| dc.description.abstract | Lamb production systems in New Zealand can vary widely in animal characteristics such as breed, sex, diet and age at slaughter. In order to move towards production systems that are more consumer-focused, there is a need to understand meat quality characteristics and cross-cultural consumer preference of loins from lambs reared under a wide range of commercial production systems. This thesis conducted a comprehensive assessment of the loins (M. longissimus thoracis) of 150 lambs from 10 forage production systems (n=15) and assessed meat quality, fatty acid composition, volatile and proteomics profiles, and consumer sensory evaluations.
Instrumental measurement of meat quality (shear force, pH, colour, and water holding capacity) showed that animal age at slaughter and diet had a greater effect on meat quality than the sex of the lamb. A chicory diet increased carcass weight (CW) of lambs resulting in a greater loin intramuscular fat (IMF) percentage compared to a perennial ryegrass diet (18.1±0.1kg vs. 16.9±0.1kg CW and 2.0-2.6% vs. 1.3-1.6% IMF, respectively). Finishing lambs in New Zealand forage systems for 12 months resulted in lower proportions of n-3 fatty acids in meat as well as a lower PUFA:SFA ratio compared to lambs slaughtered at 4- or 8-month-old (2.93-3.41% vs. 4.79-5.86% n-3 fatty acids and 0.17-0.19 vs. 0.27-0.35 PUFA:SFA, respectively). Of the 286 proteins identified among the raw lamb loins, only 17 showed significant differences in abundance between production systems which indicated that the expression of proteins was rarely affected by the production factors. For both New Zealand and Chinese consumers, the average liking scores differed among the different types of commercial lambs. Consumer clusters showed that the fatty acid profile and the volatile compounds derived from lipid oxidation seem to be a stronger driver of consumer liking of lamb for some consumers than others. | en_US |
