The use of sprouts in the human diet is becoming more and more widespread because they are tasty and high in bioactive compounds and antioxidants, with related health benefits. In this work, we sprouted rapeseed under increasing salinity to investigate the effect on free and bound total phenolics (TP), non-flavonoids (NF), tannins (TAN), phenolic acids (PAs), and antioxidant activity. Seeds were incubated at 0, 25, 50, 100, 200 mM NaCl until early or late sprout stage, i.e., before or after cotyledon expansion, respectively. Sprouting and increasing salinity slightly decreased the bound fractions of TP, NF, TAN, PAs, while it increased markedly the free ones and their antioxidant activity. Further increases were observed in late sprouts. Moderate salinity (25–50 mM NaCl) caused the highest relative increase in phenolic concentration while it slightly affected sprout growth. On the contrary, at higher NaCl concentrations, sprouts grew slowly (100 mM NaCl) or even died before reaching the late sprout stage (200 mM). Overall, moderate salinity was the best compromise to increase phenolic content of rapeseed sprouts. The technique may be evaluated for transfer to other species as a cheap and feasible way to increase the nutritional value of sprouts.

The brewing industry produces high quantities of solid and liquid waste, causing disposal issues. Brewing spent grains (BSGs) and brewing spent hop (BSH) are important by-products of the brewing industry and possess a high-value chemical composition. In this study, BSG and BSH, obtained from the production process of two different types of ale beer (Imperial red and Belgian strong beer) were characterized in terms of valuable components, including proteins, carbohydrates, fat, dietary fiber, β-glucans, arabinoxylans, polyphenols, and phenolic acids, and antioxidant activity (Ferric Reducing Antioxidant Power Assay (FRAP), 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS)). Significant concentrations of total polyphenols were observed in both BSH and BSG samples (average of about 10 mg GAE/g of dry mass); however, about 1.5-fold higher levels were detected in by-products of Belgian strong ale beer compared with Imperial red. Free and bound phenolic acids were quantified using a validated chromatographic method. A much higher level of total phenolic acids (TPA) (about 16-fold higher) was found in BSG samples compared with BSHs. Finally, their antioxidant potential was verified. By-products of Belgian strong ale beer, both BSG and BSH, showed significantly higher antioxidative capacity (about 1.5-fold lower inhibitory concentration (IC50) values) compared with spent grains and hop from the brewing of Imperial red ale. In summary, BSG and BSH may be considered rich sources of protein, carbohydrates, fiber, and antioxidant compounds (polyphenols), and have the potential to be upcycled by transformation into value-added products.