Optimization of spray drying conditions of copoazú (Theobroma grandiflorum) and açaí (Euterpe precatoria) pulps enriched with copoazú seed extract: effects on phenolic compounds, antioxidant capacity, and physicochemical characteristics

Copoazú ( Theobroma grandiflorum ) and açaí ( Euterpe precatoria ) are Amazonian fruits rich in bioactive compounds and antioxidant activity. Copoazú seeds also contain fatty acids and minerals that enhance their nutritional value. However, these metabolites are highly sensitive to temperature, humidity, and oxidation, limiting their stability and industrial application. Spray-drying microencapsulation offers an effective strategy to protect and stabilize these compounds. This study aimed to optimize spray drying conditions of copoazú and açaí pulps enriched with aqueous copoazú seed extract using a Central Composite Design (CCD) to evaluate the effects of drying temperature, maltodextrin concentration, and the copoazu seed extract incorporation on the phenolic content, antioxidant capacity and physicochemical properties of the resulting powders. Optimal conditions were defined through response surface methodology (RSM), selecting the combination with the highest desirability. The optimal formulation was obtained at 165°C, with 9.6% maltodextrin and 11.3% seed extract, producing powders with low moisture (3.5%), water activity (0.33), hygroscopicity (13.7 g/100 g), high solubility (87%), and a yield of 76.6%. Experimental results closely matched model predictions. Retention efficiency varied among compounds, with low values for catechin, quercetin, and gallic acid (2–10%), while the remaining phenolics and the antiradical capacity showed moderate to high retention (40–81%). The microcapsules exhibited rough, spherical morphology with an average particle size of 8.68 µm, and thermogravimetric analysis demonstrated improved thermal stability due to maltodextrin. These microcapsules offer a promising technological approach for diversifying Amazonian fruit-based products, enhancing functional stability, and promoting the sustainable valorization of regional biodiversity resources.