Efeito de ondas ultrassônicas e pulso de vácuo nos parâmetros de qualidade de pêras osmoticamente desidratadas

Abstract

Osmotic dehydration can be improved with the use of vacuum pulse or ultrasound waves. The influence of vacuum pulse and ultrasound waves on the osmotic dehydration of sliced pears (65 kg sucrose 100 kg-1 solution, 300 min) was tested. Several quality parameters were evaluated: mechanical properties (stress at fracture, strain at fracture and elasticity), cell structure and shrinkage. Experimental design was performed for each process using temperature (25.9 to 54.1°C) and time of the assisted process in the first minutes of the osmotic dehydration (vacuum pulse or ultrasound waves, 0 to 17.5 min) as the independent variables. The influence of vacuum pulse was verified for elasticity. Ultrasound waves influenced stress at fracture and elasticity. Temperature increasing promoted larger shrinkage of the samples. In general, the osmotic treatment, assisted or not, promoted changes in microstructure, cell deformation and cell rupture of osmotically dehydrated pear.