Viscoelasticity of oxidised starch and low methoxy pectin in the presence of glucose syrup

الملخص EN

The structural properties ofmixtures with peetin, oxidised starch and gluçose syrup were investigated using small deformation dynamic oscillation.

The composition of the mixture, pH and temperature course of analysis were designed to imitate the development of confectionery products.

In the absence of added calcium, preparations of low methoxy pectin with glucose syrup form viscous solutions, which remain crystal-free at subzero t^peratures.

Samples of oxidised starch and glucose syrup, on the other hand, exhibit solid-like behaviour due to the crystalline nature of the amylose-like helices.

Mixtures of th.e two polyssacnarides with the co-solute show clearly the phase inversion from liquid to solid-like behaviour With increasing amounts of starch in the formulation.

The transformation is reflected in the textural properties ofsamples which vary from thick solutions to firm gels.

The viscoelasticity ofthe system can be modified further by the introduction of high methoxy pectin.

Thus preparations ofhigh methoxy pectin and glucose syrup form rubbery gels whose amorphous nature undergoes a glass transition during cooling.

The energetic requirement for the formation ofthe biological rubber was in good agreement with corresponding data in the literature.