Physicochemical, volatile compounds, oxidative and sensory profiles of the Longissimus muscle of six South African sheep breeds

Abstract

Context The scarcity of water and feed for sheep is a characteristic feature in the dryland areas of South Africa, and adversely affects meat production and quality. To address this challenge, breeds with high water, feed and production efficiencies must be used to produce meat of desirable quality. Aim The study aimed to compare physicochemical, volatile compounds, oxidative and sensory profiles of the Longissimus muscle from selected South African sheep breeds raised under intensive feeding conditions. Methods Physicochemical, oxidative, volatile compounds and sensory profiles of the Longissimus muscle from lambs of indigenous (Damara, n = 10; Pedi, n = 8), indigenous composite (Dorper, n = 10; Meatmaster, n = 9) and exotic composite (Dohne Merino, n = 10; South African Merino, n = 10) breeds that were penned individually and fed a lamb-finishing diet ad libitum over a 42-day test period were evaluated. Results Dohne Merino had the highest intramuscular fat content, whereas Damara and Pedi had the lowest (P ≤ 0.05). Meat lightness increased over time, with Pedi having the highest values on Day 7 of retail display at 4°C, followed by the Merinos (P ≤ 0.05). On Day 7, meat from the Merinos had the highest lipid oxidation values, whereas Damara and Pedi had the lowest (P ≤ 0.05). The lowest meat protein oxidation values on Day 7 were recorded for the Meatmaster, followed by Dohne Merino (P ≤ 0.05). Relative to the other breeds, Dohne Merino had the greatest concentrations of alcohols, aldehydes and acidic volatile compounds, and the lowest concentrations of esters (P ≤ 0.05). In addition, the Merinos had meat that was slightly more tender and juicy (P ≤ 0.05) than that of Damara and Dorper. Conclusions Even though indigenous breeds produced meat with comparable oxidative shelf-life and sensory quality attributes to composite breeds under intensive feeding conditions, they had leaner meat than the later breeds. Implications The observed variations in meat physicochemical and oxidative shelf-life parameters allow producers to select breeds that are best suited to their production systems, resources and market requirements.