36G-1

J. E. JOHNSTON, A. L. Alderton, Y. L. Xiong, and W. B. Mikel. Dept. of Animal and Food Sciences, Univ. of Kentucky, Lexington, KY 40546-0215

Retaining a “fresh like” quality is the primary goal of preservation by freezing. Generally, faster freezing and slower thawing rates are used to help achieve this goal. Our objective was to evaluate the effects of freezing and thawing rates with storage time on quality aspects of eye of round steaks. Using a 3 x 2 factorial design with factors of freezing and thawing rate, eye of round steaks (1.91cm thickness) were frozen at -18° C in a conventional home freezer (CHF, -0.04° C/min), a mini-Blast/Plate Freezer (BPF, -0.11° C/min), and a Commercial Blast Freezer (CBF, -0.09° C/min). Frozen steaks were stored at -18°C for 7, 30, 90, or 150 days. On designated sampling days, steaks were thawed at 22° C for 3 hr or 4° C for 24 hr prior to analysis of raw color (Minolta L*a*b*), lipid oxidation (TBARS), drip loss, protein denaturation (differential scanning calorimetry), and Total aerobic Plate Count (TPC). Thawed steaks were then cooked to 71° C and analyzed for treatment effect on cook yield, Warner-Bratzler Shear Force (WBSF), and sensory characteristics by a trained panel. A fresh (unfrozen) control was analyzed on day 0 for comparison. Meat quality declined due to freezing and thawing, but freezing and thawing rates differed little in their effect on quality attributes examined. BPF steaks suffered less drip loss (%) than the other two treatments (P < 0.01), while the steaks thawed at room temperature showed a higher drip loss than those thawed at refrigeration temperatures (P < 0.01). The CBF samples experienced less freezer loss (%) than the BPF samples. A storage effect was evident over time (P < 0.05) as WBSF increased, L*(lightness) and a* (redness) color values decreased, cook yield increased, and sensory scores decreased. As a result of its faster freezing capabilities, the BPF was able to reduce drip loss in eye of round steak compared to the CHF and CBF.

Session 36G, Refrigerated & Frozen Foods: General
8:30 AM - 12:00 PM, Monday AM Room Hall I-2

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana