Other antioxidants were studied to provide antioxidant
behaviour to the packaging: green tea extract (catechins), cinnamon
essential oil and purple carrot extract (anthocyanins).
Also green tea extract combined either with vitamin E or with
cinnamon essential oil were investigated. Green tea extract at a
concentration of 0.6 g/m2 maintained longer the white colour of
mushrooms, but it showed no effect at a concentration of 0.12 g/
m2, which was the maximum concentration that could be
incorporated in the active coating without losing the mechanical
properties. Synergistic effect of green tea combined with other
antioxidant was expected. However, the used mixtures showed
similar antioxidant effect as pure green tea extract. Cinnamon
essential oil showed opponent effects depending on the concentration:
at high concentration, cinnamon essential oil caused
the devastating appearance of burnt surface, whereas at low
concentration, it showed appreciable positive results in reducing
the bacterial blotching during the second-term of mushrooms
shelf-life. Further work would be focused on the fine tuning of
the concentration of cinnamon essential oil in the active packaging.
Finally, bilberry and purple carrot extracts did not show
antioxidant properties, likely because they did not have enough
antioxidant properties to protect mushrooms.