The main reasons affecting the measurement error of crude fat in feed

The main reasons affecting the measurement error of crude fat in feed

Crude fat is an important nutrient in feed, and the crude fat content in feed is one of the criteria for evaluating feed quality. Determination of feed fat, you can use the crude fat analyzer to operate, use the crude fat analyzer when there is still a little error note the following aspects can reduce the occurrence of errors:

The water content of the sample. Water dissolves water-soluble substances in the sample, such as sugars, soluble proteins, water-soluble minerals, and salts. During the extraction process, these water-soluble substances are easily extracted together with the fat and collected together in the extraction bottle to increase the measurement result. In addition, if the water content of the sample is too high, ether will not easily penetrate into the interior of the cell tissue and hinder the dissolution of the oil by the solvent. Therefore, the sample must be dried.

The extraction rate of the sample. Soak the extractor's condensate tube, extraction tube, and extraction bottle three parts and dry it in an oven at 105°C. The extraction bottle needs to be re-baked to a constant weight, otherwise the determination result of crude fat will be affected. . Put the sample into the Soxhlet extractor and pour in ethyl ether. The volume is 2/3 volume of the receiving flask. Heat on the water bath (about 65°C). Perform the reflux extraction. The speed of extraction is pumping. The ethyl ether in the lifting tube is siphoning 6~8 times per hour (or about 120~150 drops of ether per minute of condensation).

Heating time and temperature. Heating and extraction time is too long, and the temperature is too high. The lipids, fat accompanying substances and other substances in the feed can be dissolved in the oil and the results are high. Through the oven temperature is not easy to be too high, keep at a constant temperature of 105 ± 2 °C, the drying time is not easy too long, otherwise it can make low-grade fatty acids volatilize, oxidation of unsaturated fat, so that extraction bottle weight, affect the accuracy of the results. Such as weight gain, should be based on the previous quality. Fat-rich samples can be dried in a vacuum oven to avoid errors due to fat oxidation.

When using the fat fat meter, pay attention to the above aspects, and the error will be reduced to the lowest value.