| In the processs of uccessive frying fritters26h at a high temperature, health indicatorsquality changes and frying stability of cottonseed oil in the process of frying fritters werestudied by the testing of health indicators taken from different frying time. The results showedthat after26h of successive frying, cottonseed oil acid value increased from0.23mg/g to1.40mg/g, carbonyl value increased from15.59meq/kg to76.99meq/kg, polar componentincreased from4.37%to29.99%. Controlled GB7102.1-2003" hygiene standards of ediblevegetable oil in frying ", cottonseed oil acid value after26h successive frying still meet≤5mg/g limited edition, carbonyl value exceeding50meq/kg limited time to18h, the polargroup of more than27%limited time to26h. The average oil rate of fried fritters8.01%.Soybean oil and palm oil, as commonly used frying oils were continuously fried at a hightemperature. Soybean oil, palm oil, respectively, the average oil absorption rate of friedfritters were13.86%,13.17%; acid value of palm oil, soybean oil, was increased to2.46mg,1.61mg/g of32h from0.33mg/g,0.45mg/g; carbonyl value of soybean oil increased to50.12meq/kg of16h, to110.83meq/kg of32h by5.56meq/kg, carbonyl value of palm oil bythe fried before5.57meq/kg increased to24h of50.24meq/kg, to57.37meq/kg of32h; polarcomponent content of palm oil increased by8.12%, to28.03%of30h, to29.18%of32h,soybean oil polar component content increased to27.11%of32h by0.77%. Relative tosoybean oil, palm oil, the sensory effects of fried fritters of cottonseed oil was better and itsoil rate was the lowest; the magnitude of increase of trans fatty acids was the smallest;cottonseed crude oi is darker, but the magnitude of increase is smallest in frying fritters; thetime fumes appeared is centered;acid value of crude oil and the rate of increase are smaller;carbonyl value of crude oil was slightly higher, but the increase rate residing in soybean oil,palm oil; the polarity components increased most obviously; Considering the limits of healthindicators of frying oil, fried lifetime of cottonseed oil was18h, less than24h of palm oil,more than16h of soybean oil.On the basis of cottonseed oil, soybean oil, palm oil, frying results, considering thefrying oil color, smoke point, frying life and frying stability, fatty acid composition, thecontent of trans fatty acid after frying and fried food sensory effect and product prices andother factors, the cottonseed oil, soybean oil, palm oil and proper deployment a cotton seed oilbased blend frying oil:45%of the two levels of cottonseed oil,15%of the level of soybeanoil,8degrees palm oil35%, peanut oil5%. The oil of continuously high temperature fryingfritters test results, blend frying oil in frying, its color is relatively shallow in cottonseed oil, acid value, carbonyl value relative cottonseed oil is low, the content of polar compounds isslightly higher than that of cottonseed oil, quality grade overall rise and oil should be higherthan that of cottonseed oil; harmonic fried the average absorption of13batches of fritterssample rate was9.63%, slightly higher than cotton seed oil frying fritters, sensory taste good,not greasy; after continuous frying32h, acid value oil from fried before0.18mg/g increased to1.57mg/g, carbonyl value increased from10.66meq/kg to66.65meq/kg, the content of polarcompounds increased from6.35%to24.73%. The control of GB7102.1-2003"ediblevegetable oil during frying process hygiene standards", limited oil acid value is still≤5, byfrying continuously32h, carbonyl value more than50limited time for24h, polar componentsexceeds the limit of27more than32h. Frying oil color, acid value, carbonyl value, the contentof polar compounds as the frying time increased, increased significantly compared withcottonseed oil is gentle; considering the frying life is about24h larger thanthe cottonseed oilfrying life18h, showing a clear advantage in frying stability. In summary, the formulation ofthe blend oil as a frying oil is reasonable.Considering the frying oil color, smoke point, frying life and frying stability, the contentof trans fatty acid after frying and fried food sensory effect and product prices and otherfactors, the cottonseed oil, soybean oil, palm oil and proper deployment a cotton seed oilbased blend frying oil:45%of the two levels of cottonseed oil,15%of the level of soybeanoil,8degrees palm oil35%, peanut oil5%. The oil of continuously high temperature fryingfritters test results, harmonic fried the average absorption of fritters sample rate was9.63%,slightly higher than cotton seed oil frying dough sticks, sensory taste good, not greasy. Fryingoil color, acid value, carbonyl value, the content of polar compounds, increased significantlycompared with cottonseed oil is gentle, Compared with the control of GB7102.1-2003"edible vegetable oil during frying process hygiene standards", consolidated acid value,carbonyl value, the content of polar components, frying oil lifetime was judged to be24h, itwas longer than the lifetime of frying cottonseed oil18h, showing a clear advantage in fryingstability. In summary, the formulation of the blend oil as a frying oil is reasonable.Considering the influence of different ingredients on properties of cottonseed fried, andthe intermittent characteristics of frying food in living,cottonseed oil was intermittent fryingthe potatoes and fritters. The results show that, the frying8h chips and the deep-fried fritterscottonseed oil acid value respectively by0.24mg/g,0.25mg/g before frying increased to0.71mg/g,0.89mg/g,carbonyl value respectively by frying before9.38meg/kg,9.37meq/kg to22.13meg/kg,23.52meq/kg, polar fractions respectively by frying before2.63%,2.65%to8.63%,7.21%. Compared with the frying fritters cottonseed oil, frying potatoes, cottonseed oil acid value, carbonyl value increases relatively gentle, polar component increased relativelysteep.The stability of frying oil was affected fried food in different moisture content, starchcontent, cottonseed frying oil was relatively rapidly deteriorated during frying flour flakeswith relatively high moisture content.The antioxidant vitamin E was added to cottonseed oil. Successive frying frittersexperiments were conducted at a high temperature.The results showed that, α-tocopherol,γ-fertility phenol and the total vitamin E of cottonseed oil added the antioxidant vitamin Ewere decreased over the frying time, the total amount of vitamin E was down to156.24mg/100g of32h from259.69mg/100g of the frying0h, α-tocopherol decreased to148.63mg/100g from214.45mg/100g, a decline of83.91percent30.69%; γ-tocopheroldecreased to7.60mg/100g from47.24mg/100g, a decline of83.91percent, γ-tocopherol losswas significantly higher than α-tocopherol; In terms of carbonyl index value, the fryinglifetime of cottonseed oil added vitamin E is much longer than24h, it is much larger thancottonseed oil frying lifetime(18h); In addition to fatty acid composition, frying methods(successive frying or intermittent frying), fried ingredients, the stability of cottonseed oil wasrelated to the content of its natural antioxidant vitamin E. Adding antioxidants vitamin E incottonseed oil, it can significantly improve the stability of its frying, extend its frying life. |
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