Yu, WeiDing, Haohan2021-11-152021-11-152021https://hdl.handle.net/2292/57430The traditional approaches to quality measurement for milk powder are individually tailored tests which are expensive, laborious, time consuming and somewhat off-line tests. Therefore, a new Advanced Process Control (APC) concept called Real-Time Quality which is focused on managing product quality during processing by using online mathematical tools has aroused people’s attention. Dispersibility and bulk density are the vital functional properties of instant whole milk powder (IWMP), and many milk powder properties may affect the dispersibility and bulk density of IWMP. Based on literature and our own experience, particle size and morphology may be the two most important factors. Additionally, surface texture is an important quality characteristic of milk powder, and the possibility of three-dimensional analysis for milk powder texture has aroused more interest. Consequently, the main objective of this project is to investigate the quantitive relationship between the particle size/morphology and the dispersibility/bulk density of IWMP, and to assess milk powder appearance from 3D images. The milk powders were divided into different particle size groups by sieving, and then these were remixed in different proportions. Light microscopy was combined with image processing to measure the shape factors for each particle. The New Zealand Dispersibility Test (NZDB-method) was used to test the dispersibility of each milk powder sample, and the bulk densities of these remixed milk powder samples were measured by tap testing. Then, the photogrammetry equipment was combined with the software RealityCapture to build the 3D models of milk powder samples. Principal component analysis (PCA), partial least squares (PLS), and artificial neural networks (ANN) were used to process the data, and the surface normal and contour slice were used to quantify the surface roughness of milk powder samples. In addition, various partial least squares models constructed from (i) process variables only, (ii) shape factor variables only, and (iii) process variables combined with shape factor variables were used to compare which variables are important in developing soft sensors for predicting the dispersibility and slowly dissolving particles of IWMP. It was found that the trends of the dispersibility versus the changes of shape factors (circularity, convexity, and area) in different particle size groups are different, while the bulk density trends versus the shape factor changes were similar for the different particle size range groups. Then, by the use of the particle size and shape factors, prediction models for dispersibility and bulk density were developed. The good results of these models proved that predicting the dispersibility and bulk density of IWMP by using shape factors and particle size range fractions is achievable and could be used as a model for online model-based process monitoring. Furthermore, it was also found that the dispersibility of instant whole milk powder mainly depends on the shape factor variables while the process variables and shape factor variables are both important to predict slowly dissolving particles of instant whole milk powder. Additionally, the results of the 3D image analysis indicated that the area of the triangle formed by the 3 adjacent surface normal vectors of rough-surface milk powder cone is larger than the area of the triangle formed by the 3 adjacent surface normal vectors of smooth-surface milk powder cone, while the shape of the contour for the smooth-surface milk powder cone is more circular than the shape of the contour for the rough-surface milk powder cone if the milk powder cone is sliced at a given altitude.Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.Restricted Item. Thesis embargoed until 10/2022. Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htmhttps://creativecommons.org/licenses/by-nc-sa/3.0/nz/Thesis2021-10-12Copyright: The authorhttp://purl.org/eprint/accessRights/OpenAccessQ112562995