A comparison of conventional and radio frequency defrosting of lean beef meats: Effects on water binding characteristics

The effect of defrosting rate (slow conventional air vs. fast radio frequency (RF) method) on water holding properties of lean beef meat (whole, minced and comminuted) was investigated using a conventional centrifugation method (drip loss), nuclear magnetic resonance relaxometry (NMR) and dielectric spectroscopy. Tempering by radio frequency (RF) or a conventional air method had no subsequent effect (P >= 0.05) on drip loss. However, thawing by RF resulted in a significant decrease in drip loss (P < 0.05) when compared to air thawing. Micronutrient loss (mu g/mL of drip) was also greater in air thawed samples (P < 0.05). NMR T-2 distributions did not show any marked difference between thawing methods. The dielectric properties of lean beef, measured from 0.01-20 GHz at 5 degrees C, were higher following RF thawing. Increased comminution reduced dielectric values, while fine comminution gave an additional fraction in the NMR T2 distribution. These results provide valuable information on water binding in meat following RF tempering/thawing. (C) 2009 Elsevier Ltd. All rights reserved.