Data Visual Analysis of Physicochemical Parameters of Two Batches of Frying Oil with Different Storage Time

In this paper, the acid value, carbonyl value and total polar components data measured in the two batches of frying soybean oil which were stored for 18 and 3 months respectively, were used to make some calculations and visual analysis, so as to observe the changes of physicochemical parameters of two batches of oil at the corresponding time points under the same experimental conditions, for providing convenience about the safety monitoring of frying oil. Firstly, statistical description and boxplot analysis were carried out according to the measured data of three physicochemical parameters. Secondly, the curve fitting visualization was carried out. Then, the surface and corresponding contour visualization analyses of “time-temperature-parameter’s value” were carried out. In the boxplot visualization, it was generally observed that the variation ranges of the physicochemical parameters of oil stored for a long time were larger at the same frying temperature. In the curve fitting visualization, it was found that the acid values changed most regularly, which could be used to estimate the corresponding acid values of another batch of oil under the same experimental conditions, and could also be used to estimate the storage time of another batch of oil according to the known storage time of this batch of oil. In the surface and contour visualization, it was found that 190 ℃ was a dividing point of the temperatures. In the frying process above 190 ℃, the physicochemical parameters of oil stored for a longer time increased faster, the oxidation rate increased and the oil was more unstable. At the same time, it was also found that 20 h was a dividing point of the time. After 20 h, the physicochemical parameters of oil stored for a longer time increased faster. In the case of continuous frying, the temperature should not exceed 190 ℃ and the frying time should not exceed 20 h.