Rancidity
As the cake rapidly turns rancid and may become completely unpalatable, and even harmful to animals, it must be preserved either by drying or ensiling.
Polyphenols and tannins
Olive oil cakes obtained from the 2-phase extraction process contain tannins, but they do not appear to have toxic effects on livestock. Sheep are more sensitive to olive cake tannins than goats (Yanez-Ruiz et al., 2007).
The following table presents the different types of polyphenols and tannins in olive oil cake (Molina Alcaide et al., 2008).
Type of polyphenols and tannins (g/kg DM) | Olive oil cake
Total extractable polyphenols | 13.9
Total extractable tannins | 9.78
Total extractable condensed tannins | 0.81
Total condensed tannins | 12.4
Free condensed tannins | 1.64
Fibre bound condensed tannins | 4
Protein bound condensed tannins | 5.87