Efecto del Secado por Liofilización y Atomización en las Características y Propiedades de Polvos de Frutas: Una Revisión Sistemática

Freeze-drying and spray-drying methods are widely used for the preservation of fruits in the powder form. The main concern is to produce high quality fruit powders, which requires finding the feasible method to ensure this attribute. The present review aims to analyze the scientific studies on spray drying and freeze drying to produce fruit powders under different operating conditions (temperature, time, pressure and solute) and to describe their effects on the physical properties, morphological and physicochemical characteristics of these products. Using the PRISMA methodology, 135 articles were obtained from different databases, of which 28 articles were selected based on the inclusion criteria, such as being published in English or Spanish, from 2010 to 2021. It was found that, compared to atomization, fruit powders obtained by freeze-drying presented larger particle size (48.89 µm-221 µm), higher porosity, low bulk density, higher moisture (1g water/100g product-7.8g water/100g product) and water activity between 0.204 and 0.47. On the contrary, atomized fruit powders showed lower moisture percentage (1.1g water/100g product-5g water/100g product), smaller particle size (18.6 µm-180 µm), high bulk density, leading to low porosity and water activity between 0.17 and 0.18. Both the freeze-dried and atomized products presented a spherical particle shape. It should be noted that the processing conditions and the type of fruit to be dehydrated also influence these characteristics and properties. Finally, it is concluded that both drying methods allow obtaining quality powders, however, freeze-drying allows better hydration properties, due to the characteristics and properties of the powders obtained by this technique. Therefore, in order to choose one or the other technology, the initial and final characteristics required of the product should be evaluated, as well as the economic aspects involved.