Analysis of the oil-absorption process in deep-fat fried potato cylinders (frying temperatures of 155°C, 170°C, and 185°C) allowed to distinguish 3 oil fractions: structural oil (absorbed during frying), penetrated surface oil (suctioned during cooling), and surface oil. Results showed that a small amount of oil penetrates during frying because most of the oil was picked up at the end of the process, suggesting that oil uptake and water removal are not synchronous phenomena. After cooling, oil was located either on the surface of the chip or suctioned into the porous crust microstructure, with an inverse relationship between them for increasing frying times.

The oil-absorption capacity of different restructured potato chips during deep-fat frying was investigated. Low-leach potato flake was chosen as the major ingredient, whereas native and pregelatinized potato starches were studied as complementary ingredients. Results showed that oil absorption increased significantly when reducing product thickness in all products. Interestingly, it was found that the product containing native potato starch as an ingredient picked up the lowest amount of oil when sheeted into a thick chip, whereas it absorbed the largest amount of oil when sheeted into a thin chip. Those findings were mainly attributed to crust microstructure development as revealed by electron microscopy and confocal microscopy.