Effects of fibre addition and processing on the stability, rheology and in vitro gastric digestion of whey protein-xanthan gum stabilised emulsions with high oil phase

Abstract

The aim of work was to structure and characterise the high rapeseed oil emulsions stabilised by xanthan gum rich whey protein with an inclusion of commercially available added fibre (Vitacel HF0010 plus) as an additional stabiliser. The manufactured emulsions were also tested whether they can re-build the emulsion property after drying, water addition and re-emulsification. The emulsions with a ratio of 60/40 for rapeseed oil to water phase were obtained with a fibre inclusion at 0.25, 0.50 and 1.00% using a high shear homogenisation. Drying processing, rehydration and re-emulsification only led to re-build emulsion structure with 0.50 and 1.00% fibre. After re-emulsification, some fibre occurred as insoluble particles and were allocated at the oil-water interface or continuous phase of emulsion. Interestingly, processed sample with 1.00% fibre had the greatest instability when subjected to in vitro gastric digestion assay. All primary emulsions and processed emulsions with 0.50 and 1.00% fibre, were stable against coalescence with no oil loss and resulted in almost identical droplet size after a day 30 of storage at 4(±1)°C. All the structured emulsions showed shear-thinning behaviour. The fabricated emulsions showed a feature of regaining emulsion structure, which extend their applications in food formulation as clean label emulsions.