Tannin-Rich Acorns, Not Just For Squirrels

This time of the year, if you go to the woods or even along tree-lined walkways, you’ll notice how the ground is cluttered with leaves and nuts. Perfect for children’s crafts, but also an important part of the diet of some birds, squirrels, mice, and other small animals. But, did you know that they are also fit for human consumption?

Acorns figure a lot in the diet of Californian Native Americans in the form of acorn flour or as an ingredient in soups. And like many other diets originating from California, acorn appears to be a healthy idea, as it has been demonstrated to be rich in phytochemicals.

A total of 22 hydrolyzable tannins were identified in methanolic extracts of acorn cotyledon tissue. Gallic acid derivatives predominated and included galloylated esters of glucose, hexahydrodiphenoyl esters of glucose, and methylated gallates. Galloylated esters of glucose were present as isomers of galloyl glucose, digalloyl glucose, and trigalloyl glucose. Mass spectral fragmentation patterns indicate the presence of one gallic acid-galloyl glucose isomer and two gallic acid-digalloyl-glucose isomers. No isomers of tetragalloyl glucose and pentagalloyl glucose were identified. Ellagic acid and ellagic acid pentoside were also identified.

Compared to other nuts, acorns contain more tannins, which gives it the bitter taste and requires tedious processing. Here’s a review article discussing the role of tannins on human health, most documented are its anti-carcinogenic, anti-microbial, and anti-oxidative properties.

[Photo: Wikipedia]