Elaboração e caracterização de microcápsulas obtidas a partir de extratos de folhas de moringa fermentada e não fermentada

Abstract

Moringa oleifera, also known as the “miracle tree” or “tree of life”, is a plant rich in nutrients, and phytochemicals, present in almost all parts, such as leaves, flowers, seeds and pods. Its leaves are worth mentioning, as they contain a high content of proteins and phenolic compounds. Solid-State Fermentation (SSF) has emerged as a promising tool to aid in the extraction of phenolic compounds from plant parts. However, these extracts may change due to exposure to stressful conditions, such as water, light, heat, pH, enzymes and oxygen. In this context, microencapsulation appears as an alternative to avoid the degradation of the compounds contained in these extracts. Thus, the present study aimed to evaluate the total phenolic content, antioxidant potential and physicochemical characteristics of microcapsules of extracts obtained from fermented (EFF) and non-fermented (EFNF) moringa leaves. The leaves were dried and ground and subjected to FES using Aspergillus niger. The fermented and non-fermented leaf extracts were obtained in an aqueous solution of 80% ethanol. The microcapsules were obtained by lyophilization using different proportions of extract: arabic gum (1:10, 1:6 and 1:4). The microcapsules with EFNF prepared in the proportion 1:4 showed a higher content of total phenolics (4.91 mg GAE/g of microcapsules) and morphological characteristics of glassy aspect, and the ones prepared with EFNF and EFF in the proportion 1:10, showed greater antioxidant activity (300.84 and 299.13 μmol Trolox/g, by the ABTS method, respectively). All microcapsules had good encapsulation efficiency (91.76 and 95.70%), high solubility (92.27 to 95.91%), favorable conditions of hygroscopicity (14.50 to 19.8%) and low activity of water (0.13 to 0.29). Therefore, the results indicated that the microcapsules elaborated with 1:4 (extract: Arabic gum) ratio showed the lower values of water activity and humidity, higher concentration of phenolic compounds and antioxidant activity by the FRAP method. However, further studies are needed to evaluate the toxicity of microcapsules for future applications in the pharmaceutical, cosmetic and food sectors.