Assessment of postharvest heat treatment impact on insecticidal efficacy and quality parameters in commercial dried fruits

This study evaluates the efficacy of postharvest heat treatment as a sustainable alternative to chemical fumigation for disinfestation of commercial dried fruits, while simultaneously assessing its impact on product quality. Corinthian currants, Medjool dates, and Turkish dried figs were artificially infested with Oryzaephilus surinamensis (L.)(Coleoptera: Silvanidae) and Plodia interpunctella (Hübner)(Lepidoptera: Pyralidae) and exposed to temperatures of 35 °C, 45 °C, and 55 °C for 2, 6, and 24 h. Complete adult mortality and reproductive suppression for both species was achieved at 55 °C in all commodities. Commodity type significantly influenced mortality, likely due to differences in fruit structure and moisture content affecting heat transfer. Sensory evaluation revealed that exposures up to 45 °C did not significantly alter appearance, aroma, or texture, while treatments at 55 °C for prolonged durations caused minor declines, particularly in figs. Analysis of bioactive microconstituents showed that moderate heating (35–45 °C) enhanced total flavonoid content and, in some cases, total phenolic content, whereas exposure at 55 °C occasionally led to lower values compared to those obtained under moderate heating. LC–MS profiling confirmed temperature-dependent increases in specific phenolic acids (e.g., vanillic, p -hydroxybenzoic) and flavonols (e.g., quercetin, kaempferol), while HPLC-DAD-UV analysis revealed that 5-hydroxymethylfurfural remained at trace or non-detectable levels across all treatments. This key finding serves as a robust indicator of the absence of detrimental sugar degradation or advanced Maillard reactions, proving that the proposed thermal conditions effectively preserve the dried fruit chemical integrity. Overall, the findings demonstrate that carefully optimized heat treatments can ensure complete adult mortality and progeny production suppression and preserve the nutritional and sensory quality of dried fruits, supporting their implementation as an effective, residue-free, and environmentally compatible postharvest disinfestation method.