Investigations into the antistaling effect of waxy durum in bread.
| dc.contributor.advisor | Gibson, Robert Alan | en |
| dc.contributor.advisor | Barber, Andrew | en |
| dc.contributor.advisor | Jenner, Colin F. | en |
| dc.contributor.advisor | O'Neill, Brian | en |
| dc.contributor.advisor | Gidley, Michael | en |
| dc.contributor.author | Blake, Laura | en |
| dc.contributor.school | School of Agriculture, Food and Wine | en |
| dc.date.issued | 2015 | en |
| dc.description.abstract | Bread staling leads to substantial food wastage and hence economic and environmental burdens in the industrial world. Reduced amylose waxy wheat flour has shown potential as an antistaling additive in bread, although the causal mechanism at the molecular level is not well defined. The waxy durum under investigation in this study represents a novel substrate due to its breeding history, and has shown a strong antistaling effect in bread. Bread made from waxy durum flour was about half as firm initially and 25% less firm than conventional bakers’ flour after a week’s storage. The aim of this study was to comprehensively analyse the physicochemical and functional properties of this waxy durum flour and starch, to provide insights into its antistaling mechanism. The swelling and gelatinisation properties of waxy durum were compared to those of a range of normal and waxy cereal starches. It was found that the waxy durum starch exhibited delayed swelling behaviour relative to other waxy cereal starches, most likely due to its higher relative amylose content. Surfactant treatment was found to eliminate diversity of swelling behaviour in normal, but not waxy starches. This suggested that factors other than starch surface proteins and lipids influence the swelling behaviour of waxy starches. As starch retrogradation was identified in the literature as a key factor in bread staling, flour and starch thermal properties were assessed at different water contents. The relationship between starch retrogradation and water content was also found to be different between the waxy and normal wheat starches studied, with retrogradation of waxy starches favoured by a more concentrated system. Waxy durum starch and flour in isolation were found to exhibit a higher resistance to retrogradation than normal durum, and normal and waxy bread wheat starches. Both waxy flours were found to have a similar crumb softening effect after the first day of bread storage, however only the waxy durum flour produced a significant antistaling effect over longer term storage. It was postulated that the early stage crumb softening effect was related to the impact on rheological behaviour of the dough during the baking process, but that in the longer term the waxy durum reduced amylopectin retrogradation, suggesting that its unique thermal behaviour was the primary factor influencing its antistaling effect with a secondary contribution by minor flour components. The results of this study add to the breadth of current knowledge of the physicochemical and thermal properties of waxy durum starch and flour in particular and waxy starches and flours in general, with particular emphasis on mechanisms of antistaling functionality at the molecular level. | en |
| dc.description.dissertation | Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2015 | en |
| dc.identifier.uri | http://hdl.handle.net/2440/93731 | |
| dc.provenance | This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legals | en |
| dc.subject | waxy wheat; durum; antistaling; bread | en |
| dc.title | Investigations into the antistaling effect of waxy durum in bread. | en |
| dc.type | Thesis | en |
Files
Original bundle
1 - 3 of 3
No Thumbnail Available
- Name:
- Restricted
- Size:
- 5.24 MB
- Format:
- Adobe Portable Document Format
- Description:
- Library staff access only