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 (<i>Citrus reticulata</i>, CR; <i>C. sinensis</i>, CS; <i>C. bigarradia</i>, CB; and <i>C. macrocarpa</i>, 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 (<i>p</i> < 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.