INFLUENCE OF TEMPERATURE AND RELATIVE HUMIDITY ON THE PHYSICAL STATES OF COTTON CANDY

ABSTRACT

Cotton candy is made by melting crystalline sucrose above 210C in a bowl which shoots molten liquid sucrose into the air where it rapidly cools and dries into an amorphous glassy solid state. As such, it is highly hygroscopic, picking up moisture as %RH increases and becoming rubbery. The glass transition line (T_g vs. %RH) divides the two states. When rubbery, cotton candy should collapse forming crystalline sucrose becoming unsaleable. Cotton candy was stored at 25C and at %RH from ∼0% to 75%. Moisture gain/loss, visual observations, and powder X-ray diffraction using a Seimens 5005-powder X-ray diffractometer were used to evaluate collapse and crystallization. At ∼0% and 11% RH (below T_g), cotton candy maintained a stable structure for at least 12 months. At 33% RH (just at T_g), it collapsed and crystallized within 3 days while at 45, 54 and 75% RH, collapse and crystallization occurred in less than 1 day.