Preservation of Beef with Limonene-Rich Citrus Peel Extracts: Antioxidant, Antimicrobial and Textural Benefits

Citrus peels, long used in traditional food preservation, are rich in bioactive compounds with potential antioxidant and antimicrobial properties. However, a systematic comparison of the efficacy of different citrus varieties and the underlying mechanisms in meat preservation remains limited. This study investigated the chemical composition of peels from four citrus varieties (Citrus reticulata, CR; C. sinensis, CS; C. bigarradia, CB; and C. macrocarpa, CM) and their efficacy in preserving beef quality during refrigerated storage. GC-MS analysis revealed limonene as the predominant volatile component (59.6~77.1%), with CR peel exhibiting the highest content (77.1%). CR extract also demonstrated superior antioxidant activity (DPPH: 60.8%; ABTS: 66.0%) and antimicrobial effects against five common meat microbial species. Beef samples treated with CR peel extract significantly (p < 0.05) reduced lipid oxidation (TBARS: 2.88 vs. 4.83 mg MDA/kg in control) and protein degradation (TVB-N: 270 vs. 371 mg/kg). Microstructural integrity was better maintained, as evidenced by lower surface hydrophobicity, higher sulfhydryl content, and reduced carbonyl formation. Furthermore, CR treatment suppressed microbial growth (TBC and TAC reduced by ~30%) and the accumulation of spoilage-related biogenic amines, particularly putrescine (12~18.8 vs. 27.4 mg/kg). Correlation analysis identified limonene content as strongly correlated with antioxidant and antimicrobial activities. This work validates the scientific basis of using citrus peel, particularly CR, as a natural preservative, effectively bridging traditional culinary practice with modern food science by elucidating its multi-target role in extending the shelf life and enhancing the safety of beef.