Valorization of saffron petal waste anthocyanin extract, microencapsulation storage kinetic stability, and in vitro release behavior of anthocyanin microcapsules

In this research, saffron petal anthocyanin extract was encapsulated using wall matrices consisting of sodium alginate (SA), maltodextrin (MD), and combination of sodium alginate and maltodextrin (SA:MD) at various ratios by freeze-drying method. The microcapsules were characterized in relation to moisture content, water activity, hygroscopicity, particle size, color, and encapsulation efficiency. Results showed moisture content ranged from 2.14 to 4.01%, a_w 0.23 to 0.58, hygroscopicity 10.31 to 21.12%, and particle size 188.53 to 304.30 µm, respectively. Among wall matrices, SA:MD encapsulates exhibited highest encapsulation efficiency 80.10%, anthocyanin stability 153 mg/g, and lowest ΔΕ value after 35-day storage. All the wall matrices increased the half-life of encapsulated microcapsules compared to non-encapsulated during storage. Morphological analysis showed microcapsules were smooth, uniform, and displayed little agglomeration and surface dents. The in vitro gastric conditions showed that microcapsules exhibited high anthocyanin retention than free extracts. To conclude, freeze drying could be recommended as a suitable encapsulation method for stabilizing the saffron petal anthocyanin extract.