The introduction of new technology for industrial extraction of olive oil requires a knowledge of how this could affect certain oil parameters in regulation of the extraction process. The oil's total polyphenols content, K225 and autoxidation stability were related with variations in temperature, kneading time, paste injection flow rate and oil washing in vertical centrifuges in a two-phase decanter without addition of water to the olive paste. Kneading the olive paste at low temperature, extended kneading at low paste injection rates, oil washing with hot water and high water:oil ratio, yielded oil of low stability, low polyphenols content and low bitterness.

In commercial terms, Extra Virgin Olive Oil (EVOO) is considered an exceptional food with excellent sensory and nutritional quality due to its taste, odor, and bioactive compounds; as such, it is of great health interest. This quality can be affected by the oxidative degradation, both chemical and enzymatic (the activity of oxidative, endogenous enzymes from the polyphenol oxidase and peroxidase olive fruit type), of essential components during the extraction and conservation of EVOO. In the bibliography, oxygen reduction during the malaxation process and oil storage has been studied in different ways. However, research concerning oxygen reduction in the crushing of the olive fruit or the malaxation of the paste, or both, in the “real extraction condition” is scarce. Oxygen reduction has been compared to control conditions (the concentration of atmospheric oxygen (21%)). Batches of 200 kg of the olive fruit, ‘Picual’ cultivar, were used and the following treatments were applied: Control (21% O₂ Mill–21% O₂ Mixer), “IC-NM”: Inerted crushing -Normal malaxation (6.25% O₂ Mill-21% O₂ Mixer), “NC-IM”: Normal crushing-Inerted malaxation (21% O₂ Mill-4.39% O₂ Mixer) and “IC-IM”: Inerted crushing -Inerted malaxation (5.5% O₂ Mill-10.5% O₂ Mixer). The parameters of commercial quality covered by regulation (free acidity, peroxide value and absorbency in ultra-violet (K₂₃₂ and K₂₇₀)) did not suffer any change concerning the control, and so the oils belong to the commercial category of “Extra Virgin Olive Oil”. The phenolic compounds of the olives involved in the distinctive bitter and pungent taste, health properties, and oxidative stability are increased with the downsizing amounts of oxygen in the IC-NM, NC-IM, and IC-IM treatments with an average of 4, 10, and 20%, respectively. In contrast, the total amount of volatile compounds decreases by 10–20% in all oxygen reduction treatments. The volatile compounds arising from the lipoxygenase pathway, which are responsible for the green and fruity notes of EVOO, also decreased in concentration with the treatments by 15–20%. The results show how oxygen reduction in the milling and malaxation stages of olive fruit can modulate the content of phenols, volatile compounds, carotenoids, and chlorophyll pigments in the EVOO to avoid the degradation of the compound with sensorial and nutritional interest.

This paper shows the results obtained from images processing digitized, taken with a 'smartphone', of 56 samples of crushed olives, using the methodology of the gray-level co-occurrence matrix (GLCM). The values ​​of the appropriate direction (θ) and distance (D) that two pixel with gray tone are neighbourhood, are defined to extract the information of the parameters: Contrast, Correlation, Energy and Homogeneity. The values ​​of these parameters are correlated with several characteristic components of the olives mass: oil content (RGH) and water content (HUM), whose values ​​are in the usual ranges during their processing to obtain virgin olive oil in mills and they contribute to generate different mechanical textures in the mass according to their relationship HUM / RGH. The results indicate the existence of significant correlations of the parameters Contrast, Energy and Homogeneity with the RGH and the HUM, which have allowed to obtain, by means of a multiple linear regression (MLR), mathematical equations that allow to predict both components with a high degree of correlation coefficient, r = 0.861 and r = 0.872 for RGH and HUM respectively. These results suggest the feasibility of textural analysis using GLCM to extract features of interest from digital images of the olives mass, quickly and non-destructively, as an aid in the decision making to optimize the production process of virgin olive oil.