engleski

THE EFFECT OF FREEZING ON pH VALUE AND ELECTRICAL CONDUCTIVITY OF PORK

Freezing is one of the procedures which can prolong the shelf life of food. Lowering the temperature practically discontinues chemical, biochemical and microbiological processes in meat. Water extraction in the form of ice crystals appears during the procedure whereby the speed of freezing has a direct effect to damages in meat on a cellular level. The effect of freezing on pH value and electrical conductivity is presented in this paper. The pH value was determined by puncture electrode and the electrical conductivity was determined by LF-Control system device (Würthinger, Pettenbach, Austria) in milliSiemens/cm2 (mS/cm2). The monitored parameters were measured at the cross-section of samples (N=5) m. gracilis 24 hours post mortem and after 60 days of storage at -18°C and thawing of meat. The research was conducted on pigs of Swedish Landrace breed. The pH value for fresh meat was 5.66 on average and it was 5.55 for the meat after storage at -18°C in the period of 60 days. The electrical conductivity (EC) of fresh meat was 17.50 and it was 19.32 after storage and thawing. According to the measured pH24 value, the meat of the researched pigs can be considered to be the meat of normal quality if pH24>5.5 (criterion by Forrest et al., 1998) is used as a criterion for “normal” meat. Freezing had a significant effect on pH value and electrical conductivity of meat (P<0.02).

pork; pH; electrical conductivity; freezing

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