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

Abstract

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 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 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.

Effect of sodium caseinate concentration and sonication amplitude on the stability and physical characteristics of homogenized coconut milk

“…However, the emulsion that stabilized at the submicron size (<1 µm) of the fat globules can only be achieved at a higher amplitude setting (≥80%). This is in agreement with Consoli et al () where the lower mean diameters of the droplet were achieved at higher sonication amplitude. The emulsion that reached the submicron range size of a primary size able to retard the flocculation rate as the effective size of these samples is significantly lower than its original effective size of 13 µm.…”

“…The homogenized emulsions were characterized within 24 hr after sample preparation. Microscopic, viscosity and creaming index analyses were conducted immediately after preparation to avoid harmful impact of creaming in the result of the analysis (Consoli et al, ). For other analyses, the preserved samples were brought to room temperature prior to analysis.…”

“…During sonication, pressure fluctuation of the acoustic waves causes the repetition of growth and collapse of the primary fat, which subsequently breaks up the fat into a smaller size (Leong, Wooster, Kentish, & Ashokkumar, 2009). Increasing the ultrasonic power will significantly reduce the fat size (Du Le, 2015) until it reaches the submicron size range of the fat (Consoli, Figueiredo Furtado, Cunha, & Hubinger, 2017). The ultrasonic power is strongly related to the ultrasonic amplitude.…”

“…Several studies have been conducted to determine the effect of ultrasonic homogenization on the physical properties of the emulsion with various types of vegetable oil such as olive oil (Kaltsa, Gatsi, Yanniotis, & Mandala, 2014), lime essential oil (Campelo et al, 2017), orange peel essential oil (Hashtjin & Abbasi, 2015), palm oil (Consoli et al, 2017), rapeseed oil (O'sullivan, Murray, Flynn, & Norton, 2015), sunflower oil (Leong et al, 2009) including coconut milk (Du Le, 2015;Iswarin & Permadi, 2012;Jena & Das, 2006). An extensive study on the effect of SC concentration and other types of emulsifiers on the stability of coconut milk was conducted by Tangsuphoom and Coupland (2008).…”

Use of High‐Intensity Ultrasound to Change the Physical Properties of Oleogels and Emulsion Gels

“…In particular, sonication is effective at producing emulsions with high concentration of solids. Both parameters in sonication, time and power amplitude, show substantial effects on emulsions’ physical properties (Consoli et al, ). Some of the advantages of using ultrasound as an emulsification tool include low energy consumption and minimum amount of surfactant needed to produce a homogeneous and stable emulsion.…”