Functional ingredients are substances that offer health benefits beyond their nutritional value. A novel heteropolysaccharide, named Linum water soluble polysaccharide (LWSP) was purified from Linum usitatissimum L. seeds powder and identified, via TLC and NMR, as a polymer composite of α1-2-L-arabinose, β1-2-D-xylose, β1-2-D-mannose and α1-2-D-glucose. The effect of incorporating LWSP on the quality of beef sausages, stuffed into collagen casings after 15 days of storage at 4 °C, was evaluated for texture profile analysis, color, sensory analysis and oxidation attributes. The new sausages formulated with LWSP recorded good textural attributes via reduction of cohesiveness, hardness and chewiness and improved the sensory features, especially texture, color and general acceptability. In addition, substituting ascorbic acid, a synthetic antioxidant, via the biological ingredient LWSP, retarded lipid oxidation and improved the oxymyoglobin rate until 15 days of storage. LWSP was proved to be a good natural substituent to synthetic antioxidants that definitely improves the oxidation stability and quality of sausages.