The Greek table olives/ a close-up on Kalamata olives

Historical data
The olive, according to myth, was the gift of the goddess Athena to the inhabitants of the city of Athens, who in gratitude gave the goddess’s name to their city. On the Acropolis there was the sacred olive tree of Athena, the first olive tree that the goddess gave the Greeks and the Academy the 12 holy olives and the sacred olive grove from which came the oil that was given as a prize to the Panathinaion winners. The cultivation of the olive is estimated to have started 7,000 years ago. The surveys present olive fossils in the Greek area with the impressive age of 50,000 – 60,000 years.
Botanical elements
The olive belongs to the Oleaceae family and its botanical name is Olea europaea. One of the characteristics of species of the genus Olea sp. is their longevity, which can be over 100 years, without even stopping or reducing the productivity of these trees. The olive tree is a tree that can withstand dry and warm areas as well as on barren soils. It also has the ability to germinate again after injury or disaster of its oversized part. The main varieties of olives for table use are Conservolia, Chalkidiki and Kalamon. The “Kalamon” variety is one of the best varieties for table use and is used to make the famous and unique in the world commercial type of “natural black olive olives” or even better known as Kalamata Olives olives in recent years. The tree is sturdy enough, its branches have a climbing tendency and typically large leaves. The fruit has a cylindroconic shape and for this reason the variety is also called Kalamon’s wildebeest or eagle. On average, the fruit weighs 5-6 grams and the core is smooth and easily detached from the flesh. As a tree it is moderately productive, demanding in soil and atmospheric humidity, resistant to soil salinity. As for fruit ripening, it is considered to be a medium-sized variety and matures from the end of November to December. It should be noted that the variety matures its fruit prematurely, ie in November, if the load is reduced or late in December, if its cargo is heavy. It is considered to be a variety of resistant and has specific soil, moisture and microclimate requirements in its cultivation area.
Financial data
Over the last fifteen years, the marketability of the Kalamata variety has been rising very fast. The special way of processing Kalamata olive oil and preserving the final product in brine with vinegar adds organoleptic characteristics to the highly valued product on international markets. Today it is estimated that the production of processed products exceeds 55,000 tons per year and the production of this type of trade is expected to reach 100,000 tons in the next 10 years.
Production – Table Olives Consumption
Table olives are one of the most important fermented products of plant origin in the food industry with an estimated world production of more than 2 million tons per year (IOC 2016). The growth of this product is mainly related to the Mediterranean countries, with Spain, Italy, Greece, Egypt and Turkey being the main producing countries. According to the International Olive Council, the European Union owns 33.7% of the world production of table olives. Greece contributes significantly to this figure, as it is the third country producing table olives in Europe.
Chemical composition of the olives
The main constituents of the olive flesh are oil, sugars, proteins, pectin, organic acids, tannins and inorganic ingredients. The composition of the olives differs according to the variety, the growing area, the year and the stage of development. The high quality of Greek table olives has been attributed to soil properties, increased sunshine and climatic conditions coupled with the fact that it is a natural product that is hand-picked and processed in a traditional way.
Processing olives
The harvest of Greek olives depends on the variety. Also, the olives mature at a different rate, so they are not all prepared for harvesting. Khalkidhiki olives are harvested between mid-September and mid-October, when the fruits are green, of good size and not very mature. The color of the skin of the Khalkidhiki olives is slowly changing with the progress of ripening, from green to green-yellow, then straw-yellow, pink and ends in light red, black, but never black. This is why harvesting occurs when they are green and cannot be used as black table olives. The destination is the production of green olives of the Spanish type.
The harvest of Konservolia begins in the middle of September and reaches mid-January. Its skin gradually changes its color from green, pink, reddish, violet and black to over-ripening. The green olives belonging to the family of Konservolia are harvested early, from mid-September to mid-October, and are usually intended for the production of green olives of the Spanish type.
Blissful Amfissis olives are collected in the middle of the year, from the end of October to the end of November.
Black olives belonging to the family of Konservolia (or black olives Amfissis) are harvested from the trees from mid-November to mid-January when the fruit is ripe and is reddish, violet or black.
The harvest of Kalamata olives is done late in November-December and sometimes until January. The olives are collected at the stage of full maturation, but not of over coating, when they have a deep melanogenic color and cohesive texture. Many times the fruits do not have the same color, so the harvesting of the fruit from a tree is done in part, leaving the green fruits on the tree to ripen and harvested later. Harvesting can be done by hand or by mechanical means. At the end of harvesting, the branches and leaves are removed as well as the fruits that are unsuitable for processing. After harvesting, the fruit is placed in plastic containers, with smooth interior surfaces to prevent the olives from being injured and transported to the processing areas. The olives of the Kalamata variety are processed according to the Greek method of production of natural black olives in brine. The various steps involved in making this type of table olives are as follows:
• Harvest
• Transfer to the processing area
• Classification
• Wash with water
• Place in brine
• Fermentation of olives
• Sort and rank by size
• Packaging
Olive fermentation
The process of fermenting the olive is carried out in tanks, in brine. During fermentation, microorganisms metabolize oat sugar to produce lactic acid. Along with lactic acid bacteria, yeasts play a crucial role in the fermentation of table olives. As lactic acid bacteria decrease during the fermentation of natural black olives due to the presence of phenolic compounds, the doughs dominate and contribute significantly to the organoleptic characteristics of table olives.
