Color development and acrylamide content of pre-dried potato chips

The objective of this work was to study the development of color formation in pre-dried potato slices during frying and acrylamide formation in the final potato chips. Color measurement was done by using an inexpensive computer vision technique which allowed quantifying representatively and precisely the color of complex surfaces such as those of potato chips in L∗a∗b∗ units from RGB images. Prior to frying, potato slices (Desirée variety, diameter: 37 mm, width: 2.2 mm) were blanched in hot water at 85 °C for 3.5 min. Unblanched slices were considered as the control. Slices of the same dimensions were blanched as in the previous step, and then air-dried until reaching a moisture content of 60% (wet basis). These samples were called pre-dried potato slices. Potato slices were fried at 120 °C, 140 °C, 160 °C and 180 °C until reaching moisture contents of ∼1.8% (total basis) for color quantification. Acrylamide concentration was determined only in final chips fried at 120 °C, 150 °C and 180 °C and compared with that of two brands of commercial chips produced in Chile (Moms and Frito Lay). Color values in L∗a∗b∗ units were recorded at different sampling times during frying at the four mentioned temperatures using the total color difference parameter (ΔE). Pre-drying did not affect the color of potato chips considerably when compared against blanched chips; however when fried at 180 °C, pre-dried potato chips present 44%, 22%, 44% lower acrylamide content than that of the control, Moms and Frito Lay chips, respectively.