Postharvest gas treatments for almonds: Efficacy, lipid oxidation and practical implications for quality preservation
Postharvest management of high-oil nuts such as almonds must reconcile disinfestation with preservation of lipid quality. Rigorous, life-stage–resolved comparisons that quantify both insect control and almond quality remain scarce. An integrated benchmark was conducted on shelled almonds infested with Tribolium castaneum (Herbst, 1797; Coleoptera: Tenebrionidae) and Oryzaephilus surinamensis (Linnaeus, 1758; Coleoptera: Silvanidae) (larvae and adults), evaluating three gaseous treatments: ozone (O3; 500 ppm, 6 h), phosphine (PH3; 1 g m−3, 7 d), and an ECO2Fume CO2-based treatment (50 g m−3, 3 d). Across five independent replicates, biological endpoints (mortality, fecundity, nutritional indices, energy conversion index, and almond weight loss) were quantified alongside a chemical quality panel (proteins, Thiobarbituric acid reactive substances, free fatty acids, proximate composition, minerals, total phenolics, oil). PH3 achieved the highest and most consistent mortality (≈89–99%) and markedly suppressed feeding and progeny while inducing only minor immediate changes in lipid-oxidation indices. The CO2-based treatment delivered comparable control (≈86–94%) with modest chemical shifts and pronounced reductions in consumption and weight loss. By contrast, O3 produced only moderate insecticidal effects (≈55–66% mortality) but caused clear oxidative deterioration (ΔPV = +2.31; ΔTBARS = +0.90; ΔFFA = +0.145; total phenolics ≈ −15.9%). Multivariate synthesis of Principal component analysis (PCA) and Canonical variate analysis (CVA) indicated that a primary axis dominated by oxidation markers explained ∼88% of treatment variance (Can1; P < 0.001), whereas a secondary axis captured insect-response variation (∼11%; Can2; P < 0.001). Findings delineate a practical trade-off between pest suppression and lipid-quality preservation and support prioritization of PH3 or CO2-based approaches over ozone for high-oil commodities unless oxidative impacts can be mitigated.
https://doi.org/10.1016/j.jspr.2026.102969
Improving the protective features of fresh pistachios against chilling injury and enzymatic discoloration through the synergistic application of Ajwain seeds essential oils (Trachyspermum ammi) and carboxymethylcellulose
The thymol fraction present in Ajwain seed essential oil (Aj) exhibits antioxidant properties that can mitigate horticultural crop losses after harvest. This study was designed to analyze the influence of carboxymethyl cellulose (CMC 0.5 %) in combination with three concentrations of Aj (400, 800 and 1200 mg L−1) on fresh ‘Ahmad Aghaei’ pistachio fruits. After drying at ambient temperature and packaging, the fruits were stored at 2 ± 1 °C with 85 ± 2 % relative humidity. The combined treatments of CMC 0.5 % with Aj 400 and 800 scientifically controlled weight loss, chilling injury, decay, hull H2O2 levels, and enzyme activity compared to the control sample over an extended storage duration. The highest levels of chilling injury, decay and POD activity were observed in the samples treated with distilled water (control), while the lowest sensory scores were also recorded in the same treatment. Although CMC + Aj 1200 showed the highest chlorophyll content, it resulted in a negative effect on the aroma index. Combined treatments resulted in the highest lipid and hue index at the end of the storage period. In the control sample, the phenolic compounds decreased by 54 %, whereas the pistachios treated with CMC + Aj 800 experienced a 31 % decrease in phenolics. Overall, the application of CMC + Aj 800 successfully preserved the quantitative and qualitative attributes of Ahmad Aghaei pistachios for up to 50 days.
https://doi.org/10.1016/j.jspr.2025.102858