Influence of shear stress, pectin type and calcium chloride on the process stability of thermally stabilised whey protein-pectin complexes

In this study, the effects of process (shear rate: 0, 150, 500s−1; scale: lab / pilot plant) and composition (pectin type: high / low degree of blockiness; CaCl2: 0, 15, 30mM; biopolymer concentration: c high = 5.0% WPI + 1.0% pectin, c med = 2.75 % + 0.55 %; c low = 0.5 % + 0.1 %) parameters on micro- and macro-structural characteristics of whey protein-pectin (WPI-pectin) complexes were investigated. Thermomechanical treatments of WPI-pectin suspensions in a high-pressure double gap geometry revealed a high shear-stability during complex generation at 500s−1. The degree of blockiness (DB) of pectin was identified as critical parameter influencing complex structure and biopolymer system stability. WPI-pectin complexes with a high DB pectin had a fragile structure, low DB resulted in a compact structure. The shear rate was the main parameter to adjust yield and particle size, both on the lab and pilot scale. A higher shear rate led to a higher yield consisting of smaller particles. This effect could be partially compensated by medium CaCl2 concentrations (≤10mM) or high biopolymer concentrations (≤ 5.0% (w/w) WPI + 1.0% (w/w) pectin). Modelling the parameter effects resulted in sets of processing and composition parameters suitable for the generation of WPI-pectin complexes, owning the potential as fat replacers.
Source: Food Structure - Category: Food Science Source Type: research