Obtenção e caracterização da folha da capuchinha (Tropaeolum majus L.) em pó, em spray dryer

Abstract

Nasturtium (Tropaeolum majus L.) is an unconventional edible plant with nutritional and functional potential, particularly due to the presence of bioactive compounds associated with nutraceutical properties. However, the high moisture content of fresh leaves may limit their preservation and use, making drying an important alternative for increasing stability while maintaining desirable characteristics. Therefore, this study aimed to evaluate the nutraceutical properties of nasturtium and investigate the influence of drying conditions on the physicochemical characteristics and bioactive compounds of its leaves, with emphasis on spray drying. The study was structured into two chapters. The first chapter consisted of a literature review addressing the nutraceutical properties of T. majus and the main drying methods applied to edible and medicinal plants, including studies published between 1999 and 2025. A total of 45 studies were selected, allowing the available evidence regarding the bioactive compounds of the species and the effects of different drying techniques on their preservation to be systematized. In the second chapter, nasturtium leaves were subjected to spray drying using a complete 2³ factorial design to evaluate the effects of drying air temperature, feed flow rate, and air flow rate. Fresh leaves showed a moisture content of 81.97%, as well as expressive levels of protein, crude fiber, and ash on a dry basis. The resulting powders showed moisture contents ranging from 5.58 to 7.87%, while water activity remained below 0.300 under all evaluated conditions, indicating favorable conditions for product stability. Processing conditions significantly affected several powder properties, particularly temperature, which had a pronounced effect on pigment preservation and process yield. The highest yield, 56.96%, was obtained at 140 °C, with a feed flow rate of 0.40 L·h⁻¹ and an air flow rate of 1.60 m³·min⁻¹. However, the condition of 100 °C, 0.40 L·h⁻¹, and 1.60 m³·min⁻¹ showed better performance in preserving bioactive compounds, with 1500.75 mg·100 g⁻¹ of total chlorophyll, 39.93 mg·100 g⁻¹ of carotenoids, and a high total phenolic content. Lower drying temperatures also resulted in shorter wetting times, indicating improved powder reconstitution properties. Therefore, within the conditions evaluated, moderate temperatures were more suitable for preserving the nutraceutical potential of nasturtium, whereas higher temperatures favored process yield. Overall, the results demonstrate the potential of spray drying for the technological utilization of nasturtium and provide relevant information for its application as a plant-based ingredient in food and nutraceutical products.