الفهرس 
introductionOnly 14 pages are availabe for public view
 |  | from | 117 |  |  |
| | | from | 117 | | |
Abstract
Oxiditive rancidity is considered by the meat and poultry industries as a major problem in marketing new precooked, ready-to-heat and serve poultry products .Owing to decreasing the quality of products and its public health effect. So the present study was planned out to examine the development of oxidative rancidity is some precooked poultry products during freezing storage for 6 months (shelf life). The examined samples were 216 samples taken from 9 packets of precooked chicken products (3 packets of drumsticks, 3 packets of hot-wings and 3 packets of nuggets) then examined weekly from first week of production till the end of their shelf life by peroxide value test (PV) and thiobarbituric test (TBA). 1-Peroxide value: Drumsticks: The results revealed that the mean of peroxide value increased from 0.51 ± 0.02 meq of I/kg of fat at the 1 stweek to reach the maximum value of 8.2 ± 0.27, 8.2 ± 0.43 at 8th and 9th weeks respectively then decreased till reach a nearly constant value of 3.2 ± 0.35 at 18th week where the decrease was insignificant till the end of storage. Hot-wings : The mean of peroxide value increased from 1 ± 0.29 meq of I/kg of fat at the 1 stweek to reach the maximum value of 9.5 ± 0.41 at 9th week then decreased till reach a nearly constant value of 3.9 ± 0.27 at 18th week .
Nuggets : The mean of peroxide value increased from 3 ± 0.29 meq of I/kg of fat at the lstweek to reach the maximum value of 13.5 ± 0.5 at 9th week then decreased till reach a nearly constant value of 5.1 ± 0.1 at 21thweek of storage. 2-Thiobarbituric acid: Drumsticks: The results revealed that there was an increase in the mean of TBA numbers from 0.0156 ± 0.008 mg of MA/kg of sample at 1st week till reach the maximum value of 0.996 ± 0.06 at the end of storage (at 24weeks). The mean of malonaldehyde concentration (MA conc)values also increased from 0.17 ± 0.04 gg of MA/gm of fat till reach the maximum value of 11.05 ± 0.66 at the end of storage. Hot-wings: The results revealed that there was an increase in the mean of TBA numbers from 0.081 ± 0.001 mg of MA/kg of sample at 1st week till reach the maximum value of 1.446 ± 0.06 at the end of storage (at 24weeks). The mean of MA conc values increased from 0.66 ± 0.01 gg of MA/gm of fat till reach the maximum value of 11.64 ± 0.75 at the end of storage. Nuggets: The results revealed that there was an increase in the mean of TBA numbers from 0.098 ± 0.003 mg of MA/kg of sample at 1st week till reach the maximum value of 2.772 ± 0.02 at the end of storage. The mean of MA conc values also increased from 0.65 ± 0.02 lag of MA/gm of fat till reach the maximum value of 18.46 ± 0.15 at the end of storage. from the mentioned results we found that : 1- Thiobarbituric acid numbers and malonaldehyde concentration values considered more accurate parameters for determination of rancidity than peroxide values which decreased due to decomposition of hydroperoxides. 2- There was development of rancidity during freezing storage of precooked chicken products which affected by the storage time, fat %, grinding, salt and cooking. The public health significance of rancidity as well as recommendations concerned with production of poultry products were also discussed.