Quick and reliable method of preparation of strong homogeneous calcium-pectin gels

摘要

Pectin is a highly reactive polymer playing an important role in the texture and rheologicalcharacteristics of many food systems. Currently, interest is centered on rheological data as a means ofunderstanding the relation between pectin structure and the viscoelastic properties of many processedplant based foods. Precise quantification of rheological parameters is only possible if measurementsare carried out under appropriate shear conditions. The latter are influenced by sample characteristics.Studying the rheological characteristics of pectin gels requires heating the sample to temperatures upto 95°C so as to render calcium-pectin sols more ho mogeneous. Such high temperatures depolymerizepectin. Other procedures are time consuming (≥24 hours), besides generating weak gels.Consequently, developing a method which can produce strong homogeneous gels, while limiting therisk of depolymerizing pectin, is imperative.We have developed a fast and reproducible method combining mild heating (50°C) and diffusion ofcalcium through micro-volumes of pectin solutions. This new method can be used with cone-plate andplate-plate measuring systems. Interestingly, it enables the rheological study of strong pectin gelshaving storage modulus ≥ 106 Pa within a short structure development time (≤10 hours).