The processing procedures following harvest  are: the “deamarizzazione” (elimination of the bitter taste: translator’s note), the washings and the preservation.

The purpose of “deamarizzazione” is to hydrolize and solubilize Oleuropein - which is a bitter component found in olives – through its transformation into  glucose, Elenolic Acid and Hidroxytirosol which can be eventually washed away.  

First prepare a 1.5-3% a caustic soda solution (soda concentration depends on the olive variety, room temperature, drupe ripeness – the riper the lower the concentration needed) at room temperature -  the preparation of the solution itself already develops heat, so a warm solution could peel off the fruits damaging them.

Secondly, put olives into the soda solution and make sure they stay immersed using “holding-down devices” (home-made ones consist of clean clothes or wooden boards) and every now and then stir the solution 2 –3 times in order to keep its concentration homogeneous.

The process of  “deamarizzazione” is achieved when the solution has penetrated into the mesocarp for 2/3 or ¾  if olives are to be kept for a long period, or just about as far as the stones if olives are to be eaten soon. To check how far the soda has gone into the pulp, take out 5 or 6 olives and cut them longitudinally as far as the stone: once exposed to the air, the pulp penetrated by the alkaline solution oxidizes and turns darker, while the other keeps its yellowish-green colour (a more visible check can be carried out by adding some drops of Phenolphthaleine onto the cut, because this makes  the pulp permeated by the soda turn bright red).

Olives must be kept into the solution for 8 or 12 hours, depending on the concentration of the solution, on the  ratio olives/solution and on cultivation techniques. The caustic soda attacks the tissues as follows: first there is a slow penetration through the waxy external part of the fruit, then a faster penetration into the mesocarp which is easily softened thanks to the hydrolysis due to the pectines found into the middle part of the cell wall; the higher the concentration of the solution the higher  the risk of oversoftening the olives.

The caustic soda has also other effects: it reduces the olive sugars, proteins, mineral salts and organic acids content (sugars content is necessary to fermentation while organic acid content effects the nutritional and organolectic quality of the product).

It is obvious that the best “deamarizzazione”  is obtained when olives are of the same variety, dimensions (14-15 mm diameter) and ripeness.

During the washings, make sure fruits do not come into contact with air, otherwise they turn unpleasantly dark and once the washing is over, immerse the olives again  into water as soon as possible.

The washings of olives have some peculiar functions, in fact they help:

- the elimination of a  great part of  remaining soda residues

- the elimination of  the fruit bitter taste

- the reduction of an excessive loss of some soluble fruit constituents.

They can be:

- long lasting: they are performed for more than 4-5 days, water is changed 2-3 times a day

- medium: from 2 to 5 washings within 1-2 days

- short: one washing only (part of the solution remains in the fruits).  

They are usually carried out as follows:

- a vigorous shower for 15-20 minutes to clean the soda sticking on the fruit external surface

- another washing after 2-3 hours

- 3 or 4 more washings during the following day or the following two days, according to the long-lasting washing techinque.

During long-lasting washings - untill the water does not become clear and clean - there is a high reduction of sugars, proteins etc., which invariably lowers the solution Ph during fermentation and consequently causes a reduced metabolic activity of  lactic bacteria. In this case it is not possible to reach the advisable Ph level necessary to preserve the product for a longtime and to guarantee its best organolectic features (this is the reason why  “Olive Ascolane” must be eaten within a rather short period). This problem could be partially solved by adding sugars and acids to the solution.

On the contrary, if olives are not washed enough, they are still bitter and the solution Ph lowers very slowly causing  too much bacteria activity responsible for an unpleasant alteration of the product.

Next step is fermentation and conservation. Immerse olives into a 6% to 8% saline solution (NaCl): the salt will make part of the nutrient rich cell juice come out helping the development of  acidifying lactic bacteria, preventing the development of dangerous germs and giving olives a better consistency and taste.

Ten days later, a saline balance between olives and the saline solution is reached: the original concentration of the  saline solution is reduced of 50%, so NaCl must be added to reach the original 6% - 8% purcentage. In the past, at this stage,  the people of Ascoli Piceno would prepare a new saline solution and substitute it to the old one, worsening the fermentation and conservation processes through the elimination of many nutrients and microorganisms.

During the whole fermentation process – which lasts about a month and causes a rather high development of  lactic acid – we can observe three different phases:

1 - thanks to the development of (coliform type) Gram negative and Gram positive germs (Bacillus Pedicoccus, Leuconostoc) the saline solution lowers its pH from 8 to 5, within 5-6 days;

2 - lactic bacteria and yeasts make the pH stabilize at about 4 and 5, within two weeks;

3- then lots of lactobacilli develop and Gram-bacteria disappear, while the pH reaches the stable value of 4.

It is of outmost importance to check continuously the fermentation because undesirable secondary processes of fermentation – caused by other microorganisms - might develop and produce  unpleasant smelling and tasting compounds which would damage the quality of the product. During this phase, temperature, salt concentration, development of nutrients and microorganisms play an important part.

After fermentation, the olives are ready for packaging which is the last step; Foeniculum Vulgare could be added as flavouring.

Once families of Ascoli Piceno would use an alkaline solution called “ranno” to proceed to “deamarizzazione”. This substance was prepared mixing 1 part of lime with 4  parts of wood ashes with a little water in a wooden vat whose perforated bottom was covered with a layer of filtering  straw. Water was then poured into the vat to permeate the mixture; about 10 hours later the alkaline solution (the “ranno”) started to come out from the hole: every now and then more water was poured into the vat.

“DEAMARIZZAZIONE”
(Elimination of the bitter taste: translator’s note)

Glucose +