Secagem convectiva na recuperação de compostos bioativos do resíduo do processamento da polpa de cumbeba (Tacinga inamoena).

Abstract

Cumbeba residue, a by-product generated from the processing of Tacinga inamoena (cumbeba) fruits, represents a huge amount of discarded material without further pplication, however, it is a promising source of bioactive compounds such as phenolic compounds, flavonoids and betalains, which can be used as natural antioxidants, dyes, preservatives and antimicrobials by the food, cosmetics and pharmaceutical industries, exerting several health benefits. Therefore, the extraction of these compounds represents an important path for the management and valorization of cumbeba residue, which would positively reflect on the economy of fruit processing, as well as its environmental impact. However, the stability of bioactive compounds can be affected by drying, an important and necessary step for the recovery of agrifood by-products. Thus, the aim of this study was to analyze the convective drying kinetics of cumbeba waste at different temperatures (50, 60, 70 and 80 °C) and type of treatment (untreated or whole, crushed and in the form of foam) and to evaluate its effect on the content of total phenolic compounds, flavonoids, anthocyanins and betalains; the process was also modeled and the effective water diffusivity (Def) was determined. The results showed that, regardless of the type of pretreatment, the increase in air temperature required shorter times to reach equilibrium with the drying air. Drying took place mainly in the period of the decreasing rate. Among the empirical models, the Midilli model was the best in describing the drying process of cumbeba residue. The proposed diffusive model well described the loss of water, mainly from the crushed waste, with good statistical indicators for all adjustments. Def values ranged from 6.489 to 11.190 × 10-6 m2/s, 2.928 to 12.754 × 10-9 m2/s and 1.539 × 10-8 to 12.427 × 10-6 m2/s, with activation energies of 22.307, 46.711 and 58.0736 kJ/mol, within the temperature range of 50-80 °C, obtained for the whole residue, ground and in the form of foam, respectively. Compared to the crushed and foamed residue, the dry whole residue showed higher retention of total phenolic compounds, flavonoids, anthocyanins and betalains. Thus, the results of convective drying proved to be an efficient alternative to obtain a product rich in bioactive compounds, mainly phenolic, from cumbeba residue and, thus, reuse and add value to this agro-industrial by-product.