The microencapsulation of plant bioactive compounds by spray drying enhances their stability and controlled delivery in food systems. In this study, flaxseed hydrocolloid (Linum usitatissimum L.) was evaluated as a natural wall material for encapsulating phenolic extracts from mashua (Tropaeolum tuberosum Ruiz & Pav.) and oca (Oxalis tuberosa Molina). Microcapsules were produced using hydrocolloid concentrations of 2.5–10%. The resulting particles showed low moisture content (3.79–5.42%), low water activity (0.31–0.39), and high solubility (90.94–96.45%). Encapsulation efficiency ranged from 78.67 to 62.32% for mashua and from 71.94 to 40.45% for oca, decreasing with increasing wall material concentration. Phenolic content ranged from 14.48 to 11.47 mg GAE/g (mashua) and 8.52 to 4.82 mg GAE/g (oca), with antioxidant capacity between 293.19–143.77 and 84.49–10.33 µmol TE/g, respectively. Particle size ranged from 4.02–10.50 µm (mashua) and 3.93–4.82 µm (oca), and zeta potential values (−37.86 to −27.55 mV) indicated good colloidal stability. Release kinetics showed a biphasic profile and were predominantly diffusion-controlled. The Higuchi model showed significant diffusion (p < 0.05), while the Korsmeyer–Peppas analysis indicated mainly Fickian diffusion (n = 0.234–0.426) with anomalous transport at higher mashua concentrations. These results demonstrate that flaxseed hydrocolloid is an effective and sustainable wall material for controlled release of phenolic compounds from Andean tubers.
Moscoso-Moscoso et al. (Wed,) studied this question.