Texture and hydration of expanded rice
The differences between conventionally processed and extruded puffed rice were examined, with a view to determining the reasons for their different storage behaviour in confectionery. Differences between the two forms of puffed rice have been identified, both in their performance and their properti...
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| Format: | Thesis (University of Nottingham only) |
| Language: | English |
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1998
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| Online Access: | https://eprints.nottingham.ac.uk/11620/ |
| _version_ | 1848791319015587840 |
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| author | Norton, Clive |
| author_facet | Norton, Clive |
| author_sort | Norton, Clive |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | The differences between conventionally processed and extruded puffed rice were examined, with a view to determining the reasons for their different storage behaviour in confectionery.
Differences between the two forms of puffed rice have been identified, both in their performance and their properties.
Under certain viewing conditions, the starch granules in conventionally processed and extruded rice appear to be different. The starch granules in conventionally puffed Rice remain intact, but with no crystalline structure (i.e. no Maltese crosses are visible, though starch ghosts are abundant.) Cell walls of conventionally processed rice appear to be a layer of these gelatinised intact granules. The ghostlike granules have not undergone notable swelling, remaining slightly greater than 10μm in diameter, similar to the size of unprocessed granules.
In contrast, the starch granules in extruded puffed rice are rarely visible, in either their birefringent Maltese cross form, or as gelatinised but intact ghosts.
By altering the extrusion conditions, the microscopic appearance of the product and its behaviour in water or water vapour becomes similar to that of conventionally processed rice. The extrusion parameters required for this similarity to conventionally processed rice fall within a window that is relatively narrow when compared to the ranges of variables available. Under more severe processing conditions the granules lose their integrity because shear and heat disrupt them. Under less severe conditions, the granules form clusters that do not gelatinise. The conditions at which this product is made cannot be interpolated or extrapolated from samples made under other conditions.
However, at these extrusion parameters, the extrudate does not expand. It is necessary to expand the extrudate separately from the extrusion process. A novel method for the analysis of multi-peak force responses from compression of low moisture puffed cereal products was developed. This enabled crisp and crackly to be distinguished instrumentally. The results correlated well with sensory evaluation. |
| first_indexed | 2025-11-14T18:26:37Z |
| format | Thesis (University of Nottingham only) |
| id | nottingham-11620 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T18:26:37Z |
| publishDate | 1998 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-116202025-02-28T11:14:36Z https://eprints.nottingham.ac.uk/11620/ Texture and hydration of expanded rice Norton, Clive The differences between conventionally processed and extruded puffed rice were examined, with a view to determining the reasons for their different storage behaviour in confectionery. Differences between the two forms of puffed rice have been identified, both in their performance and their properties. Under certain viewing conditions, the starch granules in conventionally processed and extruded rice appear to be different. The starch granules in conventionally puffed Rice remain intact, but with no crystalline structure (i.e. no Maltese crosses are visible, though starch ghosts are abundant.) Cell walls of conventionally processed rice appear to be a layer of these gelatinised intact granules. The ghostlike granules have not undergone notable swelling, remaining slightly greater than 10μm in diameter, similar to the size of unprocessed granules. In contrast, the starch granules in extruded puffed rice are rarely visible, in either their birefringent Maltese cross form, or as gelatinised but intact ghosts. By altering the extrusion conditions, the microscopic appearance of the product and its behaviour in water or water vapour becomes similar to that of conventionally processed rice. The extrusion parameters required for this similarity to conventionally processed rice fall within a window that is relatively narrow when compared to the ranges of variables available. Under more severe processing conditions the granules lose their integrity because shear and heat disrupt them. Under less severe conditions, the granules form clusters that do not gelatinise. The conditions at which this product is made cannot be interpolated or extrapolated from samples made under other conditions. However, at these extrusion parameters, the extrudate does not expand. It is necessary to expand the extrudate separately from the extrusion process. A novel method for the analysis of multi-peak force responses from compression of low moisture puffed cereal products was developed. This enabled crisp and crackly to be distinguished instrumentally. The results correlated well with sensory evaluation. 1998 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en arr https://eprints.nottingham.ac.uk/11620/1/366288.pdf Norton, Clive (1998) Texture and hydration of expanded rice. PhD thesis, University of Nottingham. puffed rice extrusion |
| spellingShingle | puffed rice extrusion Norton, Clive Texture and hydration of expanded rice |
| title | Texture and hydration of expanded rice |
| title_full | Texture and hydration of expanded rice |
| title_fullStr | Texture and hydration of expanded rice |
| title_full_unstemmed | Texture and hydration of expanded rice |
| title_short | Texture and hydration of expanded rice |
| title_sort | texture and hydration of expanded rice |
| topic | puffed rice extrusion |
| url | https://eprints.nottingham.ac.uk/11620/ |