Method for determining moisture of Chinese dates

Abstract

The method comprises the following steps: taking Chinese dates, removing kernels, crushing or slicing, weighing particles or fragments, pre-drying at 80-90 DEG C for 0.5-2.5 hours, heating to 105 DEG C, drying to constant weight, and calculating according to the lost weight after weighing. According to the method, the water in the jujubes is slowly dried at a low temperature (85 DEG C) through temperature programming, the water evaporation rate of an outer-layer sample is low, and the water evaporation rate of an inner sample can be kept, so that the inner and outer water evaporation balance is ensured, the number of times required by the difference between two times of weighing is reduced to 1-3, the inspection and detection time is shortened, and the detection efficiency is improved. The efficiency is improved, the reproducibility and reliability of the result are ensured, and the practical popularization and application value is achieved.

Description

Technical Field

[0001] The invention specifically relates to a method for measuring the moisture content of jujube. Background Art

[0002] Jujube, also known as red dates, dried dates and jujubes, is the mature fruit of the jujube plant of the Rhamnaceae family. It has rich nutritional value and multiple medicinal effects. It is a traditional Chinese medicinal material that can be used as both medicine and food. It has multiple medicinal effects: tonifying the spleen and stomach, replenishing qi and nourishing blood, nourishing blood and calming the nerves, protecting the liver, and anti-aging, etc. It is suitable for the treatment and health care of various diseases.

[0003] The Chinese Pharmacopoeia does not include a moisture content determination item for jujubes. However, when jujubes are used as raw materials in Chinese patent medicine prescriptions, the amount of material added must be determined by weight. The amount of water directly affects the actual amount of effective ingredients in jujubes, so it is necessary to limit the moisture content of jujubes.

[0004] According to the second method (drying method) of the moisture determination method in Part IV 0832 of the 2020 edition of the "Chinese Pharmacopoeia", the moisture content of jujube was determined. It was found that the sugar content in jujube is relatively high, which causes the outer layer of the sample to be suddenly heated to 105°C during moisture drying. The outer layer of moisture evaporates rapidly, and the sugar content increases sharply. The viscosity of the jujube sample increases, and the internal heating is slow. The moisture is wrapped in the outer layer of sugar before it is completely evaporated, resulting in uneven heating, affecting the moisture evaporation rate, and ultimately unable to accurately determine the moisture content of jujube. Summary of the invention

[0005] To solve the above problems, the present invention provides a method for measuring the moisture content of jujube, which comprises the following steps:

[0006] Take jujube, remove the core, crush or slice, weigh the particles or fragments, pre-dry at 80-90°C for 0.5-2.5h, then heat to 105°C and dry to constant weight, weigh and calculate based on the lost weight.

[0007] Furthermore, the diameter of the particles or the length of the fragments does not exceed 5 mm.

[0008] Furthermore, the diameter of the particles or the length of the fragments does not exceed 3 mm.

[0009] Furthermore, the particles or fragments are pre-dried at 85° C. for 2 hours.

[0010] Furthermore, during the drying, the granules or fragments have a flat thickness of no more than 5 mm.

[0011] Furthermore, the particles or fragments are dried to a constant weight by:

[0012] The particles or fragments are dried at 105°C for 4 h, then cooled in a dryer for 30 min, weighed, and dried again at 105°C for 1 h, cooled in a dryer for 30 min, and weighed. The drying, cooling, and weighing steps are repeated until the weight difference between the two weighings does not exceed 5 mg.

[0013] Furthermore, it comprises the following steps:

[0014] 1) Take jujube, remove the core, crush or slice, take particles with a diameter not exceeding 3 mm or fragments with a length not exceeding 3 mm, lay flat with a thickness not exceeding 5 mm, weigh, pre-dry at 85°C for 2 h, then heat to 105°C and dry for 4 h;

[0015] 2) The particles or fragments dried in step 1) are placed in a dryer to cool for 30 minutes, weighed, dried at 105° C. for 1 hour, and again placed in a dryer to cool for 30 minutes and weighed;

[0016] 3) Repeat the drying, cooling and weighing steps in step 2) until the weight difference between the two weighings does not exceed 5 mg, and calculate based on the lost weight.

