Pulsed Electric Fields-Assisted Drying and Frying of Fresh Zucchini

The objective of this work was to evaluate the potential of Pulsed Electric Field application on the enhancement of air-drying and frying kinetics of zucchini in terms of quality of final zucchini products. PEF-caused electroporation could enhance drying process, facilitating moisture removal with reduced energy consumption, or soften the surface, leading to fried products with reduced oil content. Fresh whole zucchinis (Cucurbita pepo) were PEF treated at 0.5-1.5 kV cm(-1) electric field strength for up to 0.5 s, achieving a cell disintegration index in the range of 0.12 to 0.77 (0.5-110 kJ kg(-1)). Drying experiments of zucchini slices were carried out at mild drying temperatures 40-70 degrees C. The moisture diffusion coefficients D-eff of all studied samples were compared. Deep frying of untreated and PEF treated (1.5 kV cm(-1), 500 pulses, Z equal to 0.6, PEF energy input 8.2 kJ kg(-1)) zucchini slices was carried out at temperatures 150-170 degrees C for 0-12 min. Water loss, oil uptake and browning index were determined for all studied samples. The obtained results indicate a potential benefit of PEF on drying rates of zucchini tissues. At low drying temperatures, PEF treated samples increased the effective moisture diffusivity D-eff up to 35%, reducing the corresponding drying time up to 25 min and leading to energy savings of 169 MJ kg(-1) compared to the untreated sample. In addition, PEF treatment led to final fried zucchinis with reduced oil content up to 36% compared to untreated samples while maintaining the same levels of desirable brown color.

Automated summary

The study evaluated the potential of Pulsed Electric Field for improving the drying rates of zucchini tissues and reducing oil content in fried products, while maintaining desirable color. PEF treatment at low temperatures significantly increased effective moisture diffusivity and led to energy savings in drying process.