Research On The Technology To Prevent Deterioration Of Rapeseed Oil During Storage

China is a big country that has a big amount of rapeseed oil production and consumption. Rapeseed oil is one kind of the cereals and oils difficult to preserve. Therefore, the researchers both in China and abroad take more and more attention on the study of method to preserve rapeseed oil. Currently, there have been a large number of research achievements on rapeseed oil preservation techniques, such as low-temperature, deoxidants, anti-oxidants, etc. as the requirements of high quality, nutrition, taste and safety of rapeseed oil. Research and development of new preservation technologies which are green, environmental friendly, energy saving and practical attract many researchers. Therefore, develope non-toxic and low-cost preservation methods of rapeseed oil to delay the deterioration during storage becomes the focus and trends in this research area.The study focused on three kinds of preservation method, nitrogen, tea polyphenols, nitrogen+tea polyphenols. Under different temperature conditions, rapeseed oil acid value, peroxide value and peroxide value of the blank and treatment groups were checked regularly to explore rapeseed oil storage quality deterioration. Finally, through the oxidation stability test, techniques to delay the rapeseed oil storage quality deterioration were formed which basically achieved the desired objectives. Its main contents and results are as follows:This thesis studied different methods. Filling the small package of rapeseed oil with nitrogen instead of oxygen, also adding tea polyphenols (natural antioxidants, non-toxic) as an antioxidant, rapeseed oil was stored under temperature (20,25.30,35℃) for five and a half months during this period the rapeseed oil acid value and peroxide value were tested regularly, the oxidative stability index was also determined. The technical conditions to delay rapeseed oil storage quality deterioration were as follows:1) temperature is the main factor causing the rapeseed oil quality deterioration, so in the process of rapeseed oil storage to keep the ambient temperature below 20℃, slowing the acid value and peroxide value rising speed; 2) rapeseed oil quality gradually decline as time goes on, during the storage and package, and processing. The enterprises must consider the acid value and peroxide value changes in order to ensure reliable quality within the warranty period; 3) the rapeseed oil stored in oilcan volume will change as the ambient temperature changes, the liquid level will be raised and lowered, the gas volume and composition of the oilcan upper space will change the surface rapeseed oxidative hydrolysis. It should be possible to reduce the upper space of the oilcan Oxygen, delaying the fission rate of rapeseed oil quality during the rapeseed oil in the long-term storage process; 4) the nitrogen gas as an inert gas, get from the air more easily, suitable replacement oilcan or small package air, thereby slowing the rate of hydrolysis of rapeseed oil oxidation; 5) tea polyphenols as a natural antioxidant, suitable as a food additive could be added to the rapeseed oil to extend the shelf life of the rapeseed oil; 6) adding the nitrogen and tea polyphenols is better than single nitrogen or adding the polyphenols to delaying the speed of deterioration of rapeseed oil, suitable for application in rapeseed oil storage, processing, and other fields.