Effects of breed, feed level and conditioning time on the tenderness of pork.

This study of 80 pigs compared the effects of breed (Duroc vs Large White), feed level (High vs 0.8 High, termed Low) and conditioning time (1 vs 10 days at 1 °C) on the tenderness and other aspects of the eating quality of pork. Conditioning time had the biggest effect (increase of 1.0 units on 1-8 taste panel scale between 1 and 10 days) and this was associated with an increase in the myofibrillar fragmentation index (MFI) from 19 to 24 units. Tenderness was not different between the two breeds although pork flavour intensity and overall liking scores were higher in Durocs. Durocs had higher concentrations of total lipid (marbling fat) in muscle (13.7 and 5.4 mg/g) and most polyunsaturated fatty acids except α-linolenic (C18:3 n-3) were at lower concentrations in Durocs, reflecting dilution of phospholipid fatty acids within a larger total lipid pool. Pigs fed at the high level were fatter than those fed restrictedly in terms both of P2 fat thickness and marbling fat. There was also a tendency, although not significant, for the meat to be more tender. When the data from all pigs were pooled, MFI was shown to correlate well with tenderness (r = 0.45) and marbling fat with juiciness (r = 0.36).