Obtenção e caracterização do pó do aquoso da folha de Ora-pro-nóbis (Pereskia aculeata) seco por spray drying

Abstract

Ora-pro-nóbis (*Pereskia aculeata*) is an Unconventional Food Plant (UFP) belonging to the Cactaceae family, recognized for its high protein content as well as its fiber, vitamins, and bioactive compounds. Traditionally used in cooking, its leaves can be consumed raw or sautéed. The presence of mucilage, proteins, and bioactive compounds attracts interest from both the food and pharmaceutical industries: the former for the enrichment of functional products, and the latter due to studies on antioxidant activity and nutraceutical potential. Because it is highly perishable, its consumption is largely restricted to family farming, which hinders large-scale commercialization. Drying aids in the preservation of perishable foods and facilitates the storage, transport, and application of the resulting powders in food products. Therefore, this study aimed to obtain and characterize a powder derived from the aqueous extract of ora-pro-nóbis leaves produced via spray drying. To this end, the study evaluated the effect of heat treatment prior to drying, as well as drying with and without the use of maltodextrin as a carrier agent, and the effect of temperature (100°C and 140°C) on the physicochemical properties (moisture, water activity, hygroscopicity, antioxidant activity, total chlorophylls, protein content, morphology, and particle size) of the resulting powder. The results showed that the powder obtained with heat treatment and the use of maltodextrin generally exhibited lower moisture content compared to the powder obtained without heat treatment or the carrier agent. Powder hygroscopicity ranged from 13.81% to 26.60%, influenced primarily by the addition of maltodextrin. Regarding color, the powders with higher lightness (L*)—that is, the lighter-colored ones—were those obtained using maltodextrin, likely due to the white color of the carrier agent. The powders exhibited a tendency toward green (a* parameter) and yellow (b* parameter) coloration. Antioxidant capacity was also evaluated, with the highest values observed in experiment 4, which involved heat treatment at 140°C without the use of maltodextrin. Partial degradation of the chlorophyll present in the leaves occurred due to the heat treatment, influencing the chlorophyll content results for the resulting powders. The treatments performed had no impact on protein analysis results. SEM images show that the particles generally exhibit irregular morphology, rough surfaces, and a tendency to agglomerate. The largest particle sizes were found in experiments 3 (100°C, with heat treatment, without maltodextrin) and 4 (140°C, with heat treatment, without maltodextrin).