Caracterização de extrato de erva-mate (Ilex paraguariensis) microencapsulado por spray-drying

Abstract

Yerba mate (Ilex paraguariensis St. Hill) is a native product of South America and an important part of the economy of southern Brazil. After harvesting, the yerba mate goes through the milling (drying, drying and milling) and beneficiation cycles. Then, for the formation of toasted mate tea, roasting is done. The composition of yerba mate in cludes antioxidant compounds such as phenolic acids and flavonoids, besides alkaloids like methylxanthines. Microencapsulation seeks to improve the stability and concentration of antioxidant compounds by incorporating a material of interest such as maltodextrin. Therefore, the present work seeks to evaluate how the extraction of soluble solids and microencapsulation with maltodextrin, using spray dryer technique, modify the characteristics of the toasted yerba mate, characterizing it in relation to the centesimal composition; physical properties; color; thermal parameters (via thermogravimetric analysis); identification and quantification of caffeine, quercetin and rutin (via High Performance Liquid Chromatography); and microencapsulation efficiency (via Scanning Electron Microscopy). Samples of toasted and microencapsulated yerba mate with maltodextrin presented the variations described below. The physical properties for toasted and microencapsulated toasted yerba mate were, respectively, 3.19 to 4.85 for humidity (%); 13.06 to 3.06 for ashes (%); 0.2196 to 0,9998 for lipids (%) and 83.52 to 91.70 for total carbohydrates (%). Proteins (%) did not variated. The water activity was 0.60 to 0,45; hygroscopicity (%) of 16,64 to 9.22; dissolubility (s) of 70.99 to 8,31, respectively. The amount of caffeine, quercetin and rutin were 20.305 to 7.454 mg ∙ g-1; 2.203 to 4.802 mg ∙ g-1; 3.303 to 2.294 mg ∙ g-1, respectively. In thermogravimetric analysis it was possible to observe the protection caused by microencapsulation against temperature application; There was a maximum color variation of ΔE*= 23,56 between the samples. Microencapsulation was efficient, with particles ranging from 8.6 to 118 μm. It was concluded that maltodextrin microencapsulation was efficient for the protection of compounds with antioxidant activity, despite the decrease in the amount of flavonoids and methylxanthines 10 because of the solubilization to extract the soluble solids and drying at spray dryer; microencapsulation led to increased carbohydrate and humidity content, decreased ash content, and improved physical characteristics for a powder.