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Rheological Properties of Certain Processed Rice Products
Author(s) -
Chinnaswamy R.,
Unnikrishnan K. R.,
Bhattacharya K. R.
Publication year - 1985
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19850370307
Subject(s) - retrogradation (starch) , starch , thixotropy , food science , swelling , slurry , rheology , starch gelatinization , rice flour , moisture , degree (music) , chemistry , viscosity , materials science , raw material , composite material , amylose , organic chemistry , physics , acoustics
Two popular rice products, namely expanded rice and flaked rice, are prepared from parboiled rice. As about 90% dry weight of milled rice is starch, the behaviour of rice and its products reflects largely the behaviour of its starch. The above precooked rice products which undergo a high degree of thermal and/or mechanical treatment during processing have a high degree of gelatinization and display therefore properties like those of pregelatinized starch. Both expanded rice and flaked rice have high water binding capacity and cold‐swelling properties. Under suitable moisture conditions they undergo retrogradation and show reduced hydration and viscosity. Normal steam‐parboild rice shows much lower viscosity because of a comparatively low degree of starch gelatinization during processing and its subsequent retrogradation. Rheologically the cold slurry of these products indicates a thixotropic system demonstrating time dependent thinning. Further, a dependence on slurry concentration and degree of processing and a yield value behind a certain concentration were also apparent. The cold swelling properties of flaked rice and expanded rice show potential use of their flour as a possible subsitute for pregelatinized starch in food and other industries.