title: The hydroxycinnamic acid content of barley and brewers' spent grain (BSG) and the potential to incorporate phenolic extracts of BSG as antioxidants into fruit beverages.
abstract: The hydroxycinnamic acid (HA) content of starting barley for brewers' spent grains (BSG), whole BSG and phenolic extracts from BSG was measured using high performance liquid chromatography (HPLC) and correlated with antioxidant potential. The effect of BSG phenolic extracts on antioxidant activity of fruit beverages was also assessed (using the total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays). The concentration of HA present in barley extract and BSG was in the order of ferulic acid (FA), p-coumaric acid (p-CA) derivatives, FA derivatives, p-CA, caffeic acid (CA) and CA derivatives. Results suggested that brewing and roasting decreased the HA content. Antioxidant activity was significantly (P<0.05) correlated with caffeic acid (R(2)=0.8309) and total HA (R(2)=0.3942) concentrations. Addition of extracts to fruit beverages resulted in a significant (P<0.05) increase in antioxidant activity of cranberry juice, measured by the FRAP assay. In vitro digestion significantly (P<0.05) reduced TPC, DPPH and FRAP activity of the fruit beverages.
authors.affiliation: School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
authors.forename: Aoife L
authors.initials: AL
authors.lastname: McCarthy
authors.forename: Yvonne C
authors.initials: YC
authors.lastname: O'Callaghan
authors.forename: Susanne
authors.initials: S
authors.lastname: Neugart
authors.forename: Charles O
authors.initials: CO
authors.lastname: Piggott
authors.forename: Alan
authors.initials: A
authors.lastname: Connolly
authors.forename: Marcel A K
authors.initials: MA
authors.lastname: Jansen
authors.forename: Angelika
authors.initials: A
authors.lastname: Krumbein
authors.forename: Monika
authors.initials: M
authors.lastname: Schreiner
authors.forename: Richard J
authors.initials: RJ
authors.lastname: FitzGerald
authors.forename: Nora M
authors.initials: NM
authors.lastname: O'Brien
mesh_terms: D000975:Antioxidants / Q000032:analysis; D001628:Beverages / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D003373:Coumaric Acids / Q000032:analysis*; D005503:Food Additives / Q000032:analysis*; D005638:Fruit / Q000737:chemistry*; D001467:Hordeum / Q000737:chemistry*; D010636:Phenols / Q000032:analysis*; D010936:Plant Extracts / Q000032:analysis*; D014866:Waste Products
chemical_list: D000975:Antioxidants; D003373:Coumaric Acids; D005503:Food Additives; D010636:Phenols; D010936:Plant Extracts; D014866:Waste Products
keywords: Antioxidant; Brewers’ spent grain (BSG); Ferulic acid; Fortification; Hydroxycinnamic acids; In vitro digestion; Phenolic extracts