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Davies, Suzanne (2017) Material science of in-directly expanded α (1,4) and (1,6) linked polymers. MPhil thesis, University of Nottingham.

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Abstract

This research utilises twin-screw extruded directly expanded maize grits (IP1) into a secondary extrusion process, to create a homogenous intermediate product microstructure; that is later expanded into a final product using hot oil. The aim of this research is to begin to link ingredient processing to intermediate and final product microstructures and understand how this effects final product attributes.

The impact of two versus one extrusion process on final product microstructure was demonstrated with statistically significant differences in expansion ratio, viscoelastic properties of intermediates, and water release mechanisms during heating. To overcome limitations in standard analytical methods, high heating rates were used to replicate conditions more similar to that of frying.

Using a secondary single-screw extrusion process, intermediates were manufactured with the incorporation of semi-crystalline materials at 10 % (rice flour (RF), micro-crystalline cellulose (MCC) and potato starch (PS)) into the amorphous starch matrix to design an intermediate and final product microstructure. PS increased expansion ratio but decreased cell sizes and both MCC and RF were found to decrease expansion ratio. Initial sensory screening suggested 10 % semi-crystalline material can impact the textural attributes of final products, with MCC and RF being more effective. This work has delivered proof of principle of a design-led microstructure approach to final product attributes.

Item Type:	Thesis (University of Nottingham only) (MPhil)
Supervisors:	Wolf, B. Foster, Timothy
Subjects:	T Technology > TP Chemical technology > TP 368 Food processing and manufacture
Faculties/Schools:	UK Campuses > Faculty of Science > School of Biosciences
Item ID:	48802
Depositing User:	Davies, Suzanne
Date Deposited:	27 Sep 2021 11:53
Last Modified:	27 Sep 2021 11:54
URI:	https://eprints.nottingham.ac.uk/id/eprint/48802

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