阅读说明：本技术 一种利用差示扫描量热仪快速测定马铃薯粉糊化程度的方法 (Method for rapidly determining gelatinization degree of potato flour by using differential scanning calorimeter ) 是由 宋芳芳 徐艳文 纪顺 祁岩龙 张忆洁 于洋 张俊 刘亚 宋鱼 姚国民 龚凡 于 2021-02-03 设计创作，主要内容包括：本发明涉及食品检测技术领域,提供了一种利用差示扫描量热仪快速测定马铃薯粉糊化程度的方法,本发明通过控制马铃薯粉与水的质量比为1:2～1:4,能够防止马铃薯粉不糊化,马铃薯粉糊化度结果较为稳定,能准确测定马铃薯粉的糊化度。本发明将得到的马铃薯粉的DSC样品采用差示扫描量热仪进行测试,得到马铃薯粉的DSC样品糊化热焓值δH；然后按照上述技术方案所述的方法得到马铃薯生全粉的DSC样品的糊化热焓值δH’；将上述方案得到的δH和δH’代入式(I)计算马铃薯粉的糊化度。实验结果表明,在本发明提供的测定方法下能够快速且准确的测定出马铃薯粉的糊化度,对薯粉类食品的加工过程控制有重要意义。(The invention relates to the technical field of food detection, and provides a method for rapidly determining the gelatinization degree of potato flour by using a differential scanning calorimeter, wherein the potato flour is prevented from being ungelatinized by controlling the mass ratio of the potato flour to water to be 1: 2-1: 4, the gelatinization degree result of the potato flour is relatively stable, and the gelatinization degree of the potato flour can be accurately determined. The DSC sample of the obtained potato powder is tested by a differential scanning calorimeter to obtain a gelatinization enthalpy value delta H of the DSC sample of the potato powder; then obtaining the gelatinization enthalpy value delta H' of the DSC sample of the potato raw whole flour according to the method of the technical scheme; substituting the delta H and the delta H' obtained by the scheme into formula (I) to calculate the gelatinization degree of the potato powder. Experimental results show that the gelatinization degree of the potato flour can be rapidly and accurately determined by the determination method provided by the invention, and the method has an important significance on processing process control of potato flour foods.)

1. A method for rapidly determining gelatinization degree of potato flour by using a differential scanning calorimeter comprises the following steps:

(1) mixing potato powder with water to obtain mixed slurry, and then standing to obtain a DSC sample; the mass ratio of the potato powder to the water is 1: 2-1: 4;

(2) testing the DSC sample obtained in the step (1) by using a differential scanning calorimeter to obtain a gelatinization enthalpy value delta H of the DSC sample of the potato powder;

(3) preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining a gelatinization enthalpy value delta H' of the DSC sample of the raw potato whole flour according to the method in the step (2);

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization ═ δ H '- δ H)/δ H' × 100% formula (I).

2. The method of claim 1, wherein the method of preparing potato flakes of step (1) comprises: drying the potato chips at 60-70 ℃, and crushing to obtain the potato powder.

3. The method according to claim 2, wherein the drying temperature is 60 to 65 ℃.

4. The preparation method according to claim 1, wherein the potato flour in the step (1) has a particle size of 50-300 mesh.

5. The production method according to claim 1, wherein the standing in the step (1) is performed under a sealed condition.

6. The production method according to claim 1, wherein the temperature of the standing in the step (1) is room temperature.

7. The method according to claim 6, wherein the standing time in the step (1) is 0.5 to 2 hours.

8. The method according to claim 1, wherein the parameters tested by the differential scanning calorimeter in step (2) include: the nitrogen flow is 0-60 mL/min, the pressure is 0.01-0.05 MPa, the heating rate is 5-15℃/min, the program temperature is set to be 20-100 ℃, and the temperature is kept for 0-10 min.

Technical Field

The invention relates to the technical field of food detection, in particular to a method for rapidly determining gelatinization degree of potato flour by using a differential scanning calorimeter.

