Development and optimization of oleogel made with soy protein isolate and xanthan gum using emulsion template approach and its comparison with solid fats

Abstract

This study aims to develop oleogel as a potential substitute for solid fats in the diet. A novel combination of unmodified Soy Protein Isolate (SPI) and Xanthan Gum (XG) have been utilized to gelate sunflower oil, using an emulsion template approach. The experimental trials employing Response Surface Methodology are conducted to optimize various parameters that affect the oil binding capacity, textural and rheological properties of the oleogel. The concentration of soy protein varies in the range of 5–15 %, the ratio of soy protein to xanthan gum ranges from 1:2 to 1:4, and the ionic strength varies from 0.2 to 1 M. The goal is to formulate oleogel that closely resembles solid fats. Responses namely the oil binding capacity and gel strength value of oleogel were observed best fitted to a linear model whereas, the hardness of oleogel found following a quadratic model. The SPI-XG combination was found effective in entraping more than 95 % of the oil. The best formulation of SPI: XG, 1:4; SPI concentration, 15 % and ionic strength of 1.0 M with 95.5 % of oil retention and hardness and gel strength value comparable to commercial solid fats.