Subcritical water as hydrolytic medium to recover and fractionate the protein fraction and phenolic compounds from craft brewer’s spent grain

•Subcritical water was applied to brewer’s spent grain.•High protein recovery was achieved by hydrolysis of the peptide bonds.•Fractionation of biocompounds can be achieved by selecting operating temperature.•Polar amino acids were more sensitive to temperature than non-polar amino acids.•Hydroxycinnamic acids were more sensitive to temperature than aldehyde phenolics.