Abstract:
The objective of this work was to study the stability of freeze-dried blackberry pulp. Firstly, both physical and
chemical experiments were carried out on blackberry pulp prior to the freeze-drying process. Secondly, the
freezing time for the blackberry pulp, three hours, was determined based on Plank’s method with an initial
freezing temperature of -2, 58°C. Then, experiments with the frozen pulp were conducted in a freeze-drying
equipment with three different temperature degrees: 105°C, 110°C and 120°C, and a pressure factor of 1.15 ± 0,5
mmHg. As a result, the ideal temperature for the process was found to be 110 °C at which a product with a final
humidity of 2, 5% ± 0, 2 and excellent characteristics was obtained; varied sensorial methods were applied in
order to confirm this. Besides, the adsorption isotherm for the freeze-dried product was drawn and, with both the
monolayer and critical humidity data, the stability was calculated by using Labuza’s method which finally
determined that the shelflife for freeze -dried blackberry pulp is 18 months.
