The study examined the protein profile of Pectoralis major muscle in broiler chickens subjected to different freezing and thawing methods. Pectoralis major muscle was excised from the carcasses of twenty broiler chickens and split into left and right halves. The left half was subjected to slow freezing (-20oC) while the right half was rapidly frozen (-80oC). The samples were stored at their respective temperature for 2 weeks and assigned to either of tap water (27oC, 30 min), room temperature (26oC, 60 min), microwave (750W, 10 min) or chiller (4oC, 6 h) thawing. Changes in myofibrillar proteins following the thawing methods were monitored through sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The electrophoretic profile indicated differences (p < 0.05) in intensities of the components of myofibrillar proteins among the thawing methods in both slow and rapidly frozen samples. Chiller thawing had significantly higher (p < 0.05) protein concentration than other methods in rapidly frozen samples. However, in slow freezing, there were no significant differences in protein concentration among the thawing methods. In rapidly frozen samples, the protein optical densities at molecular weight of 21, 27, 55 and 151kDa in tap water, chiller and room temperature thawing did not differ (p < 0.05). Similarly, in slowly frozen samples, protein optical densities at molecular weight of 21, 27, 85 and 151 kDa were not significantly different among chill, tap water and room temperature thawing. Microwave thawing consistently caused higher protein degradation resulting in significantly lower (p < 0.05) protein quality and quantity in both freezing methods.
This study evaluated the effects of Averrhoa bilimbi juice extract and storage temperature
on lipid oxidation and microbial spoilage of spent chicken meat. Ten, 80 weeks old spent
chickens were slaughtered, eviscerated and aged for 24 h at 4oC. Thereafter, the Pectoralis
major muscles and right thighs were excised and marinated in either A. bilimbi juice extract,
pure distilled water, or no marination (control) for either 4 or 9 h at room temperature or 9 or 24
h at 4°C. Lipid oxidation was monitored on the Pectoralis major muscles while the right thighs
were assessed for Enterobacteriacea counts. Lipid oxidation was not significantly affected
by the type or duration of marination. Marination showed a temperature dependent effect on
Enterobacteriacea counts. At room temperature, samples that were marinated by distilled water
showed significantly higher Enterobacteriacea counts than the control while those that were
marinated with A. bilimbi juice extract showed no growth at both 4 and 9 h of marination. At
chilled temperature, marination had no significant effects on the growth of Enterobacteriacea
during the 9 or 24 h storage. These results indicated that A. bilimbi juice extract marinade has
some antibacterial activities but works better when combined with refrigerated storage.