Exploring Antimicrobial Hydroxypropyl-β-Cyclodextrin Inclusion Complexes for Cheese Preservation: A Combined Theoretical and Experimental Study

Abstract

Cyclodextrin enhances the activity of bioactive compounds through the formation of inclusion complexes (ICs), but its effect on diverse compound structures and processing methods is poorly understood. Here, our goal is to provide a comprehensive and cohesive insight into hydroxypropyl-β-cyclodextrin (HPβCD) complexation with cinnamaldehyde (CINN), citral (CIT), or their combination (MIX), prepared via kneading (KN), or freeze-drying (FD) using analytical techniques and computational simulations. Thermodynamic analysis revealed an exothermic and spontaneous (ΔG < 0) complexation process, with CINN-ICs exhibiting greater stability constants at 25 °C than CIT-ICs. Among the methods, CIT-KN displayed the highest efficiency (90.7%) and drug loading (9%), while CINN-KN showcased higher zeta potential (−23.2 mV), controlled release (35%), and antimicrobial activity (against both gram-positive and gram-negative bacteria). Computer simulations confirmed the absence of ternary complexes (CINN+CIT in HPβCD) and revealed the coexistence of association and ICs. Thermal analyses demonstrated high thermal stability (up to 207 °C) of included compounds, enhancing the suitability of these complexes for high-temperature processes. Additionally, CINN-KN incorporation into methylcellulose creates an active film, which effectively inhibited the proliferation of L. monocytogenes and S. Choleraesuis in cheeses (up to 1.3 cm halo inhibition), even following exposure to temperatures as high as 50 °C. Through combined experiments and computations, we uncovered how processing affects ICs performance with bioactive compounds, confirming their associative interactions with HPβCD. Thus, we underscore that the active function of ICs containing bioactive compounds relies not only on compound structure but also on processing methods, involving a collaborative interplay between both factors.