Definition of food water activity:
Water Activity, Water Activity, or aw) main reaction food equilibrium the amount of free Water, the stability of the reaction of food and the possibility of microbial breeding, and can cause food quality change in the chemical, enzymatic and physical change, often used to measure the ability to endure dry degree. By measuring the water activity of food, choosing reasonable packaging and storage methods can reduce the use of preservative, and can judge the shelf life of food, grain and fruits and vegetables.
The effect of water activity on food:
Food water activity is one of the important parameters determine the food deterioration and shelf life, about food, flavor, organization structure and the stability of the food all have important influence on, all kinds of microbial life activities and various chemical, biological chemical change requires a certain amount of activity value, in food containing water, due to the different values of water activity of its stability are also different storage period, using the principle of water activity control water activity to improve the quality of products, extend the food storage period, has received more and more widely in food industry production value, in the international recognized HACCP food safety and quality management system is considered to be one of the frequently control standard, and in recent years, the United States, Japan and other developed countries have put it as a food testing project.
The "free water" in the sample can be harmful microbes used - such as the growth of bacteria and moulds, produce toxins and other harmful substances, but also influence such as chemical/biochemical reactions (e.g., maillard reaction), the nature of the product will be affected by its:
- stability of microbial stability (growth)
- protein and vitamin content
- color, taste and nutritional value
- stability and durability
- storage and packaging
- solubility and texture
Roast food and food additives
Baked goods are included in the shelf life of food, such as cookies, cakes, muffins, etc., they are without refrigeration, at room temperature (18 to 25 degrees) can save a long time (6 to 12 months). The moisture content of the bread in the long shelf life has been greatly reduced.
The main indicators for the quality of durable foods are safety and good taste. Both the quality and durability of the food are influenced by the ingredients, the quality, the formula, the storage conditions. For bread foods with high moisture content, their durability is limited by mold growth. Most microbes grow when water is around 0.8, but some good, dry species can still survive in water at less than 0.6.
Baked goods can be made from a variety of ingredients such as cream, nuts, praline, fruit, jam, etc. These ingredients change the different characteristics of food, especially changes in the texture of baked goods caused by microorganisms. Mixed foods are made up of one or several different layers. The water in this food is likely to be transferred from one part to another. This transfer occurs in areas with high water activity and low water activity. Water activity is a physical parameter that indicates the "energy state" of water in the material. Therefore, it is better to expound its water activity than simply to control the absolute moisture content of food.
The transfer and balance of water in food is an important issue for its shelf life. Higher baking temperatures make a difference between different food components. Therefore, the balance adjustment between different layers or food components is affected not only by the baking process but also by the production and packaging time.
Characteristics of water activity meter：
1. High precision American import sensor. High accuracy and stable performance.
2. Professional humanized design, touch color screen display, can set screen backlight brightness, realize human-computer interaction interface.
3. The measuring time is short and easy to operate.
4. Real time printing output function and curve drawing function.
5. The multi-channel can be opened at the same time and can be measured according to different time.
6. The data can be recorded and collected more conveniently and can be used for comparison and analysis of later data.
Technical parameters of GYW-1 water activity meter
(1) sensor: us import sensor
(2) accuracy: 0.015 AW
(3) resolution: 0.001 AW
(4) recovery: less than or equal to 0.005
(5) measurement range: 0.000 ~ 0.990 AW
(6) measurement accuracy: plus or minus 0.2 ℃ temperature
Activity + / - 0.015 (25 ℃) @
(7) measuring time: general sample 10-15 minutes (60 minutes maximum)
(8) measuring channel: single channel
(9) screen: large touch screen 800 x 480 DOTS
(10) calibration method: automatic calibration (correction value) standard saturated salt solution
(11) operation mode: touch
(12) display speed: real-time display detection curve
(13) sample dish capacity: 20ml
(14) temperature display: 0 to 50 ℃
(15) output mode: micro printer
(16) data interface: RS232
(17) working environment: 0 ~ 50 ℃ temperature
Humidity 0 ~ 95% RH
(18) power consumption: 20W
(19) power supply voltage: ac 220V
(20) profile size: 300mm x 260mm x 150mm
After-sales service：
One year warranty, lifetime maintenance。
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