Fatness, Rate of Chilling and Tenderness of Lamb

Abstract

40 lambs were selected to vary in amount of finish for use in determining the mechanism by which fatness affects tenderness. Lambs with thick (n = lo), intermediate (n = 20) or thin (n = 10) finish were slaughtered, chilled at 1 + 1°C and samples obtained from three muscles for chemical, histological, physical and organoleptic analyses. Subcutaneous fat was removed from one side of each carcass in the intermediate finish group to facilitate comparisons on a within-carcass basis. The data suggest that lamb carcasses which have increased quantities of fat (subjectively determined via live evaluations of finish or objectively determined via subcutaneous fat thickness measurements and marbling scores): (a) chill more slowly; (b) maintain muscle temperatures conducive to autolytic enzyme degradation for greater periods of time postmortem; (c) sustain less shortening of sarcomeres; (d) have muscles with lower ultimate pH values; (e) have less perceptible or softer connective tissue; and (f) are more tender than lamb carcasses which have limited quantities of fat. The data support the hypothesis that deposition of increased quantities of subcutaneous or intramuscular fat (particularly in carcasses with limited quantities of subcutaneous finish) increases tenderness via changes in postmortem chilling rate. An increased quantity of fat decreases the rate of temperature decline (either by insulation or via an increase in carcass mass), enhances the activity (or increases the duration of active proteolysis) of autolytic enzymes in muscle, lessens the extent of myofibrillar shortening and thereby increases the ultimate tenderness of cooked meat from a fatter carcass.

Effect of electrical stimulation, delayed chilling and post‐mortem aging on the quality of M. longissimus dorsi and M. biceps femoris of grass‐fed steers

“…16 As grass-based fattening can be accompanied by less intensive growth of the animals, they are often older at slaughter, which might be associated with less tender 17 and darker meat 21 and a lower proportion of carcass fat than in other, more intensive, feeding systems. 10 Early animal production studies 11 indicated that fatter animals usually produced meat that was more tender than that from leaner animals. This was partly confirmed by the results of the present study, where a higher cutting fat proportion was associated with a reduction in shear force in the 15 day aged LD of CO1 (r = −0.52, P = 0.04) and CO2 (r = −0.36, P = 0.14).…”

“…Because cerealbased (high-energy) diets often yield heavier and fatter carcasses than forage-based diets, tenderness might be increased as a result of decelerated post-mortem (p.m.) temperature decline in the muscles. 11 Simultaneously, enhanced early p.m. activity of proteolytic enzymes in the muscles may additionally increase the ultimate tenderness of beef from fatter carcasses. 11,12 Reduced tenderness in relation to extensive feeding could therefore be at least partly the result of interactions with slaughter/chilling technology.…”

“…11 Simultaneously, enhanced early p.m. activity of proteolytic enzymes in the muscles may additionally increase the ultimate tenderness of beef from fatter carcasses. 11,12 Reduced tenderness in relation to extensive feeding could therefore be at least partly the result of interactions with slaughter/chilling technology. Supplementation of grass with some concentrate may produce more tender meat, 13,14 although this was not always found, 15 and no difference between pasture beef and conventional beef obtained at the point of sale was found in a Swiss retail study.…”

Live animal and carcass characteristics of South African indigenous goats

“…Low carcass fat is one of the main attractions to chevon. However, the low and rather invariable subcutaneous fat cover is a particular cause for concern in commercial chevon production since it is often well below the levels considered necessary for effective carcass chilling, without the risk of cold shortening (Smith et al, 1976;Dikeman, 1996). The low subcutaneous cover has also contributed to the downgrading of goat carcasses in a number of commercial enterprises, particularly where the classification/grading schedules that are employed are based on those of lamb and mutton (Pike et al, 1973;Simela et al, 1999).…”

Consumer’s purchasing intention for lamb meat affected by country of origin, feeding system and meat price: A conjoint study in Spain, France and United Kingdom

“…The diet influences meat texture and flavour because it modifies the level of intramuscular fat and the fatty acid composition. Some studies have shown that meat from lambs fed on concentrate had higher intramuscular fat and was tenderer than those fed on pasture (Díaz et al, 2002;Priolo, Micol, Agabiel, Prache, & Dransfield, 2002;Schönfeldt, Naudé, Bok, Van Heerden, & Sowden, 1993;Smith, Dutson, Hostetler, & Carpenter, 1976). Regarding the fatty acid composition of intramuscular fat of meat, lamb from grass-fed animals had higher a-linolenic acid content than lamb from concentrate-fed animals (Aurousseau, Bauchart, Calichon, Micol, & Priolo, 2004;Cañeque, De la Fuente, Díaz, & Álvarez, 2007) which is related in some studies with a more intense lamb flavour (Fisher et al, 2000;Sañudo et al, 1998Sañudo et al, , 2000 and in some others with a less intense lamb flavour (Borton, Loerch, Mc Clure, & Wulf, 2005;Priolo et al, 2002).…”