Formulation and characterization of O/W emulsions stabilized using octenyl succinic anhydride modified kudzu starch

Kudzu starch esterified with octenyl succinic anhydride (OSA) was used as a food-grade emulsifier to formulate O/W emulsions. In addition, the difference between the physicochemical properties and emulsifying ability of native kudzu starch and those of OSA-modified kudzu starch was investigated. Granules of the OSA-modified kudzu starches increased in size after gelatinization. The interfacial tension between soybean oil and gelatinized OSA-modified kudzu starch was lower than that of kudzu starch. The droplet size of O/W emulsions decreased to 186 nm at 100 MPa after three passes. The emulsions stabilized using gelatinized OSA-modified kudzu starch were less stable when exposed to different ionic strengths (100 mM to 500 mM NaCl), than when exposed to different pH levels (2-8). The results of oil droplet size and confocal laser scanning microscopy analysis indicated that emulsions containing 2-5% OSA-modified kudzu starch remained stable at room temperature for 30 days.