Study On The Whey Protein Concentrate Based Fat Mimetic

Protein-based fat mimetic is a kind of material which can substitute fat. It is prepared through different modification methods,such as chemical modifications,physical modifications or biological modifications, on the basis of proteins. It can imitate the unique taste and flavor of fat, and also provides lower energy.In this paper, the preparation of fat mimetic based on whey protein concentrate (WPC)was studied and it was applied in ice cream. In the preparation process, chemical and physical modification methods were combined to modify WPC.Firstly, the WPC was succinylated. The reaction temperature, pH and material ratio were changed in single factor experiments and the corresponding functional properties were determined. The best succinylation condition was obtained based on the comprehensive membership value calculated from the functional properties. Functional properties measured included: emulsifying ability, emulsion stability, foaming capacity, foaming stability, water holding capacity, and oil holding capacity. Subsequently, the protein obtained by succinylation was compounded with xanthan gum, and then the micronization modification was carried out. The shear rate and shear time were determined by single-factor experiments,and WPC-FM was obtained after freeze-drying. Finally, the WPC-FM was added to the ice cream to replace the cream. Ice creams with different substitution degrees from 0 % to 100 %were made. Indexes such as expansion rate, melting rate and hardness were measured.Combined with sensory evaluation, the optimal amount of fat replacement was determined.In addition, the structure of WPC before and after modification was characterized by FTIR(secondary structure) and SEM (microstructure). DSC was applied to analyze their thermal properties.The results showed that the key preparation conditions of WPC-FM were as follows:succinylation (pH = 7, 35?, succinic anhydride 35 %); xanthan gum compounding (protein concentration 0.12 g/mL, xanthan gum concentration 3.00 g/L); micronization (10000 r/min,5 min). After succinylation, the functional properties of the protein were improved in different proportions. The emulsifying ability was increased by 55.35 %, emulsion stability by 122.41 %, foaming capacity by 250.02 % and oil holding capacity by 141.18 %. At the same time, the foaming stability and water holding capacity were also greatly improved.WPC-FM showed a good potential to substitute fat in ice cream. Substitution degree under 60 % was acceptable. And the best degree was 40 %. The sensory properties of ice cream at this point was close to none-substituted ice cream.