dc.contributor.advisor |
Quek, SY |
en |
dc.contributor.author |
Tangjaidee, Pipat |
en |
dc.date.accessioned |
2016-11-07T20:37:12Z |
en |
dc.date.issued |
2016 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/30983 |
en |
dc.description |
Full text is available to authenticated members of The University of Auckland only. |
en |
dc.description.abstract |
Rice is a high carbohydrate food which is the main energy source in Asian diet for many years. It has been identified as a high glycemic index food that can increase blood sugar level causing metabolic diseases including Type 2 diabetes. In this project, yam flour, which contains higher resistant starch content than rice flour, and konjac flour, which is known as a good source of water soluble fibre were used as rice starch substitute to produce an alternative healthy rice product. Soy protein was also added to increase the protein content of the product. The ingredients used in this product formulation including yam flour was sourced from Enshi City, China where is called the “World Capital Selenium” In addition, the rice flour also contains higher selenium because it is sourced from Yichang City near to Enshi City. The rice products were developed using a twin screw extruder and the process was optimised using Response Surface Methodology applying Central Composite Design (CCD). Three factors were chosen for optimisation: percentage of yam flour (20-60%), moisture content of feed material (25-35%), and extrusion temperature (100-120oC). Also, effect of sorghum flour and extrusion screw speed was studied to improve the textural quality of the extruded products. From the results of CCD experiments, yam flour and feed moisture content were found to have positive effect on the firmness and colour properties of the products. The feed moisture content also had a direct effect on the bulk density and water absorption index of the products. On the other hand, the extrusion temperature also had a direct influence on the breaking strength of the product. Moreover, adding sorghum flour and lowering the extrusion screw speed decreased stickiness of the cooked products. Based on the physical properties, the ingredient selected to produce the extruded product with improved textural properties was 43.21% yam flour, 10% konjac flour, 5% sorghum flour, 3% soy protein and 38.79% rice flour; and the processing conditions were 25.46% feed moisture content, 120oC extrusion temperature and 12 Hz (78 rpm). This product is shown to have higher antioxidant capacity and selenium content than the commercial jasmine rice due to the high selenium content in the raw ingredient used. The sensory profile of the extruded rice products has significant different sensory profile than the commercial jasmine rice except in grain hardness. They also have lower sensory scores for product acceptability than the commercial jasmine rice, but the score was higher than 5 which could be concluded that the extruded product was accepted by consumers. |
en |
dc.publisher |
ResearchSpace@Auckland |
en |
dc.relation.ispartof |
Masters Thesis - University of Auckland |
en |
dc.relation.isreferencedby |
UoA |
en |
dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. |
en |
dc.rights |
Restricted Item. Available to authenticated members of The University of Auckland. |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
en |
dc.title |
The Development of a Healthy Extruded Rice Product |
en |
dc.type |
Thesis |
en |
thesis.degree.discipline |
Food Science |
en |
thesis.degree.grantor |
The University of Auckland |
en |
thesis.degree.level |
Masters |
en |
dc.rights.holder |
Copyright: The author |
en |
pubs.elements-id |
544965 |
en |
pubs.org-id |
Science |
en |
pubs.org-id |
Chemistry |
en |
pubs.record-created-at-source-date |
2016-11-08 |
en |
dc.identifier.wikidata |
Q112926607 |
|