Quality evaluation of foodstuffs frozen in a cryomechanical freezer

Cryomechanical freezing is recommended for delicate products, with poor mechanical resistance (shrimps, raspberries, strawberries) or those that change their appearance during freezing (chicken, mushrooms, shrimps). The aim of this work is to study the quality aspects related to the application of cryomechanical freezing compared to the use of a conventional mechanical freezer. In order to determine whether or not the use of the combined freezer provokes an improvement in the quality of the final product, different kinds of foodstuffs were chosen and analysed before and after freezing by both methods. The selected products were: chicken escallops, hamburgers, strawberries, asparagus and mushrooms. The quality parameters analysed for this purpose were: drip loss during thawing, texture and colour. The variation in mechanical resistance was also evaluated as a function of the immersion time to determine the hardness of the protective crust formed by the liquid N-2 pretreatment. (C) 2002 Elsevier Science Ltd. All rights reserved.