This standard applies to the inspection of transparency, color, odor and flavor of commodity vegetable oils and fats. GB/T 5525-1985 Inspection of transparency, color, odor and flavor of vegetable oils and fats GB/T5525-1985 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Inspection of vegetable oilsMethods for identification of transparency, colour, odour and tasteThis standard applies to the inspection of transparency, colour, odour and taste of commercial vegetable oils. 1 Transparency identification
1.1 Apparatus and tools
1.1.1 Colorimetric tube: 100ml, diameter 25mm; 1.1.2 Milky white bulb, etc.
1.2 Operation method
GB/T 5525-85
Measure 100ml of the sample and inject it into the colorimetric tube, let it stand at 20℃ for 24h (sesame oil for 48h), then move it in front of the milky white bulb (or put white paper behind the colorimetric tube), observe the transparency and record the observation results. 1.3 Result expression
The observation results are expressed as "transparent", "slightly turbid" or "turbid". 2 Color identification
2.1 Lovibond colorimeter methodbZxz.net
2.1.1 Instruments and utensils
2.1.1.1 Lovibond colorimeter;
2.1.1.2 Funnel, conical flask, dropper, filter paper, etc. 2.1.2 Operation method
Put the instrument flat, place the observation tube and magnesium carbonate sheet, and check whether the light source is intact. Take the clarified (or filtered) sample and inject it into the colorimetric tank to a distance of about 5mm from the upper opening of the colorimetric tank. Place the colorimetric tank in the colorimeter. First fix the color value of the yellow glass slide according to the regulations, turn on the light source, and move the red glass slide to adjust the color until the color of the glass slide is exactly the same as the color of the oil sample. If the oil color has a cyan color, a blue glass slide must be added. At this time, move the red glass slide until the number of the blue glass slide reaches the minimum value, and record the total number of the numbers of the yellow, red or yellow, red, and blue glass slides, which is the color value of the oil sample to be tested. The result should be marked as not darker than yellow and red, and the thickness of the colorimetric tank should be marked. The difference between the two test results is allowed to be no more than 0.2, and the higher test result is taken as the determination result. 2.2 Potassium dichromate solution colorimetric method
2.2.1 Apparatus and utensils
2.2.1.1 Volumetric flask: 100ml;
2.2.1.2 Nessler colorimetric tube;
2.2.1.3 Balance: sensitivity 0.0001g,
2.2.1.4 Weighing blood, pipette, measuring cylinder: 2.2.1.5 Test tube rack, brown reagent bottle, mortar, etc. 2.2.2 Reagents
Potassium dichromate concentrated sulfuric acid (specific gravity 1.84, no reducing substances) solution: Accurately weigh 1g of finely ground potassium dichromate (accurate to 0.0002g), add a small amount of sulfuric acid to dissolve in a beaker, then pour all into a 100ml volumetric flask, add concentrated sulfuric acid to the scale, shake well, and put into a brown bottle as liquid No. 1.
2.2.3 Operation method
2.2.3.1 Prepare standard series: Take 7 Nessler colorimetric tubes, number them, and prepare a standard series with liquid No. 1 and concentrated sulfuric acid according to the dilution ratio specified in the table below.
Colorimetric tube!
Liquid No. 1, ml
Standard series and color value table
Concentrated sulfuric acid, ml
Count one color
Colorimetry: Take 50 ml of the clarified sample and inject it into the Nessler colorimetric tube, and compare the color with the standard series. The color value when the color is equal is the color value of the potassium dichromate method. Odor and taste identification
Take a small amount of the sample and inject it into a beaker, heat it to 50℃, stir it with a glass rod while smelling the odor, and taste it at the same time. Those with the inherent odor and taste of the oil and no odor are qualified. Those that are unqualified should indicate the odor. Additional notes:
This standard was proposed by the Ministry of Commerce of the People's Republic of China. This standard was drafted by the Grain Storage and Transportation Bureau of the Ministry of Commerce. The main drafters of this standard are Gao Xiuwu, Yang Haoran, Wu Yanxia, ​​and Lv Guifen. Issued by the National Bureau of Standards on November 2, 1985
Implementation on July 1, 1986
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