The Pretreatment Technology Of Vacuum Fried Potato Chips

In recent years,people have drawn more attention to the vacuum frying featured the excellent qualities and extensive adaptability to material.The chips made of vacuum fried vegetables and fruits were developed rapidly because of their natural color, crispness and crude components.However,because of the complexity at vacuum frying mechanism,its developments mainly rely on practice time after time,thus there are some defects in higher fat content and poorer qualities.In this paper,we've chosen potato as the representation for raw materials of fruit and vegetable chips,studied on the rules of quality changes of vacuum frying product,which was affected by the different pretreatment conditions(color-protecting,branching,freezing,infiltration and vacuum micro-wave drying),and compared the influences of the vacuum frying processing with the atmospheric frying processing on fried potato chips quality, confirmed a better pretreatment process.The first part of this paper outlined development of the processing of fruit and vegetable chips and vacuum frying technology.The second part studied the effects of color-preservation technology on quality of vacuum fried potato chips.Citric acid, sodium bisulfite and V_C were selected as the browning restrainers in the experiment. With different concentrations,the optimum technology condition for vacuum fried potato chips' color-preservation was determined.The results showed that the potato chips after the pretreatment of the forth color-preservation,that is the citric acid of 1‰,sodium bisulfite of 1‰and V_C1.5‰,have the best sensory qualities and color values.In addition,it has no significant effects on the water content,water activity and the fat content.Based on the comparison of the influences of some pretreatments such as branching,freezing,infiltration and vacuum micro-wave drying on fried potato chips' quality,the paper confirmed a better pretreatment process in the third part.Experimental results showed that the freezing parameters do not affect fried potato slices' moisture content mainly,while blanching temperature is the main influencing factor.The infiltrated potato slices,with the increasing concentration of infiltration,its moisture content reduced gradually.The freezing parameters have little impact on the fried potato slices' fat content.Shorter the blanching time,higher the fat content of the fried potato slices,and the longer the blanching time,lower the fat content of the fried potato slices.Blanched at the temperature of 75℃,and 6 min we got the lowest fat content.The higher the concentration of infiltration,the lower of the fat content of the fried potato slices.Compared with the control group,in the same frying time,the vacuum micro-wave dried fruit and vegetable chips have less water and fat content.PartⅣresearched on the pretreatments of color-preservation, blanching,freezing's impacts on the atmospheric frying processed fried potato chips quality,contrasted the technology conditions of vacuum fried potato slices with that of the atmospheric fried potato slices,fully embodied vacuum frying process' advantages.