Influência da secagem convectiva do resíduo agroindustrial de acerola verde na extração e encapsulamento de compostos bioativos.

Abstract

The acerola fruit in its unprocessed form, which part of its volume is designated for processing procedures, generating large amounts of waste that are mostly discarded. However, these residues, besides the ascorbic acid, contain the presence of important phenolic compounds with antioxidant properties. Thus, drying is one of the alternatives used for the utilization of these residues, since it enables the diversification of products. Moreover, the extraction and microencapsulation of bioactive compounds present in the acerola residue can increase the commercial value of the raw material and the profitability of acerola processing. Thus, the present study was carried out with the objective of evaluating the influence of convective drying of green acerola agroindustrial residue on bioactive compounds and antioxidant capacity. For this, bioactive extracts prepared with the residue of green acerola in natura and prepared at different drying temperatures were evaluated, performing the optimization of the extraction process and the microencapsulation process through factorial planning of the type 23 with three repetitions in the central point, in addition to the physical and physicochemical characterization of the powder that showed more bioactive activity. The analysis of the results showed that the Page model best described the drying process in all temperature conditions studied. The effective diffusivity showed satisfactory values (6.58x10- 10 and 1.85x10-9 m2

.s-1), noting that only the temperature had a significant effect on the drying process and from the thermodynamic properties it was possible to conclude that these were affected by increasing drying temperature, with reductions in enthalpy and entropy and increased Gibbs free energy indicating a non-spontaneous endergonic process. The application of ultrasound-assisted extraction optimization provided high contents of bioactive compounds, where the regression model showed satisfactory fit to the experimental data, having as the main influence on the process the contact time of the sample with solvent. In the optimization of microencapsulation, the regression model can be used for predictive purposes, where among the conditions the percentage of encapsulant was the main variable that showed significant effects, allowing to obtain microparticles rich in antioxidant compounds, due to the use of Capsul® (modified starch) encapsulant that favored a greater retention of bioactive compounds. Thus, the residue of green acerola is an interesting co-product to be reused, with great antioxidant potential, due to its bioactive compounds, which can replace synthetic antioxidants in the industry, as well as in the preparation of functional foods.