Maltodextrin on the flow properties of green coconut (Cocos nucifera L.) pulp powder

ABSTRACT The study of the flow properties and particle surfaces of a food powder is essential for predicting its behaviour during processing and commercialization. The objective of this work was to determine the powder flow properties of lyophilized green coconut pulp with different concentrations of maltodextrin. Samples containing 0, 5, 10 and 15% (m/m) maltodextrin were lyophilized, and the flow index (FI), wall friction angles and densities were determined. The microstructure of the powders was evaluated by scanning electron microscopy (SEM). The samples containing 0 and 5% maltodextrin showed 1.87 FI, classifying them as very cohesive powders, and those containing 10 and 15% cohesive powder showed 2.12 and 2.43 FI, respectively. The powder densities varied from 138.6 to 287.6 kg/m3, and the wall friction angle varied from 15.8 to 39.8°. The powder particles presented irregular shapes and rough surfaces, especially in powders containing 0, 5 and 10% maltodextrin. The powder containing 15% had smoother and less agglomerated surfaces. An increase in the amount of maltodextrin added to the pulp made the particles smoother and denser and improved the fluidity of the powder.摘要：食品粉体的流动特性与颗粒表面研究，对预测其加工及商业化过程中的行为至关重要。本研究旨在测定添加不同浓度麦芽糊精的冻干绿椰肉浆的粉体流动特性。研究制备了麦芽糊精添加量为0、5、10及15%（m/m）的样品并进行冻干处理，测定了其流动指数（FI）、壁面摩擦角与密度。采用扫描电子显微镜（SEM）对粉体的微观结构进行表征。添加0%与5%麦芽糊精的样品流动指数为1.87，归类为极强黏聚性粉体；添加10%与15%麦芽糊精的样品流动指数分别为2.12与2.43，属于黏聚性粉体。粉体密度范围为138.6~287.6 kg/m³，壁面摩擦角范围为15.8~39.8°。粉体颗粒呈现不规则形状与粗糙表面，尤以添加0、5及10%麦芽糊精的样品为甚；添加15%麦芽糊精的粉体表面更为光滑，团聚现象更少。随着椰肉浆中麦芽糊精添加量的提升，颗粒表面愈发光滑、粉体密度升高，且粉体流动性得到改善。