Factors influencing the fermentation process
The factors that affect it are mainly endogenous such as pH, water activity, availability of nutrients, organic acids, the presence of antimicrobial substances, the structure of the epidermis of the fruit as well as exogenous such as temperature, NaCl concentration.
Temperature control during fermentation at levels where bacterial bacteria exhibit their maximum activity (20-25 ° C) is one of the most important factors. Once the fermentation process has been completed, the product will have acquired certain physicochemical properties such as saline, pH and organic acids that make it stable and safe without the need for heat treatment. The initial salt concentration in the brine ranges from 6-10% depending on the variety, the stage of maturity and the method of processing the table olives.
The fermentation process is completed within 5-9 months. If the fermentation is terminated, the olives are separated from the brine and subjected to the sorting process. At this stage it is done with special machines and calibration.
The classification of each batch of olives based on the size of the fruit greatly improves the appearance of the product, facilitates its costing and indirectly also indicates the maturing stage (the larger fruits are mature). Then the size uniformity of the fruits of a batch facilitates the pitting process. After the calibration the olives are re-placed in new brine and packed.
The traditional way of packaging the table olives is in plastic containers of up to 150 Kg either in tin containers depending on the type of product and in glass packages that are heat-treated, usually pasteurization. In all cases fresh 6-8% brine is added to NaCl to fill the containers. The final product has a slightly acidic flavor, black-purple color and has good flavor and aroma characteristics. Today, table olives, in addition to traditional packaging methods, are packaged in flexible plastic films in which the free space of the package is covered either with fresh brine or vacuum is created by removing the air or by introducing a gas or a mixture gas. Lastly, multilayer plastic films are used which are molded into rigid containers into which the product is placed. Another new package is in sachets of 70-80 gr. known as Doypack. Doypack sachets could be a healthier snack alternative to traditional salty and sweet snacks as it is now essential to integrate our healthier eating habits throughout the day. Another modern way of packaging is in containers with low-salt brine, olives known as Fresh Olives (Fresh Olives). These are olives with a basic advantage of low salinity. These products are transported by refrigerated vehicles and stored in chilled areas. It is a new product, with many advantages, which meets the requirements of the modern era and the World Health Organization guidelines, to reduce the average sodium / salt intake. These products do not differ from the rest in quality and organoleptic characteristics, except in the lower salt content and in the way of preservation. They can also be consumed by groups of people who, for reasons of health, must have little salt consumption.
Beneficial properties of olive in health
The olive is an essential ingredient of the precious Mediterranean diet, rich in nutrients and rich in flavor.
Olives contain very few carbohydrates and are a rich source of monounsaturated fatty acids (oleic acid). The fruit of the olive is rich in phenolic substances, of which the most important is oleuropein, which is contained in high concentrations in the leaves of the olive tree. Studies have shown that libera is a particularly important substance as it has antimicrobial activity against pathogenic microorganisms and toxin-producing fungi. The characteristic flavor and aroma of the olive comes from the presence of polyphenols. Polyphenols are beneficial to cancer and also have significant anti-inflammatory properties. They also reduce the oxidative stress in the brain and so, by eating a portion of olives daily, memory can improve up to 25%.
Olive oil is a very good source of trace elements. It contains high concentrations of minerals such as K, Ca, P, Na, Mg and S, while in smaller quantities Fe, Zn, Cu, Mn, N and B. Vitamins are present in olives but can grow with microbial activity when fermenting the olive. When processing table olives, water-soluble vitamins are lost, while liposolubles that have antioxidant activity remain.
Table olives are studied as carriers of probiotic microorganisms entering human beings by consuming the final product. Lactic acid bacteria have been widely applied in the field in recent years. Recent probiotics have been characterized as living microorganisms that are resistant to gastric, biliary and pancreatic secretions. Increasing blood cholesterol levels is a significant risk for the occurrence of chronic cardiovascular disease in humans. Some micro-organisms have a capacity to lower cholesterol levels due to various factors. According to studies, yeast strains isolated from table olives showed a cholesterol lowering ability in excess of 60%, indicating that they could be used with a biotherapeutic purpose. Finally, they are an excellent source of dietary fiber, as an alternative to fruits and vegetables.
It seems from the above said that Kalamata olives are the “functional foods” of nature and offer many benefits to the body.
Liakakou Yioula
Food Scientist
Quality Department, AGROSPARTA