Microstructure and flow properties of lyophilized mango pulp with maltodextrin

ABSTRACT The present study had as objective to determine the flow properties and behavior of lyophilized mango pulp powder as a function of different concentrations of maltodextrin. In the samples of the powders contain 5, 10 and 15% of maltodextrin the angle of effective internal friction, wall friction angle, flow index and bulk density were determined. The microstructure was evaluated by scanning electron microscopy. The freeze-dried samples are characterized as having an amorphous structure, and the drying aid used modified the surface of the particles. The flow index was 3.19, 4.28 and 4.53 for samples containing, respectively, 5, 10 and 15% maltodextrin. Increasing the concentration of maltodextrin in the mango pulp decreased the effective angles of internal friction and wall friction. The bulk density of the powders increased with increasing concentration of maltodextrin for the samples containing 5, 10 and 15% of the maltodextrin, being equal to 597.8, 689.8 and 691.3 kg m-3, respectively. Thus, it was concluded that the addition of maltodextrin modified the shape of the particles, decreased segregation, affected the flow properties of the mango powders, facilitating flow and increasing their bulk density.

摘要
本研究旨在探究不同麦芽糊精添加浓度下冻干芒果浆粉末的流动特性与行为规律。针对添加5%、10%及15%麦芽糊精的粉末样品，分别测定了有效内摩擦角、壁面摩擦角、流动指数与松装密度。通过扫描电子显微镜（scanning electron microscopy）对样品的微观结构进行表征。冻干样品均呈现无定形结构，所使用的干燥助剂可改变颗粒表面形貌。添加5%、10%、15%麦芽糊精的样品，其流动指数分别为3.19、4.28及4.53。随着芒果浆中麦芽糊精浓度升高，有效内摩擦角与壁面摩擦角均呈降低趋势。5%、10%、15%麦芽糊精组粉末的松装密度随浓度提升依次升高，对应值分别为597.8、689.8及691.3 kg·m⁻³。综上可知，添加麦芽糊精可改变颗粒形态，降低偏析程度，改善芒果浆粉末的流动性能，使其更易流动且松装密度提升。