Utilizing Apple Pomace in Meat Products: A Systematic Review and Meta-Analysis

Apple pomace, a byproduct of juice production, is a sustainable source of dietary fiber and polyphenols with potential in food systems. This study aimed to systematically review 69 articles and perform a meta-analysis on 17 experimental studies to quantify the impact of AP on meat products. Using a random-effects model (Inverse Variance method; I² = 99-100%), mean differences (MD) and 95% confidence intervals (CI) were calculated. Results revealed that AP significantly increased total dietary fiber (MD = 1.84; p < 0.00001) and reduced pH (MD = -0.18; p < 0.00001). Regarding color, AP significantly decreased redness (a*) (MD = -1.47; p < 0.005) but had no significant impact on lightness (L*) (MD = 0.34; p = 0.70) or yellowness (b*) (MD = -1.32; p = 0.08). Sensitivity analysis confirmed the robustness of these trends across diverse meat matrices. Despite high statistical heterogeneity, the consistent direction of effect provides high certainty of evidence. Findings suggest that inclusion levels exceeding 10% may increase variability and adversely affect redness and acidity. In conclusion, AP is a promising functional ingredient for sustainable, fiber-enriched meat products. However, a successful application requires optimizing inclusion levels to balance technological performance with consumer acceptance.