Balancing yield and stability: optimizing leaf pigment extraction to minimize chlorophyll degradation

Methanol proved to be the most efficient solvent for pigment extraction using pressurized liquid extraction, while extraction temperature and static time critically influenced both the yield and stability of the pigments. Photosynthetic pigments, particularly chlorophylls and carotenoids, are central to plant physiology and are increasingly valued for their nutritional and functional benefits in the human diet. However, accurate quantification of these compounds remains challenging due to their sensitivity to degradation during sample preparation. The present study aimed to optimize extraction protocols for chlorophylls (a, b) and two major leaf carotenoids (β-carotene and lutein) from fresh parsley leaves, with a focus on balancing yield and stability. The effects of solvent type, extraction temperature, static extraction time, and number of extraction cycles were systematically evaluated using pressurized liquid extraction (PLE) and compared with conventional solvent extraction. High-performance liquid chromatography with diode-array detection was employed for quantitative analysis. Methanol consistently outperformed acetone as a solvent, yielding significantly higher recoveries of both chlorophylls and carotenoids. Optimal performance was observed under two distinct PLE conditions: three 5-min cycles at 100 °C, which provided a balanced recovery of pigments with low chlorophyll a degradation, and a single 5-min extraction at 125 °C, which maximized carotenoid yields but accelerated chlorophyll a breakdown. Extractions at 150 °C and prolonged dimethyl sulfoxide treatment resulted in substantial chlorophyll a degradation, highlighting the need for carefully controlled conditions. Compared with conventional solvent extraction, PLE reduced extraction time and offered superior yields for β-carotene and lutein. The results underscore the trade-offs inherent in pigment extraction and demonstrate that PLE, when optimized, provides a robust and efficient tool for evaluating the nutritional quality of fresh leafy vegetables. These findings may serve as a methodological foundation for both research applications and the development of more reliable, industry-relevant quality assessment protocols.