The crude fatty acid value of soybean is one of the characteristics of soybean quality.
Method, the prepared sample is loaded into a dried filter paper tube.
is also an important indicator of the "Soybean Storage Quality Judgment Rules" (GB
Samples may be loaded in multiple places to ensure that sufficient amounts of oil are extracted for later use.
t 31785-2015).
Titration determination of crude fatty acid value continued.
It is recommended to use the Soxhlet extraction method to extract crude fat first, and then press the "Food.
A layer of absorbent cotton is placed at the bottom and top of the filter paper tube to prevent the sample from being on.
Standard Determination of Acid Value in Foods (GB 5009.)229
Leakage during extraction.
2016) Cold solvent indicator titration was used to measure crude fatty acid value.
Install the bottle and the extractor that have been weighted and put it into the bottle. This method has a long detection time and cumbersome steps, and is not suitable for the filter paper tube of batch samples, open the condensation cycle, add petroleum ether, and heat the detection. In recent years, the oil extraction method has been continuously improved, ultrasonic extraction, the water bath temperature is controlled at 50 60, and 2 3 drops are maintained, 1-2].
In this experiment, the requisitioning method was adopted, and it has been widely used in the extraction of oil and fat, and the ** petroleum ether after extraction h.
1.4.2 Organic solvent extraction.
Extraction, organic solvent extraction and ultrasonic-assisted extraction.
The prepared sample was placed in a 500ml Erlenmeyer flask with a stopper, soybean oil was taken, and its oil yield and crude fatty acid value were compared.
Petroleum ether (30 60) is added to raise the solvent above the discharge layer 4
An optimal extraction method was found to ensure the accuracy of the analysis results.
After shaking for 5s with a stopper, open the stopper to deflate, and then close the bottle tightly.
and reliability, which provides a theoretical basis for the detection of crude fatty acid values.
The plug is placed on a round-trip oscillator and shakes for 2h. Remove the cone after shaking.
1 Materials and methods.
Shape the bottle, let stand for 3 5min, filter, discard the first few drops of filtrate, and receive.
Collect the remaining entire filtrate.
In an Erlenmeyer flask, rotate the base of the evaporator.
1.1 Raw materials and reagents.
This solvent is evaporated. To ensure that volatiles such as solvents and moisture are complete.
Domestic soybeans from Northeast China, imported soybeans from the United States, and imported soybeans from Brazil.
It is steamed and dried, and then placed in the electric blast drying oven of (103 2).
All of them come from the direct depot of local grain reserves.
Medium drying, take out and cool to room temperature, the oil sample in the Erlenmeyer flask is.
Anhydrous ether, isopropanol, petroleum ether (boiling point 30 60), sample to be tested.
All are analytically pure;0.1mol l potassium hydroxide standard solution, % phenol.
Ultrasound-assisted extraction.
Phthalein indicator. Weigh an appropriate amount of soybean sample into an Erlenmeyer flask and use petroleum ether.
1.2 Instruments and equipment.
30 60) is the extraction agent, the ultrasonic frequency is 50kHz, ultrasonic.
Tabletop low-speed centrifuge, electric blast drying oven, ultrasonic cleaning.
Wave power 300W, solid-liquid ratio 1 5 (g ml), extraction temperature 30, washer, BLH-5601 hammer cyclone mill, rotary evaporator.
The extraction time is 30 min, then take out the Erlenmeyer flask and let it stand for 3 5 min, 13 Sample preparation.
After that, follow 14.2-step assay.
The 150 soybean samples were removed from impurities and used by a hammer cyclone.
1.5. Determination of soybean oil yield and crude fatty acid value.
Crushed, extraction assay.
After separating the mixed oil and solvent, weigh the mass of the extraction bottle.
1.4 Soybean oil extraction method.
The difference is the quality of the soybean oil, and the oil percentage is calculated.
1.4.1 Soxhlet extraction.
Oil yield = quality of soybean oil Soybean quality 100%, refer to the "Determination of Oil Content of Vegetable Oilseeds" (GB T 14488.).1—2008）
The determination of crude fatty acid value refers to the "National Food Safety Standard Food".
Determination of acid value in products (GB 5009.)229—2016).
Received:2020-04-16
Indicator titration method.