Study On The Use Limit Of Fried Palm Oil And Its L-NMR Control System

In this paper,we taked palm oil as the research object,through sensory evaluation,the optimum of frying temperature and oil are determined,and study on the change of the quality of frying oil at different temperatures and times.In order to prolong the use time of frying oil,three methods were designed to prolong the use time of frying oil,namely,daily supplementation of frying supplemented new oil on the fifth day,with no addition of new oil According to the actual production conditions of the factory,the oil consumption of Orleans chicken breast ribs is used as an indicator to select the best replenishment plan;Finally,the low-field NMR technique was used to analyze the oil used for frying,and the correlation and significance between the physical and chemical indicators were analyzed.The quality changes of palm oil were reflected by the S21 and T21 in L-NMR,and the change of the peak area S21 was determined the frying limit.This study can help companies have a more comprehensive understanding of palm oil frying process quality changes,and provide a theoretical basis for large-scale industrial production.The frying experiments were carried out at different oil ratios and temperatures,and the sensory evaluation of the product was used to determine the optimum oil/fuel ratio of 5:1 and the frying temperature at 170?.Study on the effects of different frying time and temperature on the physical and chemical indexes such as color,acid value,peroxide value,carbonyl value,and polar component of palm oil.The results showed that the color,acid value,carbonyl value and polar component of palm oil increased with the frying time and temperature during the frying process.The peroxide value rises quickly with the extension of the frying time,and then slowly declines.It has been in a fluctuating trend and increased with the oil temperature.The acid value and the peroxide value have not exceeded the national standard during the frying process.The carbonyl value exceeded the national standard during fried temperature 190? in 27h,170? over the national standard in 30h,the polar components at 190? and 30h exceed the national standard,and the frying 30h at 170? centigrade is close to the national standardIn order to prolong the use time of oil for frying,two types of replenishing methods were studied:one is to replenish oil every day after frying,the other is to replenish oil on the fifth day of frying.Using the amount of oil per kilogram of Orleans chicken breast in the frying process as an indicator,the best way of replenishing oil is finally determined.The results show that:When adding new oil every day,the effect on the color difference has no obvious,but adding new oil on the fifth day of frying significant effect on the color difference;The two kinds of replenishing methods have the tendency of decreasing acid value after supplementing new oil.When adding new oil every day,there was no significant drop in peroxide value,and when adding new oil on the fifth day,the peroxide value showed a significant downward trend.When adding new oil every day was used for replenishing oil,the carbonyl price was close to the national standard at 39h,while adding new oil on the fifth day had a significant effect on the carbonyl value,and the carbonyl value was significantly reduced after the replenishment.After the 42h of frying,the carbonyl group The price exceeds the national health standards for edible oil;Supplemental palm oil also has a good inhibitory effect on the increase of polar component content.After adding new oil every day,the polar component is significantly reduced and the use limit is increased from the original 30h to 39h.The second replenishing mode can also reduce the polar component content.In summary,if the replenishing operation is not performed,the use limit of the oil for frying is 27 hours,and the oil consumption per unit of Orleans chicken ribs is 1.25 kg/kg.If the first method is used for replenishing oil,the oil use limit for frying oil is 36 hours,and the oil consumption per unit of Orleans chicken ribs is 1.18 kg/kg.If the second replenishing method is used for replenishing the oil,the use limit of the dying oil is 39 hours,and the oil consumption of Orleans chicken ribs is 1.03 kg/kg.In summary,the use of the second replenishing method means that the fifth day of frying is the best and the most cost-effective.Finally,according to the low-field NMR spectroscopy,during the frying process,with the increase of frying time,the peak area S21 also increases,and the change of the relaxation time T21 can simply infer whether the fat has been fried.As the frying time increases,the multicomponent T2 relaxation pattern shifts to the left.Low frequency MRI scans of palm oil fried chicken breasts at different frying times can be obtained.The image formation during the frying process becomes increasingly blurred,hydrogen proton accumulation becomes apparent,and the integrity deteriorates.Using L-NMR technology to detect fried palm oil,it can be concluded that S21 is positively correlated with frying time,acid value,carbonyl value and polar component content,but T21 is negatively correlated.This data has good significance,indicating that the values of S21 and T21 detected by L-NMR reflect the changes in the quality of palm oil.When the peak area reaches 19,000,when the relaxation time T2 is significantly shifted to the left and the peak time is 18 ms,the frying oil has exceeded the national standard and should be discarded and cannot continue to be consumed.