Functional and sustainable savory snack formulation through olive and brewing industry by-products

The snack market is experiencing significant growth; however, conventional products often exhibit an unhealthy nutritional profile. In response to consumers’ growing interest in healthier foods and sustainable production practices, this study explored, for the first time, the synergistic combination of olive pâté (OP) and brewers’ spent grain (BSG)—bioactive-rich by-products from the olive oil and brewing industries—as functional ingredients for developing nutritionally enhanced savory snacks. Four formulations differing in OP (untreated or debittered) and BSG (wet or dried) were prepared and compared with a control through proximate analysis, phenolic quantification and determination, antioxidant activity, texture evaluation, and sensory profiling. BSG addition allows compliance with EFSA nutritional claims such as “source of protein” and “high fiber” and may support a “gut health” claim due to the fecal-bulk–enhancing properties of barley fibers. OP markedly increased the snacks' phenolic content, and consequently their antioxidant activity. Textural properties were also improved: the by-products reduced hardness while increasing crispness. Sensory evaluation revealed good overall acceptance of the enriched prototypes, which were characterized by pleasant olive and malt notes. Using untreated OP was deemed acceptable and offers the opportunity to reduce processing steps and costs associated with debittering. Notably, the formulation containing wet BSG and untreated OP achieved the highest overall liking, comparable to that of the control snack. Overall, these findings demonstrate that product and process innovation through the valorization of agro-industrial by-products in line with circular economy principles is an effective strategy for producing functional, sustainable snack foods that address evolving market demands.