A comparison of freeze‐dried beef muscles of high or low ultimate pH

Abstract

Some of the deleterious effects of freeze‐drying on the texture of beef have been obviated by using muscles with a high ultimate pH. Pre‐slaughter injection of adrenaline raised the ultimate pH to 6.7. After freeze‐drying the treated beef was more tender, more juicy and less woody than controls at pH 5.6. A resultant increase in water‐holding capacity and rehydratability was demonstrated by myofibrillar swelling and increased fibre diameter. Dehydrated beef with a high ultimate pH showed less deterioration during storage at 37° in the attributes texture, flavour and colour.

Glycolysis and associated changes in beef carcasses

“…Drip loss in PSE pig muscle is caused by a reduction in the WHC of the denatured muscle proteins, accompanied by a partial disruption of the sarcolemma which allows the solution of sarcoplasmic proteins to escape from the fibre. [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] The present results suggest that similar though less severe changes occurred in the beef muscles at 8 cm deep. The increase in drip loss at 5 cm compared to 1.5 cm may also be associated with sarcoplasmic protein denaturation, as indicated by the loss of 3 0 4 0 % of CPK activity at 5 cm.…”

The effect of storage temperature on drip loss from fresh beef

“…Determination of the myoÐbrillar water-holding capacity was based on the method of Penny et al (1963). Eight grams of muscle were homogenised in 80 ml icecold 0É1 M KCl.…”

EFFECT OF ULTIMATE pH UPON THE WATER‐HOLDING CAPACITY AND TENDERNESS OF MUTTON

“…Many methods for measuring WHC have been described in the literature. Miihler and Kiermeier (1953) used sedimentation while others, including Marsh (1952), Wierbicki and Deatherage (1958), Hamm (1958b), Penny et al (1963) and Miller et al (1968), have used centrifugation.…”

“…b) stressed cattle before slaughter to produce an increase in ultimate pH but their results were equivocal. Penny et al (1963) andde Fremery (1963) induced high ultimate pH by pre-slaughter injection of epinephrine and/or iodoacetate and found that meats with a high pH were more tender and juicy than those with a low PH.…”