Threshold Microsecond Pulsed Electric Field Exposures for Change in Spinach Quality

Area of Science:

• Food Science and Technology
• Biophysics
• Plant Physiology

Background:

• Pulsed electric fields (PEFs) are utilized for food processing, particularly in pre-treatments like drying.
• Maintaining food product quality, including color and water content, is crucial for consumer acceptance.
• Electroporation, induced by PEFs, involves pore formation in cell membranes, with varying effects on tissue integrity.

Purpose of the Study:

• To determine the threshold of PEF exposure for electroporation viability in spinach leaves while preserving tissue integrity.
• To investigate the relationship between PEF parameters and the resulting changes in spinach leaf quality.

Main Methods:

• Spinach leaves were exposed to PEFs with varying numbers of consecutive pulses (1, 5, 50) and pulse durations (10 μs, 100 μs).
• A constant field strength of 1.4 kV/cm and pulse repetition of 10 Hz were maintained.
• Evaluated changes in leaf color and water content to assess food quality post-exposure.

Main Results:

• Pore formation alone did not significantly alter spinach leaf food quality (color, water content).
• Significant changes in exterior tissue integrity were only observed upon cell death, induced by high-intensity PEF treatments.
• PEF treatments can be applied up to the point of cell inactivation without diminishing consumer-perceived quality.

Conclusions:

• Reversible electroporation using PEFs is a viable treatment for leafy greens, maintaining quality for consumer products.
• This study provides critical parameters for utilizing PEF technology in food processing to avoid quality degradation.
• Findings support the future application of PEF-based technologies in the food industry.