Abstract:

In this study, soybean oil body emulsion was subjected to heat treatment at different temperatures. The changes in
physical stability, oxidative stability, the secondary structures of oleosins, interfacial tension, and interfacial characteristics in
the oil body emulsion were examined using dynamic surface tension measurement, dynamic laser light scattering, confocal
laser technology and circular dichroism to evaluate the effectiveness of heat treatment. The results showed that heat treatment
reduced surface charges and interfacial tension, and changed the interfacial strength of oil bodies. In addition, heat treatment
caused a decrease in α-helix structure from (17.71 ± 0.01)% to (15.3 ± 0.03)%, unordered structure from (29.96 ± 0.01)% to
(27.3 ± 0.06)% and β-turn from (22.34 ± 0.05)% to (21.2 ± 0.03)%, and it could increase β-sheet structure from (29.89 ± 0.06)%
to (36.1 ± 0.02)%. Heat treatment changed the forces maintaining the secondary structure of oleosins, which in turn could affect
the secondary structure contents and resulted in different interfacial properties. Furthermore, heat treatment could not significantly
promote the flocculation of oil bodies; heat treatment at 30 ℃ and 50 ℃ had relatively small amount of hydrogen peroxide. This
result suggested that heat treatment changed the interfacial properties of soybean oil body emulsion and consequently had an
important impact on its physical properties and oxidative stability.

Key words: soybean oil body emulsion, heat treatment, interfacial characteristics, stability