High solids emulsions produced by ultrasound as a function of energy density

• Published in: Ultrasonics sonochemistry 2017-09, Vol.38, p.772-782
• Main Authors: Consoli, Larissa, de Figueiredo Furtado, Guilherme, da Cunha, Rosiane Lopes, Hubinger, Míriam Dupas
• Format: Article
• Language: English
• Subjects: Flocculation; High energy emulsification; Palm oil; Sonication
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2016.11.038

•Rotor-stator device and sonication were used to produce emulsions of 30% total solids.•Sodium caseinate, maltodextrin and dried glucose syrup were used as stabilizers.•Power amplitude and sonication time were the variables and energy density was calculated.•Higher energy densities led to lower D[3,2] diameter, until reaching a saturation value.•Sonication was effective for obtaining suitable emulsions for further spray drying. The use of emulsifying methods is frequently required before spray drying food ingredients, where using high concentration of solids increases the drying process yield. In this work, we used ultrasound to obtain kinetically stable palm oil-in-water emulsions with 30g solids/100g of emulsion. Sodium caseinate, maltodextrin and dried glucose syrup were used as stabilizing agents. Sonication time of 3, 7 and 11min were evaluated at power of 72, 105 and 148W (which represents 50%, 75% and 100% of power amplitude in relation to the nominal power of the equipment). Energy density required for each assay was calculated. Emulsions were characterized for droplets mean diameter and size distribution, optical microscopy, confocal microscopy, ζ-potential, creaming index (CI) and rheological behavior. Emulsions presented bimodal size distribution, with D[3,2] ranging from 0.7 to 1.4μm and CI between 5% and 12%, being these parameters inversely proportional to sonication time and power, but with a visual kinetically stabilization after the treatment at 148W at 7min sonication. D[3,2] showed to depend of energy density as a power function. Sonication presented as an effective method to be integrated to spray drying when emulsification is needed before the drying process.