Helical structures modulate the complexation mode and release characteristics of starch-capsaicin complex

Capsaicin (CA) is a bioactive compound, known for its physiological effects, though its high pungency limits its practical applications. This study investigated the effects of starches with amorphous structures (AS), single helical and amorphous structures (SAS), and a combination of double helical, single helical, and amorphous structures (DSAS) on the complexation mode and release characteristics of CA. The SAS-CA complex exhibited the highest CA content (60.1 mg/g) and improved stability. Structural analyses using nuclear magnetic resonance spectroscopy and X-ray diffraction verified that both SAS and DSAS formed V6I-type complexes with CA stabilized by hydrogen bonding and hydrophobic interactions. In contrast, AS and CA exhibited only physical entrapment determined by differential scanning calorimetry, Fourier transform infrared, and Raman spectroscopy. The DSAS-CA complex demonstrated the slowest CA release during simulated oral digestion, attributed to its double helical structure, which resisted water erosion (17.1 %) and enzyme hydrolysis (3.6 %). Pearson correlation analysis revealed a strong positive relationship of CA release with amorphous structure, hydrolysis rate, and erosion rate, but exhibited a negative correlation with single helical and double helical structures. These findings support the development of starch-based delivery systems tailored to control the release of highly pungent bioactives like capsaicin, broadening their potential uses in food and pharmaceutical formulations.