Distribution and Quantification of Oil Uptake in French Fries Utilizing a Radiolabeled ¹⁴C Palmitic Acid

A novel method utilizing ¹⁴C palmitic acid for image analysis and liquid scintillation for quantifying oil uptake of French fries undergoing deep-fat frying is described. Radiolabeled computerized image analysis of the fried product furnished comprehensive visual information on the distribution and localization of oil uptake which was limited to the crust. A significant high linear correlation (R² = 0.977; P < 0.001) was found between oil uptake measured by liquid scintillation and differential scanning calorimetry, and between liquid scintillation and radiolabeled imaging (R² = 0.861; P < 0.001). The high specificity and sensitivity of the method allows quantifying uptake of very low oil concentrations ranging from several milligrams. Oil quantification via liquid scintillation was more sensitive than image analysis and requires up to 3 order of magnitude lower concentration of the radiolabeled marker. The low concentration and inherent stability of the radiolabeled chemical make this technique uniquely suitable for studying oil uptake mechanism during deep-fat frying of foodstuffs.