Microencapsulation of Renealmia alpinia (Rottb.) Maas pulp pigment and antioxidant compounds by spray-drying and its incorporation in yogurt.

Renealmia alpinia (Rottb.) Maas pulp was processed by spray drying using Maltodextrin (MDX), and Gum Arabic (GA), and the mixture of both encapsulating agents (MDX-GA). Yield, moisture, water activity ( a w ), apparent and bulk densities, size and morphology of capsules, color, and antioxidant potential (antioxidant activity, total carotenoids, and phenolic compounds) were analyzed. The encapsulates were incorporated as pigments in yogurt and the stability of antioxidant compounds (1, 7, 14, 21, and 28 days of storage) and the sensory properties were evaluated. The yields of all formulations (MDX, GA, MDX-GA) were around 17.86% with low moisture and a w range values (2.62-3.29% and 0.276-0.309, respectively). The microcapsules presented multiples particle sizes (0.67-27.13 µm) with irregular and smooth surfaces. Furthermore, these capsulates preserved yellow color and the retention of carotenoids was significantly higher with MDX (34.12 mg/100 g of powder), while the phenolic compounds and antioxidant activity increased with GA (474.17 mg GAE/100 g and 552.63 mg TE/100 g of powder, respectively). The main compounds β-carotene and gallic acid were identified and quantified in positive and negative mode respectively using LC-MS/MS. Finally, the addition of the encapsulated pigments to yogurt allowed to obtain a yellow coloration and the yogurt added with MDX-GA presented the best formulation with not significant changes in antioxidant activity and acceptable sensory attributes up 28 days of storage.