Background

The main component of the potato powder is starch, which accounts for about 60% of the mass of the potato powder, so that the physical and chemical properties of the potato powder have great influence on the eating quality, the processing property and the storage stability of the potato powder in the processing process of the staple food. The gelatinization degree of the starch directly influences the eating quality, the processing characteristic and the storage stability of the potato powder in the processing process of the staple food. Therefore, the determination of the gelatinization process of potato starch is of great significance.

The factors influencing the gelatinization characteristics of starch are more, such as the factors of a sample: the water content, starch type, particle size, amylose and amylopectin content, etc., and in addition, the auxiliary materials added in the product processing process, the production environment, etc., also have different degrees of influence on the gelatinization characteristics of the starch. Currently, commonly used methods for measuring the gelatinization characteristics of starch include a brabender viscometer method, an enzymatic hydrolysis method, a rapid starch viscosity meter (RapidVisco-analyzer, RVA), a Differential Scanning Calorimeter (DSC), and the like. However, due to a lot of factors influencing the starch gelatinization characteristics, the gelatinization degree values obtained by measuring the starch gelatinization by the DSC method have quite large differences, so that a method capable of rapidly and accurately measuring the gelatinization degree of potato flour is needed.

Disclosure of Invention

The invention aims to provide a method for rapidly determining the gelatinization degree of potato starch by using a differential scanning calorimeter.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a method for rapidly determining gelatinization degree of potato flour by using a differential scanning calorimeter, which comprises the following steps:

(1) mixing potato powder with water to obtain mixed slurry, and then standing to obtain a DSC sample; the mass ratio of the potato powder to the water is 1: 2-1: 4;

(2) testing the DSC sample obtained in the step (1) by using a differential scanning calorimeter to obtain a gelatinization enthalpy value delta H of the DSC sample of the potato powder;

(3) preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining a gelatinization enthalpy value delta H' of the DSC sample of the raw potato whole flour according to the method in the step (2);

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization ═ δ H '- δ H)/δ H' × 100% formula (I).

Preferably, the preparation method of the potato flour in the step (1) comprises the following steps: drying the potato chips at 60-70 ℃, and crushing to obtain the potato powder.

Preferably, the drying temperature is 60-65 ℃.

Preferably, the grain size of the potato powder in the step (1) is 50-300 meshes.

Preferably, the standing in the step (1) is performed under a sealed condition.

Preferably, the temperature of standing in the step (1) is room temperature.

Preferably, the standing time in the step (1) is 0.5-2 h.

Preferably, the parameters tested by the differential scanning calorimeter in the step (2) include: the nitrogen flow is 0-60 mL/min, the pressure is 0.01-0.05 MPa, the heating rate is 5-15℃/min, the program temperature is set to be 20-100 ℃, and the temperature is kept for 0-10 min.

The invention provides a method for rapidly determining gelatinization degree of potato flour by using a differential scanning calorimeter, which comprises the following steps: mixing potato powder with water to obtain mixed slurry, and standing to obtain a sample to be detected; the mass ratio of the potato powder to the water is 1: 2-1: 4; testing the obtained DSC sample of the potato powder by adopting a differential scanning calorimeter to obtain a gelatinization enthalpy value delta H of the DSC sample of the potato powder; preparing a DSC sample of the potato raw whole flour according to the method for preparing the DSC sample of the potato flour, and then obtaining the gelatinization enthalpy value delta H' of the DSC sample of the potato raw whole flour according to the method in the technical scheme; substituting the delta H and the delta H' obtained by the scheme into formula (I) to calculate the gelatinization degree of the potato powder. According to the invention, by controlling the mass ratio of the potato flour to the water, the potato flour can be prevented from being incapable of being gelatinized, the gelatinization degree result of the potato flour is relatively stable, and the gelatinization degree of the potato flour can be accurately measured. Experimental results show that the gelatinization degree of the potato flour can be rapidly and accurately determined by the determination method provided by the invention, and the method has an important significance on processing process control of potato flour foods.

