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Porous starch granules (PSGs) are promising biomaterials for the encapsulation, protection, and delivery of bioactive ingredients. In this study, a lipase treatment was first used to generate pores in native starch granules, and then α-amylase was used to enlarge these pores. Electron and fluorescence microscopy analysis showed that the lipase treatment exposed the starch molecules located below the lipid-rich regions on the starch granule surfaces, which increased the swelling of the granules in aqueous solutions. Moreover, lipase treatment caused the surrounding areas to become more loosely packed, which facilitated subsequent starch hydrolysis and the formation of large internal cavities. Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analyses provided further insights, these methods showed that the short-range order, long-range order, and thermal stability of the PSGs was enhanced by the sequential lipase-amylase modification. PSGs were highly resistant to amylase digestion and had strong adsorption capacity to hydrophobic and hydrophilic substances. This study shows that a combined lipase-amylase treatment can be used to fabricate PSGs, which may have health benefits due to their low digestibility and ability to encapsulate bioactive agents. These PSGs may therefore be suitable for application in the functional food, supplement, personal care, and pharmaceutical industries.

Ovalbumin (OVA)/sodium carboxymethylcellulose (CMC) colloidal particles were prepared with different compactness and morphologies by regulating the interaction between proteins and polysaccharides during heating. Electrostatic interactions between the amine groups of OVA (−NH3+) and carboxyl groups of CMC (−COO–) enhanced complex formation. The protein conformation change benefited the hydrophobic interaction between the particles. Proteins in colloidal particles were unfolded/folded under thermal induction to form aggregates having more β-sheet structures. When the OVA/CMC ratio was 1:2, the initially loosely connected OVA/CMC aggregation changed into a uniform sphere between 25 and 90 °C. The mass ratio of OVA to CMC within the final colloidal particle (90 °C) was about 1:1.4. The OVA/CMC particle stability was maintained with hydrogen bonding, hydrophobicity, and disulfide bond. When OVA levels were predominant, OVA and CMC developed an approximately hollow sphere. Moreover, the final colloidal particle composition showed the OVA-to-CMC ratio as 3:1 (w/w). OVA bound into colloidal particle pores to increase compactness. Moreover, OVA and CMC bound to the colloidal particle while the particle shrank, thereby increasing the compactness of colloidal particles. There was a significant decrease in ABTS•+scavenging activity of curcumin compared with that of the particles with a ratio of 1:2. Thus, the rational adjustment of the structure of colloidal particles could effectively enhance their functional characteristics, providing a new way for the controlled release of the active ingredients.