阅读说明：本技术 一种巴氏杀菌热处理风味酸奶中蛋白质含量的分析方法 (Method for analyzing protein content in pasteurized heat-treated flavored yogurt ) 是由 林琳 于 2019-10-31 设计创作，主要内容包括：本发明涉及一种蛋白质含量的分析方法,具体公开了一种巴氏杀菌热处理风味酸奶中蛋白质含量的分析方法。该分析方法至少包括以下步骤(1)将待分析的酸奶配置成不同的标准溶液,并使用凯氏定氮仪对其检测；对上述标准溶液分别进行前处理后,依次使用凯氏定氮仪和乳成分分析仪检测,将结果进行定标,即得标准曲线；(2)将待分析类酸奶进行前处理后,使用乳成分分析仪检测得到检测结果；(3)将步骤(1)的检测结果与步骤(2)的标准曲线相对比,即得蛋白质的含量。本发明提供的检测方法具有测试范围广、操作简便、测试高效、精准、重复性好等优点。(The invention relates to an analysis method of protein content, and particularly discloses an analysis method of protein content in pasteurized heat-treated flavored yogurt. The analysis method at least comprises the following steps of (1) preparing the yoghourt to be analyzed into different standard solutions, and detecting the standard solutions by using a Kjeldahl apparatus; respectively pretreating the standard solutions, sequentially detecting by using a Kjeldahl apparatus and a milk component analyzer, and calibrating the result to obtain a standard curve; (2) pretreating the yogurt to be analyzed, and detecting by using a milk component analyzer to obtain a detection result; (3) and (3) comparing the detection result of the step (1) with the standard curve of the step (2) to obtain the content of the protein. The detection method provided by the invention has the advantages of wide test range, simplicity and convenience in operation, high efficiency and accuracy in test, good repeatability and the like.)

1. An analysis method for the protein content in pasteurized heat-treated flavored yogurt, characterized by comprising at least the following steps:

(1) preparing the yoghourt to be analyzed into different standard solutions, and detecting the standard solutions by using a Kjeldahl apparatus; respectively pretreating the standard solutions, sequentially detecting by using a Kjeldahl apparatus and a milk component analyzer, and calibrating the result to obtain a standard curve;

(2) pretreating the yogurt to be analyzed, and detecting by using a milk component analyzer to obtain a detection result;

(3) and (3) comparing the detection result of the step (2) with the standard curve of the step (1) to obtain the content of the protein in the pasteurized heat-treated flavored yogurt.

2. The method for analyzing the protein content in pasteurized heat-treated flavored yogurt according to claim 1, wherein the mass ratio of the standard solution in step (1) is (0.1-3): 100.

3. the method for analyzing the protein content in pasteurized heat-treated flavored yogurt according to claim 1, wherein the mass ratio of the standard solution in step (1) is (1-2): 100.

4. the method for analyzing the protein content in pasteurized, heat-treated, flavored yogurt according to claim 1, wherein the pretreatment comprises centrifuging the sample to obtain a supernatant, and heating the supernatant.

5. The method for analyzing the protein content in pasteurized heat-treated flavored yogurt according to claim 4, wherein the centrifugation process is to put the sample into a centrifuge tube of 50mL or 100mL and process the sample with a centrifuge.

6. The method for analyzing the protein content in pasteurized heat-treated flavored yogurt according to claim 4, wherein the rotation speed of the centrifuge is 1300-1800r/min, and the centrifugation time is 6-10 min.

7. The method for analyzing the protein content in pasteurized heat-treated flavored yogurt according to claim 6, wherein the rotation speed of the centrifuge is 1500-.

8. The method for analyzing the protein content in pasteurized, heat-treated flavored yogurt according to claim 4, wherein the heating treatment is a constant temperature heating of the supernatant at 30-42 ℃ for 5-9 min.

9. The method for analyzing the protein content in pasteurized, heat-treated flavored yogurt according to claim 4, wherein the heating treatment is a constant temperature heating of the supernatant at 35-40 ℃ for 6-8 min.

10. The method for analyzing the protein content in pasteurized heat-treated flavored yogurt according to claim 8, wherein the constant-temperature heating manner is selected from one or more of constant-temperature water bath, constant-temperature oil bath and constant-temperature sand bath.

Technical Field

The invention relates to a method for detecting protein content, in particular to a method for analyzing the protein content in pasteurized heat-treated flavored yogurt.

Background

Protein is one of the main nutrients in milk, and the content of protein in milk can reflect the quality of the milk. The national standard stipulates that the protein content in milk is more than or equal to 2.9g/100mL, and the prior art mainly comprises three detection methods for measuring the protein content in food, namely a Kjeldahl method, a spectrophotometry method and a combustion method, but the three methods have the defects of complicated operation steps, time and labor waste, high cost and the like.

Therefore, the research on a new detection method to realize a detection method with high efficiency, wide analysis range, low cost, high accuracy and high repetition rate, especially the detection of the protein content in the pasteurized heat-treated flavored yogurt, is the focus of attention of the technicians in the field.

