EFFECT OF PRECOOKING CONDITIONS ON COLOR OF COOKED BEEF PATTIES

In three separate trials, the visually and instrumentally determined c olor of patties cooked either fresh, frozen, or after thawing was eval uated. In trial 1, the effects of thawing and packaging were evaluated . The internal color of patties cooked to 71 degrees C within 12 h of thawing at 7 degrees C remained red-pink. Only after thawing for 18 h or longer did cooking to 71 degrees C result in a well-done appearance . The color of patties thawed while vacuum packaged and then cooked wa s more red than the color of non-vacuum-packaged patties after cooking . Spectral analysis of the raw product indicated that the effects of t hawing and packaging on cooked color were linked to the level of metmy oglobin (metMb); higher levels of metMb resulted in a less red patty c olor after cooking. In trials 2 and 3, the metMb level was varied by s torage and/or processing conditions. Differences in the metMb level be fore freezing seemed to decrease during freezing and thawing. Differen ces in metMb before processing did not significantly (P > 0.05) affect cooked color. Parries cooked from the frozen state were less red than those cooked directly after processing. After 24 h of thawing, pattie s cooked to 71 degrees C were brown, irrespective of metMb level. Prem ature browning, i.e., the appearance of patties being well-done at tem peratures tower than 71 degrees C, only occurred in thawed patties. Af ter 24 h of thawing, patties appeared well-done at 65 degrees C. Ic is concluded that handling, other than internal temperature, strongly in fluences cooked beef patty color. Therefore, the color of cooked beef patties should not be used as an indicator of internal temperature.