Impact of cooking temperature on pork longissimus, and muscle fibre type, on quality traits and protein denaturation of four pork muscles

Abstract

Variations in pork quality impact consumer acceptance, and fibre type differences between muscles contribute to this variation. The aim was to investigate the influence of variations in muscle fibre types and protein denaturation peaks across four pork muscles and the influence of ageing and cooking temperature on longissimus quality traits. The longissimus, masseter, cutaneous trunci, and psoas major from 13 carcases were removed 1-day postmortem and subjected to 0- or 14-days ageing (d0, d14). Quality traits, protein denaturation peak temperature (DSC), fibre diameter and fibre type proportions were measured. Cook loss for longissimus was similar on d0 and d14, but was higher on d14 for masseter, cutaneous trunci, and psoas major. Warner-Bratzler shear force was highest, and ultimate pH was lowest, for longissimus, and similar among cutaneous trunci, masseter, and psoas major. Masseter had lowest L* and highest a* and longissimus and cutaneous trunci had highest L* and lowest a*. The DSC temperature peaks for longissimus occurred at lower temperatures relative to the other muscles. Fibre diameter was largest for type-IIb fibres relative to type-IIa and type-I. Longissimus and cutaneous trunci had predominantly type-IIb glycolytic (71%, 51% respectively), masseter had predominantly type-IIa intermediate (50%) and psoas major had predominantly type-I oxidative (48%) fibres. The glycolytic longissimus had the lowest DSC temperature peaks and the lowest quality meat. Masseter had the highest proportion of type-I fibres but was generally similar in quality traits to psoas major, and also similar to cutaneous trunci which had more glycolytic fibres than masseter.

Keywords: Cook loss; Differential scanning calorimetry; Myosin heavy chain; Pork quality; Tenderness.