Construction of different properties single and double cross-linked binary emulsion filled gels based on rice bran oil body emulsion

Abstract

Rice bran oil bodies (RBOBs) are rich in nutritional value. RBOBs are a by-product of rice processing. In this study RBOBs with different fractions (0–10%) were filled in binary networks formed by soy protein isolate (SPI) and flaxseed gum (FG). Two types of emulsion-filled gel (EFG) were constructed via Ca2+ crosslinking or double-crosslinking with transglutaminase (TG) and Ca2+. Microstructure and fluorescence spectra revealed that RBOBs were integrated into the structural matrix, resulting in altered gel network structure. Ca2+ crosslinking induced droplet aggregation and led to the formation of a segregated network structure, increasing surface roughness. TG and Ca2+ double cross-linking yielded a homogeneous gel network. Meanwhile, double-crosslinking and filling of RBOB emulsion resulted in a denser structure with higher water-holding capacity. Rheology and tribological tests demonstrated that RBOBs acted as active fillers in EFGs constructed via two crosslinking methods, improving the colloidal strength by forming different structures. Thixotropy of double- crosslinked EFG is obvious better than Ca2+-crosslinked EFG, which has higher creep recovery rate. During friction sliding, Ca2+ crosslinking and double-crosslinking resulted in different friction behavior. Filling with 10% RBOBs fraction leads to better friction behavior. This study provides a new idea for the potential application of oil bodies as fat substitutes.