Abstract: In order to investigate the impact of ozone pretreatment and lipid modification on the structure and properties of starch, ozone-pretreated banana starch-lauric acid complexes were prepared and their physicochemical properties and digestibility were evaluated. Results showed that in comparison with the native starch, the complexation index (CI) of the pretreated starch with lauric acid increased by 12.67%; the resulting complexes exhibited a significant increase in water solubility, swelling power and syneresis, an elevation in gelatinization temperature from 104.24–135.23 ℃ to 155.60–161.68 ℃, and a 6.71% increase in resistant starch, but a decrease in iodine binding capacity. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrated that lauric acid was bound to the surface of starch granules to form a complex, thereby increasing the surface height of starch granules. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) revealed that banana starch and lauric acid formed non-V-type and V-type complexes through hydrogen bonding and hydrophobic interactions. The results of contact angle and thermogravimetric (TG) analysis demonstrated that the hydrophobic properties and thermal stability of the complexes were improved. Consequently, the combination of ozone pretreatment and lauric acid modification could enhance the water solubility, swelling capacity, and thermal stability of banana starch, further improving its digestibility resistance. These findings will expand the application potential of starch in the food field.

Key words: ozone; banana starch; lauric acid