It is a single-seeded fruit that cannot be eaten as it is plucked from an olive branch. This is caused by a phenolic substance called “oleuropein”, which is found only in olives among all the fruits in the world and gives the bitter taste to olives.
The series of processes applied to remove this phenolic substance called oleuropein, which gives the bitter taste to olives, also includes table olive processing techniques. Oleuropein is also considered to be a very important substance for human health. Researchers report that the amount remaining in the olive is sufficient for human health, even if this substance is thrown out of the olive or broken down into other substances while processing table olives.
Phenolic compounds and other antioxidant substances in olives are substances that positively affect human health. The numerous benefits of olives include supporting the human body in order to prevent cancer and cardiovascular diseases, positively affecting digestion due to its fibrous structure, and delaying the aging of cells, especially with the antioxidant substances it contains.
Olive is a food containing 60-70% water, 15-30% oil, 2-6% sugar, 1-3% protein, 1-4% mineral substances and 1-5% fibrous substances. In addition to these, it contains phenolic components, which are called minor components, organic acids, pectins, colorants, vitamins and some minerals in amounts that can be considered important for human health.
Table olives are considered a food with high nutritional value due to all these substances it contains.The most important feature that makes olives different from other fruits is oleuropein, which is only found in olives, while other mono-fruits contain sugar at a high rate of 12% and oil around 1.5%. is 15-30%.
Table olive processing techniques are technologies that remove the bitterness of olives and make them edible by humans. Olives, which are processed in this way and become edible by removing their bitterness, are called “table olives”.
Some of the important table olive varieties grown in our country are as follows: GEMLIK, AYVALIK, MEMECIK, DOMAT, USLU, KALAMATA, ERKENCE, MEMELI, HALHALI, EDINCIK, etc. While most of these varieties, Gemlik and Domat, are processed as table food, a small part of them goes to oil. Other varieties are processed both as table and oil.
TABLE OLIVE PROCESSING TECHNIQUES
- GREEN OLIVE PROCESSING TECHNIQUES
In the processing of green olives, it is ensured that the olives are made edible by both natural and chemical applications.
- SCRATCHED OLIVE
In our country, scratched olive processing technology is mostly applied for Ayvalık and Domat varieties. Scratched olive making stages;
Harvest: In table olive technology, the harvest time and shape of the olive is very important. Olives must be picked by hand. Harvest time is determined according to the way of processing. In scratched olive processing, olives of the Ayvalık variety are harvested when the color starts to change from green to yellow and pink or slightly black. In the Domat variety, it is more appropriate to do it when the color turns from green to straw yellow.
Transportation: Harvested olives are not kept in the sun and are transported in 25 kg plastic baskets.
Sorting and sorting: The olives brought to the facility are first separated according to their size by passing through the sorting machine, then they are passed through the sorting band to separate the bruised, injured and bruised ones.
Scratching: After being washed with clean water to be cleaned, the drawing process is done. In the drawing process, one or more olives are drawn transversely or longitudinally.
Flavoring: The drawn olives are taken into the tanks. A perforated lid is closed on it and brine containing 2% salt and 0.2% citric acid (lemon salt) is given on them. It is filled with brine until it reaches 10-15 cm above the lid. Water is drained once a week and this process is repeated 5-6 times by adding new brine at the same rate. In the 5th and 6th repetitions, the olive is tasted and it is decided whether or not the sweetening process should be completed. If the olives have reached the taste and flavor of the boot olive, the sweetening process is terminated and they are stored and matured.
Preservation and Fermentation: The flavored olives are kept in brine containing 7% salt and 0.5-0.7% citric acid. After 1-2 months of fermentation and maturation, it is released to the market at any time. If it is to be stored for a longer time, the amount of salt can be increased to 10% and the amount of acid to 1-1.2%.
Packaging: Along with tin and plastic boxes, glass jars are frequently used in the packaging of sweetened and ripening olives. First, brine containing 5% salt and 1-1.5% citric acid is prepared. After the olives are placed in the containers, the brine is given. A good grade of olive oil is added to cover the surface of the box.
