M. Farhoodi - Department of Food Science and Technology, Faculty of Agricultural Engineering, University of Tehran, Karaj, Islamic Republic of Iran.
Z. Emam-Djomeh - Department of Food Science and Technology, Faculty of Agricultural Engineering, University of Tehran, Karaj, Islamic Republic of Iran.
A. Falah - Food and Drug Deputy, Shahid Beheshti University of Medical Sciences, Tehran, Islamic Republic of Iran.
S. Sabetghadam - Department of Food Science and Technology, Shahid Beheshti University of Medical Sciences, Tehran, Islamic Republic of Iran.
M. Nemati - College of Agriculture and Natural Resources, Islamic Azad University of Science and Research of Tehran, Tehran, Islamic Republic of Iran.

Interaction of menthol with polyethylene terephthalate bottles during storage time was tested at three different temperatures. Menthol is a mint flavor agent added to yogurt drinks in Iran and is considered as a factor affecting consumer acceptance. Absorption of menthol to packaging material could cause a loss of quality in the final product due to diminished flavor intensity. Tests were done on the effects of environmental conditions (storage for three months at temperatures of ۴, ۲۵, and ۴۵°C) on flavor stability of yogurt drink samples. Absorbed flavor was extracted from PET bottles after the specified time periods and quantified using gas chromatography coupled with FID detector. Then, the diffusion coefficient of menthol into PET bottles (Dp) was determined using concentrations of absorbed menthol. Results showed different absorption levels under various conditions. After ۹۰ days, the absorption quantities at ۴, ۲۵, and ۴۵°C were ۳۸.۲۱, ۱۸۶.۶۶ and ۷۰۰.۵۰ ng g-۱ of PET bottle, respectively. It was concluded that amounts of menthol absorption into PET bottles increased with storage time and higher temperature. Elevation of storage temperature resulted in significant increase in diffusion coefficient of menthol in PET bottle.

Absorption, Diffusion coefficient, Menthol, PET bottle, Yogurt drink