Hot Trub as a Sustainable Resource for Food and Nutraceuticals

In the context of the current trend toward a circular (bio)economy, the valorization of agro‐industrial waste has emerged as a key strategy for retrieving raw materials for diverse applications while simultaneously minimizing environmental impact. Hot trub, one of the main solid wastes of brewing, is also a promising source of valuable by‐products. The present work provides a multidisciplinary characterization of hot trub, encompassing elemental, microbiological, and physicochemical analyses, including the assessments of ash, colorimetric properties, free sugars, moisture content, mycotoxins, organic acids, phenolic compounds, and protein content. The resulting profile aims to provide detailed insight into the composition of hot trub composition and assess its potential for value‐added applications, namely in food and nutraceutical formulations. Hot trub flour displayed a favorable nutritional and safety profile, with a protein content of 14.92%, low moisture (7.16%) and ash (2.90%) contents, and significant amounts of free sugars (25% of dry matter). The presence of diverse phenolic compounds, namely flavonoids, which made up 63% of the total, alongside organic acids, suggests a potential for antioxidant and antimicrobial activity. Microbiological analyses confirmed hot trub safety, with low microbial counts, absence of pathogens, and mycotoxin levels below EU regulatory limits. Combined with its moderately bright yellow color, these features highlight hot trub as a source of valuable biomolecules, such as phenolic compounds, for applications in nutraceuticals, cosmetics, and biobased products. This study evaluates its compositional and safety suitability as a preliminary step toward food valorization.