Techno-functional properties of protein from protease-treated brewers’ spent grain (BSG) and investigation of antioxidant activity of extracted proteins and BSG residues

The study aimed to investigate the biological properties of the protein fraction of brewers’ spent grain (BSG) and its sediments as well as the techno-functional properties of BSG protein (BSGP). BSG was incubated with 0.5% protamex and a combination of protamex and flavourzyme, in addition to the control (incubation without protease). The results showed that enzymatic treatment enhanced the antioxidant activity of BSGP. Compared to the sediment fraction, BSGPs had higher antioxidant capacities than those in sediments. The current study demonstrated that the FRAP value is aligned with the amount of the polyphenolic compounds, while BSGP is responsible for ORAC and ABTS capabilities. Enzyme treatment on BSG enhanced the antioxidant properties of BSGPs and the amount of the phenolic compounds of the sediments. BSGPs treated with proteases possessed higher oil-holding capacity, foaming properties and lower emulsion capability. In conclusion, enzymatic treatment of BSG enhanced the protein functionality and bioactivity as well as intensified the antioxidant activity of its sediments allowing further valorization.</p

1st International Electronic Conference on Food Science and Functional Foods

This research aimed to conduct a comparison of 8 different forms of brewery spent grain (BSG) on their polyphenolic content and antioxidant capacity as part of their potential as a functional food ingredient. The BSGs were dried until they reached a stable weight, grounded to pass through a 385 µm sieve and were vacuum packed in non-transparent packaging for further analysis. The results showed that BSG contained a high dietary fiber content which was dominated by a insoluble dietary fiber level of about 38.0–43.9% and a soluble dietary fiber content of about 3.9–9.6%. There were three groups of polyphenolic identified: flavan-3-ols, phenolic acids and flavonols at quantities of 362.1–1165.7 mg/kg, 65.8–122.5 mg/kg and 3.6–13.8 mg/kg, respectively. Antioxidant capacity was examined using an in vitro assessment: the 2,2′-Azinobis-(3-Ethylbenzthiazolin-6-Sulfonic Acid) (ABTS) capacity ranged from 0.086 to 0.241 mmol Trolox/100 g while the ferric reducing antioxidant potential (FRAP) capacity ranged from 0.106 to 0.306 µmol TE/100 g. In conclusion, BSG as a brewery waste can potentially be used as a functional food ingredient due to its properties. It is suggested that further studies are needed to explore BSG’s impact on the development of functional food products.Keywords: brewery spent grain; valorization; agricultural by-products; functional food; dietary fiber; polyphenolic compounds; antioxidant</p