The combined effects of aging and stewing on lamb longissimus thoracis et lumborum (LTL) and semimembranosus (SM) Warner-Bratzler shear force (WBSF), texture and thermal shrinkage, and its relationship to physical and chemical properties of muscles before heating were examined. LTL and SM muscles of lambs were aged at 4°C for 1 or 5 days, and were either stewed at 95°C for 4 h or heated until the center temperature reached 90°C. The results showed that both the 5 days aging of raw lamb and the 4 h stewing at 95°C decreased the WBSF of the LTL ( P < 0.05). The increase in hardness caused by aging was eliminated by extending the stewing time from 0 to 4 hours. Aged muscles (heated to 90°C) exhibited an increase in the transverse shrinkage ratio ( P < 0.05), but there was no significant change in the longitudinal shrinkage ratio. By contrast aging did not affect transverse shrinkage when the muscles were stewed for 4 h. The physical and chemical properties of the raw lamb exerted different effects on lamb stewed at different times. WBSF of muscles (heated to 90°C) correlated with the total collagen content of raw lamb, but not when stewed for 4 h. This study provided some ideas for optimizing the processing technology of lamb stewed at 95°C. • Both 5 days aging and 4 h stewing could decrease the WBSF of braised lamb. • Hardness caused by aging was eliminated by extending the stewing time to 4 h. • Aging did not affect transverse shrinkage when the muscles were stewed for 4 h. • Properties of raw lamb exerted varied impacts on lamb stewed for different durations. • Raw lamb collagen content correlated with WBSF of lamb stewed 0 h, but not for 4 h.
Rao et al. (Fri,) studied this question.