Beetroot Extract Microencapsulated with Modified Starch and the Amino Acids L-Aspartic Acid, L-Tyrosine, and L-Lysine: Application of the Powders in the Formulation of Gelatin Gels

Abstract

The objective of this study was to evaluate the effects of the amino acids L-tyrosine (TYR), L-aspartic acid (ASP), and L-lysine (LYS) on the physical and physicochemical properties of freeze-dried beetroot extract powder produced using modified starch with octenyl succinic anhydride (MS) as an encapsulating agent. The formulations were prepared with 80% beetroot extract and 20% adjuvant mixture (MS + amino acids). The amino acid content ranged from 10% to 20% of the adjuvant mixture, and its influence on powder stability was assessed by monitoring betalain concentrations during storage at 45 °C over 49 days. Moreover, the texture and betalain concentration of gelatin gels containing beetroot extract powders were evaluated. Powders containing TYR exhibited the lowest Carr index (17.2–19.2%) and Hausner ratio (1.21–1.24), corresponding to fair flowability, which could be attributed to their larger mean particle diameters (59.17–60.16 μm). The formulation containing the highest concentration of LYS showed the longest betacyanin half-life (t1/2), reaching 64.1 weeks. Compared with the formulation containing only MS as the encapsulant agent (t1/2 = 30.6 weeks), powders produced with the highest concentrations of ASP, TYR, and LYS showed increases in betacyanin t1/2 of 10.45%, 65.35%, and 109.47%, respectively. Regarding gel production, the addition of L-aspartic acid and L-lysine at the highest concentrations resulted in the lowest betalain losses, with reductions of 5.40% and 4.33%, respectively.