Whey protein–pectin complexes as new texturising elements in fat-reduced yoghurt systems

The structural and sensory characteristics of skim milk yoghurt enriched with whey protein–pectin mixtures were studied using laser diffraction spectroscopy, rheology, tribology, scanning electron microscopy, and sensory analysis, and compared with a full-fat control. The textural impact of non-heated and heated whey protein–pectin mixtures added to the milk formulations was examined. Associative interaction of whey proteins with pectin suppressed whey protein aggregation during yoghurt manufacturing while maintaining the structuring effects of denatured whey protein in yoghurt in terms of increased firmness and flow properties. The structuring effect in yoghurt was reduced when a heated whey protein–pectin mixture was used. The use of a non-heated whey protein-high methoxyl pectin mixture in the skim milk formulations yielded a yoghurt texture resembling the full-fat counterpart. This study demonstrated the ability of whey protein-high methoxyl pectin complexes to act as fat replacers and texturising elements in reduced-fat yoghurt.