Effects of morphology on the dispersibility of instant whole milk powder

The functionality and performance of instant whole milk powder (IWMP) can be related to its physical and chemical properties; i.e. particle size, morphology and fat distribution. Dispersibility, a measure of rehydration, has become one of the most important quality characteristics of IWMP. Many milk powder properties may affect the dispersibility. Based on literature and our own experience, particle size and morphology may be the two most important factors. This work investigated the quantitative relationship between particle size, morphology and dispersibility. Samples of different brands of IWMPs were fractionated using sieving and then remixed. The powder dispersibility was then measured, and the particle morphology characteristics obtained using light microscopy combined with image processing. Principal component analysis (PCA), partial least squares (PLS) and artificial neural network (ANN) methods were used to process the data. It was found that IWMP produced by different plants have different shape factors (circularity, convexity, and area) and the trends of the dispersibility versus the changes in the shape factors (circularity, convexity and area) for different particle size groups are different. Then, by the use of the size fractions and shape factors, prediction models for dispersibility were developed. A further experiment addressed the validity of the ANN model. •ANN model development for predicting the quality of milk powder.•Image processing application for milk powder measurement.•Univariate analysis between shape factors and dispersibility of instant whole milk powder.•Key shape factors affecting dispersibility of instant whole milk powder were identified by using PCA method.