Method for detecting the content of crude fat in pet food

Abstract

The application provides a detection method for the content of crude fat in pet feed, and the detection method comprises the following steps: (1) acid hydrolysis pretreatment: adding hydrochloric acid solution into the pet feed to be detected, heating to micro boiling, keeping, cooling, filtering, obtaining residues, and washing to neutral; (2) freezing treatment: freezing the residues washed to neutral; (3) first weighing: drying the residues after the freezing treatment, adding glass beads, drying and cooling, and weighing to obtain m1; (4) extraction: Soxhlet extraction, controlling the temperature to make the refluxing times 10-20 times / hour, and extracting for 1-3 hours; (5) second weighing and (6) calculation: obtaining the content of crude fat X. Through the modification of the detection steps and the solvent, the application can realize the rapid detection of the content of crude fat in pet feed, has good accuracy, can meet the detection and formula research and development requirements of the pet feed, and provides technical support for the research and development and standard development of the pet feed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of feed detection, and particularly relates to a detection method for the content of crude fat in pet feed. BACKGROUND

[0002] In recent years, the pet industry in China is developing vigorously, and the development of pet feed (which can also be called pet food) is particularly concerned.

[0003] In addition to providing comprehensive and balanced nutrition to meet the growth and development of the muscles, bones, blood, hair and other organs of pets, pet feed also needs to consider the special needs of the hair, body shape and different physiological periods of pets. With the diversification of pet feed, consumers gradually realize the importance of pet feed for pet health, and thus have higher requirements for the quality and safety of pet feed.

[0004] Crude fat is an important chemical component in animal feed and is one of the essential nutrients for the growth and development of animals. Pet dogs are omnivorous animals with a preference for meat, and pet cats are strict carnivorous animals. Fat is a necessary nutrient in their food. Therefore, accurately determining the content of crude fat in animal feed is of great significance for evaluating the quality and formula optimization of pet feed.

[0005] There are various methods for determining the content of crude fat, including the extraction method, the residue method, the filter bag method, the rapid solvent extraction method and the fat determination instrument method. Among them, the Soxhlet extraction method is the most important method for detecting the content of crude fat in animal feed due to its high accuracy and good stability.

[0006] However, the Soxhlet extraction method takes a long time, and according to the research of Li Xiuhua, the fat content measured by the Soxhlet method for processed food is much lower than the actual value, which easily causes errors in the measurement results. In addition, pet feed contains high content of oil, protein and other raw materials, and the matrix interference is complex. Therefore, it is of great significance to develop a method for extracting and detecting the content of crude fat in pet feed, which is short in detection time, accurate and suitable for pet feed. SUMMARY

[0007] To solve the above technical problems, the application provides a detection method for the content of crude fat in pet feed.

[0008] To achieve the above purpose, the application adopts the following technical solutions:

[0009] A detection method for the content of crude fat in pet feed, comprising the following steps:

[0010] (1) Acid hydrolysis pretreatment: adding hydrochloric acid solution to the pet feed to be measured, heating to micro-boiling, keeping, cooling, filtering, obtaining residue, and washing to neutral;

[0011] (2) Freezing treatment: freezing treatment of the residue after washing to neutral;

[0012] (3) First weighing: drying the residue after freezing treatment, adding glass beads, drying and cooling, and weighing to obtain m1;

[0013] (4) Extraction: Soxhlet extraction, controlling the temperature to make the refluxing frequency 10-20 times / hour, and extracting for 1-3 hours;

[0014] (5) Second weighing: removing the solvent and drying to constant weight to obtain m2;

[0015] (6) Calculation: obtaining the crude fat content X.

[0016] Preferably, the particle size of the pet feed to be tested in step (1) is 20-60 mesh.

[0017] Further preferably, the pet feed includes pet compound feed and pet additive premix feed (except pet special dairy products).

[0018] Preferably, the concentration of the hydrochloric acid in step (1) is 2-3 M.

[0019] Preferably, the time kept in step (1) is 0.3-0.5 h.

[0020] Preferably, the freezing treatment in step (2) is: placing the residue at -20 to -15 ℃ for 0.5-1 h.

[0021] Preferably, the solvent for Soxhlet extraction in step (4) is petroleum ether, diethyl ether and ethyl acetate.

[0022] Further preferably, the volume ratio of the petroleum ether, diethyl ether and ethyl acetate is 1:3:1.

[0023] Further preferably, the conditions for Soxhlet extraction in step (4) are: Soxhlet extraction, controlling the temperature to make the refluxing frequency 13-16 times / hour, and extracting for 1.5-2.5 hours.

[0024] Preferably, the method for removing the solvent in step (5) is: distillation or boiling water bath.

[0025] Preferably, the calculation formula of the crude fat content X in step (6) is:

[0026] The beneficial effects of the present application are:

[0027] The present application can realize rapid detection of the crude fat content of pet feed through modification of the detection step and the solvent, has good accuracy, can meet the detection and formula research and development needs of pet feed, and provides technical support for the research and development and standard development of pet feed. DETAILED DESCRIPTION

[0028] Other advantages and benefits of the present application will become apparent to those skilled in the art upon consideration of the disclosure herein. The present application can be embodied in other different specific embodiments and applied to other different specific situations without departing from the spirit of the present application. Various modifications and changes can be made with respect to the details of the present application based on different viewpoints and applications without departing from the spirit of the present application.

