Use of encapsulation technology to increase the stability of anthocyanins

Beetroot extract, rich in anthocyanins, was microencapsulated into alone or combination of maltodextrin (MD) and gum arabic (GA) sodium caseinate (SC) by freeze-drying. The most successful wall formulation was determined as MD:GA:SC in terms of encapsulation efficiency (95.36%), 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging power (88.43%), release rate (89.44%). In order to determine the protective effect of the wall materials on beetroot anthocyanins, free and microencapsulated beetroot extract were subjected to different pH (2.5, 4.5, and 6.5) and temperatures (40, 60, 80, and 100 °C) treatments for 6 hours. The decrease in the amount of anthocyanin at the end of pH and heat treatments was evaluated with kinetic parameters. The degradation of anthocyanins was best described by the first-order kinetic model. It was determined that the reaction rate constant (k) decreased and the half-life (t1/2) increased with microencapsulation. The k and t1/2 values of free and microencapsulated (MD:GA:SC) beetroot anthocyanin at pH 2.5 and 100 °C decreased from 0.056 to 0.013 1/min and increased from 9.800 to 31.846 min, respectively. The temperature-dependent degradation of anthocyanins is described by the Arrhenius equation. The activation energy (𝐸 𝑎 ) of beetroot anthocyanin degradation increased with pH and the microencapsulation process. The 𝐸 𝑎 values for anthocyanin degradation in free and MD, GA, MD:GA, and MD:GA:SC microcapsules at pH 6.5 were determined as 23.273, 27.586, 26.053, 57.027, and 62.045 kJ/mol, respectively. These results indicated that the optimum wall material formulation was MD:GA:SC in the microencapsulation process to increase the thermal stability of beetroot anthocyanins. Artificial Neural Network model yielded accurate in prediction of degradation behaviors of free and microencapsulated beetroot anthocyanin. Keywords: Beetroot, Anthocyanin, Encapsulation, Thermal degredation, Artificial neural network