The loss of weight that occurs when dehydrated potatoes, carrots, cabbage, and onions are heated in a vacuum oven has been studied as a function of time, temperature, fineness

A new reference method for the determination of moisture content of dehydrated vegetables involves addition of a large amount of water to a weighed sample of vegetable; freezing and drying in the frozen state (lyophilization); and completion of the drying in a vacuum oven or vacuum desiccator in the presence of an efficient water adsorbent. The last step can be completed in a relatively short time at, or slightly above, room temperature, because of a marked increase in drying rate brought about by lyophilization. Data presented for white and sweet potatoes, beets, and carrots show that the lyophilized materials can be dried unambiguously to constant weight and that the loss in weight may be taken as a measure of the moisture content.As the final dry weight is virtually independent, within wide limits, of the temperature of drying, the new method obviates the necessity of careful control of drying temperature.

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