RESUMEN
This research aimed to evaluate the influence of high-intensity ultrasound (HIU) levels (control: 0; high: 747.79; ultra-high: 1344.17 Wcm-2) on pH, instrumental color (redness, R630/580, hue angle and chroma) and oxidative stability (lipid and protein oxidation) of Psoas major (PM) muscle from Nellore cattle raised in two feeding systems: grain and pasture. Using a structural equation modeling (SEM) approach, the relations (P > 0.05) between exogenous (HIU levels) and endogenous (pH, color, lipid and protein oxidation) variables were observed. In beef from grain-fed animals the pH was directly and negatively related to lipid oxidation (γ = -0.321), hue angle (γ = -0.847) and chroma (γ = -0.442) and protein oxidation (γ = -0.752). In PM from pasture-fed HIU exhibited a negative relation with lipid (γ = -0.144) and protein (γ = -0.743) oxidation, suggesting a possible positive influence on the oxidative stability of meat and a positive relation with redness (γ = 0.197) and R630/580 (γ = 0.379). The HIU positively influenced the color and oxidative stability of beef from Bos indicus cattle, and a synergistic effect of HIU and feeding system on beef from pasture-fed animals.
RESUMEN
The aim of the present research was to evaluate the influence of organic and non-organic production systems on color stability and lipid oxidation of broiler meat Pectoralis major (PM) stored under refrigeration (4°C) for 9 days. PM samples from organic (ORG) and non-organic (NORG) production systems were compared based on physicochemical analyses (instrumental color, myoglobin concentration, metmyoglobin reducing activity (MRA), pH, and lipid oxidation) performed in 4 different trials (n = 4). In general, NORG broilers demonstrated higher (P < 0.05) b* and lipid oxidation values than ORG, whereas ORG samples exhibited increased (P < 0.05) MRA, ratio of reflectance at 630 per 580 nanometers (R 630/580), and a* values. The lower color stability observed in NORG samples can be partly due to lipid oxidation. Therefore, the production system can affect color and lipid stability of broiler breast meat during storage.