Secagem de grama de trigo (Triticum aestivum L.) em spray dryer

Abstract

Wheatgrass is a microgreen commonly consumed as a supplement, mainly in the form of juice processed after harvesting. It is a rich source of bioactive compounds with potential applications in the food industry, however, drying processes for wheatgrass preservation are rarely explored in scientific literature. This study aimed to investigate the production of wheatgrass powder by spray drying and the influence of thermal treatment by immersion bleaching. Initially, the effect of bleaching was investigated using a 24 factorial design, followed by a central composite design to obtain mathematical models. The drying parameters evaluated were drying air temperature (96-163°C), feed flow rate (0.25-0.95 L∙h-1), and drying air flow rate (0.95-1.65 m3∙min-1). The wheat grass used was harvested after 9 days of growth. Physical-chemical analyses were performed on moisture content, water activity, yield, solubility, color, and bioactive compounds (chlorophyll, carotenoids, total phenolic compounds, and total flavonoids). The results showed that the dry material obtained from bleaching generally had lower moisture content and higher yields when compared to material that had not undergone heat treatment. In terms of color, the bleached samples showed less color loss, resulting in greener particles. Bleaching contributed to greater retention of chlorophyll and carotenoid pigments.