Comarsion of potassium and other chemical constituents as indices of pork carcass composition.

Abstract

Thirty-two Duroc pigs were used to investigate the relationship of potassium in the live animal and carcass to physical and chemical carcass composition. The interrelationships were determined between chemical constituents in the wholesale cuts, the composite right side and yields of lean cuts and fat. Potassium was determined by the 40K content of live pigs and unsplit carcasses and by flame photometry of samples from individual wholesale cuts. Nitrogen, sodium, fat and moisture determinations were made of samples from the individual wholesale cuts. Potassium content differed among the various wholesale cuts when calculated on a wet basis. However, when calculations were made on a fat-free or fat-free-moisture-free basis, the soft tissues of the ham and loin were the same with the shoulder, belly and jowl having lower levels of potassium. The lowest potassium levels were observed in the fat and skin. Bone was intermediate between soft tissues and fat. Significant positive relationships (P<.01) were observed between potassium content of live pigs (40K) and their carcasses (40K and flame photometry) and yields of the lean cuts, percent moisture, ash and protein of the carcass. Potassium analyses using flame photometry or 40K content of the carcass were more closely associated with carcass composition than potassium from 40K content of the live animal. Relationships between potassium content of the carcass (40K and flame photometry) and yields of lean cuts and fat were of similar magnitude as relationships between moisture, fat and protein of the carcass and yields of lean cuts and fat.