Sunday 3 July 2016

Rheological characterisation of sol–gel phenomenon and stability of green gram and foxtail millet flour gels

Published Date

January 2016, Vol.65:917–923, doi:10.1016/j.lwt.2015.08.066

Title

Rheological characterisation of sol–gel phenomenon and stability of green gram and foxtail millet flour gels

Author

Nagaprabha P.

Sila Bhattacharya^,^,

Grain Science & Technology Department, CSIR-Central Food Technological Research Institute, Mysore, India

Received 1 June 2015. Revised 23 August 2015. Accepted 26 August 2015. Available online 1 September 2015.

Highlights

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Stability of greengram and foxtail millet gels showed either a zero or first order kinetics.
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Initial average gelling temperature 2–3° higher for sol–gel phenomena for all flour.
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Highest initial gelling temperature of 49 °C observed for foxtail millet starch sol/gel.

Abstract

The sol–gel transition was investigated employing temperature sweep tests from 60 to 25 °C. Four model sol dispersions, prepared from the green gram and foxtail millet flour, and their isolated starches, were examined. The formed gels were determined by performing the low strain (5%) stress relaxation test. The gelling temperatures were 38–47 °C for all the flour/starch gels. The starting gelling temperatures were about 2 to 3 °C higher than their corresponding average gelling temperatures. At the sol and gel states, the ratio of storage and loss moduli was between 7 and 9, and between 11 and 19, respectively. The different stability indices related to rheological characteristics followed either a zero or first order kinetics. The application of principal component analysis indicated that sols/gels made from foxtail millet flour and both starches, the average and starting gel temperatures behaved in a similar manner.