β-cyclodextrin versus hydroxypropyl-β-cyclodextrin: is inclusion complexation a suitable alternative to improve the properties of hop-derived β-acids?

Cyclodextrins (CD) are versatile molecules that have been widely studied in several technological areas, as efficient carrier molecules for natural bioactives, through inclusion complexes (IC) formation. The present study aimed to investigate and compare the host:guest interaction between two types of CD (beta-cyclodextrin 'beta CD' and 2-hydroxypropyl-beta-cyclodextrin 'HP beta CD') with a commercial beta-acid rich hop extract (beta HE), identifying how beta-acids properties can be affected by inclusion complexation. Results evidenced that IC formation enhanced beta-acids thermal and oxidative stability. Both IC demonstrated great application prospects, however, some differences were observed for the IC structures (observed through DLS, FTIR, XRD, TGA, and SEM analyzes) as well as the properties such as bioctives release, particle stability, antioxidant and antibacterial activities of beta-acids. Probably due to a higher content of beta-acids on the molecule's outer face, beta CD:beta HE presented a lower stability, nevertheless, exhibited faster release into meat products simulant solution, along with a higher antibacterial activity.