The Sterol and Erythrodiol + Uvaol Content of Virgin Olive Oils Produced in Five Olive‐Growing Zones of Extremadura (Spain)

Abstract

IntroductionToday, olives are grown in all the countries of the Mediterranean basin, especially in central and southern Spain, Italy, Greece, Turkey, Tunisia and Morocco. The world's total area of olive groves is around 10 million ha [1], of which approximately 98 % is in this Mediterranean region, with Spain standing out for its 24.4 % of the global total. Olives are the most important crop in Extremadura in terms of acreage, with some 269,350 ha, of which 70 % are in the province of Badajoz and 30 % in the province of Cáceres. Of this area, about 92 % corresponds to olives for milling [2]. Extremadura's olive oil production is about 52,600 t/ year, representing 3.36 % of Spain's total olive oil [1]. There are 117 mills.Following the European Union's establishment of a criterion for homogeneous production of olive oil [3], in Extremadura 12 olive-growing zones were defined: (1) Gata-Hurdes, (2) Vera-Ambroz, (3) Ibores, (4) Logrosán-Guadalupe, (5) Montánchez, (6) Rest of Cáceres, (7) Alburquerque, (8) Vegas del Guadiana, (9) Tierra de Barros, (10) La Siberia, (11) La Serena and (12) Jerez-Llerena. Currently in Extremadura there are two Protected Designations of Origin (PDO)-"PDO Gata-Hurdes" in the province of Cáceres, which protects virgin olive oils (VOOs) produced in the olive-growing zones of Gata-Hurdes and La Vera-Ambroz, and "PDO Aceite Monterrubio" in the province of Badajoz, for VOO from the olive-growing zones of La Serena and La Siberia. These PDOs certify the origin, authenticity and quality of the olive oils produced in a specific geographic zone.The most representative cultivars in terms of their percentage of cultivated area of the olive-growing zones studied are "Manzanilla Cacereña" with 95.2 and 90.3 % Abstract The content of sterols and erythrodiol + uvaol was studied in 273 virgin olive oil samples from 40 mills in five olive-growing zones of Extremadura (Spain). An analysis of variance showed significant differences at a confidence level of 95 % between the different zones in each of the main sterols and in the sum of erythrodiol + uvaol. The results of a linear discriminant analysis, considering the different olive-growing areas as categorical dependent variables and the different sterols as independent variables, explained 78.2 % of the variance with the first two discriminant functions. The resulting model correctly classified 86.9 % of the samples analysed. A validation study was conducted to verify the goodness of the discriminant analysis, resulting in 79.3 % of the new samples used for validation being correctly classified. In the graphical representation of the different groups studied considering the proposed model's first two discriminant functions, the centroids of the Sierra Norte de Cáceres, Vegas del Guadiana and Tierra de Barros olive-growing zones were clearly separated, but this was not the case for the other two zones-La Serena and La Siberia.

Preliminary Study and Observation of “Kalamata PDO” Extra Virgin Olive Oil, in the Messinia Region, Southwest of Peloponnese (Greece)

“…A similar case was observed in campesterol, where a total of 21.7% of the examined samples exceeded the legal maximum of 4%, with a mean value of 3.71% and ranged from 2.78 to 4.70%. A trend of higher campesterol has also been reported for cv Koroneiki, as well as for other cultivars cultivated in different countries [44,45], whereas the total sterol concentration of the most studied Spanish and Italian cultivars is always within the minimum limit of 1000 mg/kg [46][47][48][49][50].…”

Influence of environmental growth temperature on tocopherol and sterol oil concentrations in olive fruit

“…Arbequina agree with previous studies at different geographical locations that have suggested that environmental factors influence total sterols. [23][24][25]47,48 For example, total sterols were more than 2000 mg kg −1 oil at a warm location in California (USA), while they did not exceed 1800 mg kg −1 oil at cooler locations. 48 Moderate temperature increases under controlled, experimental conditions have also been shown to increase total sterols in soybean seeds, as reviewed by Carrera and Seguin.…”

“…30 Analysis of olive oils from five different growing regions in Extremadura, Spain, showed differences in total sterol and composition. 23 In Tunisian oils, differences were observed between regions in total and some individual sterols, particularly in ⊎-sitosterol, stigmasterol, and Δ7-stigmastenol. 24 Lower levels of campesterol in Tunisian oils were also observed in comparison with Portuguese or Spanish oils, although this may have been related to genotypic or environmental differences.…”

“…22 Several studies have shown that sterol composition in olive oil changes with fruit development, genotype, and geographical origin. [23][24][25][26] Both total sterol content and the percentage of the main individual sterols (⊎-sitosterol and campesterol) decreased when comparing oils from early fall with those from late fall harvests, 27 and sterols remained stable during late ripening. 25,28 Some authors report that sterol synthesis occurs primarily during the first phases of fruit growth, and then they are converted to other sterol forms such as stanol and steryl esters 29 or become saponifiable lipids, steroidal hormones, or vitamins.…”

Pigment Profile, Color and Antioxidant Capacity of Arbequina Virgin Olive Oils from Different Irrigation Treatments

“…Thus, 100% of the new samples used in the validation were classified correctly. This general validation strategy has been commonly used [21][22][23]. Linear regression was carried out to understand any relation between all analyzed parameters and irrigation treatment.…”