It can be offered for sale by adding various spices and flavoring substances according to the market and consumer demand. Heat treatments increase the guarantee of the product in the market. It provides a healthier product and ensures that the product stays on the shelf longer.
- CRACKED OLIVES
Although cracked olives are a form of olive processing that families do mostly at home to meet their own needs, recently cracked olives have become a demanded product in the market.
Harvest: In cracked olive processing, the harvest is usually done during the green maturity period. In this way, it is desired to prevent premature softening that may occur due to the cracked process by preserving the hard structure of the fruit.
Transport: Harvested olives are not kept in the sun, they are transported in 25 kg plastic baskets.
Sorting and sorting: The olives brought to the facility are first separated according to their size by passing through the sorting machine and then passed through the sorting band to separate the bruised, injured and bruised ones.
Cracking After washing with clean water to be cleaned, cracking is done. In the cracking process, care is taken not to break the olive pit. This is why sizing is important. In the manual cracking process, it is ensured that the olive is broken from one side without breaking the core.
Other processing steps in cracked olives are the same as in scratched olives. However, by changing the water every day in both boots and cracked olives, the olive can be sweetened and consumed in a short time like two weeks. However, in this case, since the olive can soften in a shorter time, it becomes necessary to consume it quickly.
- BLACK OLIVE PROCESSING TECHNIQUES
- BRINE TYPE TABLE BLACK OLIVES
NATURAL BRINE BLACK OLIVES
Harvest: In olives to be harvested for brine processing, it is expected that the color will turn black and there will be a color change of 1-2 mm under the skin or up to half of the flesh. It is important to harvest by hand.
Transportation: Harvested olives are not kept in the sun and are transported in 25 kg plastic baskets.
Sorting and sorting: The olives brought to the facility are first passed through the sorting machine and separated according to their size, and then they are passed through the sorting band to separate the bruised, injured and bruised olives.
Washing: Since the harvest of olives is usually in the rainy season, it is natural for them to be earthy and muddy. For this reason, it should be thoroughly washed before being taken into tanks or pools.
Salt water or fermentation: Fermentation or placing in brine can be done in two ways.
The method applied abroad is as follows:
Washed olives are transferred to tanks or pools, where some of the 10% salty brine prepared beforehand is placed at the bottom. After it is covered with perforated lids, brine is added to cover the lid by 15-20 cm.
Then salt and pH controls are made in the brine. Since salt will enter the olive’s body, the salt content of the environment decreases. For this reason, salt content is brought to 10% by adding salt again. The pH gradually drops with the onset of fermentation.
In plastic or polyester tanks, the pH can go down to 4.2-4.6, but in pools, the pH does not go below 5 very much. If the inside of the pool is not covered with paint or plastic parts, the acidity is consumed by substances that dissolve from the concrete over time. Therefore, the pH usually remains at 5 and above. If the pool is covered with plastic parts, the pH can drop to 4.2. However, in this case, changes can be seen in the color of the olives. Olives in colors such as eggplant purple, burgundy and dark brown can also be found. This is an indication that olives are processed naturally.
Recirculation should be done every 15-20 days for the homogeneous distribution of the salt in the brine. Mold layers accumulating on the surface should be cleaned in a timely manner. When not cleaned, it causes softening in olives. In order to prevent this, the surface of the pool or tank is covered with solid paraffin and the contact of the brine surface with air is cut off. This prevents deterioration on the surface. In hot weather, the amount of salt in the brine can be increased up to 12-14%. In this case, olives become edible between 6 and 12 months.
Another method of natural brined black olive processing is the brined black olive method known as the Gemlik method in our country. It is used quite widely. The difference from the method described above; is the placing of olives by folding them with salt. The amount of salt is determined as 10% of the olive weight. 25% of the salt is sprinkled between the olives and the remaining 75% is spread over the top and covered with lids.
Again, weights varying between 10-20% of the olive weight are placed on it equally. Then, clean water is given to cover 15-20 cm. In the later controls, the amount of salt that has fallen is added. The amount of salt usually varies between 10 and 18%. In summer, the amount of salt can usually go up to 18%.
