Effects of sucrose addition on the rheology and structure of iota-carrageenan
2020
期刊
Food Hydrocolloids
Sucrose addition contributes to the rheology of carrageenan, which improves the quality of food that includes
carrageenan as an additive. In the present study, the rheological behaviours of sucrose-supplemented iota carrageenan at different concentrations (0–20%, w/v) were determined. Easier gelation with a higher gelling
temperature (51.4–57.4 °C) could be achieved by sucrose addition, and the trend could be predicted using
mathematical models. Application of the Kirkwood-Buff theory demonstrated that exclusion effects of water and
direct binding between sucrose and iota carrageenan are the possible mechanisms for the stabilisation, which act
by providing significantly greater ΔGu2 than ΔGu1 from all samples using Clausius-Clapeyron equation ( ΔGu1
and ΔGu2 are calculated KB parameters representing the contribution of the rearrangement of water and cosolvent around the solute to the thermodynamics of sol-gel transition). Fourier transform infrared spectroscopy
further confirmed the bindings by detecting band shifts (from 845 to 835 cm−1
). The gel was the strongest
(251.71 Pa) at 5% (w/v) sucrose; however, too much sucrose decreased the gel strength. The Winter-Chambon
equation provided the fractal dimension df (2.22) and critical gel strength Sg (12.52 Pa•s
n
) at 5% (w/v) sucrose
concentration, indicating the highest density and critical strength. The zeta potential (−0.92 mV) and confocal
laser scanning microscopy images also showed the most abundant aggregates at 5% sucrose. Excess sucrose may
form sucrose-sucrose hydrogen bonds that loosen the iota carrageenan network. A schematic representation was
provided to show how sucrose could affect the structure and gelation of iota carrageenan (differs from kappa
carrageenan) and the potential bonds related to the effect.
