Effects of Rubaiyat grape skin extract on ground beef color and lipid oxidation

Retail losses from beef discoloration and lipid oxidation motivate meat processors to introduce clean-label processing strategies, including antioxidant application, to maximize the benefits of producing animal proteins. This study evaluates antioxidants in Rubaiyat grape-skin extract and its effect on ground beef color and oxidative stability. More specifically, antioxidants in grape skin extract were characterized using reverse-phase liquid chromatography-mass spectrometry. Further, antioxidant effects of grape skin extract and grape skin emulsion on ground beef color, lipid oxidation, and cooked profiles were determined. Ten 100-g patty treatments were prepared: no-additive control (CN), vehicle controls, extract at 1% and 2%, and emulsions at 4% and 8% formulated to deliver ~1% and ~2% extract equivalents. Patties were over-wrapped in PVC film and displayed for 72 h at 4 °C under continuous display lighting. Instrumental color (L*, a*, b*, chroma, hue, and %metmyoglobin), pH, water holding capacity, lipid oxidation as thiobarbituric acid reactive substances (TBARS), cooking loss, shear force, and cooked color were determined to assess the effects of grape skin extract inclusion. Metabolomics detected multiple phenolic compounds, with flavonoids (quercetin, isoquercetin, and miquelianin) representing the predominant constituents. Antioxidant capacity was expressed as % radical scavenged, and the grape skin extract had (DPPH/ABTS), and total phenolics were 2.77 ± 0.05 mg gallic acid equivalent/g. The water-based grape extract treatment and grape skin emulsion maintained greater (P < 0.05) redness (a*)/chroma and lower %metmyoglobin accumulation compared with control with no additives. Emulsion treatments in general had lower TBARS values than extract treatments on day 3 of storage. There were no differences (P > 0.05) in pH, shear force, or cooked color among treatments. Cooking loss was greater in grape skin emulsion treatments than in the control without any added ingredients. Overall, Rubaiyat grape-skin extract improved fresh ground beef color, supporting its potential application in fresh beef.