Abstract: Soy protein isolate was used to prepare protein emulsion gels due to its emulsifying and gelling properties, and the gels were used for co-delivery of vitamin E and sodium isoascorbate. The effects of pectin addition on gel structures and the stability of vitamins were investigated. The results indicated that emulsion droplet size was increased with increasing pectin content, and protein-pectin mixtures pre-heated at higher temperature resulted in bigger droplet size. Emulsion gelation was induced by glucono-δ-lactone (GDL), and the gelling time and gel strength were both significantly affected by pectin content. Textural analysis revealed that pectin content and pre-heating temperature did not affect gel hardness, and springiness was firstly increased and then decreased with pectin content. When mixed vitamins were incorporated within emulsion gels, the stability of vitamins was decreased with pectin content, and sodium isoascorbate was degraded at higher rates than vitamin E. It was concluded that the structural properties of the emulsion gels could be modulated by the addition of pectin, and that the stability of vitamins was associated with gel structures.

Key words: emulsion gel, pectin, texture, vitamins, stability