Study On The Frying Performance Of Cyperus Esculentus Oil

Cyperus esculentus is a new type of edible vegetable oil resource that has been vigorously developed in China in recent years.Cyperus esculentus oil is a high oleic acid type oil,which has the potential to be developed as a frying oil from the perspective of fatty acid composition.At present,there are few reports on the frying performance of Cyperus esculentus oil.Using potato chips,tofu,and chicken breast as representative frying ingredients,palm oil and soybean oil as controls,this paper measured the changes in physical and chemical indicators and the retention of beneficial active components of Cyperus esculentus oil during the frying process through a 32 hour continuous frying experiment,revealing the frying stability of Cyperus esculentus oil;According to the optimal proportion of fatty acids consumed by the human body,a blended oil of Cyperus esculentus oil with a balanced proportion of fatty acids was developed.The frying stability of the blended oil was evaluated through a 32 h continuous frying experiment of potato chips;Through the study on the quality of fried food made from Cyperus esculentus oil and its blended oil,the performance of Cyperus esculentus oil and its blended oil in frying applications was further studied.The main research results are summarized as follows.(1)Using Cyperus esculentus oil,palm oil,and soybean oil to continuously fry French fries,the results showed that the rate of color deepening of the three frying oils during the frying process was as follows: palm oil > Cyperus esculentus oil > soybean oil;the increase of viscosity was as follows: soybean oil(215.8 m Pa.s)> Cyperus esculentus oil(152.0m Pa.s);the increase of acid value was as follows: palm oil(3.05 mg KOH/g)> Cyperus esculentus oil(2.81 mg KOH /g)> soybean oil(0.75 mg KOH /g);the increase of anisidine value was as follows: soybean oil(248.56)> Cyperus esculentus oil(105.31)> palm oil(91.43);the increase of polar components was as follows: soybean oil > palm oil > Cyperus esculentus oil;the decrease of polyunsaturated fatty acid ratio was as follows: soybean oil(6.16%)> palm oil(4.27%)> Cyperus esculentus oil(3.40%);trans fatty acid content was as follows: soybean oil(1.10%)> Cyperus esculentus oil(0.51%)> palm oil(0.46%);vitamin E loss rate was as follows: palm oil(95.64%)> Cyperus esculentus oil(93.69%)> soybean oil(69.85%);sterol loss rate was as follows: palm oil(53.85%)> soybean oil(35.89%)>Cyperus esculentus oil(23.57%).According to the national standard for food safety GB2716,the acid value of frying oil should not exceed 5 mg KOH/g and the content of polar components should not exceed 27%,and the frying life of Cyperus esculentus oil,palm oil and soybean oil were 27 h,21 h and 17 h.From the aspects of frying life and nutrient retention,it was concluded that the frying performance of Cyperus esculentus oil was better than that of palm oil and soybean oil.(2)Considering that different frying ingredients have different effects on the frying stability of Cyperus esculentus oil due to their different compositions.Three representative ingredients,French fries(high starch-based ingredient),tofu(high moisture ingredient),and chicken breast(meat ingredient),were continuously fried for 32 h in Cyperus esculentus oil.The results showed that the trends of each index during the frying of different ingredients were the same,but the rates of change were different.The rate of color deepening was as follows: fried chicken breast > fried tofu > fried French fries;the increase of viscosity was as follows: fried chicken breast(169.5 m Pa.s)> fried French fries(152.0 m Pa.s)> fried tofu(82.5 m Pa.s);the increase of acid value was as follows: fried chicken breast(10.03 mg KOH/g)> fried tofu(5.14 mg KOH/g)> fried French fries(3.47 mg KOH/g);the increase of anisidine value was followed by: fried French fries(108.56)> fried chicken breast(88.42)>fried tofu(72.73);the rate of increase of polar components was followed by: fried chicken breast > fried French fries > fried tofu;the content of trans fatty acids was followed by: fried chicken breast(0.43%)> fried tofu(0.29%)> fried French fries(0.21%);the loss rate of vitamin E was followed by: fried French fries(92.08%)> fried tofu(71.43%)> fried chicken breast(39.30%);the loss rate of sterols was as follows : fried French fries(23.61%)>fried tofu(10.96%)> fried chicken breast(5.42%).According to the national standard for food safety GB 2716,the acid value of frying oil should not exceed 5 mg KOH/g,and the content of polar components should not exceed 27%,resulting in the frying life of 27 h,32 h,and 16 h for fried French fries,tofu,and chicken breast in Cyperus esculentus oil,respectively.From the aspect of frying life and retention of nutrients,it was concluded that the stability of frying high-moisture ingredients in Cyperus esculentus oil was higher than that of frying chicken breasts.(3)Based on the superior frying performance of Cyperus esculentus oil.According to the recommendations of the Dietary Guidelines for Chinese Residents: daily intake of saturated fatty acids: monounsaturated fatty acids: omega-6 polyunsaturated fatty acids:omega-3 polyunsaturated fatty acids is optimally 20:60:15:5.After calculation,15% palm oil,75% Cyperus esculentus oil,5% soybean oil,and 5% linseed oil were mixed in order to develop a Cyperus esculentus blend oil with a balanced fatty acid ratio.Frying of French fries for 32 h in Cyperus esculentus blend oil.The results showed that the changes of the physical and chemical indexes of the blended oil during frying were similar to that of Cyperus esculentus oil,and the decreases of vitamin E(91.2%)and sterols(11.5%)were smaller than that of Cyperus esculentus oil and palm oil.At 25 h of frying,the polar component exceeded the maximum limit of the national standard(27%).According to the national standard for food safety GB 2716,the frying life of Cyperus esculentus blend oil,Cyperus esculentus oil and palm oil were 25 h,27 h and 21 h,respectively.From the aspect of frying life and nutrient retention,it can be concluded that the frying performance of Cyperus esculentus blend oil is slightly lower than that of Cyperus esculentus oil and higher than that of palm oil.(4)The types and contents of volatile substances were determined for Cyperus esculentus oil,Cyperus esculentus blend oil,palm oil,soybean oil and French fries,and the sensory evaluation was performed for French fries.The results showed that 28 and 32 volatile substances were detected in Cyperus esculentus oil and Cyperus esculentus blend oil,respectively,which were lower than soybean oil(45)and higher than palm oil(25),among which aldehydes were the main volatile substances in Cyperus esculentus oil and Cyperus esculentus blend oil;29 and 30 volatile substances were detected in Cyperus esculentus oil fried fries and Cyperus esculentus blend oil fried fries,respectively,which were lower than soybean oil(58)and palm oil(35),among which aldehydes and esters were the main volatile substances.Evaluating the quality of French fries in terms of five indicators: color,flavor,crispness,greasiness and overall preference,it was concluded that the overall popularity of French fries fried in four vegetable oils was: Cyperus esculentus blend oil > palm oil >Cyperus esculentus oil > soybean oil.As a conclusion,the frying performance of Cyperus esculentus oil is better than palm oil and soybean oil,and it is more suitable for frying high moisture ingredients.15% palm oil,75% Cyperus esculentus oil,5% soybean oil and 5% linseed oil are blended to make Cyperus esculentus blend oil,which has the advantages of balanced fatty acid composition,rich nutrients and better frying performance.The fries are more popular among consumers than Cyperus esculentus oil,palm oil and soybean oil.