<i>Cyamopsis tetragonoloba</i> Gum‐Based Active Coatings Incorporated With <i>Pycnocycla bashagardiana</i> Essential Oil for Reducing Postharvest Losses of Fresh <i>Pistachio</i> Fruits

Fresh pistachios, prized for their distinct flavor and aroma, suffer from limited postharvest shelf life due to fungal contamination, particularly aflatoxin-producing species. This study investigates the efficacy of guar coatings (0.25%, 0.5%, and 1%), incorporating <i>Pycnocycla bashagardiana</i> essential oil (PBEO) with varying concentrations (50, 100, and 200 μL), in extending the storage life of fresh pistachios over 60 days. The physicochemical properties of the coating solutions (zeta potential (ζ), particle size (PD) and contact angle (CA)) were characterized, alongside pistachio quality attributes including weight loss, peroxide value (PV), phenolic content (PC), titratable acidity (TA), texture firmness, antioxidant capacity, and total soluble solids (TSS). Antifungal activity against <i>Aspergillus</i> and <i>Penicillium</i> was also assessed. GC/MS and GC-FID analysis identified E-beta-(ocimene), Myristicin, Z-beta (-ocimene), and oleic acid as major components and fatty acids profile of PBEO and guar gum, respectively. The FTIR spectrum of guar gum reveals the presence of key functional groups within the polysaccharide structure. Increasing the concentration of PBEO in the solution preparation led to a significant increase in PSD, ζ, and CA magnitude. Results indicate that PBEO-loaded guar coatings significantly enhanced PC and antioxidant capacity, reduced weight loss and PV, maintained TSS and firmness, and retarded loss of TA. 200 μL PBEO-loaded guar at 0.25% effectively inhibited <i>Penicillium</i> growth, while 50 μL demonstrated optimal control of both <i>Aspergillus</i> and <i>Penicillium</i>. The PBEO-loaded guar coating extended pistachio shelf life from 30 to 60 days based on microbial counts.