The influence of carrot pretreatment, type of carrier and disc speed on the physical and chemical properties of spray-dried carrot juice microcapsules

Abstract

Nowadays microencapsulation of pigments is widely applied to create stable powders. The aim of this study was to investigate the effect of thermal blanching as a form of pretreatment before pressing and carrier type on stability of microencapsulated carrot juice powder. Raw material used in the study was the carrot variety Kazan. One part of carrots was blanched before pressing the juice. Mixtures of low-crystallized maltodextrin (MD) with Arabic gum (AG) in different proportions (1:1, 2:1) and whey protein isolate (WPI) were used as carriers. Drying was carried out in a spray-drier at inlet air temperature of 160 °C. Two speeds of the disc were used (28,000; 39,000 rpm). Viscosity, soluble solid content, density, and carotenoid content were measured in juice. Water content, water activity, apparent and bulk density, size of particles, morphology, and carotenoid content were tested in powders. Carrot blanching resulted in higher viscosity, without influencing its density or soluble solid content of the juices in comparison with those without pretreatment. In most cases, blanching treatment caused a decrease in carotenoid content and increases in densities and diameters of powder particles. The change of carrier material from MD:AG mixtures to WPI caused an increase in diameter d50 and carotenoid content and decrease in density values.

Keywords:

• Word
• carrot powders
• juice
• encapsulation
• blanching
• spray drying
• morphology

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

The study was supported by an internal grant of Warsaw University of Life Sciences. The work was also co-financed by a statutory activity subsidy from the Polish Ministry of Science and Higher Education for the Faculty of Food Sciences of Warsaw University of Life Sciences.