Study On The Frying Performance Of Different Oils And The Formulation Of Special Frying Oil

Frying has a history of thousands years as a traditional way of cooking,Fried food has become popular in European and American countries because of its special flavour,china’s frying industry is in the rising stage of development.oil has been geartly developed as a medium of fried ingredients during frying,Therefore,the performance and quality of oil during the frying are getting more and more attention,and different oils has different quality and performance,no oils can be used as ideal frying oil,so we put forward a concept of special frying oil.The research on frying special oil is still in its infancy in China,Therefore,promoting the research of frying performance of different oils and special frying oil are of significance to frying industry.This research studied the preparation of special frying oil by palm oil,soybean oil,rapeseed oil and a kind of grease with good frying performance,which based on the stability of frying oil、frying life、the ratio of fatty acid and the value of PUFA/SFA(the content of PUFA/the content of SFA),and studied the performance of special frying oil,we found the special frying oil had long frying time,reasonable fatty acid composition and good frying stability,at the same time,the lower the value of PUFA/SFA,the longer the frying life of oil.First,we researched the frying performance of three kinds of oil with high yield and low price: palm oil,soybean oil and rapeseed oil,and researched and evaluationed the frying quality and performance of three oils by indicators of acid value,peroxide value,polar components,color and frying quality of french fries,etc.Palm oil had little color change,long frying life,good fried appearance of french fries,the low loss rate of tocopherol and PUFA,low oil absorption rate of french fries,high temperature of fumes,and its foam happened late during frying,It has advantages over soybean oil and rapeseed oil.the frying life of palm oil,soybean oil and rapeseed oil was about 29 h,16h and 14.5h respectively,the frying life of palm oil was 44.8% and 50.0% longer than that of soybean oil and rapeseed oil,respectively.palm has obvious advantages.The changes of color and acid value of soybean oil were smaller than rapeseed oil,and the performance and oil absorption rate of soybean oil were better than rapeseed oil,the loss rates of tocopherols in two oils were similar.Generally,the performance and quality of palm oil was best among three oils,soybean oil is better than rapeseed oil.Secondly,the performance and quality of corn oil,peanut oil,sunflower oil,high oleic peanut oil were researched.Choosed a kind of oil as the auxiliary material for special frying oil based on frying life,frying stability,fatty acid composition and physicochemical index,etc.This research found that peanut oil and high oleic peanut oil showed good frying quality and performance during frying,high oleic had longest frying life,about 27.5h,which was 1.5 h,10.5 h and 17.5 h longer than peanut oil,corn oil and sunflower oil,respectively.The acid value of peanut oil and high oleic acid peanut oil increased by 1.93 mg/g and 2.37 mg/g respectively in the frying process,the changes were larger than that of corn oil and sunflower oil,but they did not exceed the national standard limit.The time of occurrence of foam was simillar to the valid time of oils during frying.The peroxide value of sunflower oil was at a high level.The oil absorption rate of french fries in peanut oil was 9.92%,and the other three oils were similar.The loss rates tocopherol of sunflower oil was 96.3%,followed by corn(82.3%),high oleic peanut oil(78.4%),peanut oil(63.9%).The frying performance of the four oils was evaluated comprehensively,high oleic peanut oil = peanut oil > corn oil > sunflower seed oil.Considering the price factor,frying performance and popularity,peanut oil is the auxiliary oil for special frying oil.The research showed that negative correlation between the value of PUFA/SFA of oil and the frying life of oil,the linear equation is y=-3.7316x+31.2363,R2=0.9362.Considering the main factors such as frying life,PUFA/SFA value and fatty acid balance,nutritional health and raw oil cost,we researched the preparation of special frying oil.Three special frying oils were prepared with palm oil,soybean oil,rapeseed oil and peanut oil.The value of PUFA/SFA of formulation oils 1,2 and 3 were 0.71,1.08 and 1.66 respectively.The ratio of raw material oil,palm oil: soybean oil: rapeseed oil: peanut oil was 5:1:3.5:1,5:4:0.5:0.5,3:6:0.5:0.5,respectively,and studied and verify the performance of formulations,the result showed the frying life of formulation 1 was about 25 h,13.6% and 15.0% longer than formulation 2 and 3,respectively.The change of color and the oil absorption rate of French fries of formulation 1 are the smallest,but the changes of viscosity and acid value were largest among three formulations,the peroxide value of formulation 2 changed less.three formulations all have good quality in french fries,generally,formulation 1 have good frying performance and quality,followed by 2 and 3,Confirmed the shorter the ratio of PUFA/SFA,the longer the frying life of oil,compared with soybean oil and rapeseed oil,the frying life and frying quality of the three formulation oils had been significantly improved,the cost is much lower than that of peanut oil,the proportion of fatty acid is more reasonable and balanced than that of palm oil,and the saturation of the three formulation oils is significantly lower than that of palm oil.On the basis of the above research,the harmful substances and volatile substances in the frying process of raw oil and formula oil were detected and analyzed,The results showed that the contents of triglyceride dimer,triglyceride oligomer,triglyceride oxide and free fatty acid were continuous rise during frying,The content of 3-MCPD decreased during frying generally.The change trend of GEs in different frying oils is not obvious,but some oils increase slightly in the frying process,the number of volatile substances in the three formulation oils increased first and then decreased during the frying process.Overall,peanut oil,palm oil and three formulation oils produced less harmful substances and volatile substances in the frying process.