Storage and Defensive Cells

Appears in
On Food and Cooking

By Harold McGee

Published 2004

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Cacao beans consist mainly of the embryo’s storage leaves, or cotyledons, and contain two distinct groups of cells. Around 80% of the cells are storage depots of protein and of fat, or cocoa butter, nutrients that will feed the seedling as it germinates and develops on the shady floor of the tropical forest. The other 20% are defensive cells meant to deter the many forest animals and microbes from feasting on the seed and its nutrients. These cells are visible in the cotyledons as purplish dots, and contain astringent phenolic compounds, their chemical relatives the anthocyanin pigments, and two bitter alkaloids, theobromine and caffeine. The beans are moist, around 65% water. The composition of the dried fermented beans is shown in the box.