Effect of Carrier Agents and Inlet Temperature on Physicochemical Properties of Encapsulated Carrot Coagulum Powder

Abstract

Background: The carrot (Daucus carota L.) is a popular root vegetable grown throughout the world. In the present study, an attempt was made to use the carrot outgrades, which are purely rejected for aesthetic reasons, not meeting the standards based on size and shape. Further enzymes (Pectinase and Cellulase) are used to extract the carrot coagulum from carrot outgrades. Carrier agents were mixed into carrot coagulum and spray dried at three different inlet air temperatures (160, 170, and 180 °C) to encapsulate enzyme-extracted carrot coagulum. Aim: Carrots are nutritious and mainly rich in carotenoids. Often, very high losses are incurred during post-harvesting operations. A significant proportion of carrots are rejected due to bad aesthetics. Therefore, the objective of the study was to utilise such non-commercial carrot out-grades to recover carotenoids and produce encapsulated powder using spray drying. Methodology: The process of spray drying of enzymatically extracted carrot coagulum was standardised by varying carrier agents (maltodextrin and gum arabica) concentration and at different inlet temperatures. Pectinase (Pectinex Ultra SPL from Aspergillus aculeatus aqueous solution, ≥3,800 units/mL) and cellulose (Celluclast 1.5L from Trichoderma reesei aqueous solution, ≥700 units/g) were obtained from Novozymes, Bangalore. Trans-β-carotene was obtained from Sigma Chemical Company. All other chemicals used were of analytical grade. Results: All physicochemical properties were significantly affected by the carrier agents and temperature. Carotenoid content was highest (9.80%) at an inlet temperature of 170 °C with MD100. Overall moisture content was reduced, while other physical properties were enhanced when the temperature increased. Increasing the gum Arabica content showed a significant increase in moisture content and wettability time, as well as poorer physical properties. Results showed that the physicochemical and microstructural properties of encapsulated carrot coagulum powder (ECCP) were affected by inlet temperatures and carrier agents. Conclusion: Among all the spray-dried powders, the powder dried at 170 °C using maltodextrin at 15% alone had comparatively lower moisture content, good flowability, higher solubility, and less wetting time compared to other combination treatments and inlet temperatures, and thus fulfills the requirement of good quality spray-dried powders. Certainly, carrot out grades have a significant content of total carotenoids, which makes the utilisation of such material worthwhile for processing.