Detailed Description

The invention provides a method for rapidly determining gelatinization degree of potato flour by using a differential scanning calorimeter, which comprises the following steps:

(1) mixing potato powder with water to obtain mixed slurry,

(2) then standing to obtain a DSC sample; the mass ratio of the potato powder to the water is 1: 2-1: 4;

(2) testing the DSC sample obtained in the step (1) by using a differential scanning calorimeter to obtain a gelatinization enthalpy value delta H of the DSC sample;

(3) preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining a gelatinization enthalpy value delta H' of the DSC sample of the raw potato whole flour according to the method in the step (2);

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization ═ δ H '- δ H)/δ H' × 100% formula (I).

According to the invention, potato powder and water are mixed to obtain mixed slurry, and then standing is carried out to obtain a DSC sample.

In the present invention, the preparation method of the potato flour preferably comprises: drying the potato chips at 60-70 ℃, and crushing to obtain the potato powder.

In the present invention, the method for producing potato chips is preferably: fresh potatoes are peeled, washed and cut into slices. The thickness of the potato chip is not particularly limited, and can be adjusted according to needs. In the invention, the thickness of the potato chip is preferably (2-8) mm, and more preferably 4 mm. In the present invention, when the thickness of the potato chip is within the above range, the potato chip can be dried more easily.

The source of the potatoes is not particularly limited in the present invention, and the potatoes can be obtained by those skilled in the art. In the present invention, the potato is preferably a gram-new potato.

In the invention, the drying temperature is preferably 60-65 ℃. In the invention, when the drying temperature is in the range, the prepared potato flour has low gelatinization degree and is closer to the raw potato flour.

The drying time is not particularly limited, and the moisture content of the dried potato chips can be 9-11% of the weight of the dried potato chips. In the present invention, when the moisture content of the dried potato chip is within the above range, the subsequent crushing of the potato chip and the control of the gelatinization process are facilitated.

In the invention, the grain size of the potato powder is preferably 50-300 meshes, and more preferably 100-200 meshes. In the invention, when the grain size of the potato powder is in the above range, insufficient combination and dissolution of the potato powder and water caused by the overlarge grain size of the potato powder can be prevented, and a gelatinization degree is low because partial starch does not undergo gelatinization reaction.

The crushing operation mode is not particularly limited, and the crushing mode known to a person skilled in the art can be adopted to ensure that the grain size of the potato powder is within the range. In the invention, the crushing device is preferably a pulverizer.

In the invention, the mass ratio of the potato powder to the water is 1: 2-1: 4, preferably 1: 3-1: 4. In the invention, when the mass ratio of the potato powder to water is higher than 1:2, the potato powder has insufficient water absorption and can not form uniform potato powder paste due to the existence of dry powder; when the mass ratio of the potato powder to the water is lower than 1:4, the formed starch paste has large water content, uniform potato paste cannot be formed, and the potato powder can quickly generate precipitates; when the mass ratio of the potato flour to the water is within the range, the potato flour can be ensured to be fully gelatinized.

The mixing mode of the potato flour and the water is not particularly limited, and the potato flour and the water can be fully and uniformly mixed by adopting the mixing mode known by the technical personnel in the field. In the present invention, the potato powder is preferably mixed with water by using a homogenizer. The parameters for mixing by the homogenizer are not specially limited, and the potato powder and the water can be uniformly mixed by adjusting the using amount of the potato powder and the water to be mixed according to the requirement.

After the mixed slurry is obtained, the DSC sample is obtained by standing the mixed slurry.

In the invention, the temperature of the standing is preferably room temperature, and more preferably (20-25) DEG C; the standing time is preferably 0.5-2 h, and more preferably 1-2 h. In the invention, when the standing temperature and the standing time are in the range, the potato powder is favorable for water absorption and swelling, and the subsequent gelatinization of the potato powder is more favorable.

