The impact of processing on sensory and objective measurements of sheep meat eating quality

Abstract

The impact of processing factors on sheep meat eating quality was investigated in an experiment in which stimulation (stimulation and no stimulation), chilling rate (fast and slow chilling) and carcass suspension (tenderstretch and normally hung by Achilles tendon) treatments were overlaid on 80 lamb and 40 mutton carcasses processed over 2 days, at 2 different abattoirs. Within each carcass, 3 muscles ('M. longissimus thoracics et lumborum', 'biceps femoris' and 'serratus ventralis') were collected from both sides and aged for 2 of 3 ageing periods (2, 5 or 14 days), before sensory testing for tenderness, juiciness, like flavour and overall liking, using a consumer taste panel. Processing treatments of stimulation and chilling were variable in their effect on the rates of pH and temperature decline and temperature at pH 6 (temp@pH6), between the 4 slaughter groups. Therefore chilling rate and electrical stimulation were considered as tools by which temp@pH6 could be manipulated, rather than as treatment effects per se. Age category (lamb or mutton) had the largest impact on tenderness score, followed by muscle, ageing and carcass suspension. There were significant interactions for tenderness and overall liking scores between muscle × ageing, age category × muscle and carcass suspension × muscle (P<0.05). The magnitude of the tenderstretch advantage in sensory scores was a function of temp@pH6. In normally hung carcasses, the highest sensory scores were evident at about 21°C temp@pH6, with a decrease in sensory scores at high (>30°C) or low (<10°C) temp@pH6. There was a tendency for sensory scores (particularly for the like flavour score) to decline for the 'biceps femoris' when it was stored for extended periods (14 days).