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Method for controlling water activity and application thereof

A moisture and activity technology, used in material inspection products, testing food, etc., can solve problems such as difficulty in meeting experimental needs and large humidity effects

Inactive Publication Date: 2017-12-22
INST OF AGRO FOOD SCI & TECH CHINESE ACADEMY OF AGRI SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, in the process of using a constant temperature and humidity incubator, the action of opening and closing the door also has a great impact on the relative humidity, and it is difficult to meet the experimental requirements for high accuracy of water activity. Methods for research on material quality and regulation of metabolic activities such as microbial growth and toxin production

Method used

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  • Method for controlling water activity and application thereof
  • Method for controlling water activity and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] Example 1 According to the experimental requirements, prepare the required saturated salt solution

[0073] Under the condition of 25°C, the water activity values ​​that can be precisely controlled by this method are 0.064, 0.113, 0.328, 0.4320.529, 0.576, 0.649, 0.709, 0.743, 0.753, 0.809, 0.810, 0.843, 0.851, 0.902, 0.936 and 0.973. According to the needs of the experiment, refer to Table 1 to prepare the required saturated salt solution.

[0074] Table 1 Water activity value produced by saturated salt solution at 25°C

[0075] Numbering

Types of supersaturated salt solutions

Aw(25℃)

1

Lithium bromide saturated solution

0.064

2

Lithium chloride saturated solution

0.113

3

Magnesium chloride saturated solution

0.328

4

Potassium Carbonate Saturated Solution

0.432

5

Saturated solution of magnesium nitrate

0.529

6

Sodium bromide saturated solution

0.576

7

Saturated Cob...

Embodiment 2

[0094] The adjustment of embodiment 2 sample water activity

[0095] The water activity of the sample needs to be adjusted to the target water activity. The specific operations used are as follows:

[0096] A universal pulverizer is used to grind and pulverize the sample, and then n different amounts of water are added to the ground sample, wherein the number of n is 6-10. Under the condition of 4°C, equilibrate overnight, adopt Aqualab 4TE (Decagon Devices, the United States, the accuracy is ± 0.005) to measure the water activity of the sample after equilibration, and use Moisture Analyzer MJ33 (MettlerToledo, Switzerland) to measure the moisture content of the sample after equilibration, Take the water content as the ordinate and the water activity as the abscissa to establish the water activity-moisture content curve. According to the curve, calculate the amount of sterile water that needs to be added for the target water activity of the sample experiment, and use it for ...

Embodiment 3

[0097] Embodiment 3 water activity control accuracy monitoring

[0098]Randomly select two target water activities of 0.843 and 0.936 for accuracy monitoring.

[0099] When the target water activity is 0.843, add saturated potassium chloride solution at the bottom of the drier. The amount of saturated potassium chloride solution added should be no less than 10% of the volume of the drier and no more than the separator of the drier. Adjust 100g of corn with water activity to 0.843, and divide it into four parts and place it on a dry partition (such as figure 1 shown). Move in parallel along the upper opening of the desiccator, cover the desiccator cover coated with petroleum jelly, and place it in a constant temperature incubator at 25°C. Set up three replicates.

[0100] When the target water activity is 0.936, add saturated potassium nitrate solution at the bottom of the drier. The amount of saturated potassium nitrate solution added should not be less than 10% of the volu...

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Abstract

The present invention relates to a method for controlling water activity and application thereof. The method is as follows: according to the water activity needed to be kept in a material, a saturated salt solution is selected, the material and the saturated salt solution are placed in a same confined space, and the water activity of the material is kept. The method is applicable to regulation of growth or metabolism of microorganisms by water activity, particularly the growth or metabolism of food-source microorganisms. The method is simple in operation and can control the water activity with high precision. In actual operation, the saturated salt solution is selected specifically according to the water activity of the material, systematic studies on the growth or metabolism of the water activity regulation microorganisms on different substrates can be effectively carried out, and theoretical and technical supports are provided the goal of blocking of the growth or metabolism of the microorganisms by controlling of water activity regulation.

Description

technical field [0001] The invention relates to a method for controlling water activity and its application. Background technique [0002] Water activity (Aw) refers to the ratio of the vapor pressure of water when the grain or food reaches equilibrium in a closed container to the saturated vapor pressure of pure water at that temperature. Water activity is a reliable thermodynamic concept that reflects food stability and has a good correlation with the rate of many degradation reactions in food. At the same time, the control of water activity is the key link to prevent the growth of harmful microorganisms and other adverse effects. [0003] In a certain environment, when the liquid water and gaseous water of the material reach equilibrium, the water activity can be expressed by measuring the relative humidity (RH) of the air. Therefore, in the study of how water activity regulates the metabolic processes such as microbial growth and toxin production in food, the method of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N33/02
CPCG01N33/02
Inventor 刘阳赵月菊宗英华晓童邢福国王龑
Owner INST OF AGRO FOOD SCI & TECH CHINESE ACADEMY OF AGRI SCI