Bordo grape skin extract was microencapsulated by spray-drying and freeze-drying, using gum arabic (GA), partially hydrolyzed guar gum (PHGG), and polydextrose (PD) as encapsulating agents. Total phenolics and total monomeric anthocyanin, antioxidant activity, color, moisture, water activity (aw), solubility, hygroscopicity, glass transition temperature (Tg), particle size, and microstructure of the powders were evaluated. The retention of phenolics and anthocyanins ranged from 81.4% to 95.3%, and 80.8% to 99.6%, respectively, while the retention of antioxidant activity ranged from 45.4% to 83.7%. Treatments subjected to spray-drying had lower moisture, aw, and particle size, and greater solubility, while the freeze-dried samples were less hygroscopic. Tg values ranged from 10.1 to 52.2°C, and the highest values corresponded to the spray-dried microparticles. The spray-dried particles had spherical shape, while the freeze-dried powders showed irregular structures. The spray drying technique and the use of 5% PHGG and 5% PD has proven to be the best treatment.

a b s t r a c tOsmotic dehydration of banana (Musa sapientum, shum.) was optimized with respect to temperature (25e55 C), salt (0e10 g/100 g) and sucrose (30e60 g/100 g) concentrations through response surface methodology. The solution of Fick's law for unsteady-state mass transfer in a cylindrical configuration was used to calculate the effective diffusivities of water, sucrose and NaCl. Analyses were conducted in triplicate for moisture, sugar and salt contents. Peleg's model was used to predict the equilibrium condition, which was shown to be appropriate for water loss and solute uptake. For the above conditions of osmotic dehydration, the effective diffusivity of water was found to be in the range of 5.19e6.47 Â 10 À10 m 2 s À1 , the sucrose effective diffusivity between 4.27e6.01 Â 10 À10 m 2 s À1 and that of NaCl between 4.32e5.42 Â 10 À10 m 2 s À1 . The working conditions that simultaneously optimize these 3 variables were the temperature of 25 C with a solution composed of 30 g/100 g of sucrose and 10 g/100 g of sodium chloride. This condition provided values of 4.80 Â 10 À10 m 2 s À1 for effective diffusivity of water, of 3.21 Â 10 À10 m 2 s À1 for effective diffusivity of sucrose and 4.49 Â 10 À10 m 2 s À1 for effective diffusivity of sodium chloride.

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This study aimed at microencapsulating palm oil, containing high carotenoid content, with chitosan/xanthan and chitosan/pectin, using the complex coacervation method, followed by atomization and lyophilization. The DSC technique was used to confirm the encapsulation. The atomized microparticles had spherical shape and irregular size, and the lyophilized microparticles had irregular shape and size. Lyophilization resulted in lower carotenoids losses, and higher yield and encapsulation efficiency. In addition, the release profile in both water and gastrointestinal fluid was satisfactory. Prior to their application in food, a greater percentage of carotenoids was released in the fluid that simulates gastrointestinal conditions; however, the compounds were degraded after their release. In this case, the chitosan/pectin microparticles showed the best release profile. After processing, the release was lower and the released compounds were not degraded. Thus, the chitosan/xanthan microparticles showed the best potential for practical application, particularly, in yogurt preparation.