Study comprehensively analyzed how key drying parameters (temperature, duration, air velocity, and moisture content) affect saffron’s bioactive compounds: crocin, picrocrocin, and safranal. Findings indicated that both high (70–110 °C) and low (< 60 °C) temperatures were generally found to enhance these compounds, with over 50% of studies supporting this trend. However, prolonged drying durations negatively affected metabolite retention. Air velocity increased crocin levels but reduced safranal concentration, while lower moisture content boosted crocin yet stabilized or diminished picrocrocin and safranal. Among drying methods, hot air drying (HAD), infrared drying (IR), and oven drying (OD) yielded the highest metabolite concentrations, whereas freeze drying (FD) and microwave drying (MWD) were the least effective. A major insight from this study was that dryer design alone cannot determine optimal conditions; instead, advanced techniques such as TOPSIS and meta-analysis provide more accurate evaluations. TOPSIS ranking highlights IR, photovoltaic-thermal (PV-T), and refractance window (RW) dryers as the most effective, with RW excelling in reducing drying duration. Despite extensive research on low-temperature drying, the effects of high-temperature drying remained underexplored, particularly for picrocrocin and safranal. Furthermore, the role of air velocity and moisture content in metabolite stability required further investigation. The present study bridged existing knowledge gaps by integrating both descriptive non-statistical evaluation and meta-analytical approaches. Its findings paved the way for future innovations, including hybrid drying systems, real-time monitoring, and machine learning-driven optimization. By refining drying techniques, the saffron industry can achieve higher quality, efficiency, and sustainability, ensuring long-term competitiveness in global markets.

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