Effect of grape pomace on oxidative and microbial quality of chill-stored beef model systems

Grape pomace, a by-product of winemaking, is rich in bioactive compounds and has recently attracted attention for its potential application in functional foods. In this study, grape pomace powder (GPP) derived from the local Kösetevek grape variety was incorporated into beef model systems at concentrations of 0.5 %, 0.75 %, and 1.0 % to evaluate its effects on oxidative and microbial stability. GPP supplementation significantly reduced lipid oxidation and metmyoglobin formation, and it also decreased lightness and yellowness values, resulting in a darker appearance in meat batters (p < 0.001). However, the 1.0 % GPP group did not provide additional oxidative protection compared to the 0.5 % and 0.75 % groups. Textural attributes such as hardness and chewiness were affected by GPP, with the 1.0 % group exhibiting the highest chewiness values (p < 0.001). Although microbial counts were lower in GPP-treated samples than in the control, all samples exceeded acceptable spoilage thresholds by day 6. Overall, GPP at concentrations up to 1.0 % may serve as a natural additive to improve the shelf life and functional quality of meat products. • Taxifolin and luteolin-7-glucoside were identified for the first time in Kösetevek grape pomace. • GPP addition significantly reduced TBARS values in meat batter formulations. • GPP treatments suppressed MetMb formation, thereby slowing oxidative deterioration. • GPP treatments reduced lightness and yellowness, resulting in a darker appearance in meat batters. • GPP-treated samples showed lower microbial counts than control and BHT.