Air Jet Impingement-Assisted Air Frying of Potatoes: Oil Absorption, Lipid Oxidation and Acrylamide Formation for Improved Nutritional Quality.

Abstract

Air jet impingement technology has attracted increasing attention in food processing because of its high heat transfer efficiency, which enables rapid heating and improved control of thermally induced chemical reactions. In the present study, frozen French fries and potato wedges were processed using a prototype air jet impingement oven integrated with an air-frying function and systematically compared with conventional deep-fat frying and convection oven cooking. The effects of processing temperature, air velocity, tray position, and cooking/frying time on product quality and food safety-related parameters were evaluated using response surface methodology. The investigated quality attributes included moisture content, color development, texture, oil absorption, lipid oxidation (TBARS), sensory acceptance, energy consumption, acrylamide formation, and microstructural characteristics. Compared with deep-fat frying, air jet impingement-assisted air frying significantly reduced oil content and oil absorption in both French fries and potato wedges while maintaining acceptable textural and sensory properties. The optimum processing conditions were determined as 160°C, 15 m/s, and 15 min for French fries, and 200°C, 15 m/s, and 5 min for potato wedges. Under optimized conditions, acrylamide formation was markedly suppressed, and the acrylamide content of potato wedges remained below the limit of quantification (LOQ = 0.1 mg/kg), as determined by LC-MS/MS analysis. TBARS values and oil absorption increased with increasing air velocity and cooking/frying time; however, optimized impingement conditions minimized lipid oxidation and improved overall product quality. Under optimum air jet impingement conditions, TBARS values were maintained at low levels, reaching 1.812 mg malonaldehyde/kg product for French fries and 2.805 mg malonaldehyde/kg product for potato wedges, corresponding to approximately 43.4% and 16.3% lower lipid oxidation than deep-fat frying, respectively. In addition, the air jet impingement oven reduced oil absorption by 36.2% in French fries and 38.8% in potato wedges, while decreasing energy consumption by approximately 80% compared with deep-fat frying. Improved microstructural properties were also observed. Air jet impingement-assisted air frying represents a promising processing strategy for producing potato products with enhanced nutritional quality, reduced formation of harmful thermal contaminants, and improved energy efficiency within a food safety-oriented process control framework.