Longissimus from Berkshire pigs in a small-scale supply chain have increased oxidative metabolism, tenderness and water-holding capacity, compared with Large White × Landrace pigs in a modern commercial supply chain.

Context: Selection for leanness in the modern Australian pig has resulted in inconsistent quality, including a lack of pork tenderisation during ageing. Inconsistent quality is potentially a result of differences in supply chain and breed as well as the variation in muscle fibre-type proportion in pork longissimus. Aim: The aim was to investigate differences in fibre-type proportion and pork quality between Large White-Landrace pigs in a large supply chain and Berkshire pigs processed in a small supply chain. Methods: Pigs (n = 22) from two suppliers with different breeds (Supplier 1, Large White × Landrace, SC1-LWLR, n = 12, modern commercial pigs; Supplier 2, Berkshire, SC2-Berk, n = 10, heritage pigs) were slaughtered and samples from the longissimus were extracted at 3, 24, and 48 h postmortem for enzyme and pH analyses. Longissimus samples were subjected to ageing for either 2 or 16 days postmortem (Day 2, Day 16), assessed for colour, muscle fibre-type proportion (%), muscle fibre diameter (μm), water-holding capacity (purge, % and cook loss, %), Warner–Bratzler peak shear force (WBSF, N), and protein denaturation temperature using differential scanning calorimetry (DSC, peak temperature, °C). Key results: SC1-LWLR had higher purge than SC2-Berk (2.85% and 1.83% respectively; standard error of the difference (SED) = 0.33; P = 0.003), higher cook loss on Day 16 (24.63% and 16.79% respectively; SED = 1.62; P = 0.017) and higher WBSF on Day 2 and Day 16 (Day 2, 30.9 N and 26.7 N respectively; Day 16, 28.6 N and 22.0 N respectively; SED = 0.98, interaction P = 0.003). SC1-LWLR had a lower proportion of Type I (10.1% vs 16.0%; SED = 0.51) and Type IIA (14.0% vs 22.0%; SED = 0.77) and a higher proportion of Type IIB (75.9% vs 62.0%; SED = 0.74) (P < 0.001 for all) fibres. SC1-LWLR had lower DSC temperatures for two peaks. SC2-Berk had higher citrate synthase activity (P = 0.003) and glycolytic potential (P < 0.001) than SC1-LWLR. Conclusions: SC2-Berk longissimus had improved quality compared with SC1-LWLR pork, most likely owing, in part, to higher proportion of oxidative and intermediate fibres in the Berkshires. However, effects of differences in environmental conditions and/or processing conditions cannot be ruled out. Implications: The experiment increased our understanding of how variation in supply chains and muscle fibre-type proportion can impact the production of consistently high-quality pork. Inconsistent pork quality, especially tenderness, is related to differences between supply chains and breeds. We investigated differences between supply chains, breed, and muscle metabolism and identified the influence of muscle fibre proportion on pork quality. Pork loins with increased proportions of oxidative fibres, from small supply chains rather than large modern commercial supply chains, have improved quality. [ABSTRACT FROM AUTHOR]