Effects of a Step-up Ractopamine Feeding Programme on Growth and Low-sodium Ham Characteristics of Berkshire Pigs11 December 2013
Research at Iowa State University has revealed that although a low-sodium curing solution made hams paler and gave them a less intense flavour, this is an effective way to reduce sodium content without significant detrimental processing or sensory effects. Feeding ractopamine improved bodyweight, daily gain and feed conversion.
In a paper in Journal of Animal Science, B.M. Bohrer and colleagues at Iowa State University explain that the objectives of their experiment were to test the effect of a low-sodium curing solution on processing characteristics of hams from purebred Berkshire pigs that were fed a step-up ractopamine HCl (RAC) feeding programme or a negative control diet.
Sixty pairs (n = 120) of hams were selected from two blocks of purebred Berkshire pigs (n=200) that were fed either a control diet or 7.4mg of ractopamine per kg of diet for 14 days followed by 10.0mg of ractopamine per kg of diet for the last 14 days before slaughter.
Three-piece, section-formed hams were cured with a standard (1.98 per cent sodium chloride NaCl; REG) curing solution or a low-sodium with potassium chloride (KCl) replacement (0.67 per cent NaCl and 1.29 per cent KCl; LOW) curing solution.
Pigs fed RAC had 3.18 per cent greater bodyweight, 11.90 per cent greater average daily gain and 10.34 per cent greater gain:feed ratio than control pigs.
No differences (P≥0.07) were detected for the effect of diet, curing solution or the interaction between diet and curing solution for ham weights, pump uptake or cook yield (i.e. cooked weight ÷ green weight × 100).
Break strength - an indication of protein interaction and bind strength - (5.97 versus 6.99kg) - and protein fat-free values (24.58 versus 25.98 per cent) were less (P≤0.05) in hams cured with LOW curing solution than hams cured with REG curing solution.
Lightness (L*) and yellowness (b*) values were greater (P≤0.03), while redness (a*) values were lower (P<0.01) in hams cured with LOW curing solution than those cured with REG curing solution.
A trained sensory panel detected less (P=0.03) flavour intensity in hams cured with LOW curing solution compared with hams cured with REG curing solution. Yet, no differences (P≥0.55) were detected between hams cured with LOW or REG curing solution for saltiness.
Overall acceptability of hams cured with LOW curing solution tended to be lower (P=0.09) than hams cured with REG curing solution but the magnitude of this difference was just 0.34 on a 1 to 9 scale.
Bohrer and colleagues concluded that hams cured with LOW curing solution made hams paler and have a less intense flavour than hams cured with REG curing solution but this was a justifiable way to lower sodium content by 64 per cent units (1.44 versus 4.04 per cent sodium), without detrimental processing or sensory effects.
Bohrer B.M., J.M. Kyle, K.L. Little, H.N. Zerby and D.D. Boler. 2013. The effects of a step-up ractopamine feeding program on growth performance and low-sodium ham characteristics of purebred Berkshire pigs. J. Anim. Sci. 91(11):5535-5543. doi: 10.2527/jas.2013-6854
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