Oil droplet breakup during pressure swirl atomization of food emulsions: Influence of atomization pressure and initial oil droplet size

Taboada, Martha L.; Schäfer, Ann‐Christin; Karbstein, Heike P.; Gaukel, Volker

doi:10.1111/jfpe.13598

Cited by 12 publications

(35 citation statements)

References 24 publications

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“…Model food oil-in-water emulsions were prepared for the investigations following the procedure described in [9]. Medium chain triglycerides oil (MCT oil, WITARIX ® MCT 60/40, Hamburg, Germany) was used as model disperse phase.…”

Section: Model Emulsionsmentioning

confidence: 99%

“…Atomization experiments were performed in a spray test rig, similarly to previous studies [9,26]. The rig is equipped with a laser diffraction spectroscope (Spraytec, Malvern Instruments GmbH, Herrenberg, Germany) which allows the inline measurement of the SDSD during atomization.…”

Section: Atomization Rigmentioning

confidence: 99%

“…The desired oil droplet size distribution (ODSD) in the powder is usually adjusted in a homogenization step prior to spray drying. However, in our previous study we showed that oil droplets dispersed in the feed for spray-drying may breakup during atomization with pressure swirl (PS) atomizers [9], which are used in the vast majority of spray drying applications for foods [2,10]. Oil droplet breakup during atomization changes the previously adjusted ODSD.…”

Section: Introductionmentioning

confidence: 99%

“…A schematic view of the PS nozzle is depicted in Figure 1a. The high liquid pressures and the thin liquid film at the atomizer exit in PS nozzles can lead to shear stresses in the order of ~10 6 s −1 [9,17]. These shear stresses may also lead to breakup of the dispersed oil droplets in emulsions during atomization.…”

Section: Introductionmentioning

confidence: 99%

“…These shear stresses may also lead to breakup of the dispersed oil droplets in emulsions during atomization. In fact, we reported a reduction of the Sauter mean diameter (SMD) in food emulsions from >20 µm to submicron values at a typical operation pressure of 100 bar [9]. PS atomizers appear therefore unsuitable for applications in which oil droplet breakup is undesired or oil droplets in the resulting powder after spray drying >1 µm are required.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Oil Droplet Breakup during Atomization of Emulsions: Comparison of Pressure Swirl and Twin-Fluid Atomizers

Taboada

Zapata

Karbstein

et al. 2021

Fluids

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The goal of this study was to investigate oil droplet breakup in food emulsions during atomization with pressure swirl (PS), internal mixing (IM), and external mixing (EM) twin-fluid atomizers. By this, new knowledge is provided that facilitates the design of atomization processes, taking into account atomization performance as well as product characteristics (oil droplet size). Atomization experiments were performed in pilot plant scale at liquid volume flow rates of 21.8, 28.0, and 33.3 L/h. Corresponding liquid pressures in the range of 50–200 bar and air-to-liquid ratios in the range of 0.03–0.5 were applied. Two approaches were followed: oil droplet breakup was initially compared for conditions by which the same spray droplet sizes were achieved at constant liquid throughput. For all volume flow rates, the strongest oil droplet breakup was obtained with the PS nozzle, followed by the IM and the EM twin-fluid atomizer. In a second approach, the concept of energy density EV was used to characterize the sizes of resulting spray droplets and of the dispersed oil droplets in the spray. For all nozzles, Sauter mean diameters of spray and oil droplets showed a power-law dependency on EV. PS nozzles achieved the smallest spray droplet sizes and the strongest oil droplet breakup for a constant EV. In twin-fluid atomizers, the nozzle type (IM or EM) has a significant influence on the resulting oil droplet size, even when the resulting spray droplet size is independent of this nozzle type. Overall, it was shown that the proposed concept of EV allows formulating process functions that simplify the design of atomization processes regarding both spray and oil droplet sizes.

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Section: Model Emulsionsmentioning

confidence: 99%

Section: Atomization Rigmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Investigation of Oil Droplet Breakup during Atomization of Emulsions: Comparison of Pressure Swirl and Twin-Fluid Atomizers

Taboada

Zapata

Karbstein

et al. 2021

Fluids

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Breakup and Coalescence of Oil Droplets in Protein-Stabilized Emulsions During the Atomization and the Drying Step of a Spray Drying Process

Taboada

Chutani

Karbstein

et al. 2021

Food Bioprocess Technol

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The goal of this study was to investigate the changes in oil droplet size in whey protein–stabilized emulsions during the atomization and the subsequent drying step of a spray drying process. For this purpose, experiments were performed in an atomization rig and a pilot spray dryer with two commercial pressure swirl atomizers. By comparing the oil droplet size before atomization, after atomization, and after spray drying, the changes in oil droplet size during each process step were quantified. The effect of oil droplet breakup during atomization was isolated by atomizing emulsions with 1 wt.% oil content and a protein to oil concentration ratio of 0.1. At 100 bar, the Sauter mean diameter of oil droplet size was reduced from 3.13 to 0.61 μm. Directly after breakup, coalescence of the oil droplets was observed for emulsions with a high oil content of 30 wt.%, leading to a droplet size after atomization of 1.15 μm. Increasing the protein to oil concentration ratio to 0.2 reduced coalescence during atomization and oil droplets with a mean diameter of 0.92 μm were obtained. Further coalescence was observed during the drying step: for an oil content of 30 wt.% and a protein to oil concentration ratio of 0.1 the mean droplet size increased to 1.77 μm. Powders produced at high oil contents showed a strong tendency to clump. Comparable effects were observed for a spray drying process with a different nozzle at 250 bar. The results confirm that droplet breakup and coalescence during atomization and coalescence during drying have to be taken into consideration when targeting specific oil droplet sizes in the product. This is relevant for product design in spray drying applications, in which the oil droplet size in the powder or after its redispersion determines product quality and stability.

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Factors influencing droplet size in pneumatic and ultrasonic atomization and its application in food processing

Camacho-Lie,

Antonio-Gutiérrez,

López-Díaz

et al. 2023

Discov Food

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Droplet size has significant scientific and industrial relevance in the effectiveness of atomization for several applications in the chemical, pharmaceutical, and food industries. This technology is widely employed in the food industry for processes such as spray drying, microencapsulation, edible coatings, and food disinfection, among others. This work comprehensively reviews the effect of liquid properties and equipment operating factors influencing droplet size in pneumatic and ultrasonic atomization. The discussion on the atomization theories includes the different models for estimating droplet size as a function of selected variables for both processes. The different model approaches are reviewed, focusing on their advantages, disadvantages, applications, and limitations. Furthermore, selected models were employed to carry out different sensitivity analyses showing the effect of variables related to the liquid properties, the type and characteristics of the atomizers, and the operating conditions, allowing the reader to appreciate the most critical factors in both atomization systems.

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Oil droplet breakup during pressure swirl atomization of food emulsions: Influence of atomization pressure and initial oil droplet size

Cited by 12 publications

References 24 publications

Investigation of Oil Droplet Breakup during Atomization of Emulsions: Comparison of Pressure Swirl and Twin-Fluid Atomizers

Investigation of Oil Droplet Breakup during Atomization of Emulsions: Comparison of Pressure Swirl and Twin-Fluid Atomizers

Breakup and Coalescence of Oil Droplets in Protein-Stabilized Emulsions During the Atomization and the Drying Step of a Spray Drying Process

Factors influencing droplet size in pneumatic and ultrasonic atomization and its application in food processing

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