[0017] The method for determining the moisture content of jujubes of the present invention slowly dries the moisture in jujubes at a relatively low temperature (85°C) through programmed temperature increase, and the moisture evaporation rate of the outer layer sample is relatively slow, which is beneficial to maintaining the moisture evaporation rate of the inner sample, thereby ensuring the balance of the evaporation of the inner and outer moisture, reducing the number of times required for achieving the difference between two weighings to 1-3 times, shortening the inspection time, improving the efficiency, ensuring the reproducibility and reliability of the results, and having practical promotion and application value.

[0018] Obviously, according to the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, other various forms of modification, replacement or change may be made.

[0019] The above contents of the present invention are further described in detail below through specific implementation methods in the form of embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above contents of the present invention belong to the scope of the present invention. DETAILED DESCRIPTION

[0020] Example 1 Determination of moisture content of jujube of the present invention

[0021] Take jujube, remove the pit, crush into particles or fragments with a diameter or length not exceeding 3mm, take 2-5g, spread flat in a flat volumetric bottle that has been dried to constant weight, with a thickness not exceeding 5mm, accurately weigh, open the bottle cap and dry at 85℃ for 1 hour, then heat to 105℃ and dry for 4 hours, cover the bottle cap, move to a desiccator, cool for 30 minutes, accurately weigh, dry at 105℃ for 1 hour, cool in a desiccator for 30 minutes, weigh, repeat the drying at 105℃ for 1 hour, cool in a desiccator for 30 minutes, and weigh until the difference between two consecutive weighings does not exceed 5mg. Calculate the water content (%) in the test sample based on the lost weight.

[0022] The beneficial effects of the present invention are further illustrated by test examples below:

[0023] Test Example 1 Study on the determination of moisture content of jujube in the present invention

[0024] 1. Comparison of the water content determination method of jujube in the present invention with that in the pharmacopoeia

[0025] 1.1 Methods

[0026] A batch of samples were selected and measured using the jujube moisture determination method in Example 1 and the drying method of the moisture determination method in the Chinese Pharmacopoeia, respectively. Each method was measured 3 times, and the moisture determination results, the number of repeated drying times, and the total drying time were recorded.

[0027] The second method (drying method) in Part IV 0832 Moisture Determination Method of the 2020 edition of the Chinese Pharmacopoeia is as follows:

[0028] Take 2-5g of the sample, quickly make it into particles or fragments with a diameter or length not exceeding 3mm before weighing, spread it flat in a flat weighing bottle that has been dried to constant weight, with a thickness not exceeding 5mm, accurately weigh it, open the bottle cap and dry it at 100-105℃ for 5 hours, cover the bottle cap, move it to a desiccator, cool it for 30 minutes, accurately weigh it, dry it at 100-105℃ for 1 hour, cool it, and weigh it until the difference between two consecutive weighings does not exceed 5mg. Calculate the water content (%) in the sample based on the lost weight.

[0029] 1.2 Results

[0030] See Table 1 for details.

[0031] Table 1 Comparison results of moisture determination methods

[0032]

[0033] It can be seen from the results that the moisture determination result of the present invention is 20.96%, and the determination result of the pharmacopoeia method is 20.20%. The deviation of the two methods is 1.85% (less than 2%), and the method of the present invention is more feasible; the present invention is dried three times for 8 hours, and the pharmacopoeia method is dried 11 times for 16 hours. The number of repeated drying times and the total drying time are significantly different, and the detection efficiency of the present invention is significantly better than that of the pharmacopoeia method.

[0034] 2. Comparison of moisture content between pitted and non-pitted jujubes

[0035] According to the current literature, the pit of jujube has no clear nutritional value or clinical value. The method recorded in the Chinese Pharmacopoeia does not require the sample to be pitted when determining moisture. Considering that the pit will affect the moisture of jujube, the moisture of pitted and non-pitted jujube is determined according to the jujube moisture determination method in Example 1. The same batch of jujube samples were selected, and 6 samples were measured for each batch. The results are shown in Table 2.

