BACKGROUND
The concept of olive oil yield is understood as its total oil content level expressed in percentage by weight. It is well known that in any industrial process, the optimization yield of a process never reaches 100%, and an oil extraction process in an olive mill is no exception. In this context, we must also mention the concept of industrial yield, understood as the amount of oil extracted per kilogram of olives.
Industrial yield is easy to determine by conducting a warehouse inventory at any point during the campaign:
This variable is only precise at the end of the process, but there are formulas that allow very approximate estimates, which are valid for setting a price negotiation in advance as the producer delivers the olives. By applying a correction index to the total fat yield, we can estimate the industrial yield.
Theoretical Industrial Yield = Total Fat Yield – Correction Index
OLIVE LIPOGENESIS
Lipogenesis refers to a biological process by which fat is synthesized and stored within cells. In the case of olives, this occurs during their development and maturation on the tree. These fat cells are also known as adipocytes, responsible for storing lipids within the fruit, which directly influences its oil content. This process unfolds over several months, during which the olive undergoes changes in both composition and color. Although the exact timing varies, depending on climatic and geographical factors, lipogenesis typically initiates around June. This is when lipids begin to form within the pulp, and the fruit changes color, becoming a deeper green. Lipogenesis accelerates during the summer, resulting in more oil formation, until September when the veraison begins.
Lipogenesis is understood as the biological process by which fat is generated and stored inside cells, with these fat cells known as adipocytes, storing lipids that directly influence the oil content in the fruit pulp.
Referring to this process, when the olive changes from green to yellowish tones, it marks the beginning of its ripening phase. Although fat generation continues at this point, the rate decreases notably. It is approximately, depending on climatic and environmental conditions in the area, late November when the olive should complete its ripening processes. It is recommended that olive oil production should come from early harvesting, just as the veraison begins and the olives still maintain green hues. This is because these fruits have not undergone oxidative reactions, thus preserving their higher levels of polyphenols. However, the disadvantage is that these fruits will have less pulp and lower yields.
Some authors suggest that to strike a balance between quality and productivity, besides finding the optimal harvesting time, reliance on bioactive compounds for this purpose should also be considered.
INFLUENTIAL VARIABLES IN FAT YIELD
Climatic Conditions
To optimize olive cultivation in terms of oil yield, high temperature and radiation areas are recommended over cold or shady areas. Additionally, specific meteorological conditions can influence the yield, such as delayed flowering due to spring rains or decreased photosynthetic activity caused by milder winter temperatures or an excess of normalized conditions.
Olive Load
Olive groves are biennial bearing, meaning they alternate between high and low production years. Thus, if there is a significant load, the nutritional resources must be distributed among all the set fruits.
Olive Variety
The variety of olives in a plantation affects the yield of the olives. Some varieties have a very high yield, even exceeding 20% oil content from olives. Examples include the Picual variety (used by Aceites Vallejo), Cornicabra, Picudo, and Arbequina.
Olive Care
The care given to olive trees directly influences the yield of the olives. For instance, pruning is done to ensure good lighting for the branches and thus increase yield. If an olive tree is under water stress, it reduces water consumption and will produce olives with a lower yield. Additionally, pests and diseases weaken the olive tree, reducing its harvest and the yield of the olives.
CARE AND APPLICATIONS FOR INCREASING OLEIC ACID IN OLIVES
Oleic acid is the most representative fatty acid naturally present in olive oil, directly correlated with fat yield. Numerous studies confirm that the use of boron and calcium through foliar application can increase the oleic acid content in treated olives. This is also supported by subsequent autumn applications of bioactive biostimulants. During the filling process, the use of biostimulants derived from algae improves the nutritional status of the plant, providing essential nutrients such as nitrogen, calcium, and potassium, which are directly involved in olive maturation and the final oil quantity. Additionally, these formulations supply essential amino acids, which are part of the enzymes involved in lipogenesis (oil formation).
See the parallel information on Fruit, production and maturation of olives, which also specifies the vital importance of managing water stress through highly antioxidant active compounds. These compounds help eliminate reactive oxygen species (ROS), promoting the generation of photoassimilates and the vascular flow of the olive tree, thereby increasing resistance to this type of stress.
CULTIFORT RECOMMENDATIONS
A seaweed emulsion that promotes cell division, with easily assimilable active ingredients such as phytohormones and growth regulators (cytokinins, auxins, gibberellins, betaines, abscisic acid, and brassinosteroids), matrix and reserve polysaccharides (alginates, carrageenans, agar, ulvans, mucopolysaccharides and their oligosaccharides, fucoidan, laminarin, starch, and fluoridean), oligosaccharides, biotoxins, and antioxidant compounds (polyphenols, bromophenols, flavonoids, fluoroglucinol polymers, gallic esters, coumarins, flavanones, phlorotannins, oligomeric proanthocyanidins, diterpenes and polyhalogenated monoterpenes, halogenated ketones, and isoprenoid compounds), chlorophylls and carotenes, xanthophylls, minerals (iron, calcium, magnesium, phosphorus, iodine, nitrogen, potassium, barium, boron, cobalt, copper, magnesium, manganese, molybdenum, nickel, and zinc), organic matter, mannitol, vitamins, amino acids and proteins, alginic acids, fulvic acids and other organic acids (palmitic, butyric, oleic, linoleic), enzymes, sterol, and fucosterol.
This rich composition found in seaweed is responsible for the beneficial effects that its application generates in the fat content yield of olive pulp.