Acta Univ. Agric. Silvic. Mendelianae Brun. 2007, 55, 105-118

https://doi.org/10.11118/actaun200755020105
Published online 2014-11-27

Validation of methods for determination of free water content in poultry meat

Jarmila Žítková1, Jana Simeonovová2

1Veslařská 153, 637 00 Brno, Česká republika
2Ústav technologie potravin, Mendelova zemědělská a lesnická univerzita v Brně, Zemědělská 1, 613 00 Brno, Česká republika

Methods for determination of free water content in poultry meat are described in Commission Regulation EEC No 1538/91 as amended and in ČSN 57 3100. Two of them (method A and D) have been validated in conditions of a Czech poultry processing plant. The capacity of slaughtering was 6000 pieces per hour and carcasses were chilled by air with spraying. All determinations were carried out in the plant’s lab and in the lab of the Institute of Food Technology. Method A was used to detect the amount of water lost from frozen chicken during thawing in controlled conditions. Twenty carcasses from six weight groups (900 g–1400 g) were tested. The average values of thaw loss water contents ranged between 0.46% and 1.71%, the average value of total 120 samples was 1.16%. The results were compared with the required maximum limit value of 3.3%. The water loss content was in negative correlation with the weight of chicken (r = –0.56). Method D (chemical test) has been applied to determine the total water content of certain poultry cuts. It involved the determination of water and protein contents of 62 representative samples in total. The average values of ratio of water weight to proteins weight WA/RPA were in breast fillets 3.29, in legs with a portion of the back 4.06, legs 4.00, thighs 3.85 and drumsticks 4.10. The results corresponded to the required limit values for breast fillets 3.40 and for leg cuts 4.15. The ratio of water weight to proteins weight WA/RPA was correlated with the weight of chicken for breast fillets negatively (r = –0.61) and for leg cuts positively (r = 0.70). Different correlations can be explained by the distribution of water, protein and fat in carcasses. The evaluation of methods in the parameter of percentage ratio of the average value to the limit showed that method D (results were at the level of 97% of the limit) was more exact than method A (results were at the level 32% of the limit) but it is more expensive. Both methods were tested with the same technological equipment and at the same time. As far as the validation is concerned, it can be concluded that no substantial modification of methods is necessary.

References

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