Composto de café e yacon obtido por secagem em camada de espuma

Abstract

The search for functional foods has been increasing in Brazil, mainly due to the growing interest in bioactive properties capable of supporting metabolic and physiological functions in the body. These compounds are sensitive and degrade through various reactions that occur within the food matrix. In this context, drying emerges as an important preservation method. Among the available techniques, foam mat drying (FMD) is a valid alternative, as it operates at lower temperatures and requires shorter drying times compared to other conventional methods. The objective of this study was to evaluate the potential of FMD technology by investigating the influence of the foaming agent (albumin and whey protein) and drying temperature (50 and 70 °C) on the physicochemical characteristics and functional potential of powders obtained from a mixture of coffee extract and yacon juice. The foams were optimized for density using two central composite rotational designs (CCRD) and were subjected to drying in a convective air tunnel. Drying kinetics were evaluated, and the resulting powders were analyzed for moisture content, hygroscopicity, solubility, water activity, total phenolic content, and fructan retention. Increasing the drying temperature from 50 to 70 °C resulted in reduced drying time and greater solubility and hygroscopicity of the powders. A reduction in total phenolics and fructans was also observed after drying, attributed to thermal sensitivity of the compounds and oxygen exposure. However, formulations dried at 70 °C, especially those containing albumin, showed higher values of total phenolics and fructans compared to the other treatments.