Leucocarpa, the Dazzling White Olive From Magna Graecia

We asked researchers why the Leucocarpa olive variety is completely white throughout its development cycle.

Leucocarpa olives (Photo by Gino Vulcano)
Oct. 1, 2018
By Ylenia Granitto
Leucocarpa olives (Photo by Gino Vulcano)

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Leucocarpa, also called Leucolea, is an olive vari­ety char­ac­ter­ized by small fruits which, dur­ing ripen­ing, take on an ivory-white color. Mainly wide­spread in the regions of south­ern Italy, with a strong pres­ence in Calabria, it was prob­a­bly intro­duced dur­ing Magna Graecia’s col­o­niza­tion,” Innocenzo Muzzalupo, a researcher at the Council for Agricultural Research and Economics, Research Centre for Olive, Citrus and Tree Fruit (CREA-OFA), told Olive Oil Times.

Due to the white color of fruits, which in west­ern cul­ture sym­bol­izes purity, it ended up being used mainly for reli­gious pur­poses.- Innocenzo Muzzalupo, CREA-OFA

The extra vir­gin olive oil made from this vari­ety has the same char­ac­ter­is­tics as all the oth­ers with regard to the com­po­si­tion of fatty acids, fla­vors, and aro­mas typ­i­cal of a light fruity prod­uct,” he clar­i­fied.

A small num­ber of pro­duc­ers use it in blends with other pre­dom­i­nant cul­ti­vars, but due to the white color of fruits, which in west­ern cul­ture sym­bol­izes purity, it ended up being used mainly for reli­gious pur­poses.” That is why Leucocarpa is often grown near con­vents, where its oil, after receiv­ing a bless­ing, is intended for the sacra­ments and other Catholic rites and, in the past, to anoint the emperor dur­ing the coro­na­tion cer­e­mony.

Leucocarpa olives (Gino Vulcano)

This is fur­ther evi­dence of how ancient peo­ple, inde­pen­dently of their creed, asso­ci­ated the olive tree and olive oil with sacred­ness, as hap­pened in Athens, and many other places through­out the Mediterranean basin, to such an extent that nowa­days the olive tree is uni­ver­sally con­sid­ered a sym­bol of peace.

Going back to Leucocarpa, genetic char­ac­ter­i­za­tion estab­lished that it belongs to a unique strain, whose lim­ited spread­ing is prob­a­bly due to uneasy prop­a­ga­tion. Then, farm­ers take good care of these olive trees, which dur­ing fruit-bear­ing sea­son give a rav­ish­ing aes­thet­i­cal effect, which accord­ing to a study con­ducted by Muzzalupo with other researchers of CREA and the University of Calabria, is due to a switch-off” of flavonoids and antho­cyanins.

Olive ripen­ing involves two phases: first, the pas­sage and syn­the­sis of chloro­phyll which causes the fruit to be green, then the degra­da­tion of chloro­phyll when the olive lose its color,” our researcher explained. At the same time, gen­er­ally, in olives as in most fruits, the syn­the­sis of antho­cyanins and other flavonoids is acti­vated, and this causes their bluish or black­ish color.”

We should recall that some vari­eties, dur­ing the first part of drupe ripen­ing, takes on a very pale shade of green which is nearly white. For exam­ple, Biancolilla, whose name recalls the color white (Bianco in Italian), is improp­erly called Leucocarpa in some areas, because after chloro­phyll degra­da­tion, fruits remain light-col­ored even twenty days until the pig­dos are acti­vated.

In the Leucocarpa cul­ti­var, flavonoids and antho­cyanin acti­va­tion does not occur at all,” Muzzalupo explained. This is the only vari­ety which remains white at any stage of mat­u­ra­tion, and if we leave the fruits on trees until late win­ter, we will find them white, at most tend­ing to yel­low­ish due to the oxi­da­tion of lipids. In our study we tried to under­stand why this hap­pens.”

The researchers found that the tran­scrip­tion of spe­cific genes is blocked at the level of cer­tain enzymes by a process of reg­u­la­tion; then, they dis­cov­ered which reg­u­la­tory mech­a­nisms occur, through spe­cific microRNAs. This lat­ter find­ing led to the pub­li­ca­tion of the research Deep sequenc­ing of olive short RNAs iden­ti­fies microRNAs tar­get­ing involved in drupe ripen­ing.’

The char­ac­ter­i­za­tion of tran­scripts from flavonoid and antho­cyanin biosyn­thetic path­ways and the analy­sis of their expres­sion level in olive fruits is an impor­tant goal, not only to under­stand the verai­son event of fruits, but also to increase the knowl­edge on these antiox­i­dant mol­e­cules, which are impor­tant for human health,” Muzzalupo noted.

He also reported the result obtained by milling this vari­ety with a Keurig-like device called Revoilution.

We pit­ted Leucocarpa olives and froze the pulp in liq­uid nitro­gen; then we crushed it and put it into the machine,” the researcher explained. Basically, com­pletely avoid­ing oxi­da­tion, we obtained a great medium fruity extra vir­gin olive oil with ideal organolep­tic char­ac­ter­is­tics, which had the sole par­tic­u­lar­ity of being col­or­less. It was very good, with a pleas­ant spicy and bit­ter taste.”

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