Grain Relativity Humidity Real-Time Prediction Based on Different Saturated Humidity Models in the Process of Storage
A mathematical model was selected and established based on the granary internal temperature and humidity real-time monitoring. In the experiment, the relative humidity of different water content corns were predicted by using different saturated vapor pressure formula and select the fittest model by comparing with the calculations and the test results. The humidity calculated by the saturated vapor pressure at formula 3 was closest to the actual measurement in them. Using the model it was possible to predict the evolution of grain relativity humility. During the experiment process, the calculation appeared the fluctuation because the internal humidity of grain was greatly influenced by the temperature and relativity humidity of the environment.
Determination of Grain Stack's Equilibrium Absolute Humidity and Dewpoint Tempertaure
A moisture sorption equation named CAE was adopted to fit the EMC/ERH data of wheat,paddy and shelled corn,and the parameter-known CAE used for making curve graphs of equilibrium absolute humidity and equilibrium relative humidity of each grain species.The value of grain equilibrium absolute humidity was better for aeration decision than that of grain equilibrium relative humidity.Referring to atmosphere absolute humidity and dewpoint temperature,one can quickly make a decision on grain stack's aeration after checking the grain equilibrium absolute humidity and dewpoint temperature.
Water activity and its estimation in food systems: theoretical aspects
One of man's earliest discoveries for food preservation must have been the fact that fresh foods become much less perishable when their water content is drastically reduced. It is general knowledge that not all biological products show the same behavior in this respect. The various biological products as well as their components show great differences in water-binding proper­ ties. For example, potato starch containing 24% moisture on dry basis is perfectly stable, whereas crystalline white sugar (sucrose) may spoil, albeit slowly, even at only 4% moisture. These and comparable phenomena in the area of food deteriora­ tion have been poorly understood for many decades until it was realized that not the actual water content, but some other factor related to the "nature" or "state" of the constituent water, de­ termined eventual spoilage. It was a problem to find a convenient expression for this state of the water or better the "availability" of water for deterioration reactions in foods.