The close relationship between functional nutrition and healthy lifestyle has presented new challenges in the food industry. Developing effective strategies for food functionalization, including the choice of functional ingredients and vehicles, has become increasingly important. Based on the documented role of oxidative stress in the development and progression of numerous human diseases, several attempts to develop antioxidant-enriched foods have been proposed (Irfan et al., 2023; Sheikh et al., 2023). For those purposes, due to the strong redox-active and antioxidant properties of several phytochemicals, parts of plants have been widely used as functional ingredients (Gaglio et al., 2019; Kabakcı, Türkyılmaz, & Özkan, 2020). In this context, agro-industrial wastes, such as seeds, leaves, and peels, have gained attention as potential sources of functional ingredients in efforts to minimize food waste impact (Chamorro et al., 2022; Liguori et al., 2020).

Stability of plant bioactive components in fortified foods and their impact on sensory and technological properties must be considered. In this regard, bread is gaining considerable attention as a suitable vehicle for functional molecules due to its widespread consumption and limited functional value. Various studies evaluated the potential use of bread for delivering antioxidant molecules, by addition of natural raw materials, especially food wastes. For instance, leaves from Amaranthus viridis, Solanum macrocarpon, and Telfairia occidentalis (Alashi, Taiwo, Oyedele, Adebooye, & Aluko, 2019), as well as stinging nettle leaves (Urtica dioica) (Đurović et al., 2020) and purslane flour (Portulaca oleracea) (Melilli et al., 2020), have proven effective as functionalizing agents in bread, elevating the levels of polyphenolic compounds and enhancing antioxidant activity. Additionally, recent assessments have examined the functional potential of bread fortified with cladodes from prickly pear (Liguori et al., 2020; Msaddak et al., 2017).

Red raspberry is the fruit of Rubus idaeus. Its production has significantly increased in recent years, also in Italy, owing its profitability. This fruit is highly appreciated not only for its delightful taste and aroma, but also for healthy benefits, attributed to the presence of high amounts of bioactive components (Burton-Freeman, Sandhu, & Edirisinghe, 2016; Derrick, Kristo, Reaves, & Sikalidis, 2021; Rao & Snyder, 2010). This berry is a notably rich in vitamin C and contains significant amounts of polyphenols, which have been shown to exhibit favorable bioaccessibility and potential bioavailability (Mihailović et al., 2019). In addition to being used for fresh consumption, because of their pronounced perishability, much of the harvest fruits are industrially processed to produce jams, juices, jellies, syrups, and freeze-dried products. Juice from fruit pressing is the most common industrial raspberry application, resulting in a considerable quantity of pomace, contains seeds with pulp and peel residues, The valorization of raspberry pomace has been already evaluated. For instance, Četojević-Simin et al. (2015) reported that it possess considerable amount of phenolic compounds and exhibit antioxidant, antiproliferative, and antibacterial activity. On the other hand, the cold pressing of washed and dried raspberry seeds is currently exploited to obtain a valuable oil (Ispiryan, Viškelis, & Viškelis, 2021). During the seed pressing to obtain raspberry oil, it is also produced an organic insoluble residue mainly consisting of seed coats (Waste Raspberry Seed Powder, WRSP). This residue, representing the final agro-industrial waste from the industrial processing of raspberry fruits, has yet to find potential applications.

In our previous work, we demonstrated that WRSP is an extraordinary source of bioactive molecules, especially proanthocyanidins. Moreover, it displayed to possess high radical-scavenging and antioxidant activity in several models, including those assessing lipid peroxidation in a cell system. In addition, microbiological assays indicated that WRSP is harmless against pro-technological bacteria, specifically lactic acid bacteria, commonly employed in food fermentation processes (Mannino et al., 2021).

In this work, our aim was the assessing of the suitability of WRSP use as a functional ingredient of white bread. In particular, we evaluated the effect of the replacing flour/semolina mixture with two different amounts of WRSP [5% (w/w) or 10% (w/w)] on antioxidant value of bread. Additionally, we evaluated the effects on microbiological factors, technological aspects, and sensorial attributes in both functionalized doughs and breads.