A composition comprising water-soluble C5 oligosaccharide hydrolysate and optionally water-soluble C5 monosaccharide hydrolysate, wherein the water-soluble C5 oligosaccharide hydrolysate comprises: 15% by weight to 30% by weight, based on total weight of water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of C5 disaccharides; 12.5% by weight to 17.5% by weight, based on total weight of water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of C5 trisaccharides; 5% by weight to 20% by weight, based on total weight of water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of C5 tetrasaccharides; 2% by weight to 20% by weight, based on total weight of water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of C5 pentasaccharides; 10% by weight to 35% by weight, based on total weight of water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of C5 saccharides having at a degree of polymerization of at least 6; less than 3700 ppm by weight in total, based on total weight of said water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of elements; wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn; and less than 150 ppm by weight, based on total weight of said water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of sulfur; wherein the water-soluble C5 oligosaccharide hydrolysate is processed from lignocellulosic biomass using supercritical, subcritical, or near critical water extraction, or a combination thereof. 15% by weight to 30% by weight, based on total weight of water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of C5 disaccharides; 12.5% by weight to 17.5% by weight, based on total weight of water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of C5 trisaccharides; 5% by weight to 20% by weight, based on total weight of water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of C5 tetrasaccharides; 2% by weight to 20% by weight, based on total weight of water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of C5 pentasaccharides; 10% by weight to 35% by weight, based on total weight of water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of C5 saccharides having at a degree of polymerization of at least 6; less than 3700 ppm by weight in total, based on total weight of said water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of elements; wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn; and less than 150 ppm by weight, based on total weight of said water-soluble C5 oligosaccharide hydrolysate and water-soluble C5 monosaccharide hydrolysate in said composition, of sulfur; wherein the water-soluble C5 oligosaccharide hydrolysate is processed from lignocellulosic biomass using supercritical, subcritical, or near critical water extraction, or a combination thereof.