Understanding how pulsed electric field pretreatment affects microstructural changes and starch digestibility in air-fried French fries

Abstract

Direct air-frying of raw potato strips usually leads to an undesirably hard texture and poor sensory qualities. Although blanching pretreatment improves the texture, it increases starch digestibility and requires excessive processing time and energy consumption. In this study, we evaluated the potential of pretreatment with a pulsed electric field (PEF) as an alternative for enhancing the quality of air-fried French fries. Scanning electron microscopy revealed that PEF created a porous matrix structure, enhancing water evaporation and heat transfer during air-frying. Compared with untreated samples, PEF pretreatment at 0.5 kV/cm significantly reduced the hardness from 4,979.87 to 3,232.34 g, yielding a softer texture. Notably, compared with thermal blanching, PEF pretreatment significantly increased the resistant starch (RS) content from 17.23% to 24.59%, indicating reduced starch digestibility. Fourier transform infrared spectroscopy and X-ray diffraction analyses confirmed that PEF caused less damage to short- and long-range structures than blanching, thereby enhancing their resistance to enzymatic hydrolysis. This study provides the theoretical foundation and technical guidance for applying PEF technology to develop fried foods with healthier profiles and optimal textural properties.

Keywords

Pulsed electric field (PEF) / Air-fried / French fries / Digestibility

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