Date of Award:

1986

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Nutrition, Dietetics, and Food Sciences

Department name when degree awarded

Nutrition and Food Sciences

Advisor/Chair:

Daren P. Cornforth

Abstract

A pink color defect is commonly observed in freshly cut surfaces of cooked turkey rolls and fades rapidly upon exposure to air. The non uniform pink color makes the product appear undercooked, and the product must be discounted. The oxidation-reduction potential of the meat is important in development of pink defect. A pink color similar to that of commercial product was observed when the cooked meat was treated with either sodium nitrite or sodium dithionite. The pink color in nitrite treated meat was due to nitroso pigment formation, but in samples treated with dithionite the pink color was due to formation of a hemochrome complex. Pink color was also observed in turkey rolls formulated with nicotinic acid, nicotinamide or sodium nitrite. Reflectance and absorbance spectrophotometric studies on commercial or laboratory prepared samples having pink defect showed that the responsible pigment was a reduced hemochrome rather than a nitroso pigment. The hemochrome is probably a nicotinamide-denatured globin complex with ferrous iron of the heme molecule.

Oxidation-reduction potential measurement of meat systems showed that hemochrome formation is promoted by reducing conditions and prevented by oxidizing conditions. All constituents necessary for formation of pink defect are present in turkey meat, the variable most affecting its appearance being the redox potential of the meat.

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