Amarasate® is a bitter extract derived from New Zealand hops, recognised for its appetite-suppressing properties, and is currently used as a dietary supplement. However, its intense bitterness, stickiness, and the instability of its bioactive compounds (alpha and beta acids) present significant challenges for incorporation into functional food products. This study addresses these limitations through a targeted encapsulation strategy aimed at improving stability, controlling release, and enabling integration into diverse food systems using food grade hydrocolloids.

Initial formulation involved the development of water-in-oil emulsions (365 nm) stabilised with oil, soy lecithin, and whey protein. These emulsions demonstrated high stability over 14 days and were successfully converted into dry powders via spray- and freeze-drying, retaining bioactive integrity and exhibiting excellent dispersibility across various food matrices. However, sensorial analysis identified remaining issues with palatability.

Accordingly, to further enhance delivery efficiency, bioaccessibility, and palatability, four microgel formulations were developed using different ratios (2:1:1 to 2:1:10) of sodium alginate, gelatin, and maltodextrin through microgelation and co-extrusion techniques. Encapsulation was performed using an InoTech Encapsulator and scaled up with a Büchi B-390 Encapsulator.

The resulting microcapsules (about 150 µm; wet beads) were hardened, UV-cured, and freeze-dried. In vitro gastrointestinal digestion studies confirmed effective protection of hops bioactives during the simulated gastric phase, with up to 75% release of adhumulone and complete (100%) release of adlupulone during the intestinal phases, demonstrating both protective encapsulation and targeted release.

The encapsulated ingredient was successfully incorporated into a range of food formulations. Sensory trials validated the encapsulation approach, with the scaled-up formulation achieving about 75% consumer acceptability rate across all tested applications. Minor residual bitterness, attributed to surface oil, suggests scope for further refinement.

Overall, this work presents a structure–function-guided encapsulation strategy that enhances chemical stability, shelf life, bioactive bioaccessibility, and ingredient palatability, supporting the integration of Amarasate® into functional food systems and future clinical applications.

Keywords: Nutrient bioaccessibility; Bitterness masking; Functional foods; Bioactive microencapsulation; Biopolymer microgels.