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

Abstract

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 (R 2 = 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 (R 2 = 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. Keywords: Deep-fat frying; radiolabeled; liquid scintillation; image analysis; oil uptake.

Microstructural evaluation of deep-fat fried chicken nugget batter coating using confocal laser scanning microscopy

“…This signifies that fat content decreases from the surface towards the core of the sample. Some authors have asserted that fat absorption in fried foods is limited to the crust (Bouchon et al, 2003;Keller et al, 1986;Lamberg et al, 1990;Saguy et al, 1997). Bouchon and Aguilera (2001) showed a 3-D image of fried potato obtained using stack of 2-D images obtained from CLSM.…”

Direct observation of the surface structure of French fries by UV–VIS confocal laser scanning microscopy

“…Some author studied oil uptake at the scale of the microstructure. Firstly, oil uptake was localized in the outer crust surface of fried products thanks to the use of stained or radiolabeled oils Keller, Escher, & Solms, 1986;Saguy, Gremaud, Gloria, & Turesky, 1997). During the frying of French fries, oil impregnation was shown to increase with the thickening of the crust until 1 mm (Lamberg, Hallstroem, & Olsson, 1990).…”

Oil Uptake by Potato Chips or French Fries: A Review

“…It is only when the capillary is taken off from the frying medium; the oil is sucked inside after cooling and water vapor condensation. Various studies have explained that capillaries do not play a major role in the oil absorption phenomena …”