High internal phase emulsions stabilized solely by soy protein isolate.

We demonstrated soy protein isolate (SPI) at pH 3 is suitable for preparing edible HIPEs with internal phase of corn oil, even at protein concentration as low as 0.5% (w/v). The highest internal phase volume reached 90% (v/v). There was no remarkable difference in appearance of the HIPEs after heating, but phase separation happened after freeze-thaw treatment. Interestingly, no distinct difference can be found in appearance of the heated HIPEs with internal phase volumes of 85% and 90% after freeze-thawing thrice. All the HIPEs exhibit a solid-like behavior as revealed by the results that the G′ value was higher than G′′ value. The increased surface hydrophobicity after heating suggested interaction of protein can happen after emulsion heating. The confocal laser scanning microscope confirmed the interaction of SPI and emulsions. The HIPEs can be utilized to encapsulate β-carotene. The β-carotene retention in HIPEs was 74.1%, significantly higher than that in corn oil. • SPI at pH 3 is able to stabilize HIPEs with internal phase volume up to 90%. • Heating significantly improved the freeze-thaw stability of SPI-stabilized HIPEs. • Protein interaction is responsible for the improved stability of HIPEs after heating. • β-Carotene stability was enhanced after encapsulation in the SPI-stabilized HIPEs. [ABSTRACT FROM AUTHOR]