菜籽油实罐储存品质变化规律研究

通过对2010~2014年大、中、小不同罐容实罐储存的四级菜籽油,采取定点、定罐、定层、定期跟踪观察油罐"三温"变化并取样检测,发现罐温、油温均随着气温的变化而变化,其中罐温最高,油温从上至下依次降低。菜籽油的水分及挥发物、色泽、气味、滋味、加热试验(280℃)等指标在储藏期间变化均较平稳,酸值和过氧化值均呈不断上升趋势,且不同年限的菜籽油其过氧化值上升幅度明显高于酸值。油罐容量越大,满罐存储时其存油品质的稳定性越好。罐内上、中、下层酸值变化差异不明显,上层和底层的过氧化值明显高于中层。严格控制好入罐油品质量,菜籽油储藏4~5年后酸值、过氧化值等质量指标仍可保持在国家限量标准以内。

THE STORAGE QUALITY CHANGE REGULATION OF RAPESEED OIL DURING STORAGE

The 4th grade rapeseed oil stored in large,medium and small-sized tanks from 2010 to 2014 were choosed to monitor the "three-temperature" regularly at fixed-point,fixed-tank,fixed-layer ahd test the quality.The results showed that the temperature of tank and oil changed with variation of air temperature.The tank temperature was the highest one in them.The oil temperature was gradually reduced from top to bottom.The change of the moisture volatile matter,the colour,the odor and flavor,the heating test data (280℃) of rapeseed oil,were more stable in storage period.The peroxide value rised significantly higher than the acid value for different years harveted rapeseed.The larger tank capacity,the better stability when the oil stored in full tank.The acid value changed in upper,middle and bottom were not obvious in the tank,but the upper and lower peroxide value was significantly higher than in middle.It's possible to keep the acid value and the peroxide value remain within national standards if the quality of oil purchased was controlled strictly.