Structural, physicochemical properties, and digestibility of lotus seed starch-conjugated linoleic acid complexes

This paper describes a new method combining octenyl succinic anhydride (OSA) esterification and high hydrostatic pressure for starch modification, which interacts with conjugated linoleic acid (CLA) to form an octenyl succinic anhydride-lotus seed starch-conjugated linoleic acid (OSA-LS-CLA) complex. This method proves the formation of complex observed by fourier transform infrared spectroscopy and complex index. The stable structure of the complex was derived from increasing molecular weight by introducing macromolecular conjugated linoleic acid and the higher crystallinity than original starch observed by X-ray diffraction. The formation method and changes of complex were observed by scanning electron microscopy and confocal laser scanning microscope. The solubility and swelling power of the complex increases as the temperature increased, significantly at 75 °C. The formation of the OSA-LS-CLA complex significantly reduced the digestion rate of LS, which was 26 % lower than that of LS. These results indicate that the OSA-LS-CLA under high hydrostatic pressure can form a complex with stable structure, which makes up for the deficiency of raw starch to a certain extent. And the formation of this structure can improve the thermal stability of the complex and has strong digestion resistance, which provides a potential direction for further research in reducing starch digestibility.