Physico-chemical properties of spray dried anthocyanin extract from hibiscus flowers (Hibiscus rosasinensis L.) as food colourant

Flowers are a rich source of bio-pigments like carotenoids, anthocyanins and betalains. Among these, anthocyanins are the most abundant pigments and Hibiscus flowers are one source of anthocyanin pigments. The major drawback in using hibiscus anthocyanins as a food colourant is their stability. Hence, to enhance stability, microencapsulation of aqueous extract of hibiscus petals was attempted with maltodextrin encapsulation at different TSS levels and temperatures and the physico-chemical and functional properties of spray dried hibiscus powder were assessed. Microencapsulation of anthocyanin extract with maltodextrin at 15° brix and 180 °C resulted in the highest dried powder recovery (17.85%), anthocyanin content (64.81 c3g eq.mg/L) and water solubility (99.58%). Physical properties like bulk density (0.593 g/m3) and tapped density (0.695 g/m3), was significantly higher in spray dried hibiscus powder obtained with maltodextrin 20 °brix at 170 °C. Based on Hausner’s ratio (1.16), Carr index (14.04) and hygroscopicity (17.85%), hibiscus spray dried powder exhibited good flowability when dried with maltodextrin 15 °brix at 180 °C. Chromometer values of spray dried encapsulation with maltodextrin 15 °brix at 180 °C proved a deep red shade with more darkness (L*38.5) and (a* 23.50 and b* -0.67) when compared to other treatments. The spray dried powder also exhibited significant colour stability when used as food colourant in aonla juice, lemon juice, curd and butter cream. This study explored the potential of spray-dried anthocyanin extract from hibiscus flowers as a bio-colourant in the food industry.