Micro-Encapsulation and Characterization of Anthocyanin-Rich Raspberry Juice Powder for Potential Applications in the Food Industry

Abstract

Raspberry juice obtained from fresh raspberry fruits was encapsulated separately using gum Arabic (GA), maltodextrin (MT), and waxy starch (WS) (1:10, w/v) and freeze-dried to develop raspberry juice powders (RBJP). The powders were characterised based on their physicochemical and phytochemical composition and their rheological and antioxidative properties, which significantly varied among the carriers. GA- and MT-encapsulated RBJP exhibited a better colour, higher yield, oil holding capacity, total anthocyanin content, and antioxidant properties. WS-encapsulated powder showed a better water holding capacity and total phenolic content; however, the powder was characterised by low solubility, total soluble solids, and redness. Hygroscopicity and titratable acidity did not significantly (p > 0.05) vary among the powders. Cyanidin diglucoside, the main anthocyanin compound identified in the RBJP, was significantly higher in MT (2549.89 µg/g) compared to GA (1935.45 µg/g) and WS (1458.81 µg/g). The RBJP produced using MT and GA showed irregular-shaped and non-spherical particles, which were less agglomerated and relatively larger, while the WS powder exhibited more uniform, spherical particles, which agglomerated together. An X-ray diffraction analysis showed that GA and MT powders had an amorphous structure with minimum crystallinity, while RBJP from WS was crystalline. It can be concluded that GA and MT produced RBJP with quality attributes relevant to the food industry.