In the present invention, the standing is preferably performed under sealing. In the present invention, the seal can exclude air and can prevent moisture from evaporating when left standing. The operation mode of the sealing is not particularly limited, and the mixed slurry can be in a sealed environment. In the present invention, the seal is preferably: and (3) placing the mixed slurry in a crucible, covering the crucible cover, and sealing by using a sample pressing machine.

After the DSC sample of the potato powder is obtained, the DSC sample of the potato powder is tested by a differential scanning calorimeter to obtain the gelatinization enthalpy value delta H of the DSC sample of the potato powder.

According to the invention, the DSC sample of the potato powder is preferably sealed and then tested by a differential scanning calorimeter. In the present invention, the operation mode of sealing the DSC sample of potato starch is the same as the operation mode of sealing at the time of standing, and is not described herein again.

In the invention, the DSC sample of the potato powder is sealed and then weighed, the total weight is recorded, the DSC sample of the potato powder is weighed again after being stabilized, and the front and the rear masses are inconsistent, so that the air leakage phenomenon needs to be determined again. In the invention, the DSC sample of the potato powder is sealed and then tested by adopting a differential scanning calorimeter, so that the phenomenon that water is evaporated along with the rise of temperature in the DSC measurement process of the potato powder to influence the gelatinization process can be prevented.

In the present invention, the parameters tested by the differential scanning calorimeter preferably include: raising the temperature from 20 ℃ to 100 ℃ at a programmed temperature setting of 0-10 min under the conditions that the nitrogen flow is 0-60 mL/min, the pressure is 0.01-0.05 MPa, the temperature raising rate is 5-15℃/min; more preferably, the nitrogen flow is (20-40) mL/min, the pressure is 0.03MPa, the heating rate is 10 ℃/min, the temperature is programmed to be increased from 20 ℃ to 100 ℃, and the temperature is maintained for 10 min. In the invention, when the parameters tested by the differential scanning calorimeter are in the range, the potato flour can be ensured to be fully gelatinized, and the gelatinization process of the potato flour can be rapidly and accurately researched.

After the gelatinization enthalpy value delta H of the DSC sample is obtained, the DSC sample of the potato raw whole flour is prepared according to the method of the technical scheme.

The raw potato whole flour is not particularly limited in source, is the same as the potato of the potato flour to be detected, and is prepared by the preparation method of the raw potato whole flour well known to the technical personnel in the field. In the present invention, the method for preparing the raw potato whole flour preferably comprises: selecting, cleaning, peeling, slicing, rinsing, freeze-drying and powdering.

In the present invention, the preparation method of the DSC sample of the potato raw whole flour is the same as the preparation method of the DSC sample, and the detailed description thereof is omitted.

After the DSC sample of the potato raw whole flour is obtained, the DSC sample of the potato raw whole flour is tested according to the parameters for testing the DSC sample by adopting the differential scanning calorimeter, and the gelatinization enthalpy value delta H' of the DSC sample of the potato raw whole flour is obtained.

After obtaining the gelatinization enthalpy value delta H of the DSC sample and the gelatinization enthalpy value delta H' of the DSC sample of the potato raw whole flour, the gelatinization degree of the potato flour is calculated according to the formula (I):

degree of gelatinization ═ δ H '- δ H)/δ H' × 100% formula (I).

In the present invention, the degree of gelatinization is directly reflected in the degree of gelatinization of the starch. According to the invention, the gelatinization degree of the potato flour can be obtained through the formula (I).

The method provided by the invention can prevent the potato powder from being not gelatinized by controlling the mass ratio of the potato powder to the water, can accurately measure the gelatinization degree of the potato powder, and has important significance for processing process control of potato powder food.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

(1) Preparing potato powder: selecting fresh gram new potatoes, peeling, cleaning, cutting into 4mm slices, and drying at 65 ℃ until the water content of the potato slices is 9-11%. The potato chips are crushed by a powder grinding machine and then screened by a 100-mesh sieve.

