Thermal, Mechanical and Molecular Relaxation Properties of Frozen Sucrose and Fructose Solutions

MARIA L HERRERA, JUAN I M'CANN, CRISTINA FERRERO, TOMOAKI HAGIWARA, NOEMI E ZARITZKY, RICHARD W HARTEL

FOOD BIOPHYSICS

Springer

Lugar: New York; Año: 2007 vol. 2 p. 20 - 28

1557-1858

Model frozen systems formulated with 20 wt% sucrose or fructose and with addition of 0.3 or 0.5 wt% of xanthan gum (XG), guar gum (GG), locust bean gum (LBG) or a 50 wt% mixture of XG and LBG were studied by differential scanning calorimetry, dynamic mechanical analysis and 1H-pulsed nuclear magnetic resonance. The glass transition temperature (midpoint) of the maximally concentrated frozen matrix (T´g) was located at            -32.6°C for sucrose solutions and at  -42.2°C for fructose solutions. T´g was not affected by the addition of hydrocolloids to sucrose or fructose solutions. Ice content was lower in fructose than in sucrose systems. Addition of the blend of XG and LBG significantly diminished ice content only in the case of fructose solutions. Hydrocolloids decreased molecular mobility for either frozen sucrose or fructose solutions, especially the addition of XG/LBG blend. Relaxation times and storage modulus were significantly lower than the control frozen sugar solutions.