9,4 Mb - formato pdf - Enoteca Regionale
9,4 Mb - formato pdf - Enoteca Regionale
9,4 Mb - formato pdf - Enoteca Regionale
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PROCESSING AND CONSERVATION METHODS<br />
The “Spanish method” processing cycle is as follows:<br />
- debittering by soaking in a dilute caustic soda solution;<br />
- fermentation in brine.<br />
DEBITTERING aims to solubilize the bitter element in the olives, oleuropein, a glycosidetype<br />
substance. Debittering is achieved with dilute solutions of caustic soda (NaOH) to<br />
hydrolyse oleuropein to glucose, enolic acid and dihydroxyphenylethanol, compounds that<br />
later removed by rinsing. Concentrations used may oscillate from 2 to 2.2%, depending<br />
on ambient temperature, variety and ripeness of the fruit. During the alkaline treatment,<br />
the olives are constantly immersed in the aqueous solution, since they turn black if left<br />
in the air and debittering would be partial, with negative effects on product edibility;<br />
moreover, the soda must be changed regularly in order to keep the concentration constant.<br />
The debittering treatment is complete when the soda solution has penetrated 2/3-3/4 of<br />
the flesh of the olives, a limit not be exceeded if the quality and quantity ratio equilibrium<br />
of the fruit is to be safeguarded for the product in pursuing fermentation which may<br />
effects the end results of this process negatively if they develop incorrectly.<br />
This alkaline treatment usually takes 7-10 hours, depending mainly on the concentration<br />
of the soda and the temperature.<br />
WASHES: the olives are washed by leaving them in water that is changed a regular basis<br />
until the pH is found to be about 7-7.5. During these operations it is important to avoid<br />
too much ventilation of the mass and exposing the fruit to the air, which will cause damaging<br />
oxidising browning that depreciates the commercial value of the end product.<br />
Three rinses are generally performed, requiring a total time of 24-27 hours.<br />
The rinsing water can be changed at flexible intervals without adverse effects on the end<br />
result, nevertheless, when choosing and scheduling washes a series of technical factors<br />
must be considered, inherent to the specific characteristics of each variety and the concentration<br />
of soda used in the olive debittering phrase, since the flavour of the finished<br />
product will depend on this.<br />
FERMENTATION: after the olives have been washed they must be left to soak in a saline<br />
solution with the NaCI concentration at 7-8%, prepared with water that has limited alkaline-earth<br />
metals (Ca, Mg, Ba) content, which may create abnormal flavour in the fruit.<br />
A salt balance is generally achieved between the olives and the brine after 7-12 days,<br />
and periodic additions of salt (NaCI) are necessary since the concentration of brine will<br />
decrease by 40-50% compared to the initial quantity. The olive fermenting process comprises<br />
three stages that may be distinguished by the different microbic composition of<br />
brine for each one: 1) stage one, typified by the development of Gram-negative Coli-<br />
iformes-type and Gram-positive germs, with a brine pH that passes from the initial value<br />
of about 8 to 5-5.6 in about 3-5 days; 2) stage two, characterized by the development<br />
of lactic bacteria and yeasts with a brine pH that falls to 4.5-5 in 10-15 days, with a progressive<br />
decrease of negative germs; 3) stage three characterized by a massive development<br />
of lactobacilli, onset of Gram-negative bacteria and brine pH of about 4 after 20-30<br />
days.<br />
The process is complete after 25-40 days, when the olives are straw yellow-green in<br />
colour, with firm flesh and a pleasant, rather sharp flavour of lactic acid, and they are<br />
then ready to be sold, whole or pitted.<br />
STORAGE: olives prepared in this way can be kept naturally if the solution pH is about 4<br />
and the brine never less than 7-8%, otherwise pasteurization is recommended.<br />
Materials, specific equipment used in preparation and conditioning: modern technologies<br />
are sensitive to quality and cost reduction issues so the entire transformation<br />
process is performed in large containers. Here the olives, which have been handpicked to<br />
avoid irreversible lesions or damage that will depreciate the product, stripped of leaves<br />
and, preferably a graded size, are treated applying the strictest control of process factors<br />
that may condition fermentation, so as to guarantee standardised production batches.<br />
PLANTS AND SYSTEMS: 1. water; 2. electrical system: must be compliant with the most<br />
recent workplace safety regulations; 3. lighting: must provide a level of artificial lighting<br />
that allows working and inspection operations to be performed correctly.<br />
Minimum line equipment shall include: hopper for loading olives – defoliator and waste<br />
separator – forklift – conveyor belt for moving olives – sorting bench – grader with mobile<br />
diverging chains – water tanks - concentrated soda tanks – tanks for preparing soda<br />
and brine solutions etc. – PVC containers for storing graded olives – fermentation vessels<br />
– containers for storing fermentation brine.<br />
Description of processing and conservation premises: the premises chosen for processing<br />
plants must have adequate road, electricity and water networks for its needs.<br />
In particular, there must be a plentiful supply of water, bearing in mind that water consumption<br />
for processing olives is estimated to be seven times the amount of the end product.<br />
The same sort of care is required to ensure the best disposal solution for waste waters.<br />
The areas where the olives will be stored must be given careful consideration since<br />
the fruit arrives at the plant in traditional stacked crates; storage must be such as to ensure<br />
easy transfer of the crates to the processing line. The area that will house the fermentation<br />
vessels must be about 8 metres in height. Lastly, it should be remembered that<br />
the plant must have a basement section (for about half of the surface area of that enclosed<br />
buildings), dedicated to the storage of olives being processed with special systems,<br />
especially during hot weather.<br />
NATURAL OR TRANSFORMED VEGETABLE PRODUCTS 219