Muscle Protein Composition and Eating Quality of Fresh and Frozen Turkeys

Abstract

SUMMARY Fifty‐four Beltsville small white male turkeys were studied either fresh‐unfrozen or frozen‐stored for 5 and 10 months. Samples of raw muscle were removed for protein analysis; the turkeys were then roasted at 325°F to end‐points of 165, 17.5, and 185°F in the thigh muscles and eating quality was evaluated. Quantitative changes in muscle proteins as separated from extracts made with KCl‐borate buffer or with de‐ionized water were not marked. There was a decrease in actomyosin nitrogen of pectoralis major and some indication of proteolytic Changes. The magnitude of these changes in turkey muscles stored up to 10 months was not expected to alter eating quality as much as the longer cooking times required to reach the end‐point temperatures when cooking frozen‐stored turkeys. Moisture losses were higher, and cooked thigh muscles were more tender and mealy from frozen‐stored than fresh turkeys. Cooked pectoralis major muscles required more force to shear after 5 months storage than at either 0 (fresh‐unfrozen) or 10 months storage. There was some indication that an undesirable flavor developed in thigh meat of turkeys stored 10 months.

Effect of Freezing and Marginal Finish Differences on the Preparation of Chicken Broiler Carcasses by Pressurized Deep-Fat Frying

“…The final product originating from frozen carcasses was favorable in all respects even though bone darkening was readily apparent and reductions in moisture content were measurable. Differences in cooking loss between fresh and frozen broiler chickens were a converse to that reported earlier by Hoke et al (1968) using turkeys. Whereas pressurized deepfat frying of broilers which had been frozen led to an improved cooking yield, there was a decrease with oven-prepared turkeys.…”

“…Meat-skincoating composite samples all contained less moisture when the carcasses had been frozen than if held fresh. Hoke et al (1968) also found this same observation with oven-cooked turkeys and they further noted that differences progressively disappeared as end-point internal cooking temperature was increased.…”

“…Hence, not only is there an increased cooking loss should the carcass be kept intact but a longer mean cooking time as observed by Hoke et al (1968) to heat the additional free water. Increasing the extent of denaturation by further cooking and/ or higher temperatures moderates these tissue differences by reducing the proportion of unaffected macromolecules.…”