Accurately weighing 3.00g of potato powder in a homogenizing bag, then adding 6.00g of distilled water, homogenizing for 2min by a homogenizer, and fully and uniformly mixing to obtain mixed slurry formed by the potato powder and the water; accurately weighing 5mg of mixed slurry, placing the mixed slurry in a hydraulic stainless steel crucible, flatly paving a sample at the bottom of the crucible, covering a stainless steel crucible cover, sealing the sample by using a sample press, and weighing the total weight of the sample after sealing; then standing the sealed crucible for 2 hours to obtain a DSC sample; the mass ratio of the potato powder to the water is 1: 2;

(2) testing the DSC sample obtained in the step (1) by using a differential scanning calorimeter to obtain a gelatinization enthalpy value delta H of the DSC sample; the parameters tested were: under the conditions of a nitrogen flow of 20mL/min, a pressure of 0.03MPa and a heating rate of 10 ℃/min, the temperature of the program is set to be increased from 20 ℃ to 100 ℃ and kept for 10 min. The gelatinization enthalpy value delta H of the obtained DSC sample is shown in the table 1;

wherein, the data processing of the test result by adopting a differential scanning calorimeter is automatically obtained after being analyzed by DSC Universal Analysis software of a computer. Each set of data was tested in 3 replicates, averaged and calculated. The orthogonal design and its analysis of variance results were performed in a software orthogonal design assistant, and the data correlation analysis and Relative Standard Deviation (RSD) were performed in Microsoft Excel.

(3) Preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining the gelatinization enthalpy value delta H 'of the DSC sample of the raw potato whole flour according to the method in the step (2), wherein the gelatinization enthalpy value delta H' is 4.88;

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization (δ H '- δ H)/δ H' x 100% formula (I)

The gelatinization degree of the potato flour is 49.1 percent through calculation.

Example 2

The difference between the step (1) and the step (2) and the embodiment 1 is that the mass ratio of the potato powder to the water is 1:3, and the rest steps are the same as the embodiment 1. The gelatinization enthalpy value delta H of the obtained DSC sample is shown in the table 1;

(3) preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining the gelatinization enthalpy value delta H 'of the DSC sample of the raw potato whole flour according to the method in the step (2), wherein the gelatinization enthalpy value delta H' is 4.88;

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization (δ H '- δ H)/δ H' x 100% formula (I)

The gelatinization degree of the potato flour is 69.3 percent through calculation.

Example 3

The difference between the step (1) and the step (2) and the embodiment 1 is that the mass ratio of the potato powder to the water is 1:4, and the rest steps are the same as the embodiment 1. The gelatinization enthalpy value delta H of the obtained DSC sample is shown in the table 1;

(3) preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining the gelatinization enthalpy value delta H 'of the DSC sample of the raw potato whole flour according to the method in the step (2), wherein the gelatinization enthalpy value delta H' is 4.88;

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization (δ H '- δ H)/δ H' x 100% formula (I)

The gelatinization degree of the potato flour is 69.5 percent by calculation.

Comparative example 1

The difference between the step (1) and the step (2) and the embodiment 1 is that the mass ratio of the potato powder to the water is 1:1, and the rest steps are the same as the embodiment 1.

From the experimental results of comparative example 1, it can be seen that when the mass ratio of potato flour to water is 1:1, a uniform potato mash cannot be formed when the DSC sample is tested, because too little water content results in insufficient gelatinization of the potato flour and a uniform potato mash cannot be formed.

Comparative example 2

The difference between the step (1) and the step (2) and the embodiment 1 is that the mass ratio of the potato powder to the water is 1:5, and the rest steps are the same as the embodiment 1.

From the experimental results of comparative example 2, it was found that when the mass ratio of potato flour to water was 1:5, a uniform potato starch paste could not be formed when the DSC sample was tested, because the water content was too high to form a uniform liquid, a precipitate was rapidly generated, and thus a uniform potato starch paste could not be formed.

