Valorization of Hibiscus Flower (Hibiscus sabdariffa L.) Anthocyanins to Produce Sustainable Spray-Dried Ingredients

Abstract

The recent increase in sustainability awareness has triggered the industry to establish novel, eco-friendly sources of plant-based ingredients. In the present study, hibiscus flowers (Hibiscus sabdariffa L.) were investigated as a sustainable source of anthocyanins for use in spray-dried ingredients with antioxidant capacity. To this end, the extraction and spray-drying microencapsulation of hibiscus flower anthocyanins were optimized and the final products were evaluated for their oxidative stability index. Initially, preliminary experiments were carried out to evaluate the effects of selected processing parameters on anthocyanin extraction. Next, the extraction was optimized through a 22 central composite design, considering ethanol concentration (44–56% v/v) and extraction time (1.6–6.4 h) as independent factors. The optimum extraction conditions (8 h, 41.6% v/v ethanol concentration) were used to produce anthocyanin-rich extracts, which were microencapsulated by spray drying using a 22 central composite design with the carrier addition rate (1–3% w/v) and inlet temperature (160–192 °C) as factors. Maximum values of solids recovery (60.8%) and anthocyanin retention (96.0%) were reached when 3.2% w/v of starch–alginate carrier blend and a 170.7 °C inlet temperature were used. Finally, when hibiscus microcapsules were added to soybean oil, higher oxidative stability was achieved compared to the control. Overall, we demonstrate an industrially friendly and scalable approach that takes advantage of abundant hibiscus flowers as a viable source of anthocyanins for multiple applications.