[0029] Before further describing the specific embodiments of the present application, it should be understood that the scope of protection of the present application is not limited to the following specific embodiments; it should also be understood that the terms used in the embodiments are used to describe the specific embodiments, but not to limit the scope of protection of the present application.

[0030] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified by the present application, both endpoints of each numerical range and any number between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0031] The present application does not limit the source of the raw materials used, and unless otherwise specified, the raw materials used in the present application are all commercially available in the technical field. Unless otherwise specified, the solvent used in the solution of the present application is water, preferably distilled water.

[0032] Embodiment 1

[0033] A method for detecting the crude fat content in pet feed, comprising the following steps:

[0034] (1) Acid hydrolysis pretreatment: add 3M hydrochloric acid solution (enough to immerse the pet feed to be tested) to the pet feed to be tested, heat to micro-boiling, keep for 0.3h, cool, filter, get the residue, wash to neutral;

[0035] (2) Freezing treatment: place the residue washed to neutral at-20℃ for 0.5h for freezing treatment;

[0036] (3) First weighing: dry the residue after freezing treatment, add a few glass beads (2-3 beads), dry and cool, weigh to get m1;

[0037] (4) Extraction: Soxhlet extraction, petroleum ether, diethyl ether and ethyl acetate with a volume ratio of 1:3:1 as the extraction solvent, control the temperature to make the refluxing times 10 times / hour, extract for 1 hour;

[0038] (5) Second weighing: remove the solvent by distillation or boiling water bath, dry to constant weight, get m2;

[0039] (6) Calculation: through the formula: Calculate the crude fat content X.

[0040] Example 2

[0041] A detection method of crude fat content in pet feed, comprising the following steps:

[0042] (1) Acid hydrolysis pretreatment: add 2M hydrochloric acid solution (enough to immerse the pet feed to be tested) to the pet feed to be tested, heat to micro boiling, keep for 0.3h, cool, filter, get the residue, wash to neutral;

[0043] (2) Freezing treatment: place the residue washed to neutral at-15℃ for 1h, freeze treatment;

[0044] (3) First weighing: dry the residue after freezing treatment, add a few particles of glass beads (2-3 particles), dry, cool, weigh to get m1;

[0045] (4) Extraction: Soxhlet extraction, petroleum ether, diethyl ether and ethyl acetate with a volume ratio of 1:3:1 as the extraction solvent, control the temperature to make the refluxing times 20 times / hour, extract for 3 hours;

[0046] (5) Second weighing: remove the solvent by distillation or boiling water bath, dry to constant weight, get m2;

[0047] (6) Calculation: through the formula: Calculate the crude fat content X.

[0048] Example 3

[0049] A detection method of crude fat content in pet feed, comprising the following steps:

[0050] (1) Acid hydrolysis pretreatment: add 2.5M hydrochloric acid solution (enough to immerse the pet feed to be tested) to the pet feed to be tested, heat to micro boiling, keep for 0.4h, cool, filter, get the residue, wash to neutral;

[0051] (2) Freezing treatment: place the residue washed to neutral at-18℃ for 40min, freeze treatment;

[0052] (3) First weighing: dry the residue after freezing treatment, add a few particles of glass beads (2-3 particles), dry, cool, weigh to get m1;

[0053] (4) Extraction: Soxhlet extraction, petroleum ether, diethyl ether and ethyl acetate with a volume ratio of 1:3:1 as the extraction solvent, control the temperature to make the refluxing times 15 times / hour, extract for 2h;

[0054] (5) Second weighing: remove the solvent by distillation or boiling water bath, dry to constant weight, get m2;

[0055] (6) Calculation: through the formula: Calculate the crude fat content X.

[0056] Comparative Example 1

[0057] A method for detecting the crude fat content in pet feed, comprising the following steps:

[0058] (1) Acid hydrolysis pretreatment: add 3M hydrochloric acid solution (enough to immerse the pet feed to be tested) to the pet feed to be tested, heat to micro-boiling, keep for 1h, cool, filter, get the residue, wash to neutral;

[0059] (2) First weighing: dry the residue after freezing treatment, add a few particles of glass beads (2-3 particles), dry, cool, weigh to get m1;

[0060] (4) Extraction: Soxhlet extraction, petroleum ether, diethyl ether and ethyl acetate with a volume ratio of 1:3:1 as the extraction solvent, control the temperature to make the refluxing times 10 times / hour, extract for 1h;

[0061] (5) Second weighing: remove the solvent by distillation or boiling water bath, dry to constant weight, get m2;

[0062] (6) Calculation: through the formula: Calculate the crude fat content X.

