Impact of pre-treatment with pulsed electric field on drying rate and changes in spinach quality during hot air drying

This study aimed to compare the impact of a pulsed electric field (PEF) with that of hot water (HW) and control (CONT) on subsequent drying rate, shrinkage, and quality parameters (degradation of L-ascorbic acid (L-AsA) and color) of spinach during hot air drying. PEF pre-treatment was conducted in 2.8 kV/cm of the electric field strength and 27.1 kJ/kg of the specific input energy. We found that the drying rate for PEF sample was increased compared with CONT and HW samples due to the inhibition of shrinkage during drying. Further, degradation of L-AsA and the surface color in PEF sample were significantly inhibited compared with HW sample, therefore we confirmed that PEF treatment could resolve the elution of water-soluble components caused by HW treatment. These findings showed that pre-treatment with PEF is suitable for reducing drying time and producing high-quality dried spinach.

Automated summary

This study compared the effects of pulsed electric field (PEF), hot water (HW), and control (CONT) on drying rate, shrinkage, and quality parameters of spinach during hot air drying. Results showed that PEF treatment increased drying rate, inhibited shrinkage, and reduced degradation of L-ascorbic acid (L-AsA) and color compared to HW treatment. This suggests that PEF pre-treatment is effective in reducing drying time and producing high-quality dried spinach.