Variability in marbling in Angus steers and an evaluation of subjective marbling assessment

摘要

Abstract Currently there are no marbling grades within the New Zealand beef classification system, yet within some of our major markets (e.g., the United States and Japan) marbling is an important component of the grading system. This paper aims to examine the extent of marbling within Angus steers in New Zealand and relate these data to US and Japanese marbling grades. The amount of intramuscular fat (marbling) in the M. longissimus thoracis at the 12th rib site was estimated for samples from 259 Angus steers using NIRS. Carcass weight ranged from 220 to 540 kg and explained 66% of the variability in chemical fat. For carcasses in the 300 to 400 kg range, intramuscular fat content increased at average rate of 3.5 g kg?1 fresh weight of muscle for each 10 kg increase in carcass weight. Marbling was assessed in 118 ribeye steaks by 11 novice panellists using both the Japanese (JMGA) and United States (USDA) marbling grading standards and the scores obtained were compared against the predicted chemical fat ...