Study On Vacuum Frying Technology Of Potato Chips And Quality Controlling Investigation

Low temperature vacuum fried potato chips is a new type food employed by low temperature vacuum fried technology.Compared with other leisure food,it has the advantages of low fat,low calorie,rich diet,good taste and flavor,favored by the majority of consumers.In this paper,we studied the pretreatment,vacuum frying and food storage conditions in the process of food production,in order to screen out the best technological conditions,so as to produce potato chips with good taste and not conceal the flavor of potato itself.The main work is as follows:1.Through the analysis it is concluded that the best color need by citric acid,sodium bisulfite,Vc compound use three kinds of Browning inhibitors,experimented with different concentration ratio,studies the potato by 0.5%,citric acid,sodium bisulfite1.5‰,the Vc l.5‰distribution proportion of the best sensory quality and color and lustre degree,and potatoes of fat,moisture content,water activity is not affected.This paper mainly analyzes the specific application methods of hot,freezing and other related methods in the process of vacuum frying,and the correlation between different intervention methods and the quality of potato chips.It can be seen from this study that the hot treatment of potato will affect its water loss,while the freezing treatment will have a small impact on its water loss.In addition,the infiltration process also has an impact on the reduction of moisture.The research shows that the moisture of potato chips will decrease with the increase of the infiltration concentration.The freezing process has little influence on the fat content of potatoes.However,for hot stamping,the fat content is high for a shorter time,while the fat content will decrease for a longer time.The fat content is the lowest after seven minutes at 80?.2.Under the condition of vacuum degree of 0.02?0.04MPa,the single factor test of vacuum frying temperature and frying time was carried out.After frying,the frying basket was lifted and the single factor test of centrifugal speed and centrifugal t ime was carried out.By measuring and comparing the sensory score,oil content and moisture content of the products,the optimal level of the technological conditions of vacuum frying was determined:the temperature range of vacuum frying was 95?100?,the time of vacuum frying was 9?15min,the centrifugal speed was about 300r/min,and the time of centrifugation was 6?8min.The variation of moisture and oil content of potato chips in the process of vacuum frying was studied according to the first-order kinetic law,and the nonlinear regression equation between the moisture and oil content of samples and the time of vacuum frying was obtained.The results show that water content plays a key role in the oil absorption process of potato chips,and the oil content and water content of potato chips have a very significant negative correlation.In addition,response surface regression model was established to analyze the optimal process parameters of vacuum fried potato chips:frying temperature 94?,frying time 10.9min,centrifugal speed312.9r/min,and the lowest oil content was predicted to be 17.26%.3.The effects of different storage conditions on the quality of potato chips were studied.The results showed that with the increase of temperature,the moisture content increased in one month,while the content of V_C decreased.The fat content had little change at different temperatures.Through the study of isothermal hygroscopic law,it can be concluded that compared with temperature,the effect of water activity on the equilibrium moisture content is more important.On this basis,by measuring the related physical and chemical indicators of the oil contained in potato chips,the results showed that the acid value,peroxide value and carbonyl value of the oil in potato chips increased gradually with the extension of the storage time.According to the prediction method of shelf life,potato chips could be stored at 60?for about 7 days.The shelf life of potato chips at 5?,25?and 40?is predicted to be 13.4 months,9.2 months and 5.4 months,respectively,by measuring the oil oxidation time of potato chips and combining with the first order kinetic exponential equation.