Microencapsulation of Black Glutinous Rice Anthocyanins Using Maltodextrins Produced from Broken Rice Fraction as Wall Material by Spray Drying and Freeze Drying

Abstract

© 2016 Wiley Periodicals, Inc. Anthocyanins from black glutinous rice (BGR) bran fraction were used as core material. Maltodextrins with 3 dextrose equivalent (DE) at DE10, 20 and 30 (BRM10, BRM20 and BRM30) were enzymatically produced from broken BGR fraction and then used as wall materials. Spray-drying condition was varied for three inlet air temperatures (IAT; 140, 160 and 180C). Increasing IAT enhanced microencapsulation efficiency (MEE), but reduced total anthocyanin content (TAC), surface anthocyanin content (SAC) and antioxidant activities of the microcapsules. BRM20 provided microcapsules with higher/similar levels of TAC and antioxidant activities compared with a commercial maltodextrin DE10. Increasing both IAT and DE decreased the color L*, a*, b* and C* but enhanced the h°; however, spray drying produced a brighter microcapsule color than freeze drying. Although freeze drying showed higher MEE and TAC, the storage stability of freeze-dried anthocyanin was much lower (19.7–100.0%) than those produced by spray drying. Practical Application: To improve the color and eating quality of rice, black rice is sold as milled rice in some rice markets. The two by-products of rice milling, bran and broken rice fractions, can be used to produce anthocyanins microcapsules. Black rice bran anthocyanins were successfully encapsulated with maltodextrins produced from broken rice fraction by both spray drying and freeze drying methods. Maltodextrin from broken rice fraction can be used as wall material to replace the commercial maltodextrin. Because of high storage stability, spray drying was recommended for BGR anthocyanin microencapsulation.