The present work proposes using the ultrasound technology to incorporate microencapsulated nutrients during pre-treatments for drying of food products. Both hydrophilic and lipophilic nutrients were evaluated: incorporation of microcapsules of iron (obtained by spray drying using maltodextrin as wall material) and carotenoids (obtained by hot emulsification and solidification using hydrogenated palm oil as wall material). The ultrasound pre-treatment was applied in water and ethanol, where the microcapsules were dispersed, and food samples were immersed. Pumpkin and apple were selected as suitable food material to perform the iron and carotenoid incorporation, respectively. Ultrasound allowed more homogeneous iron incorporation in pumpkin. The iron content increased more than 1000% in pre-treated samples compared to control. In the same manner, carotenoid content increased in about 430% when ultrasound was applied. After drying, the carotenoid content decreased by 65% in control samples. However, better carotenoid retention was obtained after drying in ultrasound processed samples. The results show that pre-treatment with ultrasound can be used to incorporate nutrients into the food matrix, increasing not only the incorporated quantity but also promoting their preservation. Nevertheless, future studies must be performed to determine the nutrient bioavailability and bioaccessibility.
Keywords: Carotenoids; Convective drying; Food matrix; Iron; Microencapsulated nutrients; Ultrasound.
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