[0036] Table 2 Comparison of moisture content between pitted and non-pitted jujubes

[0037]

[0038] From the above results, we can see that the reproducibility of the moisture content of unpitted jujube is poor. The reason is that the jujube pit is relatively hard and difficult to crush. The crushed pit is uneven in size (packing), which leads to uneven sampling, thus affecting the reproducibility of the moisture content determination results. Therefore, it is necessary to remove the pit when determining the moisture content of jujube.

[0039] 3. Effect of preheating temperature on jujube moisture determination

[0040] During the moisture determination process, preheating the sample to be tested can avoid the impact of drastic temperature changes on the measurement results, but the preheating temperature needs to be precisely controlled to ensure accurate test results while improving detection efficiency.

[0041] A batch of samples was selected, and the moisture content was measured by changing the preheating temperature based on the jujube moisture determination method in Example 1, and the moisture determination results, the number of repeated drying times, and the total drying time were recorded. The results are shown in Table 3.

[0042] Table 3 Preheating temperature change measurement results

[0043]

[0044] From the results, it can be seen that when the preheating temperature is 85℃, the number of repeated drying times is the least and the total detection time is the shortest. When the temperature is lower than 85℃, the low temperature causes the water to evaporate more slowly, so the total drying time is longer; when the temperature is higher than 85℃, the high temperature causes the water on the surface of the jujube pulp to evaporate faster, and the sugar content becomes more viscous, forming an isolation barrier, which causes the water inside the pulp to evaporate more slowly, so the total drying time becomes longer. Therefore, when measuring the water content of jujube, it is necessary to preheat at a low temperature of 85℃.

[0045] In summary, the present invention slowly dries the water in the jujube at a relatively low temperature (85°C) through programmed temperature increase, and the water evaporation rate of the outer layer sample is relatively slow, which is beneficial to maintaining the water evaporation rate of the internal sample, thereby ensuring the balance of the evaporation of the inner and outer water, and reducing the number of times required to achieve the difference between two weighings to 1-3 times, thereby shortening the inspection time, improving efficiency, ensuring the reproducibility and reliability of the results, and having practical promotion and application value.

Claims

1. A method for measuring the moisture content of jujube, characterized in that: It includes the following steps: Take jujube, remove the core, crush or slice, weigh the particles or fragments, pre-dry at 80-90°C for 0.5-2.5h, then heat to 105°C and dry to constant weight, weigh and calculate based on the lost weight.

2. The method according to claim 1, characterized in that: The diameter of the particles or the length of the fragments does not exceed 5 mm.

3. The method according to claim 2, characterized in that: The diameter of the particles or the length of the fragments does not exceed 3 mm.

4. The method according to claim 1, characterized in that: The particles or fragments were pre-dried at 85°C for 2 h.

5. The method according to claim 4, characterized in that: During the drying process, the granules or fragments are laid out with a thickness not exceeding 5 mm.

6. The method according to claim 1, characterized in that: The method of drying the particles or fragments to constant weight is: The particles or fragments are dried at 105°C for 4 h, then cooled in a dryer for 30 min, weighed, and dried again at 105°C for 1 h, cooled in a dryer for 30 min, and weighed. The drying, cooling, and weighing steps are repeated until the weight difference between the two weighings does not exceed 5 mg.

7. The method according to any one of claims 1 to 6, characterized in that: It includes the following steps: 1) Take jujube, remove the core, crush or slice, take particles with a diameter not exceeding 3 mm or fragments with a length not exceeding 3 mm, lay flat with a thickness not exceeding 5 mm, weigh, pre-dry at 85°C for 2 h, then heat to 105°C and dry for 4 h; 2) The particles or fragments dried in step 1) are transferred to a dryer and cooled for 30 minutes, weighed, and then dried at 105° C. for 1 hour, and transferred to a dryer and cooled for 30 minutes and weighed again; 3) Repeat the drying, cooling and weighing steps in step 2) until the weight difference between the two weighings does not exceed 5 mg, and calculate based on the lost weight.

Images