Food simulants affected the migration of essential oil and film structure in chitosan based composite films

In order to investigate the migration mechanism of three essential oil (thyme, cinnamon and lemon) from chitosan film to food simulants (distilled water, 3% acetic acid, 10% ethanol, 50% ethanol and 95% ethanol), the physical and chemical properties of essential oil and composite films were estimated. The results showed that cinnamon essential oil had high lipid/water partition coefficient and dissolution ability in 50% ethanol compared with the other food simulants. But lemon essential oil showed good dissolution with the increasing ethanol concentration. In comparison, the migration of essential oil was positive correlation with the film solubility in all food simulants, but negative correlation with the swelling degree in 95% ethanol. Moreover, the film structure was destroyed seriously in 3% acetic acid which resulted in fast swelling, solubility and migration of essential oil. Both 50% ethanol and 10% ethanol also improved the swelling and solubility of films. SEM showed that the state of essential oil in films was variable based on the type of food simulants. The O-H bond of chitosan matrix was greatly impacted by 3% acetic acid and 95% ethanol. The study provided a new insight for migration mechanism of chitosan-essential oil film in food simulants. The migration of essential oil from film depends on its dissolution in food simulants.The migration of essential oil was inconsistent with the polarity of food simulants.Cinnamon essential oil significantly restricts the swelling of chitosan film compared with thyme and lemon essential oil.