Abstract
This paper investigated the interaction characteristics between flavonoids and homologous starch in tigernut (Cyperus esculentus L.) oil cake. Infrared spectroscopy and X-ray diffraction analyses exhibited that the tigernut flavonoids can bind starch through hydrogen and hydrophobic interactions. SEM and CLSM images revealed a less dense structure in starch-flavonoids complexes, which further confirmed their strong interaction. This interaction increased starch crystallinity, thermal stability and antioxidant properties, but reduced the viscoelasticity of the starch (P < 0.05). Moreover, the presence of flavonoids significantly strengthened the digestion-resistant characteristic of starch by reducing the content of rapidly digestible starch (RDS) by 30.73 % while concurrently increasing the content of resistant starch (RS) by 21.32 % (P < 0.05). The tigernut flavonoids exhibited a slightly greater inhibition of α-glucosidase activity than α-amylase. This research established the theoretical foundations for the development of tigernut flavonoids and starch-based healthy foods and their industrial applications.