The invention relates to a low sugar or sugar free concentrated polyphenolic extract comprising at least about 30 % polyphenols (w/w) and a protein-polyphenol aggregate matrix comprising at least about 15% polyphenols (w/w). The invention further relates to methods of producing a low sugar or sugar free concentrated polyphenolic extract comprising (a) extracting a low sugar or sugar free plant tissue with an aqueous solvent to produce an extract having an aqueous portion and a solids portion； (b) filtering the extract to separate the aqueous portion from the solids portion； and (c) reducing the volume of the separated aqueous portion, and methods of producing a protein-polyphenol aggregate matrix comprising about 1% to about 40% polyphenols (w/w) using the low sugar or sugar free concentrated polyphenolic extract of the invention.
