The use of suitably selected parameters of ultrasound pretreatment
can positively affect the content of carotenoids in dried carrots
[29]. Carotenoids content after drying process, in the most
cases, increased as compared to the fresh carrots (Fig. 5).
Untreated dried samples contained 20% more carotenoids than raw carrots, which may be explained by biological diversification
of material or influence of heat, which causes the dissolving of
the cellulose in the cell walls and releases compounds from the
cell. Carrot has a hard cell wall, what stops carotenoids inside
the cells. The result is that the human body is able to convert into
vitamin A less than 25% of b-carotene contained in carrots. Thermal
treatment causes dissolution of the cellulose, from which are built
cell walls, and due to it, release of the compounds structured in
cells can occur [4]. Moreover, long time of heating may cause the
increase of the carotenoids content, because of breaking up carotenoids
complexes with proteins, what results in easier extraction
[49]. Furthermore, the total carotenoid content may change
depending on the size of carrots and its species [50].