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Rheological, Thermal and Microstructural Properties of Whey Protein‐Cassava Starch Gels
Author(s) -
AGUILERA J.M.,
ROJAS E.
Publication year - 1996
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1996.tb10911.x
Subject(s) - differential scanning calorimetry , rheometry , whey protein isolate , rheology , whey protein , starch , dynamic mechanical analysis , microstructure , materials science , scanning electron microscope , viscoelasticity , chemical engineering , dynamic modulus , elastic modulus , chemistry , chromatography , composite material , polymer , thermodynamics , organic chemistry , physics , engineering
Mixed gels of cassava starch (CS) and a whey protein isolate (WPI), obtained by heating solutions of 10% total solids, pH 5.75 to 85°C, were characterized as a function of the starch fraction, θ s , by axial compression, small‐amplitude oscillatory rheometry, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Gelation did not occur for θ s > 0.7. In the range 0<θ s < 0.4 mixed gels showed higher mechanical (E, elastic modulus) and rheological (G′, storage modulus) properties than pure gels, with maximum values for θ s = 0.2–0.3. Viscoelastic measurements as a function of time showed that gels containing higher levels of WPI developed a larger G. Blends of both biopolymers showed independent thermal transitions in DSC measurements, related to gelatinization and denaturation. Microstructure of a mixed gel formed at θ s = 0.2 showed a continuous matrix formed by strands of WPI particle aggregates and an independent CS phase.