Title: NOTE: Measuring oxidative gelation of aqueous flour suspensions using the Rapid Visco Analyzer Authors
|Ross, Andrew -|
|Bettge, Arthur -|
|Kongraksawech, Teepakorn -|
Submitted to: Cereal Chemistry
Publication Type: Research Notes
Publication Acceptance Date: December 2, 2013
Publication Date: N/A
Interpretive Summary: Batter based baked products such as pancakes and fry coatings depend on the viscosity of the batter being correct. The Bostwick consistometer (BC) is a proven method to test viscosity differences of wheat flours by oxidative gelation of a flour-water mixture with hydrogen peroxide. Use of a Rapid Visco Analyzer (RVA) as an alternative measurement of oxy-gel properties was demonstrated as an improvement to the BC method in reducing the number of steps needed, overall speed of testing and additional information available in the RVA software such as shear rate.
Technical Abstract: The Rapid Visco Analyzer (RVA) was investigated as a tool to measure oxidative gelation capacity (OGC) of aqueous wheat-flour suspensions. One, club-wheat patent flour was used to determine optimal hydration time and 33 straight-grade flours (representing 12 hard and 31 soft varieties) were used to observe varietal differences in OGC. A 33.3% w/w flour/water suspension was tested in the RVA at 30°C and 160 rpm for 1 min to establish the flour/water baseline viscosity then 65 'L 3% H2O2 was added and the viscosity of the suspension measured at 160 rpm for a further 5 min. Flour from the club-wheat showed that 20 minutes prehydration was needed to observe full OGC potential. For the 33 straight grade flours final RVA water viscosity was correlated with Bostwick Consistometer (BC) flow (r = -0.93, p ' 0.01) and RVA H2O2 peak viscosity was correlated with H2O2 BC flow (r = -0.81, p ' 0.01). The RVA was able to differentiate H2O2-reactive from non-reactive flours. The RVA can observe phenomena not observable using the BC method (e.g. viscosity reduction over time at constant shear rate) and this can provide potentially valuable additional information about the nature of OGC in wheat-flour suspensions.