TABLE 1 influence of different mass ratios of potato flour to water on gelatinization properties of potato flour

Powder to water ratio	Initial temperature T0	Peak temperature TP	Termination temperature TC	Gelatinization enthalpy value delta H	Degree of gelatinization of potato
						1：2	65.55±0.35b	68.45±0.07b	72.7±0.14b	2.486±0.06b	49.1％
1：3	65.25±0.07b	68.05±0.21ab	71.7±0.28a	1.497±0.04a	69.3％
						1：4	64.35±0.21a	67.55±0.21a	71.7±0.14a	1.49±0.16a	69.5％

As can be seen from Table 1, different mass ratios of potato flour to water have an effect on the gelatinization properties of potato flour, but these ratios both gelatinize the potato and can be used to determine the gelatinization degree of the potato. In contrast, in combination with comparative example 1 and comparative example 2, the potato flour was not completely gelatinized when the water-flour ratio was 1:1 or 1: 5. From the results, it can be shown that when the mass ratio of the potato flour to the water is limited to the above range, the gelatinization degree of the potato flour can be accurately determined, and the method has important significance for processing process control of potato flour foods.

Example 4

The difference from the embodiment 1 is that the temperature in the step (1) is controlled to be 60 ℃ to dry the potato chips until the moisture of the potato chips is 9-11%. The potato chips are crushed by a powder grinding machine and then screened by a 100-mesh sieve. The remaining procedure was the same as in example 1. The gelatinization enthalpy value delta H of the obtained DSC sample is shown in the table 3;

(3) preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining the gelatinization enthalpy value delta H 'of the DSC sample of the raw potato whole flour according to the method in the step (2), wherein the gelatinization enthalpy value delta H' is 4.88;

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization (δ H '- δ H)/δ H' x 100% formula (I)

The gelatinization degree of the potato flour is 37.1 percent through calculation.

Example 5

The difference from the embodiment 1 is that the temperature in the step (1) is controlled to be 65 ℃ to dry the potato chips until the moisture of the potato chips is 9-11%. The potato chips are crushed by a powder grinding machine and then screened by a 100-mesh sieve. The remaining procedure was the same as in example 1. The gelatinization enthalpy value delta H of the obtained DSC sample is shown in the table 3;

(3) preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining the gelatinization enthalpy value delta H 'of the DSC sample of the raw potato whole flour according to the method in the step (2), wherein the gelatinization enthalpy value delta H' is 4.88;

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization (δ H '- δ H)/δ H' x 100% formula (I)

The gelatinization degree of the potato powder is 49.6 percent through calculation.

Example 6

The difference from the embodiment 1 is that the temperature in the step (1) is controlled to be 70 ℃ to dry the potato chips until the moisture of the potato chips is 9-11%. The potato chips are crushed by a powder grinding machine and then screened by a 100-mesh sieve. The remaining procedure was the same as in example 1. The gelatinization enthalpy value delta H of the obtained DSC sample is shown in the table 3;

(3) preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining the gelatinization enthalpy value delta H 'of the DSC sample of the raw potato whole flour according to the method in the step (2), wherein the gelatinization enthalpy value delta H' is 4.88;

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization (δ H '- δ H)/δ H' x 100% formula (I)

The gelatinization degree of the potato flour is 47.5 percent through calculation.

