Fabrication and characterization of O/W emulsion stabilized by Octenyl Succinic Anhydride (OSA) modified resistant starch

Reducing fat content without compromising its sensory qualities is a major technological challenge to the food industry in manufacturing healthy tasty food. Based on the fact that Octenyl Succinic Anhydride (OSA) starch emulsifiers have been successfully applied in food applications for stabilizing oil-in-water (O/W) emulsions, further converting native starch to resistant starch is an attractive alternative which does not require fat reduction but can protect fat droplets against enzymatic digestion. The main purpose of this study was to determine the feasibility of a combined process of debranching and OSA esterification to prepare resistant starch emulsifier for food applications. Following debranching, the resistant starch content of the modified starches markedly increased in comparison with the native starch and reached 43.09% when the enzyme concentration was set at 80 NPUN/g. In contrast, the degree of substitution (DS) of resistant starch was significantly decreased compared with native starch. The resulting resistant starch emulsifier exhibited weaker emulsifying capacity compared to native counterparts, this is caused probably by their lower DS. The environmental stability of resistant starch emulsions has also been investigated and it was observed that these emulsions remained stable after a storage period of 21 days at 4 and 25 °C, respectively however, they showed reduced stability at low pH, increased ionic strength and heat treatment. The overall research study provides useful insights into the utilization of resistant starch emulsifiers in novel food formulations for reduced fat digestion.