Archaeological evidence of avocados has been found in caves in the Tehuacán area of South-Central Mexico dating to 7,000 B.C. Evidence in the caves showed a gradual increase in the size of the avocado seeds. Researchers proved that avocados were planted and cultivated stream-side beginning by at least 6,500 B.C. The increased fruit size from selective cultivation was slowed by the long-life of the avocado trees and the presence of many smaller fruited trees, but it was nonetheless effective by 900 B.C. Archaeological evidence also showed that the people in nearby Oaxaca did not engage in the same crop improving methods.
Avocado pits were also found at burial sites. The fruits would have been presents for the dead to maintain fertility in the after life.
Scientists have hypothesized that the avocado may have evolved alongside giant mammals that are now extinct. Giant Ground Sloths or Gomphotheres, large elephant like mammals that roamed North and South America, may have eaten the fruits, passing the seeds through their digestive systems intact.
Avocado Persea Americana belongs in the family Lauraceae, which includes sassafras, spicebush, and bay leaves. There are three strains of avocados, Mexican, West Indian and Guatemalan. The Mexican strain, which evolved in tropical highlands is the most cold hardy, surviving temperatures below 20F at maturity. The Foliage of the Mexican strain is reported to have an Anise scent that the others do not. Their fruits also have the highest percentage of oil. Fruit from the West Indian strain have lower percentages of oil and they are the most sensitive to cold. The third group is the Guatemalan Avocado which ripens in the winter, nine to fourteen months after flowering. Avocados from the Mexican strain and the West Indian strain are fast maturing, taking approximately 6 to 8 months to go from flower to fruit. Because of the differing seasons inter-strain hybrids became very import for bridging the gap in the seasonal market. The famous Fuerte cultivar is a naturally occurring cross between the Mexican and Guatemalan avocados.
Avocados are the perfect example of dichogamic protogyny. Which is a fancy way to say that the male and female parts of the flower open at different times, with the female flowers opening first, closing, and then reopening the next day as male flowers. Avocados are harvested before they are ripe because there is a compound in the stem that prevents the fruit from ripening on the tree. In nature avocados would fall off of the tree and ripen on the ground often bruising and effecting the quality of the fruit in the fall. In commercial avocado groves the avocados are picked when they are still green and ripened synthetically using ethylene gas, (the same effect as ripening tomatoes with an apple in a paper bag.) The avocados are harvested using long poles with a v-shaped attachment, the avocado then falls into a cloth sack at the top of the pole to avoid damaging the fruit. Workers in the groves also wear gloves to avoid cutting the skin with their fingernails.
As a fruit avocados have many good properties. They are rich in healthy fats that are proven to reduce bad cholesterol and raise good cholesterol, with regular consumption. On a seven day diet LDL was lowered 22% and HDL was increased 11%. Avocados also have the highest fiber content of any fruit, approximately 6.7g per 100g serving. The fiber consists of 75% insoluble fiber and 25% soluble fiber. Avocados were touted by healthnut and colon/enema freak John Harvey Kellogg (brother of Kellogg Cereal founder W.K. Kellogg) for their health giving benefits in his book, New Diectics, what to Eat and how. As an aside, both of the Kellogg brothers were vegetarians in accordance with their Seventh-Day Adventist faith.
Tomorrow I will be posting about the world’s most famous avocado the Hass cultivar and its accidental incpetion.