The potential of spent grain as a functional food ingredient: comparison of physico-chemical properties from 8 different breweries

This research was aimed to identify the potential of brewer’s spent grain (BSG) as a functional food ingredient and the variability of their physico-chemical properties which were collected from eight different breweries. The BSG were dried until they reached a stable weight, grounded to pass 385 µm sieve and they were vacuum packed in non-transparent packaging and kept in room temperature conditions for further analysis. The result showed that BSG contained high dietary fiber content which was dominated by insoluble dietary fiber about 38.0-43.9% while soluble dietary fiber content about 3.9-9.6%. There were three groups of polyphenolic identified: flavan-3-ols, phenolic acids and flavonols about 362.1-1165.7 mg/kg, 65.8-122.5 mg/kg and 3.6-13.8 mg/kg respectively. Antioxidant capabilities were carried out in in-vitro assessment: ABTS capability was ranging from 0.086 to 0.241 mmol Trolox/100 g while FRAP capacity was from 0.106 to 0.306 µmol TE/100 g. Proximate as well as physical properties including colour, water activity, hydration properties, oil holding capacity and density showed a variability within all eight BSG samples. In conclusion, BSG as a brewery waste is potentially to be used as a functional food ingredient for their properties. It is suggested that further studies are needed to explore their impact on the development of functional food products.