Woo, Meng WaiLi, Charles2021-01-192021-01-192020https://hdl.handle.net/2292/54309Full Text is available to authenticated members of The University of Auckland only.Cream is a very important dairy export from New Zealand. One approach to exporting cream is to process the cream into the frozen form. The hardness of the frozen may be an important product quality to control as it affects how the cream can be broken down (at the consumers) and thawed prior to use. This project aims to better understand how the hardness of the frozen cream is controlled by the rate of freezing of the cream. Experiments were undertaken by freezing small samples of fresh cream (purchased from the local supermarket) under varying freezing rates in a bar freezer. Different freezing rates were generated by means of controlling the temperature of the bar freezer in combination with different insulation layers on the samples. It was found that slower freezing rates lead to lower hardness in the cream and vice versa. This was confirmed penetration texture analysis measurements. Further examination the microstructure of the frozen cream showed that this may be linked to the larger water ice crystal size formed via the lower freezing rates. On the flipside, the freezing rates has the propensity to result in a cream with lower stability. This manifested in the form of grainy looking cream (when thawed) and significantly shorter over-whipping time. Such instability was also reflected in the higher inconsistency in the rotational viscosity measurements of the cream frozen via the lower freezing rates and the lower frequency required to increase the elastic component of the cream during oscillatory rheology measurements. Findings from this work will be useful as a basis for scaling up further hardness study to larger size industrial sample of frozen cream.Restricted Item. Full Text is available to authenticated members of The University of Auckland only.Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htmThesis2021-01-16Copyright: the authorQ112952757