| In the process of successive heating 26 h at 120℃, 140℃, 160℃,180℃ four consecutive temperature gradient, health indicators quality changes and frying stability of cottonseed oil in the process of frying fritters were studied by the testing of health indicators taken from different temperature and different frying time.The results showed that after 26 h of successive heating, palm oil, peanut oil, rapeseed oil acid value at 0 h were 0.18 mg, 0.79 mg/g and 0.14 mg/g, heating to 26 h at 120 ℃and 180 ℃the acid value were increased to 1.21mg/g, 1.22 mg/g,0.80mg/g,2.32mg/g, 2.64mg/g 2.12mg/g;The carbonyl value at 0h were 3.58meq/kg, 2.59meq/kg, and 4.38meq/kg, successive heating to 26 h at 120℃ and 180℃the carbonyl value were increased to 63.03meq/kg, 77.00meq/kg, 70.20meq/kg, and 83.95meq/kg, 94.98meq/kg,91.58meq/kg;The polar components in front of the heating were 4.00%, 5.53% and 5.82%, respectively, heating to 26 h at 120 ℃ and 180 ℃the polar components were increased to 27.97%,29.18%,30.31%,32.83%,34.07%,34.31%; Controlled GB 7102.1-2003 " hygiene standards of edible vegetable oil in frying ",After 26 h successive frying three kinds of frying oil acid value is still ≤ 5mg/g limited edition, palm oil carbonyl value after 26 h successive frying exceeding 50meq/kg limited time to 22 h,20h, 20 h and 16 h. Peanut oil carbonyl value after 26 h successive frying exceeding 50meq/kg limited time to 20 h, 16 h, 14 h and 14 h. Rapeseed oil carbonyl value after 26 h successive frying exceeding 50meq/kg limited time to 20 h, 16 h, 12 h and 12 h.In the process of discontinuity heating 26 h at120℃,140℃,160℃,180℃ four consecutive temperature gradient, health indicators quality changes and frying stability of cottonseed oil in the process of frying fritters were studied by the testing of health indicators taken from different temperature and different frying time.The results showed that after 26 h of discontinuity heating, palm oil, peanut oil, rapeseed oil acid value 0h were 0.18mg/g, 0.79 mg/g and 0.14mg/g, heating to 26 h at 120 ℃ the acid value were increased to 1.28mg/g, 1.98 mg/g and 1.05mg/g,heating to 26 h at 180 ℃ the acid value were increased to 3.48mg/g, 3.79 mg/g and 3.03mg/g; The carbonyl value at 0 h were 3.58meq/kg, 2.59meq/kg and 4.38meq/kg, heating to 26 h at 120 the carbonyl value we℃ re increased to 70.26meq/kg, 70.26meq/kg and 74.49meq/kg, heating to 26 h at 180 ℃the carbonyl value were increased to 86.60meq/kg, 86.60meq/kg and 94.39meq/kg; After 26 h successive frying three kinds of frying oil acid value is still ≤ 5mg/g limited edition, palm oil carbonyl value after 26 h successive frying exceeding 50meq/kg limited time to 20 h, 20 h, 20 h and 12 h. Peanut oil carbonyl value after 26 h successive frying exceeding 50meq/kg limited time to 18 h, 16 h, 14 h and 10 h. Rapeseed oil carbonyl value after 26 h successive frying exceeding 50meq/kg limited time to 20 h, 16 h, 10 h and 10 h.With fries as frying material, palm oil, peanut oil, rapeseed oil keep sustained heating and frying test at 160℃. The results show that the palm oil acid value by frying is 0.18mg/g.The acid value increases to 1.80mg/g after 160 continuous air burn for 26 h.The ℃acid value increases to 1.90mg/g continuous frying for 26 h at 160℃. The peanut oil acid value by frying is 0.79mg/g.The acid value increases to 1.97mg/g after 160 ℃ continuous air burn for 26 h.The acid value increases to 2.90mg/g continuous frying for 26 h at 160℃. The rapeseed oil acid value by frying is 0.14mg/g.The acid value increases to1.71mg/g after 160 continuous air burn for 26 h.The acid value increases to 1.℃ 84mg/g continuous frying for 26 h at 160℃. The original carbonyl value of frying palm oil is 3.58meq/kg.After continuous heating for 18 h at 160 it increases to 46.68meq/kg.℃ After 26 h the carbonyl value is further increasing to 80.25meq/kg. With continuous frying at 160 ℃after 12 h the carbonyl value increases to 47.18meq/kg and after 26 h it is 83.07meq/kg; The original carbonyl value of frying peanut oil is 2.59meq/kg.After continuous heating for 14 h at160 ℃it increases to 51.45meq/kg. After 26 h the carbonyl value is further increasing to 94.95meq/kg. With continuous frying at 160 after 10 h the ℃ carbonyl value increases to 49.52meq/kg and after 26 h it is 90.97meq/kg. The original carbonyl value of frying rapeseed oil is 4.38meq/kg.After continuous heating for 10 h at 160 it increases to 52.06meq/kg.After 26 h the ℃ carbonyl value is further increasing to 85.76meq/kg. With continuous frying at 160 after 10 h the ℃ carbonyl value increases to 56.11meq/kg and after 26 h it is 88.86meq/kg. The polar groups of palm oil content is 4% initially. At 160 continuous ℃ heating 12 h polar components content increase to 16.68%.After 26 h it is increase to 30.94%. At 160 ℃in the continuous frying 12 h polar components content increase to 19.91%.After 26 h it is up to 36.26%.The polar groups of peanut oil content is 5.53% initially. At 160 ℃continuous heating 12 h polar components content increase to 18.37%.After 26 h it is increase to 32.70%. At 160 ℃in the continuous frying 12 h polar components content increase to 19.91%. After 26 h it is up to 36.26%.The polar groups of rapeseed oil content is 5.82% initially. At 160 continuous ℃ heating 12 h polar components content increase to 18.65%. After 26 h it is increase to 33.11%. At 160 ℃in the continuous frying 12 h polar components content increase to 19.42%. After 26 h it is up to 37.34%.Compared with continuous heating, fried potato strips of cottonseed oil acid value, carbonyl value and the content of polar compounds increases relatively large. Explaining that the effect of frying stability of edible oil is affected by fried food species such as starch content of moisture content, frying ingredients, frying oil deterioration relatively fast. |
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