Study On Soybean Oil Oxidation Stability In Nitrogen Storage

It is a meaningful thing that control of oil oxidative stability in storage period toensure quality oil supply and nutritional health of residents. Soybean oil is Chinesemajor edible oil since it is high value of nutrition and rich in raw materials, andexpanding in oil consumption market. But soybean oil containing linoleic acid andlinolenic acid, other higher unsaturated fatty acid and trace elements will be oxidativedeterioration due to external factors, and resulting in aldehydes, ketones and othersubstances in consumption and processing, which not only deteriorates of the flavorbut also the membrane, enzymes, protein damage and even lead to many diseases ofaging and serious harm to human health. In order to suppress the oxidation of oils, onthe one hand, it is adding anti-oxidants to the oil. On the other hand, it is studying themechanism of lipid oxidation, developing antioxidant packaging materials and new oilstorage technology. In this article, we investigated the application of nitrogen storagein refined soybean oil by simulating the tank, supermarkets and family environment,and proposed critical impact factors and control points, provided the theoretical basisnitrogen that the application of storage technology was in the oil storage. Specificstudies were as follows.Several key factors affecting oil oxidation stability in nitrogen storage of refinedsoybean, such as oil temperature, moisture content, the amount of nitrogen andsurface area/volume were studied through orthogonal experiment. The result showedthat temperature was the factor having the most significant influence on soybean oiloxidation stability, and that the amount of nitrogen, water content and surface area/volume also had significant influence on it. Soybean oil presented good oxidationstability in the condition of a lower temperature (below25oC), the amount of watercontent (0.02-0.05%), adequate nitrogen (100%) and larger surface area/volume.The effects of adding nitrogen，antioxidants (TBHQ) and untreated (blankcontrol) on the deterioration in quality were studied by simulating supermarketenvironment. The results showed that peroxide value, acid value and p-anisidine valuein three treatments models gradually increased with time during5months storage.Peroxide value reached to0.63mmol/kg,1.46mmol/kg,1.14mmol/kg after5months,respectively; acid value was less than safety indicators0.20KOHmg/g; p-anisidinevalue was changed a little; Yellow color was8,9.9,9.4, and red color was0.9,0.9,1. The effects of adding nitrogen，antioxidants (TBHQ) and untreated (blankcontrol) on the deterioration in quality were studied by simulating family environment,and conventional analyses (peroxide, acidity value and p-anisidine value) wereemployed to evaluate the quality of soybean oil in the three months. The resultsshowed that peroxide value, acid value and p-anisidine value in three treatmentsmodels gradually increased with time during3months of consumption. Peroxidevalue reached to safety targets5.0mmol/kg in70,50,50days, respectively, acid valuewas less than safety indicators0.20KOHmg/g, and p-anisidine value was changed alittle. Compared with anti-oxidants preservation, nitrogen preservation improves thestability of soybean oil in the same, and nitrogen preservation can be a green storagemethod.The rapid detection methods of peroxide value and acid value of soybean oilwere built by the near infrared technology and the regression model of partial leastsquares (PLS) on the basis of collecting soybean samples spectral data, and thenwhich was used to predict soybean oil quality indicators. The results showed that theconstructed model of the peroxide value and acid value had a good effect ofprediction, and the correlation coefficients were0.8759and0.9978. Near-infraredspectroscopy can be used for the rapid test of soybean oil peroxide value and acidvalue.