Methods and apparatus for determining sorption isotherms

Apparatus for determining sorption isotherms of food by inverse chromatography comprising:

• (a) means for passing a mobile phase having a known solute concentration at a known flow rate in a downstream direction through a stationary phase comprising a known mass of a food while maintaining the mass of food at a known temperature, whereby the mobile phase will pass downstream from the mass of food;
• (b) means for measuring the concentration of said solute in the mobile phase passing downstream from the stationary phase;
• (c) means for determining the amount of said solute which has passed into the mass of food at selected time intervals during operation of said passing means from said known solute concentration, said known flow rate and the time elapsed since the beginning of passage of said mobile phase having known solute concentration into the mass of food;
• (d) means for determining the amount of said solute in said mobile phase which has passed downstream from the mass of food at each of said selected time intervals from said measurements of said concentration of said solute in said mobile phase;
• and
• (e) means for determining the amount of solute taken up by said food at each of said selected time intervals by determining the difference between the amount of solute which has passed into the mass of food and the amount of solute which has passed downstream from the mass of food.