Influence of ultimate pH on biochemistry and quality of Longissimus lumborum steaks from Nellore bulls during ageing

Abstract

Ultimate pH (pH u ) is an indicator that influences post-mortem meat quality. We studied physiological and biochemical changes of steaks obtained from Nellore bulls (Bos indicus) during post-mortem ageing. To this, Longissimus lumborum (LL) muscles were classified into three groups: Normal-pH u (≤5.79), Intermediate-pH u (5.80-6.29) and High-pH u (≥6.30) groups, portioned into steaks, vacuum packaged and matured at 2°C for 0, 7, 14, 21 and 28 days. High-pH u steaks exhibited impaired colour stability and were darker compared to the other groups. High-and Normal-pH u steaks showed improved tenderness and myofibrillar fragmentation linked to proteolysis. Intermediate-pH u steaks were associated with a lower meat tenderness and decreased collagen solubility. High-pH u steaks retained a high pH during ageing and increased water-holding capacity. These findings provide evidence that highlight pH u as a strategy for the classification of pH u -dependent beef quality from Nellore bulls that can be adopted by the Brazilian meat industry.

H2O2-induced oxidative stress improves meat tenderness by accelerating glycolysis via hypoxia-inducible factor-1α signaling pathway in postmortem bovine muscle

“…Normally, the pH drops from 7.2 to around 5.4–5.7 and causes the gradual acidification of muscle during postmortem aging, which further affects the development of quality attributes including tenderness, color, and juiciness ( Kamenik et al, 2021 ). For instance, when the pH falls below 6.0, proteolytic enzymes such as calpains and caspases are activated to degrade myofibrillar proteins, driving the onset of meat tenderization ( Baron et al, 2021 , Ma et al, 2022 , Xing et al, 2021 ). Besides, the pH decline is also associated with protein denaturation, myoglobin oxidation, and water migration ( Kamenik et al, 2021 , Li et al, 2020 ).…”

“…2 D). It is noteworthy that a low pH in the early postmortem period promotes the hydrolysis of myofibrillar proteins, resulting in a fast tenderization process during postmortem aging ( Baron et al, 2021 , Ma et al, 2022 ). Therefore, shear force and MFI were evaluated in this study to confirm whether ROS affect meat tenderization by accelerating postmortem glycolysis.…”

Effect of postmortem pH on the physical, biochemical, and sensory characteristics of bovine longissimus thoracis et lumborum muscle

“…The pH meter was calibrated using standard buffers at pH 4.0 and 7.0. Based on the aging studies by Jiang et al ( 2010 ) and Barón et al ( 2021 ), no further pH measurements after 24 h were carried out. Kim et al ( 2015 ) and Li et al ( 2013 ) posited that over a duration of 2 weeks, aging had little or no impact on the pH regardless of the aging method.…”

Meat (Longissimus lumborum Muscle) Quality in Males of the Family Cervidae

“…The average values of pH in the LL muscle were typical of normal-quality meat, i.e. 5.5 -5.8 (Barón et al, 2021). According to Hoffman (2001), lower acidity of meat from most game animal species is the consequence of pre-mortem stress associated with the harvest method (the use of beaters, hunting dogs, means of transport).…”