In spite of growing commercial importance of pulse proteins, pulse starch, a major co-product of the pulse processing industry, shows limited industrial application. The objective of the study was to expand the utilization of pulse starch as an emulsifier by using octenyl succinic anhydride (OSA) modification. Pea starch (PS), along with commercial normal corn starch (NCS) and waxy corn starch (WCS), was modified with 1, 3 or 5wt% OSA. Structure, functional and emulsifying properties of OS-starches were characterized. All OS-starches showed lower pasting temperatures and higher peak viscosities compared with their corresponding controls. Canola oil (5wt%)-in-water emulsions were prepared with 2wt% OS-starches by high-pressure homogenization. The OS-PS dispersion decreased oil-water interfacial tension from 21.1 to 6.9-9.5 mN/m, similar to other modified starches. The droplet size of fresh emulsion stabilized by OS-PS was 160 nm, which increased considerably to 295 nm after storing at 4 C for 28 days. In contrast, emulsion stabilized by OS-WCS exhibited better stability as the droplet size (154 nm) remained unchanged. The emulsions formed by OS-PS showed excellent stability under mild pH conditions (7.0 to 5.0) and heating at 90 C for 30 min; however, they destabilized when the pH further dropped to the range 4.0 to 2.0 or when 0.1 M sodium chloride was present in the system. Overall, OS-PS showed the ability to create an emulsion with relatively small droplet size, but the emulsions were less stable against environmental change and long-term storage compared to emulsions formed by OS-WCS.
