Oil Absorption of Potato Slices Pre‐Dried by Three Kinds of Methods

Abstract

During frying process, pre‐drying affects oil content of samples, but whether and how pre‐drying affects oil absorption remains unclear. In this study, the effect of pre‐drying, including hot air (HD), vacuum microwave (VMD), and infrared (IRD), on the water and oil state breaking force of fried potato slices is investigated. The results show that pre‐drying of HD, VMD, and IRD can effectively hinder the oil absorption of fried potato slices and have no negative effects on its breaking force. Compared to the control, the total oil content (TOs) of potato slices with initial water content of 50 g 100 g−1 (wb) pre‐dried by HD or VMD or IRD reduces by 47.29%, 46.46%, and 39.20%, respectively. Penetrated surface oil (PSO) is the main factor which attributed to TOs reduction of fried potato slices after pre‐drying. Compared to the control, PSO of potato slices pre‐dried by HD, MVD, and IRD decreases by 61.53%, 58.62%, and 55.38%, respectively. Low field nuclear magnetic resonance shows that pre‐drying can significantly shorten the transverse relaxation time (T2) and decrease the proportion of the water from the vacuole (M23) of potato slices (p < 0.05). Confocal laser scanning microscopy and stereomicroscope images show that oil content and distribution of fried potato slices are different due to the changes of initial water state produced by pre‐drying.Practical Applications: Low‐oil foods could be helpful to decrease the incidence of obesity, high blood pressure, and coronary disease. Making sure how the pre‐drying affects the oil absorption behavior and quality is important to process the low‐oil potato slices that still retain the desirable characteristics. The research on the effects of pre‐drying on oil absorption could contribute to the exploration of oil reduction mechanism and help to process the low‐oil and high quality product.The effect of pre‐drying on the water evaporation and oil absorption, and breaking force of fried potato slices, are investigated, and results show that pre‐drying reduced the oil content and PSOs is the main factor. However, it has no negative effects on its breaking force. The pre‐drying changed moisture states and water distribution meanwhile, affect the oil fraction and distribution.