Bioactive, Physicochemical and Sensory Properties as Well as Microstructure of Organic Strawberry Powders Obtained by Various Drying Methods

This study compared the quality of organic strawberry powders, obtained by convective drying (CD), freeze drying (FD) and spray drying (SD) methods. In the study, such analyses were performed: the content of vitamin C and polyphenols by liquid chromatography method, antioxidant activity using ABTS+center dot radicals, microstructure using a scanning microscope, sensory quality by profile method and the determination of the physicochemical properties. The FD powders were characterised by the highest content of vitamin C and polyphenols, obtained values were close to fresh strawberries after conversion to the dry matter content. The content of these ingredients in CD and SD powders was lower by 55%-80% for vitamin C, and 80% for the polyphenols content. Strawberry flavour was most beneficial for the FD powders, while smoothness and homogeneity of appearance were equally rated for the FD and SD powders. Strawberry powders are a concentrate source of bioactive compounds and, therefore, the FD powders should especially be mainly used as a valuable component of high-value foods, especially functional foods, while CD and SD powders can be used to enrich food with vitamin C and as a valuable natural flavour and colouring component, replacing food additives.