Conservation of apple and pear juice concentrates. Synergic effect of heat and radiation

Abstract

This paper aims at assessing the feasibility for conserving apple and pear-juice concentrates through the synergic action of heat and radiatíon. The material was packed in sterile 100-μm polyethylene bags and, after the treatment was applied, the resulting fractions were stored under room temperature (25°C ± l°C ). The temperatura applied to the samples before irradiation was 50°C during 10 minutes and the doses were 100, 200, 300 and 400 krad. Periodical microbiological, chemical and organoleptic controls of the food were performed on both control and on irradiated samples, with or without heat. A single alterating microorganism was isolated from all The samples, which was featured as Saccharomices rouxii. Adopting the temperature as an application variable and the absorbed dose as a constan, the above osmophyiic yeast is considerably more sensitive to radiations when it is suspended in a 50% sucrose solution, after the latter was submitted to a 50°C temperature treatment.