The difference between water and water activity

一、 Water content? Water activity? what's the difference?

In order to increase the understanding of the current status of green beans, you can refer to another parameter commonly used in the food industry: Water Activiy, AW. The above mentioned free water can be directly used by microorganisms, and the vapor pressure is the pressure value generated after the free water evaporates. , And the definition of AW is the ratio of the vapor pressure of the article to the vapor pressure of pure water under the same conditions. The value is between 0 and 1. The closer to 1 means the more water in the article that can be used by microorganisms. In other words, it means that the more easily affected by molds, bacteria, etc., the quality and flavor will be reduced.

二、 How much water activity is needed?

The suggestion for water activity of raw soybeans is generally between 0.4 and 0.6. Above 0.6, it means that microorganisms have more free water available, and there is a risk of mold and fungus infection for raw beans. If it is lower than 0.4, it may be due to excessive drying during processing of green beans, or excessive drying of the environment during transportation and storage, which affects the original flavor and subsequent coffee roasting.

三、 How to control water activity?

No matter whether it is AW or water content, it cannot completely indicate whether the green beans have been subjected to proper drying procedures, or good preservation and transportation processes, but it can be regarded as the current state of the green beans, whether there is a risk of microbial influence, etc., and it can also As a reference index for the subsequent preservation of green beans and the quality of green beans.