The word cashew comes from the Tupi-Indian word Acaju, which just means “nut”. Instead of growing like conventional nuts, they grow out of the base of cashew apples like little tails. For this reason, they are the only nut sold solely unshelled because the outer shell causes skin irritation.
The seed is surrounded by a double shell containing an allergenic phenolic resin containing a anacardic acid. This composition is a potent skin irritant. Chemically, this resin is related to the more well known allergenic, oil urushiol, which is also a toxin found in poison ivy. Some people are allergic to cashew nuts. What is much more common is the allergy to outer coating on the skin of the fruit.
The cashew was first discovered by Europeans in Brazil around 1558. Because of the irritating shells, they were thought to be inedible at first. Over time it was realized that it was the fruit skin and not the seeds that were irritating. It was the local native tribe, the Tupi-Indians, that showed the Europeans otherwise. The Portuguese were given instructions on how to roast the cashews to get the irritant off.
Europeans found the cashew seed to be quite tasty. However, they also used the cashew apple pulp to make wine. Interestingly enough, the natives had learned to eat cashews from the local capuchin monkeys. The primates use primitive tools to break the shells off and throw the nuts in away.
The Modern History Of The Cashew
As a consequence of finding out how to each the seed of the cashew, the Portuguese brought cashews to Goa in about 1560. Ultimately, the nut thrived in the new climate and then travelled to India soon after. The Indian people discovered healing properties in the nut and cashews became very popular. In the second half of the 16th century, cashews spread to Southeast Asia and Africa. Presently, many countries and culture depend on cashew seeds as a food staple and for their commerce.
The modern history of the cashew reached the United States in around 1905. The cashew did not become popular until the mid-1920’s when the General Food Corporation started to ship them regularly to the United States and Europe. Ultimately, the cashew became popular and by 1941, about 20,000 tons of cashews were shipped from India annually.
Cashews – Excerpt from entry in CredoReference
Luncz et al. Wild capuchin monkeys adjust stone tools according to changing nut properties. Nature.Scientific Reports.