in feedlot meat compared with the other two systems (in the three cuts studied). Pasture system presented a higher antioxidant capacity compared with feedlot system in the aged striploin cut. In the second part of the thesis, the effect of supplementating with organic selenium in the diet of Aberdeen Angus steers in feedlot, on the oxidative stability of fresh and aged meat, was evaluated. A lower protein oxidation and a higher GPx activity were found in the striploin, and a higher catalase activity in the tenderloin and the striploin cuts were found, from supplemented steers compared with not supplemented. In the third part, the aim was to determine if meat from Aberdeen Angus steers produced in pasture and in feedlot had differential oxidative and colour stability, when submitted to refrigerated retail display conditions. Lower lipid and protein oxidation, and a greater colour stability was found in meat from pasture system compared with meat from feedlot, during display. This is backed up by the higher content of β-carotene and α-tocopherol (antioxidants) found in fresh meat from steers produced in pasture.