19 Secondary processing of poultry

Insha Rafiq Syed

1. Aging

• Aging or “maturing is the process of holding meat for a period of time between death and deboning in order to prevent toughening
• Aging allows the muscle tissue to relax and tenderize before eating.
• Aged chicken is more tender and have better flavour than meat processed immediately after the kill.
• Aging time for broiler chicken meat is storing the carcass under refrigeration until 4 hr after death .
•  The aging period is expensive due to the energy, labor and space required. Also due to water dripping from the muscle which reduces meat yield .
• Poultry meat needs to age for at least 4 hrs (6 to 8 hours in turkeys) before it is eaten or frozen, or it will be tough because of rigor mortis
• As bird is dead muscle cells continue metabolizing energy left in the muscles switching from aerobic metabolism to the less efficient anaerobic
• Rigor mortis sets in gradually as the muscles depletes their energy stores. After a while the muscle structure starts breaking down and the muscle becomes flexible again. Tenderness is directly related to aging.
• Aging is done after slaughter and initial chilling. It improves tenderness and flavour of meat
•  Meat subjected to aging is held at refrigeration temperature. The breakdown of muscles and connective tissues at this temperature makes the meat tender.

Steps involved in aging process:

1.  Wrap each chicken in cotton cloth to retain moisture

2.  Place chickens in a refrigerator

3.   Ensure sufficient space between birds exists for proper air circulation

4.    Ideally, place chickens on racks, not solid shelves, to facilitate circulation

5.    Remove the chicken in 1-3 days for quartering, freezing, canning or eating.

2. Deboning

Deboning process is done after evisceration. The chicken to be deboned should be clean and attractive. Steps to be taken into consideration for deboning :

Further deboning process

Thigh and drum stick are deboned as:

1. For the thigh, knife is inserted in-between the bone and the meat to slice out the connections of the bone and the meat.
2. Then the meat is. separated from the bone, same is done on other side.
3. For the leg, as the skin has been already removed, insert the knife in between the bone and the meat from the joint where leg and thigh has been pulled apart.
4. Then slice. around the bone to sever the connections between the bone and the meat.
5. Slice around the bone until you are able to pull out the bone from the meat cleanly.

Suggested Readings

• Allred, L. C. et al. (1990). Protein quality and iron bioavailability of mechanically and hand deboned turkey meat fed to rats. Poult. Sci. 69(2): 341-347.
• Angel, S. et al. (1987). Upgrading spent layer meat by mechanical deboning and further processing. Proc. Europ. Mtg. Meat Res. Workers. #33, V. II, 6(13): 288-289.
• Chant, J. L. et al. (1977). Composition and palatability of mechanically deboned meat and mechanically separated tissue. J. Food Sci. 42(2): 306-309.
• Mast, M. G., et al. (1982). Effect of auger-and press-type mechanical deboning machines on selected characteristics of mechanically deboned poultry. J. Food Sci. 47(6):1757-1762, 1766.
• Murphy, E. W., et al. (1980). Health and Safety Aspects of the Use of Mechanically Deboned Poultry. Report, USDA, FSQS.
• Padda, G. S. (1983). Mechanical deboning – a way to full utilization of poultry meat. Poultry Guide 20(7): 92-94.
• USDA Foreign Agricultural Service. 2006, 2007,  2008. http://www.thepoultrysite.com /articles.
• Wise D.R. (1970). Carcass conformation comparisons of growing broilers and laying strain chickens. British Poultry Science 2, 325-332.