In general, olives processed with this method can be sweetened and presented to the market in 6-12 months. Although circulation is not done much in the Gemlik method, it is better for a homogeneous distribution of salt. Working with a high amount of salt prevents the olive from spoiling in terms of microbial, but it can also cause sensory deterioration. In addition, due to excessive pressure, wrinkles and cheeks occur in olives.
Aeration: It is a process done to remove color differences in olives whose fermentation has been completed. Thanks to the oxygen in the air, the color materials are oxidized and the desired black color is formed. Aeration can be done either by removing the olives to the pans and keeping them for 2-3 days or by giving air through a compressor in the containers they are in.
Packaging: The olives, which are relatively color-matched by airing, are packaged after being passed through the sorting band to separate the crushed or injured ones. Packaging can be done in two ways, with and without brine.
In brine packaging, 8-10% salt brine is used by adjusting the pH to 4.5 with optional lactic, citric, acetic acid or vinegar. In order to prevent possible deterioration, preservatives such as potassium sorbate (0.1%) or sodium benzoate (0.05%) can be added to the packaging brine. If heat treatment is to be applied, preservatives may not be needed.
Olives to be packaged without brine; They are kept in the brine containing 6-10% salt and 0.2-0.5% lactic, citric, acetic acid or vinegar and 0.1% preservatives for 1-2 weeks, then taken to the pans and kept in the ultraviolet rays of the sun for 2-3 days. Tin cans, glass jars and polyethylene bowls can be used for packaging.
- a) FLAVORING
Recently, people’s complaints about too much salt have brought along new searches. One of the methods that can be considered new is the method in which the olive can be sweetened earlier by giving air and its structure can be preserved better.
Black olives can be tasted in a short time like 3-4 months by providing the air produced by a compressor with PVC devices placed in the tank or pool, and by ensuring that dissolved oxygen is found all over the brine.
If black olives are to be given air for 24 hours, 0.1 lt of air per hour for 1 liter of brine, if 8 hours a day, 0.3 liters of air per hour should be given. A continuous circulation is provided by giving air to the brine.
The amount of salt is usually kept around 10%. The pH of the brine should be adjusted between 4.2-4.5 with acetic acid during processing. In this processing, the olive color is darker than the traditional method due to the air given, and its structure is harder and stronger.
Olives, whose fermentation is finished and are ready to be eaten, are packaged in brine with pH adjusted to 4.2-4.5 and salt 8-10% and are put up for sale by pasteurizing or using preservatives in appropriate amounts according to the Food Codex.
- SADDLE TYPE TABLE BLACK OLIVES
Fully ripe olives are used in saddle type black olive processing. For harvesting, it is expected that the color will occur at almost every point under the bark. The injured, bruised and bruised olives are washed well after being separated. The olives, whose juice is filtered, are placed in the saddles with one layer of olive and one layer of salt.
In saddle type olive processing, coarse-grained rock salt is adjusted to be 10-20% of the olive weight. The filled saddles are covered with a cross-stitch cloth and sewn. The saddles are kept in sloping concrete and in places where drainage channels are made. Thus, it is ensured that the bitter water that will flow from the saddles is removed from the environment without accumulating under the saddles.
After the saddles are kept for 2-3 days at first, they should be turned right and left, up and down every other day, so that the salt comes into contact with the entire olive surface. Olives processed in this way become edible within 4-5 weeks. The flavoring of the olives in the saddle should be determined correctly.
The flavored olives are removed from the saddles, desalinated and prepared according to the demands of the market. Olives should not be washed in the saddle, so as not to reduce the shelf life. Sele olives are more durable than pickled olives. It is difficult to store for a long time. The packaging of olives produced in this type should be done carefully.
10% dry salting method can be used for packaging. In addition, dry packaging is done by dipping it in olive oil with vinegar. With a study carried out in the Olive Research Institute in 2003, it was ensured that saddle type olives can be stored for a long time by pasteurizing them in jars without brine.
- TIN TYPE TABLE BLACK OLIVES
It is a widely used olive processing method. Tin olives are produced in two ways, with and without brine.
