Physicochemical, Rheological and Structural Properties of Cold-set Emulsion-filled Gels Based on Whey Protein Isolate-basil Seed Gum Mixed Biopolymers

The present study aimed to elaborate the impact of basil seed gum (BSG) (0–0.5%, w/w) on the physicochemical, rheological, and microstructural characteristics of cold-set whey protein isolate emulsion-filled gel (EFG). Emulsions without BSG and with 0.3% BSG showed the lowest and highest droplet size (1.44 vs. 4.38 μm) and polydispersity index (0.31 vs. 0.77). The amplitude sweep results showed that in the linear viscoelastic region, the highest and lowest values of G′LVE\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${G^\prime}_{LVE}$$\end{document} and G″LVE\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${G^{\prime\prime}}_{LVE}$$\end{document} were found for the EFGs containing 0.3% BSG (8852.4 and 1531.9 Pa), and the control sample (4438.3 and 751.4 Pa), respectively. Moreover, in all samples, G′\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${G}^{\prime}$$\end{document} and G″\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${G}^{\prime\prime}$$\end{document} crossed over each other, so that with a rise in the BSG concentration, strain and stress levels rose. Based on frequency sweep results, the addition of BSG enhanced elasticity so that the EFG containing 0.3% BSG had the greatest value of k′\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$k^\prime$$\end{document} (8882.0 Pa). In comparison to the control sample, the 0.3% BSG-contained sample displayed the highest values of chewiness, adhesiveness, and cohesiveness. These findings were in agreement with the microstructure analysis, where the control sample had a loose structure and the 0.3% BSG-contained sample showed a compact and uniform microstructure. Also, raising the BSG level from 0 to 0.5% directly enhanced the water-holding capability (75.49–85.07%) and swelling ratio (0.20–4.57%), and decreased syneresis (from 11.08 to 7.09%). The results emphasized the advantages of using BSG in whey protein-based emulsion-filled gel for techno-functional properties improvement.