The objective of this study is to determine the effect of the addition of hydroxypropyl methylcellulose (HPMC) (from 0.5 to 2.0% w/w, starch basis) with three different viscosities (40-60, 80-120, and 2,600-5,600 mPa⋅s) to corn starch (30% w/w, total basis) gels. Average viscosimetric molecular weights (M v ) of tested HPMC were determined (from 27.2 × 103 to 82.7 × 103 g/mol). Water retention capacity of HPMC varied linearly with M v . The formation and curation of gels were monitored by rheology employing consecutive steps such as heating ramp (25-90°C), time sweep (90°C), cooling ramp (90-25°C), time sweep (25°C), and frequency sweep. Additionally, creep-recovery tests were performed. HPMC above 1.5% w/w delayed the range of gelatinization temperature of starch up to 2°C. Viscoelasticity and stiffness of corn starch gels with HPMC depend on both the amount of polymer added and M v of the HPMC. Finally, to achieve corn gels with mimetic viscoelastic properties to wheat gel (with constant total solids), HPMC with relatively low viscosity (low M v ) is necessary to be added at certain content.
Keywords: average viscosimetric weight; creep and recovery; gelatinization; intrinsic viscosity; viscoelasticity.
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