The development and characterization of novel in-situ bigel formulation

Abstract

The preparation of a novel in-situ bigel system, using hot emulsification, based on a glycerol monostearate (GMS) oleogel and a gelatin hydrogel, with the addition of lecithin and glycerol as surfactant and co-surfactant, respectively, was established. This combination led to the formation of a bi-continuous system of a hydrogel polymeric network and an oleogel crystalline network. The effect of bigel composition, water:oil ratio, and homogenization time on bigel structure, hardness, and stability was examined. A positive relationship was found between the structuring agent concentration and gel hardness and stability, with maximum enhancement at 2 %wt. gelatin and 25 %wt. GMS. Lecithin showed maximum strength enhancement and stabilization at 5 %wt. of the oil phase, above which a significant decrease was observed. Increasing oil content up to 50 %wt. led to an increase in hardness, but further increasing of oil content above 50 %wt. failed to produce stable bigels. Superior mechanical and stability properties were observed when the samples were homogenized for 3 min. Optimized bigel systems maintained their mechanical integrity for 90 days with a moderate decrease in OBC. Moreover, low PV, below 10 meqkg−1, were maintained for 30 days at 4 °C, 25 °C, and 40 °C, compared with the oil sample. An opposite trend was, however, observed in the TBA values, suggesting different transition kinetics between the primary and secondary oxidation products. These results provide a comprehensive overview of the composition-structure-function relationship of the bigel system, which should be considered in future development of textured food products.