Olives harvested in tin brine production are kept in 10-12% brine in tanks or pools, and then put into lacquered tin boxes to be released to the market. 8% of brine and 25% of the total volume of fine vinegar are put into the tin. When the salt balance of olive and brine is formed, 0.5-0.75% acetic acid is added.
In addition, placing 25-250 ml of quality olive oil in cans, depending on their size, affects the formation of taste and aroma, as well as plays a role in the preservation of olives. This type of olives last for a long time without spoiling with the help of added salt and acid.
In the production of tin olives without brine, the ripe olives that are harvested are filled into tins after they are thoroughly washed. 16-17 kg tins hold approximately 12-13 kg olives, and according to this calculation, they are closed after 1 kg of coarse salt, 150-200 grams of olive oil and 100 grams of fine vinegar are put in, and just like the olives, they are turned right or left every other day. they are turned up and down.
Depending on the temperature and variety, they will sweeten in approximately 2-5 months. Without vinegar, olives can be processed in the same way with the dry tin method by using 750-1,000 grams of salt and 500 grams of quality olive oil per 12-13 kg of olives.
- VINEGAR (KALAMATA TYPE) TABLE BLACK OLIVES
In this method, which is widely used in the world and known as kalamata type olive processing, olives are given taste and aroma with vinegar and various spices. It is an important form of production especially for export. Olives with vinegar can be produced in several ways. As the name suggests, it is essential to flavor olives with vinegar. The ripened olives are harvested and after being washed, they are passed through the boot machine and tasted just like the boot olives, and then treated with vinegar.
The first way: The olives, which are flavored by drawing, are then kept in good grade vinegar for 1-2 days. Olives extracted from vinegar are taken into packages and 8% brine is added on it. Due to the vinegar in the olive, an acidity of 0.5-0.75% occurs in the environment. If not, acidity can be regulated by the addition of acetic acid. If desired, olive oil, a couple of slices of lemon, garlic or bay leaf can be added. Calcium chloride at the rate of 0.1% can be added to prevent softening of olives during sweetening.
Second way: Since there is a lot of vinegar consumption in the first method, the olive flavor with vinegar can be created by adding 1.2-1.5% acetic acid to the packaging brine of sweetened olives and released to the market.
Third way: In this method, the harvested olives are sweetened by changing the water in the tanks without being scratched, they are kept in 8-10% brine, and then, when desired, they are taken out of the container and scratched, then packaged as in the second method and released to the market.
- CAUSTIC TYPE TABLE BLACK OLIVES
Processing of caustic type olives is a method developed especially in order to give the product to the market at the desired time. It is a method that has been used in all olive producing countries for almost a century. This type of processed products constitute the majority of our country’s exports. There are two more commonly used methods.
- a) CANNED TYPE BLACK OLIVE PROCESSING
This method, which was developed in the United States at the beginning of the last century, is now widely used all over the world. As we mentioned above, olives, which are sweetened in a period of 6-12 months with natural fermentation, can be sold in a short time like a week with this processing method. For this reason, it is widely used in the commercial environment.
In this type of processing, it is very important to determine the harvest time correctly. Harvest time plays an important role in the color and firmness of the olive’s flesh.
Harvest: It is done when the olive color turns from green to pink. When harvested when the color is still black, the color of the olive is good, but the flesh may become soft. Harvesting must be done by hand and olives must be transported in 20-25 kg crates. After the olives coming to the plant are sorted, they must be passed through the separation band and classified in terms of both injured bruises and color. Thus, a more homogeneous product is obtained.
Transportation: Harvested olives are not kept in the sun and are transported in 25 kg plastic baskets.
Sorting and sorting: The olives brought to the facility are first separated according to their size by passing through the sorting machine and then passed through the sorting band in order to separate the bruised, injured and bruised olives into green, pink and black according to their color.
Caustic application and aeration: In this processing method, caustic application is generally done in 3 stages. In this method, since all the substance that gives bitterness to the olive is removed, caustic application is made until it penetrates the core. Since caustic will be applied in three stages, caustic is prepared in three different densities.
