Cacao shells are waste of cocoa or chocolate productions. I have been searching ways on how to use it. I already tried using it as wood fire but failed, it barely burned, other materials such corn and palay waste are more superior. Cacao shells are good as plant mulch, fertilizer and soil conditioner as stated on post of luntiancorner.
I found another possible use of cacao shells! As source of Vitamin D!
According to study of Arthur William Knapp the cacao shells have high Vitamin D content. The vitamin D is attributed to fermentation and drying. The egosterol – a precursor of Vitamin D – is produced during the fermentation process. Then the Vitamin D is synthesized during the drying process.
Using cacao shells as source of Vitamin D might solve the problem about its deficiency or the Hypovitaminosis D. The illness is due to lack of vitamin D intake and lack of exposure to suns rays. This might also help reduce waste disposal problem of cacao shells. Lastly, this will be a cheaper source of Vitamin D.
However, cacao shells taste bad. It should not be included in cocoa making or chocolate processing or it will render the products inedible. Human body is able to synthesize Vitamin D by exposure under the sun. Any supplement might be unnecessary. And the cheapest Vitamin D source is the big sun.
His study was received for publication way back 1935. I have not heard of cacao shells used as food, feed or nutritional supplement. Maybe no one was interested or have discovered how to use it.