Disclosure of Invention

In order to solve the technical problem, the invention provides an analysis method for the protein content in pasteurized heat-treated flavored yogurt, which at least comprises the following steps:

(1) preparing the yoghourt to be analyzed into different standard solutions, and detecting the standard solutions by using a Kjeldahl apparatus; respectively pretreating the standard solutions, sequentially detecting by using a Kjeldahl apparatus and a milk component analyzer, and calibrating the result to obtain a standard curve;

(2) pretreating the yogurt to be analyzed, and detecting by using a milk component analyzer to obtain a detection result;

(3) and (3) comparing the detection result of the step (2) with the standard curve of the step (1) to obtain the content of the protein in the pasteurized heat-treated flavored yogurt.

As a preferable technical scheme of the invention, the mass ratio of the standard solution in the step (1) is (0.5-2): 100.

as a preferable technical scheme of the invention, the mass ratio of the standard solution in the step (1) is (1-2): 100.

in a preferred embodiment of the present invention, the pretreatment includes centrifuging the analyte to obtain a supernatant, and heating the supernatant.

In a preferred embodiment of the present invention, the centrifugation is performed by loading the sample into a 50mL or 100mL centrifuge tube and using a centrifuge.

As a preferable technical scheme of the invention, the rotating speed of the centrifuge is 1300-1800r/min, and the centrifugation time is 6-10 min.

As a preferable technical scheme of the invention, the rotating speed of the centrifugal machine is 1500-1700r/min, and the centrifugal time is 7-9 min.

As a preferable technical scheme of the invention, the heating treatment is to heat the supernatant at the constant temperature of 30-42 ℃ for 5-9 min.

As a preferable technical scheme of the invention, the heating treatment is to heat the supernatant at the constant temperature of 35-40 ℃ for 6-8 min.

In a preferred embodiment of the present invention, the constant temperature heating mode is selected from one or more of a constant temperature water bath, a constant temperature oil bath, and a constant temperature sand bath.

Has the advantages that: the invention provides an analysis method of protein content in pasteurized heat-treated flavored yogurt, which is characterized in that a special pretreatment mode is selected according to the basic characteristics of the yogurt, the advantages of a Kjeldahl apparatus and a milk component analyzer are combined, and the analysis method of the protein content in the pasteurized heat-treated flavored yogurt is obtained.

Detailed Description

The disclosure may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the examples included therein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

The term "prepared from …" as used herein is synonymous with "comprising". The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted to include the ranges "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.

The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. "optional" or "any" means that the subsequently described event or events may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

In addition, the indefinite articles "a" and "an" preceding an element or component of the invention are not intended to limit the number requirement (i.e., the number of occurrences) of the element or component. Thus, "a" or "an" should be read to include one or at least one, and the singular form of an element or component also includes the plural unless the stated number clearly indicates that the singular form is intended.

In order to solve the technical problem, the invention provides an analysis method for the protein content in pasteurized heat-treated flavored yogurt, which at least comprises the following steps:

(1) preparing different standard solutions of the yogurt to be analyzed and distilled water, and detecting the standard solutions by using a Kjeldahl apparatus; respectively pretreating the standard solutions, sequentially detecting by using a Kjeldahl apparatus and a milk component analyzer, and calibrating the result to obtain a standard curve;

(2) pretreating the yoghourt to be analyzed, and detecting by using a milk component analyzer to obtain a detection result;

(3) and (3) comparing the detection result of the step (2) with the standard curve of the step (1) to obtain the content of the protein in the pasteurized heat-treated flavored yogurt.

In a preferred embodiment, the mass ratio of the standard solution in the step (1) is (0.5-2): 100.

in a more preferred embodiment, the mass ratio of the standard solution in the step (1) is (1-2): 100.

in a preferred embodiment, the pretreatment is to centrifuge the analyte to obtain a supernatant, and heat-treat the supernatant.

In a preferred embodiment, the centrifugation process is to load the analyte into a 50mL or 100mL centrifuge tube and process the analyte by using a centrifuge.

In a preferred embodiment, the rotation speed of the centrifuge is 1300-1800r/min, and the centrifugation time is 6-10 min.

In a more preferred embodiment, the rotation speed of the centrifuge is 1500-.

In a preferred embodiment, the heating treatment is to heat the supernatant at a constant temperature of 30-42 ℃ for 5-9 min.

In a more preferred embodiment, the heating treatment is to heat the supernatant at a constant temperature of 35-40 ℃ for 6-8 min.

In a preferred embodiment, the constant temperature heating mode is selected from one or more of constant temperature water bath, constant temperature oil bath and constant temperature sand bath.

In experiments, the inventor of the present application finds that a sample is subjected to centrifugation and pretreatment by heating, and a detection method of a kjeldahl azotometer and a milk component analyzer is combined to obtain a high-efficiency and accurate test result, and the reason why the high-efficiency and accurate test result is possible is that when the sample detected by the present invention contains special components, such as fruit juice, lactobacillus bulgaricus and streptococcus thermophilus, and the protein content in the sample is detected, the interference of impurities on the detection result can be reduced by selecting a specific centrifugation rate and a specific heating temperature, so that the effects of wide detection range, high efficiency, accuracy and high repetition rate are realized.

It should be noted that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and that the insubstantial modifications and adaptations of the present invention by those skilled in the art based on the above disclosure are still within the scope of the present invention.