The effect of air frying and deep fat frying on the cellular structure of doughnut was studied in order to find out how the different frying conditions impacted their structures. The porosity and characteristics of doughnut crumb Pore were quantified and analyzed using Image J software. Additionally, tortuosity was measured using MATLAB based on gray-weighted distance transform algorithm. The porosity profile of the doughnut slice exhibited differences between the air fried and deep fat fried samples. This can be explained by the non-uniformity in the processing conditions resulting in different areas with varying porosities. In air fried doughnuts, lower porosity (54 ± 1.8%) and cell circularity were found in the bottom of the slice due to compression forces during frying. However, the upper zone of the slice was more porous (66 ± 2.4%) because of expansion but deep fat fried doughnut had a homogenous structure. Results of tortuosity confirmed that relative path length was lower along the width related to the expansion of the doughnut during frying. Additionally, the relative path length through the pores was shorter in the air fried doughnuts than the deep fat fried ones. Oil absorption in air-fried doughnuts (12.8 ± 1.1%) was lower than deep fat fried samples and (32 ± 0.9%). Crust thickness and crust parting from crumb were also lower in air fried doughnuts.

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