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Rheological and Functional Properties of Potato and Sweet Potato Flour and Evaluation of its Application in Some Selected Food Products

Avula, Ramesh Yadav (2005) Rheological and Functional Properties of Potato and Sweet Potato Flour and Evaluation of its Application in Some Selected Food Products. PhD thesis, University of Mysore.


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Though different workers have reported on the possible use of potato and sweet potato flours for product development, the properties of the flour desired for preparation of various products such as noodles, pudding, gravy, sauces, gruel, and bakery products vary. The swelling, solubility, gelatinization temperature, cold paste viscosity, gel consistency, etc., are important characteristics, if the flour has to be considered for product development. However, most information on functional properties refers to the isolated starch, instead of flour. The flour functional properties are different from those of starch, since extra constituents available in flour (non-starch polysaccharides, protein, fat, etc.), restrict access of water into the starch granules. The RVA viscoamylograph pasting parameters of the flour, determined in the present investigation, were not correlated to the RVA pasting parameters of the purified starch. An attempt has been made in the present investigation to determine the functional - rheological properties of flour as affected by physical, chemical and enzymatic treatments. The extent of changes in starch as a result of processing / modification has also been investigated, since the accessibility of starch in flour is less to water and heat comapared to an isolated starch. The relation between the functional properties of flour and the structural changes in their starches has also been established. Textural quality, the degree of crystallinity and the double helical content (in the amorphous and crystalline domains) of tuber and root starches have not beeen thoroughly investigated. Consequently, the influence of these parameters on enzyme susceptibility, gelatinization, retrogradation and rheological properties could not be propertly ascertained. Furthermore, many researchers have used only one technique for determining gelatinization and retrogradation properties of tuber and root starches. This approach is not sound, since various methods such as DSC, Xray,NMR, FT / IR spectroscopy measure different properties of the material. A more advantageous approach may be to use these methods collectively to obtain a deep insight into the physico - chemical properties. There is thus, a need to carry out a systematic nvestigation on the properties of modified flours using a variety of analytical techniques and experimental conditions. With a view to provide information on the properties of native, thermally processed, acetylated and enzymatically modified potato and sweet potato flours the studies were carried out with the following objectives. I. Preparation of potato and sweet potato flours by physical (drum dried and hot air dried), chemical (acetylated) and enzymatic treatments. II. Optimization of process conditions for acetylated and enzyme modified flours from potato and sweet potato. III. Structural properties of modified flours by GPC, FTIR, SEM etc. IV. Rheological and functional properties of differently treated flours of potato and sweet potato by RVA,TPA, DSC etc. The rheological and functional properties have been investigated to find the potential application of potato and sweet potato flours in foods.

Item Type: Thesis (PhD)
Uncontrolled Keywords: Potato flour Sweet potato flour rheological properties functional properties structural properties
Subjects: 600 Technology > 08 Food technology > 23 Vegetables > 02 Potato
600 Technology > 08 Food technology > 14 Physical properties
Divisions: Fruit and Vegetable Technology
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 03 Dec 2007 07:13
Last Modified: 28 Dec 2011 09:31
URI: http://ir.cftri.res.in/id/eprint/1529

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