[0063] Comparative Example 2

[0064] A method for detecting the crude fat content in pet feed, comprising the following steps:

[0065] (1) Acid hydrolysis pretreatment: add 2.5M hydrochloric acid solution (enough to immerse the pet feed to be tested) to the pet feed to be tested, heat to micro-boiling, keep for 0.4h, cool, filter, get the residue, wash to neutral;

[0066] (2) Freezing treatment: place the residue washed to neutral at-18℃ for 40min, freeze treatment;

[0067] (3) First weighing: dry the residue after freezing treatment, add a few particles of glass beads (2-3 particles), dry, cool, weigh to get m1;

[0068] (4) Extraction: Soxhlet extraction, using petroleum ether as the extraction solvent, controlling the temperature to make the refluxing frequency 20 times / hour, and extracting for 3 hours;

[0069] (5) Second weighing: removing the solvent by distillation or boiling water bath, and drying to constant weight to obtain m2;

[0070] (6) Calculation: the crude fat content X was calculated by the formula:

[0071] Comparative Example 3

[0072] A detection method of the crude fat content in a pet feed, comprising the following steps:

[0073] (1) Acid hydrolysis pretreatment: adding 2.5M hydrochloric acid solution (enough to immerse the pet feed to be detected) into the pet feed to be detected, heating to micro-boiling, keeping for 0.4 hours, cooling, filtering to obtain residues, and washing to neutral;

[0074] (2) Freezing treatment: placing the residues washed to neutral at-18℃ for 40 minutes for freezing treatment;

[0075] (3) First weighing: drying the residues after freezing treatment, adding a few glass beads (2-3), drying, cooling, and weighing to obtain m1;

[0076] (4) Extraction: Soxhlet extraction, using petroleum ether, diethyl ether and ethyl acetate with a volume ratio of 1:1:1 as the extraction solvent, controlling the temperature to make the refluxing frequency 20 times / hour, and extracting for 3 hours;

[0077] (5) Second weighing: removing the solvent by distillation or boiling water bath, and drying to constant weight to obtain m2;

[0078] (6) Calculation: the crude fat content X was calculated by the formula:

[0079] The commercially available M brand of full-value cat food was taken as the detection object to further illustrate the technical effects achieved by the present application.

[0080] The full-value cat food was crushed, passed through a 40-mesh sieve, 4.000g of the undersize was weighed, and the detection method of the above examples and comparative examples was used to detect the crude fat content, and each group was measured for 3 times, and the average value was taken.

[0081] Meanwhile, 4.000g of the undersize was weighed, and the second method in GB / 5009.6-2016 Determination of Crude Fat in Foods, acid hydrolysis method was used to detect the crude fat content in the sample, and the results were shown in Table 1.

[0082] Table 1 Comparison of the crude fat content in the full-value cat food detected by different detection methods

[0083] ​​ Detection method Crude fat content % Example 1 16.7 Example 2 17.9 Example 3 17.5 Comparative example 1 11.1 Comparative example 2 12.7 Comparative example 3 13.2 GB / 5009.6-2016 17.3

[0084] From the above, the detection method of the application realizes rapid detection of crude fat, and the detection effect is better consistent with the national standard.

[0085] From the above, the detection method of the application realizes rapid detection of crude fat, and the detection effect is better consistent with the national standard.

[0086] The above is only a preferred embodiment of the application, and does not limit the application, and any simple modification, change and equivalent structural change of the above embodiment according to the technical essence of the application still belong to the protection scope of the technical solution of the application.

Claims

1. A method for detecting the content of crude fat in pet food, characterized by, The method comprises the following steps: (1) acid hydrolysis pretreatment: adding hydrochloric acid solution to the pet feed to be tested, heating to micro-boiling, keeping, cooling, filtering, obtaining residue, washing to neutral; (2) freezing treatment: freezing treatment of the residue washed to neutral; (3) first weighing: drying the residue after freezing treatment, adding glass beads, drying, cooling, and weighing m1; (4) extraction: Soxhlet extraction, controlling the temperature to make the refluxing frequency 10-20 times / hour, and extracting for 1-3 hours; (5) second weighing: removing the solvent and drying to constant weight to obtain m2; (6) calculation: obtaining the crude fat content X; The keeping time in step (1) is 0.3-0.5h; The freezing treatment in step (2) is: placing the residue at-20 to-15℃ for 0.5-1h; The solvent for Soxhlet extraction in step (4) is petroleum ether, diethyl ether and ethyl acetate, and the volume ratio of the petroleum ether, diethyl ether and ethyl acetate is 1:3:

1.

2. The detection method according to claim 1, characterized in that, The particle size of the pet feed to be tested in step (1) is 20-60 mesh.

3. The detection method according to claim 2, characterized in that, The pet feed comprises pet compound feed and pet additive mixed feed.

4. The method of claim 1, wherein The concentration of the hydrochloric acid in step (1) is 2-3M.

5. The method of claim 1, wherein The conditions for Soxhlet extraction in step (4) are: Soxhlet extraction, controlling the temperature to make the refluxing frequency 13-16 times / hour, and extracting for 1.5-2.5 hours.

6. The method of claim 1, wherein The method for removing the solvent in step (5) is: distillation or boiling water bath.

7. The method of claim 1, wherein, The formula for calculating the crude fat content X in step (6) is: .

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