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

Area of Science:

• Agricultural Science
• Analytical Chemistry
• Food Science

Background:

• Photosynthetic pigments (chlorophylls, carotenoids) are vital for plant physiology and human nutrition.
• Accurate quantification is hindered by pigment degradation during sample preparation.
• Optimizing extraction is crucial for assessing nutritional quality.

Purpose of the Study:

• To optimize extraction protocols for chlorophylls (a, b) and carotenoids (β-carotene, lutein) from parsley leaves.
• To evaluate the impact of solvent, temperature, and time on pigment yield and stability.
• To compare pressurized liquid extraction (PLE) with conventional methods.

Main Methods:

• Pressurized liquid extraction (PLE) and conventional solvent extraction were employed.
• Methanol and acetone were tested as solvents.
• Extraction temperature, static time, and cycles were systematically varied.
• High-performance liquid chromatography with diode-array detection (HPLC-DAD) was used for quantification.

Main Results:

• Methanol yielded significantly higher chlorophyll and carotenoid recovery than acetone.
• Optimal PLE conditions varied: 3 cycles at 100°C balanced yield and stability; 1 cycle at 125°C maximized carotenoids but degraded chlorophyll a.
• High temperatures (150°C) and prolonged DMSO use caused substantial chlorophyll a degradation.
• PLE reduced extraction time and improved β-carotene and lutein yields compared to conventional methods.

Conclusions:

• Methanol is the most efficient solvent for pigment extraction via PLE.
• Extraction temperature and static time critically influence pigment yield and stability.
• Optimized PLE offers an efficient method for assessing the nutritional quality of leafy vegetables.
• Findings provide a foundation for research and industry quality assessment protocols.