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Title:Evaluation of the microencapsulation performance by spray drying with a three-fluid nozzle
Author(s):Cai, Jingwen
Director of Research:Lee, Youngsoo
Doctoral Committee Chair(s):Feng, Hao
Doctoral Committee Member(s):Cadwallader, Keith R.; Lee, Soo-Yeun
Department / Program:Food Science & Human Nutrition
Discipline:Food Science & Human Nutrition
Degree Granting Institution:University of Illinois at Urbana-Champaign
spray drying
three-fluid nozzle
sugar beet pectin, maltodextrin
soybean oil
contact time
flow rates
control release
sodium reduction
modified starch
Abstract:Microencapsulation is an effective method to entrap core material with a wall material, which can increase the stability, control delivery, and mask off-notes of the core material. Spray drying is one of the most commonly used microencapsulation techniques in the food industry. Both material properties and process conditions will affect the characteristics of the microcapsules produced by spray drying. Recently, a three-fluid nozzle (3FN) is designed for spray dryers. It separates wall material and core material into two feed channels, which eliminates the need for the formation of emulsion or mixture before spray drying and provides a possibility to encapsulate core compounds using an incompatible wall material. However, there is a limited amount of information available related to the factors that affect microencapsulation performance in spray drying with a 3FN. The goal of this research is to correlate the properties of feed material and process parameters with the properties of microcapsules that are spray dried with a 3FN. The outcome of this research can be used to expand the application of 3FN in the food industry. First, sodium chloride was encapsulated with maltodextrin DE 10 and octenyl-succinic-anhydride (OSA) modified starch by spray drying with a conventional two-fluid nozzle (2FN) and a 3FN. Compared to the 2FN, the 3FN has the potential to control the release of sodium by creating microcapsules. The shape of microcapsules was round and uniform and the particle size of microcapsules changed with the type and concentration of the wall materials. The sodium release rate from water could be controlled by changing wall material types and concentrations. Then, soybean oil as core material and sugar beet pectin combined with maltodextrin DE 10 as wall material were used as the model system to create microcapsules by spray drying with 3FN. Properties of microcapsules including morphology, particle size, density, flowability, color, and encapsulation performance were characterized. The rheological properties of the wall material solution were altered by varying wall solution compositions. Most spray-dried samples had a wrinkled surface with a hollow core. As the viscosity of the wall material increased, the particle size distribution of microcapsules became wider and the surface oil content increased. The contact time between the wall and core material in the 3FN was adjusted by modifying the inner channel lengths. The contact time had a more significant impact on the properties of the microcapsules made with higher pectin concentrations. When the feed flow rates were varied at three levels, the microcapsules presented similar properties regardless of the flow rates, indicating the possibility to improve the throughput of spray drying by increasing the flow rates. Microcapsules made with a 2FN had a rounder morphology and smaller particle size compared to those made with 3FN. Although samples made with 2FN showed a lower surface oil content, the entrapment ability of oil was not as high as the samples made with 3FN. This study related the properties of microcapsules spray dried with a 3FN to properties of feed materials and process parameters. The results implied the potential to use a 3FN for encapsulation without forming emulsions or mixing core and wall materials. Further studies can explore the effect of other process parameters like temperature and atomization pressure on the properties of microcapsules. Also, instead of using the model materials, other active compounds with more practical applications can be the next step for the studies using 3FN.
Issue Date:2021-06-29
Rights Information:Copyright 2021 Jingwen Cai
Date Available in IDEALS:2022-01-12
Date Deposited:2021-08

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