Cold-set NaCl-induced gels of soy protein isolate and locust bean gum: How the ageing process affect their microstructure and the stability of incorporated beta-carotene

Abstract

This study aimed to evaluate the effects of solid lipid particles (SLP) incorporation on the aging process of NaCl-induced gels of soy protein isolate and locust bean gum. The feasibility of incorporating beta-carotene (BC) into emulsion-filled gels (EFGs) was evaluated and the stability of the carotenoid was determined in two systems, SLP and NaCl-induced EFGs. Non-filled gels (NFG) and EFG were characterized to determine their microstructural organization, rheological properties and water holding capacity (WHC) throughout storage. In addition, the amount of BC contained in SLP and EFG was quantified for 30 days. SLP dispersions were stable and retained about 57% of the encapsulated bioactive carotenoid after 30 days. Given the good stability of the SLPs, they were considered suitable for incorporation into the gels and for the production of EFGs. Their incorporation increased the stability of the gel systems. The strength and WHC of NFG systems decreased with aging, while those of EFGs increased. EFGs provided greater protection of encapsulated beta-carotene (about 90% of retention after 30 days of storage) than SLPs, indicating that gelation of the continuous phase is a good strategy to prevent the degradation of encapsulated bioactive carotenoid.