Effect of multistage process on the quality, water and oil distribution and microstructure of French fries

The production of French fries is a multistage process (blanching, pre-frying, freezing and final frying). Pre-stage processing can result in drastic changes related to the quality of the final product. In this study, we investigated the effect of multistage process on quality properties, water and oil distribution and microstructure of fries prepared with different oils. Results showed that freezing treatment had little effect on water and oil content, color and volumetric shrinkage of pre-fried fries. Final fried fries exhibited drastic changes involved in the content and status of water and oil, color, texture, volumetric shrinkage and microstructure compared with other processing stage. Besides, magnetic resonance imaging visualized a thicker crust in finish-fried fries. Among all the oils, fries fried in high-oleic sunflower oil showed the best mouthfeel. This will provide a theoretical guidance for food enterprise to produce high-quality French fries.