Modified atmosphere packaging improves retail display life of lamb cuts with variation between loin and knuckle

Abstract

This study was conducted to determine the effect of electrical stimulation [control or stimulated (applied for 20 s using a constant current of 600 mA peak and maximum voltage of 550 V with a frequency of either 14 Hz or 10 Hz], ageing period (7, 21 or 35 days) and packaging method [modified atmosphere packaging (MAP) or overwrapped] on the retail display life of lamb [bone-in loin (M. longissimus thoracis et lumborum) chops and boneless leg steaks from the knuckle (M. quadriceps femoris)]. The colour and retail acceptability of lamb cuts were assessed both subjectively and objectively, using a chromameter, after 3 (midpoint of commercial retail display life; midpoint) and 5 (endpoint of commercial retail display life; endpoint) days for overwrapped product and at 5 (midpoint) and 9 (endpoint) days for MAP product. Retail display life of lamb (assessed both objectively and subjectively) was improved (P<0.001) by packaging lamb cuts into modified atmosphere compared with overwrapped lamb cuts. Electrical stimulation and length of ageing period before preparation into retail cuts did not influence colour or retail display life of lamb loin chops or leg steaks. Although the interaction of ageing period and packaging method were significant (P<0.001) for subjective colour, acceptability and retail grade of lamb loin chops and leg steaks at the midpoint of display life, these effects were inconsistent. This study highlighted that further work is necessary to determine potential means of improving the colour stability of lamb to enhance its retail display life, particularly cuts of the M. quadriceps femoris.