Faculty of Agronomy and Agroindustries, National University of Santiago del Estero-CONICET, Santiago del Estero, Argentina.
Departamento de Química, Universidad Nacional de Colombia, AA 14490 Bogotá, Colombia.
Food Res Int. 2018 Sep;111:423-430. doi: 10.1016/j.foodres.2018.05.058. Epub 2018 May 24.
The encapsulation of betaxanthins from orange Opuntia megacantha fruits was performed as a stabilisation strategy for these natural pigments. Betaxanthin-rich extract (BE) was encapsulated by two methodologies, spray drying (SD) and ionic gelation (IG). Encapsulates were obtained by using two encapsulating agents (EA), a mixture of maltodextrin-cactus cladode mucilage and sodium alginate (SA) for SD and IG, respectively. Their properties were compared with the freeze-dried cactus fruit pulp (CP) as control. Total betaxanthin content, moisture content, water activity (a), particle size, morphology by SEM, colour parameters (CIELab), and thermogravimetric properties were analysed in the encapsulates. Additionally, the antioxidant activity, total dietary fibre content, and pigment stability of encapsulates under two relative humidity conditions were also evaluated. The results showed that the encapsulation technique, EA concentration, and the BE/EA ratio affected the particle size and morphology, the glass transition temperature, and the mass loss of encapsulated materials. The best pigment stabilisation was obtained for the SD capsules, although both encapsulation techniques allowed improving the pigment stability in comparison with the CP taken as control. These results provided evidence that betaxanthins from Opuntia megacantha have the potential to be used as natural pigments, soluble in water, with functional properties for the food industry.
从橙色仙人掌果实中包封甜菜红素是稳定这些天然色素的一种策略。采用喷雾干燥（SD）和离子凝胶化（IG）两种方法对富含甜菜红素的提取物（BE）进行包封。使用两种包封剂（EA）分别获得包封物，即麦芽糊精-仙人掌茎髓黏液和海藻酸钠（SA）的混合物用于 SD 和 IG。将其性质与冻干仙人掌果肉（CP）作为对照进行比较。对包封物进行总甜菜红素含量、水分含量、水分活度（a）、粒径、SEM 形貌、颜色参数（CIELab）和热重特性分析。此外，还评估了两种相对湿度条件下包封物的抗氧化活性、总膳食纤维含量和色素稳定性。结果表明，包封技术、EA 浓度和 BE/EA 比对粒径和形态、玻璃化转变温度和包封材料的质量损失有影响。SD 胶囊获得了最佳的色素稳定性，尽管与 CP 相比，两种包封技术都能提高色素稳定性。这些结果表明，来自仙人掌的甜菜红素有可能被用作天然色素，可溶于水，具有食品工业的功能性特性。
