Porous coatings to control release rates of essential oils to generate an atmosphere with botanical actives

Essential oils have been used in diverse areas such as packaging, agriculture and cosmetics, for their antimicrobial and pesticide activity. The organic volatile compounds of the essential oils are involved in its activity. Controlling their release helps to prolong their functionality. In this study, a functionalized calcium carbonate porous coating was employed to control the release of thyme and rosemary oil in a confined space. The release rate was evaluated at 7 °C and 23 °C, gravimetrically. It was shown that the capillary effect of the porous coating slowed down the release of the volatiles into the headspace compared to the bulk essential oil. A linear drive force model was used to fit the obtained data from both essential oils. The model showed that rosemary reached the asymptotic mass loss equilibrium faster than thyme. This result can be explained by the diverse composition and concentration of monoterpenoids between the two essential oils. Temperature and degree of loading also played important roles in the desorption of the essential oils. It was observed that at high degrees of loading and temperatures the desorption of essential oils was higher. The above-described technology could be used for applications related to food preservation, pest control among others

Application of antimicrobial packaging based on modified calcium carbonate and EOs for RTE meat products

Highly porous modified calcium carbonate (MCC) powder has been successfully integrated into packaging material as a coating and the coated packaging films were loaded with 5, 10 or 30 wt % thyme and rosemary essential oil (EO). Resulting MCC labels were applied as labels and showed antimicrobial activities against L. innocua in in vitro test. After 6 days MCC labels with 10 and 30 wt % thyme EO showed significant reductions in in vitro tests (2.9 and > 8.5 log CFU/filter). When MCC labels with rosemary EO were used, only 30 wt % loading showed a significant reduction (1.6 log CFU/filter). Subsequently, the antimicrobial activity of MCC labels with 30 wt % EOs against L. innocua on ready to eat meat product were studied under normal atmosphere and modified atmosphere (MA). Use of MCC labels with 30 wt % thyme EO loading combined with MA packaging showed a significant microbial reduction of 1.2 log CFU/g on cooked ham after 21 days (compared to untreated MCC labels packaged under MA). On the other hand, use of MCC labels loaded with 30 wt % rosemary EO (with MA) showed significant reductions of L. innocua on sliced cooked chicken breast (2.6 log CFU/g) as well as cooked ham (1.3 log CFU/g)