Air-, water- and vacuum-thawing of frozen pork legs.

A comparative experimental study of thawing of frozen pork legs of different weights in air, water and vacuum steam heat systems has been made with respect to thawing time, weight loss and appearance, and a mathematical model and computer programme have been developed which enable accurate prediction of thawing time for any weight of leg under any thawing condition. Very good agreement has been obtained between computed figures and experimental results. Thawing in water is faster than in air at any given temperature but vacuum thawing is not appreciably faster than water thawing. The pork legs increased in weight by 1 ± 0.3% under all conditions except high velocity air and higher vacuum thawing temperatures when losses of up to 1% were recorded. The appearance of legs thawed in air was superior to those from water and vacuum systems. Satisfactory microbiological results were obtained at a thawing temperature of 10 oC in all systems.