In the first stage, caustic (temperature should not be more than 18 degrees) prepared at the rate of 1.5-2.0% is applied. It is ensured that the caustic is processed just below the crust. After it is determined that it has penetrated under the peel, the caustic is taken to another tank and the olive is washed with normal water until the pH reaches 5.5-7.0. Then the olive is given air. If possible, air can be supplied in the tank by means of a compressor. If not, the olives are allowed to aerate by taking them into the trays and mixing them from time to time. Thus, darkening of the color is ensured due to the oxygen in the air.
In the second stage, caustic with a density of 1-1.5% is prepared and used. It is important for all caustic applications that the temperature is below 18 degrees. Caustic is applied up to half of the olive meat. Then the olive is washed and ventilated.
In the third stage, 0.5-1% caustic is prepared and applied to the core. After the caustic is removed from the olive and washed, it is ventilated and the process necessary to fix the different colors of the olive is started (ferro gluconate or ferro lactate application).
Ferro gluconate or Ferro lactate application: 0.1% ferro gluconate or 0.05% ferro lactate is used to fix the color in washed and aired olives. It is kept in this water for about 24 hours. After the first few hours, the ventilation process continues.
Pasteurization: The product obtained after this step is a low salt product with low acidity. Therefore, spoiling microorganisms can multiply and cause deterioration. Therefore, pasteurization is important in this type of processing. Partial pasteurization can be done by keeping it at 60-65 degrees for 45 minutes or by cutting it after steaming at 90-95 degrees, and better preservation can be achieved in the brine.
Selection and sorting: It is especially done to eliminate color differences before packaging.
Packaging and sterilization: The ready olives are 3% salty and their pH is between 5.5-7.5. Therefore, it must be subjected to heat treatment. If there is no heat treatment, it can cause Clostridium botulinum poisoning. Packing brine prepared with 1-4% salt is heated to 90-95 degrees and put into lacquered tin cans. Calcium chloride 0.1% can be added to the packaging brine for tissue stiffness. The boxes, which are then sealed airtight and watertight, should be sterilized at the required temperature and time according to the container sizes as follows.
- b) PROCESSING BLACK OLIVES WITH PARTIAL FERMENTATION CAUSTIC
The purpose of this type of processing is to preserve the taste and aroma of the olive by providing a partial fermentation and to add a distinctive flavor. It is a method that is widely used in our country and in the world. With this method, the sweetening period, which lasts for 6 to 12 months in naturally brined black olives, is reduced to a short period of 2 months.
For the olives to be processed with this method, the harvest time is before the full ripening of the olive. Olives are hand picked. After sorting and sorting, the olives are taken into the tanks. Caustic prepared previously between 1.5-2.0% is applied. It is ensured that the caustic is processed up to 2/3 of the olive meat. Ambient temperature and variety affect the processing time of caustic. Olives are washed after caustic application. The washing process is done until the pH of the washing water drops to around 7. At the same time, the ventilation process is applied.
Then, ferro gluconate or ferro lactate is applied to fix the color. 0.1% ferrous gluconate or 0.05% ferrous lactate is applied.
Meanwhile, 4-8% salt is added to the brine and if the pH rises, pH adjustment is made with acid. It takes 24 hours. Thus, the olives whose color is fixed are left for fermentation by increasing the salt content in the brine to 8-10% or by taking them into new brine with 8-10% salt.
The pH values that rise during the fermentation are adjusted between pH 4.5-5. At the end of the fermentation, which will last for 1.5-2 months, the pH will automatically drop to 4.2-4.5. During the fermentation, pH, salt and acidity controls must be made.
Yeast and molds accumulating on the surface should be cleaned. Olives, whose fermentation is completed, are ready to be put on the market.
Packaging should be put up for sale after pasteurization or sterilization in both glass jars and lacquered cans.
Packing brine with 6-8% salt and pH adjusted to 4.2 can be used for olives to be served in this way. If necessary, 0.1% potassium sorbate or 0.05% sodium benzoate can be added as a preservative. If the business does not have the possibility of heat treatment, olives can be marketed in cold environments with the addition of 10-12% salt brine, pH 4.2-4.5 and preservatives. Otherwise, there will be distortion.