Table 3: influence of drying temperature on gelatinization characteristic of potato flour

Drying temperature	Initial temperature T0	Peak temperature TP	Termination temperature TC	Gelatinization enthalpy value delta H	Gelatinization degree of potato flour
						60	67.75±0.64b	70.25±0.35a	72.4±0.14a	3.07±0.11d	37.1％
65	65.75±0.78a	69.8±0.71a	73±0.21ab	2.46±0.14c	49.6％
						70	68.85±0.78b	70.9±0.85ab	75±0.71c	2.56±0.11c	47.5％

As can be seen from Table 3, the initial temperature changes irregularly, the peak temperature gradually decreases, and the final temperature increases and then decreases as the drying temperature increases in the potato powder obtained by drying the potato chips at different temperatures (60-70 ℃). With the increase of the treatment temperature, the gelatinization enthalpy value of the potato flour shows irregular change of increasing and then decreasing. The heat enthalpy value of the potato powder at the same thickness and different temperatures has obvious change, the gelatinization heat enthalpy is maximum at 60 ℃, and the gelatinization heat enthalpy value of the dried powder at the temperature is maximum.

Example 7

The difference from the example 1 is that the potato chips in the step (1) are crushed by a powder grinding machine and then screened by a 50-mesh sieve. The remaining procedure was the same as in example 1. The gelatinization enthalpy value delta H of the obtained DSC sample is shown in the table 4;

(3) preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining the gelatinization enthalpy value delta H 'of the DSC sample of the raw potato whole flour according to the method in the step (2), wherein the gelatinization enthalpy value delta H' is 4.88;

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization (δ H '- δ H)/δ H' x 100% formula (I)

The gelatinization degree of the potato flour is 57.3 percent through calculation.

Example 8

The difference from the example 1 is that the potato chips in the step (1) are crushed by a powder grinding machine and then sieved by a 200-mesh sieve. The remaining procedure was the same as in example 1. The gelatinization enthalpy value delta H of the obtained DSC sample is shown in the table 4;

(3) preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining the gelatinization enthalpy value delta H 'of the DSC sample of the raw potato whole flour according to the method in the step (2), wherein the gelatinization enthalpy value delta H' is 4.88;

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization (δ H '- δ H)/δ H' x 100% formula (I)

The gelatinization degree of the potato flour is 45.1 percent through calculation.

Example 9

The difference from the example 1 is that the potato chips in the step (1) are crushed by a powder grinding machine and then sieved by a 300-mesh sieve. The remaining procedure was the same as in example 1. The gelatinization enthalpy value delta H of the obtained DSC sample is shown in the table 4;

(3) preparing a DSC sample of the raw potato whole flour according to the method in the step (1), and then obtaining the gelatinization enthalpy value delta H 'of the DSC sample of the raw potato whole flour according to the method in the step (2), wherein the gelatinization enthalpy value delta H' is 4.88;

(4) calculating the gelatinization degree of the potato powder according to the formula (I):

degree of gelatinization (δ H '- δ H)/δ H' x 100% formula (I)

The gelatinization degree of the potato flour is 23.6 percent through calculation.

Table 4: influence of potato powder particle size on gelatinization characteristics

Particle size	Initial temperature T0	Peak temperature TP	Termination temperature TC	Gelatinization enthalpy value delta H	Degree of gelatinization of potato flour
						50	69.75±0.28a	73.45±0.21a	77.5±0.21a	2.08±0.03a	57.3％
200	69.1±0.42a	72.8±0.42a	76.6±0.42a	2.68±0.17b	45.1％
						300	68.85±0.57a	72.45±0.21a	76.8±0.35a	3.73±0.27c	23.6％

As can be seen from table 4, the smaller the potato flour particle size, the lower the onset temperature, and the longer the time to peak, the gradually lower the termination temperature. The gelatinization enthalpy value of the potato powder changes along with the change of the size of the crushed particles of the potato powder, the larger the potato powder particles are, the smaller the gelatinization enthalpy value of the potato powder particles are, probably because the crushed particles are larger and are not sufficiently combined and dissolved with water, and partial starch is not gelatinized. The smaller the crushed particles are, the larger the gelatinization enthalpy of the potato powder is, which proves that the smaller the particles are, the more the starch is fully fused with water, the more the heat is absorbed, and the larger the enthalpy is. Therefore, the degree of gelatinization of potato starch can be investigated by controlling the particle size of potato starch to the above range.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.