Obtenção de extratos de amorapreta (Rubus sp.), ricos em antocianinas e estabilizados por liofilização ou microencapsulação por spray-drying, e avaliação de seus potenciais de utilização como corantes naturais para alimentos

Abstract

Blackberry, due to its high respiratory rate and fragile structure, has a short postharvest life, requiring special care in post-harvest conservation. Microencapsulation by spray-drying, and lyophilization (freeze-drying), protect bioactive compounds from degradation, increasing their solubility. In this context, the objective was to evaluate the process of obtaining blackberry extracts rich in anthocyanins, either lyophilized or microencapsulated by spray-drying, and also the potential of using these extracts as natural food dye. The extracts, obtained from two blackberry varieties (Guarany and Tupy), were quantitatively analyzed for bioactive compounds and the variety with the highest concentration of anthocyanins (Guarany) was used for the test as dye in natural yogurt. Microencapsulation by spray-drying proved to be promising to obtain an extract rich in anthocyanins, among other phenolic compounds, with high antioxidant activity and with potential to be used as natural dye in yogurts. The morphology of the produced microcapsules consisted of similar and spherical structures. The structure of particles obtained by freeze-drying was mostly plate-like, with irregular shapes, which is typical for the method, while those obtained by spraydrying presented spherical-like shape. The natural dye from blackberry showed intermediate stability in in vitro models simulating digestive processes. The application of the natural dye from blackberry to natural yogurt samples provided an acceptable pinkish red color with high consumer purchase intent. The lyophilization and spray-drying microencapsulation were efficient in protecting the anthocyanins naturally present in blackberry extracts.