Evaluation of effect of vacuum frying on textural properties of food products

Vacuum frying (VF) is known as the most popular food processing method for the production of ready-to-eat snacks. It includes simultaneous mass and heat transfer in very low temperature and frying period to provide higher qualitative products. The quantity of oil used for frying is less in the vacuum frying method as compared to other frying methods. Numbers of physical, chemical, and structural changes occur during the frying process by evaporation of moisture, obstruction of oil movement, gelatinization of starch, denaturation of protein structure, and solubilization of pectin cells. These changes lead to textural modification of fried products and VF successfully enhances the textural properties at optimum process parameters which are according to the consumers' acceptance. In this context, this review is an update of the VF, showing the effect of different process parameters on the improvement of the texture of the fried snacks. Additionally, the mechanism behind the development of texture due to VF has been described in detail along with proper figures. Also, a comparative study of VF and atmospheric conventional frying on the increment of textural characteristics in various food materials starting from fruits and vegetables to fish and meat products have been highlighted. Moreover, to enhance the food texture during VF, several pre/post frying treatments are carried out which have been taken into discussion. Further, some novel techniques adopted along with VF, which influence highly on texture development of food materials, have been mentioned.