From By-Product to Functional Ingredient: Effect of Mushroom Stipe Powders on Gelation, Texture, and Lipid Oxidation of Processed Meat Systems

This investigation assessed the efficacy of mushroom stipe powders as functional substitutes for meat and starch in emulsion-type sausages, leveraging the intrinsic nutritional profile of mushroom by-products and evaluating product quality over a 30-day refrigerated storage period. Proximate analysis revealed that mushroom stems possess significant protein (22.02-35.21 % dry basis) and carbohydrate (55.25-68.64 %) contents, with negligible fat (<1.71 %). Total phenolic content ranged from 5.05 to 12.98 mg GAE/g, while antioxidant activity varied between 82.52 % and 90.72 %, underscoring their potential as natural antioxidants. Four sausage formulations were developed: Control, BM5 (5 % meat replacement with button stipe powder), OMS (complete starch replacement with oyster stipe powder), and a Hybrid formulation (combined substitutions). Proximate composition analysis indicated comparable protein levels (13.85-14.50 %) across treatments, with substituted samples exhibiting slightly elevated moisture content (up to 54.39 %). Although water holding capacity (WHC) declined during storage, BM5 maintained the highest initial WHC (87.73 %), whereas the Hybrid formulation demonstrated the lowest cooking loss (0.85 % at day 0) compared to the Control (1.91 %). Rheological assessments confirmed elastic gel behavior (G′ > G″) across all samples, with BM5 exhibiting the highest storage modulus. Textural profiling revealed that BM5 possessed the highest initial hardness, while OMS displayed the lowest. While lipid oxidation increased over time, Hybrid and BM5 formulations exhibited significantly lower malondialdehyde (MDA) values relative to the Control. Collectively, these findings validate the hypothesis that stipe-derived polysaccharides and phenolics can mechanistically reinforce emulsion matrices and delay lipid oxidation, positioning dual-substituted mushroom stipe powders as a novel, clean-label functional ingredient for sustainable meat reformulation.