The effect of fatty acid composition on the oil absorption behavior and surface morphology of fried potato sticks via LF-NMR, MRI, and SEM

The oil absorption behavior of food during deep-frying greatly affects the quality of the final fried food. However, the research on oil absorption lacks comprehensive analysis and understanding. In this paper, the oil content, moisture content, oil distribution, and microstructure changes of fried potato sticks were explored via traditional method as well as advanced instruments, including low field nuclear magnetic resonance, magnetic resonance imaging, and scanning electron microscopy, and the differences and their corresponding relevance were analyzed and discussed. Results showed that the fatty acid composition of oils is highly related to their viscosity and surface tension, influencing the oil uptake of final products. Oil content was positively correlated with the peak height in the range of 20 ms–1000 ms (r(2) = 0.99348 at 140 ℃, r(2) = 0.99060 at 180 ℃). Oil distribution and microscopic morphology of the fried strips were affected by oil type and temperature.