Obtaining bio-based nutraceutical matrices through bioencapsulation of natural antioxidants in spent yeast

The growing demand for functional ingredients and sustainable delivery systems has driven the development of new encapsulation strategies based on renewable biomaterials. In this context, spent brewer's yeast represents an innovative alternative due to its composition rich in structural biopolymers, capable of interacting with natural bioactive compounds. This work proposes obtaining bio-based nutraceutical matrices through the bioencapsulation of natural antioxidants in spent yeast, with the aim of improving the stability and protection of these compounds against environmental factors. Furthermore, it seeks to add value to the byproduct of the brewing industry under a circular economy and sustainability approach. The developed matrices could constitute promising systems for pharmaceutical, nutraceutical, and food applications, favoring the design of functional formulations with potential controlled release and greater oxidative stability. Spent brewer’s yeast was conditioned and used as a biosorbent matrix for the incorporation of antioxidant compounds obtained from olive pomace extracts. Biosorption experiments were performed under different operating conditions to maximize polyphenol uptake. Hybrid encapsulation systems combining yeast biomass with bio-based wall materials, such as maltodextrin and starch, were subsequently developed. The resulting formulations were stabilized by drying and/or freeze-drying. Encapsulation efficiency, total phenolic content, antioxidant activity, and physicochemical properties were evaluated.Preliminary results showed that spent brewer’s yeast was able to incorporate significant amounts of polyphenolic compounds through biosorption. The incorporation of additional wall materials improved the stability of the obtained matrices. The encapsulation efficiency (%), total phenol content, particle size, storage stability, and sorption isotherms were evaluated. DSC and SEM assays were also performed. The proposed approach demonstrates the potential of spent brewer’s yeast as a sustainable carrier for natural antioxidants, contributing to the development of bio-based nutraceutical matrices and promoting the valorization of agro-industrial residues within a circular economy framework.