Collection methods

The olive harvest is one of the most delicate phases in the production of olive oil, as it directly affects the quality and organoleptic characteristics of the final product. The time of harvesting is decisive and varies depending on the variety of the olive tree, the climatic conditions and the production objective, which can be oriented towards obtaining a fruitier or sweeter oil. A timely and careful harvest allows you to reduce the risk of unwanted fermentation and to better preserve the aromas and nutritional properties of the oil.

There are several harvesting methods, each with advantages and disadvantages:

Image : woman involved in olive picking- source: Freepik.com (n.d.)

1. Manual harvesting: this is the most traditional method and is carried out by hand by operators who detach the olives directly from the branches. In the past, this activity was mainly carried out by women, who patiently and dedicated themselves to harvesting the olives by hand, often using wicker baskets to transport them. This system allows the fruits to be carefully selected, harvesting only those that have reached the right degree of ripeness. However, it is a very time-consuming and labor-intensive process, making it economically viable only for limited or high-quality productions.
2. Mechanical harvesting: involves the use of machinery such as shakers, which shake the branches to make the olives fall on nets or sheets placed on the ground. This method is much faster and more efficient than manual harvesting, reducing production costs. However, it can cause damage to the fruits and branches, which can affect the quality of the oil.
3. Brucatura: similar to manual harvesting, stripping consists of picking the olives directly from the branches, one by one, without letting them fall to the ground. This method allows you to preserve the quality of the fruit and obtain

a high-quality oil, but it is even slower and more expensive than classic manual harvesting.

1. Bacchiatura: it consists of hitting the branches with sticks to make the olives fall on sheets spread on the ground. It is an intermediate method between manual and mechanized harvesting, but it can damage both the olives and the branches, affecting the plant's productivity in subsequent seasons.
2. Natural fall harvesting: the olives are spontaneously dropped to the ground and then harvested. This method is the least expensive, but it carries a greater risk of deterioration of the olives, with a possible increase in the acidity of the oil.

Image : olive harvesting- source: istockphoto.com (n.d.)

Processing techniques

After harvesting, the olives must be processed as quickly as possible to avoid fermentation processes that could compromise the quality of the oil. The transformation process begins with the cleaning and milling of the olives, followed by the extraction of the oil through different methods that affect the yield and sensory properties of the final product. The main objective of these techniques is to preserve the aromas and nutritional properties of the oil in the best possible way, while ensuring high quality and good shelf life. The main techniques used are as follows: Once harvested, the olives are processed following different techniques to extract the oil:

• Cold pressing: this method, which involves extracting the oil at temperatures below 27°C, allows the organoleptic and nutritional properties of the oil to be kept unaltered, guaranteeing a high quality product, this method is widespread especially in Italy and Spain.
• Centrifugation: widely used in Greece and Tunisia, this technique involves the olive paste obtained from pressing being subjected to a separation process by centrifuges, which separates the oil from the vegetation water and solid residues. The olive paste obtained from the pressing is subjected to a separation process by centrifuges, which separates the oil from the vegetation water and solid residues.
• Filtration: very common in France and Portugal, this step eliminates impurities and micro residues, improving the shelf life of the oil and ensuring greater sensory stability over time.
• Traditional pressing: Still used in some rural areas of Greece and Morocco, this technique involves the use of mechanical presses to extract the oil, separating the liquids from the solids. This method is less prevalent today due to lower efficiency compared to centrifugation.
• Two-stage decanter extraction: A modern system, widespread in Spain and Italy, which reduces water consumption compared to traditional methods, improving efficiency and reducing environmental impact. The system is called two-phase because it provides for the oil to come out on one side and the wet pomace on the other.
• Ultrasound extraction: An innovative technique that is finding application in countries with strong technological innovation such as Israel and Australia. It uses ultrasonic waves to improve oil extraction, increasing yield and preserving product qualities.

Quality Control in Olive Oil Production

Quality control is a fundamental aspect in the production of extra virgin olive oil. Guaranteeing a product of excellence means monitoring every phase of the process, from harvesting to processing, up to storage and distribution. Quality checks are not only a regulatory obligation, but also a duty to guarantee the safety and genuineness of the oil that arrives on consumers' tables. To ensure superior quality extra virgin olive oil, rigorous controls are carried out throughout the production chain:

• Chemical analyses: These analyses make it possible to evaluate essential parameters such as free acidity, which must not exceed 0.8% for an extra virgin olive oil, and the number of peroxides, an indicator of the oxidative stability of the oil. In addition, phenolic compounds, responsible for antioxidant properties, and the fatty acid profile are analyzed to verify compliance with quality standards.
• Organoleptic tests: expert tasters evaluate the taste, aroma and appearance of the oil to identify strengths and weaknesses. Among the positive parameters, fruitiness, bitterness and spiciness are sought, while defects such as rancid, heating or mold, signs of a non-optimal production process, are avoided.
• Quality certifications: Brands such as PDO (Protected Designation of Origin) and PGI (Protected Geographical Indication) attest to the geographical origin and compliance with strict production regulations, giving added value to the product. In addition, some oils can receive organic certifications that guarantee the absence of pesticides and pesticides in the production process.