FLAVEDO

The 'flavedo' (also known as the 'exocarp' or, in culinary applications, 'zest') is the outer part of the rind of citrus fruit, which bears oil glands and pigments.

Contents

Composition

Constitution in citrus fruits

References

Composition

Flavedo is mostly composed of cellulosic material but also contains other components, such essential oils, paraffin waxes, steroids and triterpenoids, fatty acids, pigments (carotenoids, chlorophylls, flavonoids), bitter principles (limonin), and enzymes.

Constitution in citrus fruits

In citrus fruits, the flavedo constitutes the peripheral surface of the pericarp. It is composed by several cell layers that become progressively thicker in the internal part; the epidermic layer is covered with wax and contains few stomata, which in many cases are closed when the fruit is ripe.
When ripe, the flavedo cells contain carotenoids (mostly xanthophyll) inside chromoplastids which, in a previous state, contained chlorophyll.
The internal region of the flavedo is rich in multicellular bodies with spherical or shapes, which are full of essential oils.

References

★ Citrus fruits - contains diagram, although the page itself appears to have been poorly translated from another language