Kinetics of Potato Color and Texture Development during Baking, Frying, and Microwaving with the Addition of Liquid Smoke

ABSTRACT:  The rate of color and texture development in par-fried French fries coated with liquid smoke and thermally processed was determined. Liquid smoke containing 8% to 11% carbonyls was diluted to 30% and applied to 1 side of French fries at 0%, 1%, 3%, or 5% by weight. The fries were immersion fried at 190.6 °C for 4 min, microwaved (900 watts) for 4 min, or baked at 190.6 °C for 20 min. Color and texture measurements were recorded at intervals during processing. Liquid smoke increased the rate of browning in French fries. Browning followed pseudo zero-order kinetics, with the a value, Browning index, and total change in color (ΔE) showing the best fit. When liquid smoke was added in high concentrations the reaction rate did not increase as more liquid smoke was added because the carbonyls were no longer limiting the rate of Maillard browning. The rate of color development in French fries was also affected by the thermal processing method. Frying developed color at the fastest rate, followed by microwaving and baking. Although liquid smoke increased the rate of color development in French fries, it did not affect French fry texture. Through sensory testing, it was determined that liquid smoke can be used to improve the color of microwaveable French fries without affecting French fry flavor or texture.