Composition and organoleptic characteristics of oil from Arbequina olive (Olea europaea L) trees under deficit irrigation

This study evaluated the effects of different regulated deficit irrigation (RDI) strategies applied to olive (Arbequina cultivar) trees on the qualitative and quantitative parameters of the resulting oil during the maximum evaporative demand period for three consecutive crop seasons. Quality indices, fatty acid composition, pigments, colour, α‐tocopherol and phenolic contents, bitter index, oxidative stability and organoleptic properties of the oil were determined. Irrigation did not affect those parameters used as criteria for classifying olive oil in its commercial grades. Only polyphenol and o‐diphenol contents and, consequently, the bitter index and oxidative stability were affected by the RDI strategy, with increasing values as the water applied decreased. Regulated deficit irrigation resulted in important savings in irrigation requirements without detriment to oil quality. © 2002 Society of Chemical Industry     

Chemical composition of Arbequina virgin olive oil in relation to extraction and storage conditions

The chemical composition of virgin olive oils from Arbequina olives cultivated in Córdoba (Argentina) was studied in relation to the oil extraction system and production year. Significant variations were found between oils obtained by pressure (PEOs) and centrifugation (CEOs) systems. PEOs were characterised by higher values of acidity, pigments and oleic acid, while CEOs showed greater phenol content. Moreover, a significant effect of crop year was observed. Arbequina oils produced in Córdoba contained lower amounts of oleic acid but higher amounts of phenolic compounds than Arbequina oils produced in Spain. A storage stability test was carried out in order to study the combined effects of oil extraction system and storage conditions (packaging material and illumination) on quality indices related to oxidative stability. Multivariate analysis applied to the chemical data emphasised the differences between PEOs and CEOs, indicating that variations due to extraction system were greater than those due to illumination condition and package type. Cluster analysis of oils from each extraction system stressed the influence of illumination condition on the oxidative stability of olive oils, showing increased amounts of secondary oxidation products in oils exposed to light. Glass and tin packages appear to be the most appropriate containers for maintaining the quality of olive oils, but this supposition is strongly dependent on the type of oil (PEO or CEO) and its initial chemical properties. Copyright © 2006 Society of Chemical Industry     

Chemical composition of virgin olive oils from Koroneiki cultivar grown in Tunisia with regard to fruit ripening and irrigation regimes

The impact of different irrigation regimes based on two ripeness index, on the quantity and quality of virgin olive oil from the introduced olive cultivar Olea europaea L. Koroneiki grown at a high‐density olive orchard in northern Tunisia, was assessed. Olive trees were subjected to three treatments (T1, T2 and T3) that received a seasonal water amount equivalent to 50%, 75% and 100% of the estimated local evaporative demand by a drip irrigation system and olives were collected in two different ripeness index. The olive oil content decreased when the water applied was increased but rose during ripening. The quality indexes and fatty acid composition were less affected by the irrigation schedule but most significantly by the maturity of olives. Moreover, phenol contents increased according to fruit ripening whereas no clear cut differences or consistent effects were observed by irrigation. α‐tocopherol decreased slightly in the oils as ripening progressed while insignificant differences between the irrigation treatments studied were obtained. Consequently, a restitution of 75% of crop evapotranspiration (ET_c.) was sufficient to achieve good minor compounds; however, higher water volumes (100% ET_c.) gave little additional α‐tocopherol and phenols increases.     

L‐Phenylalanine ammonia‐lyase activity and concentration of phenolics in developing olive (Olea europaea L cv Arbequina) fruit grown under different irrigation regimes

Changes in L ‐phenylalanine ammonia‐lyase (PAL, EC 4.3.1.5) activity and total phenolic, ortho‐diphenolic and fat contents of olive flesh in response to different irrigation treatments applied to olive tree cv Arbequina were studied during fruit ripening. Results indicate that the fat content of olive flesh at harvest was not affected by irrigation, although olives from the most heavily irrigated treatment reached their final fat content (dry weight) earlier than those from other irrigation treatments. PAL activity and phenolic content, expressed on a dry weight basis, decreased during fruit development and were affected by irrigation, being lowered as the water supplied increased. Good correlations were established between PAL enzymatic activity and the polyphenol and ortho‐diphenol contents of olive flesh, indicating that PAL is involved in the phenolic metabolism of olive fruit. The phenolic content of the oil depends on the PAL activity in the fruit, which varies with changes in water status. © 2002 Society of Chemical Industry     

Genetic and chemical assessment of Arbequina olive cultivar grown in Córdoba province,Argentina

BACKGROUND: Thirty‐eight accessions of olive (Olea europaea L.) originating from Córdoba province (Argentina) and preliminarily identified as belonging to the Arbequina variety were genotyped using AFLP (amplified fragment length polymorphism) DNA markers. Also, the oil chemical composition was studied during three consecutive crop years. The objectives of the work were (a) to investigate genetic intra‐cultivar diversity and (b) to evaluate the oil chemical composition and compare it with that of Arbequina oil produced in Spain. RESULTS: The 19 primer combinations employed to perform the AFLP analysis produced 98 polymorphic bands. A reduced genetic heterogeneity was obtained, confirming that (a) the selected accessions belong to the Arbequina variety and (b) the traditional vegetative propagation practice has caused low genetic erosion in this variety cultivated in Córdoba. The main features that characterise the Argentinian Arbequina oils studied are the lower content of oleic acid and higher levels of phenolics and high‐molecular‐weight volatile compounds compared with those found in Spanish Arbequina oils. CONCLUSION: In spite of the small proportion of intra‐cultivar variability, the Arbequina variety grown in Argentina produces oils with different chemical traits from those obtained in the original Spanish growing region. These differences can be attributed mainly to the particular environmental conditions of the olive‐growing areas in these countries. Copyright © 2008 Society of Chemical Industry     

Transfer of phenolic compounds during olive oil extraction in relation to ripening stage of the fruit

The transfer of phenolic compounds of Olea europaea L. cv. Arbequina variety during olive oil extraction in relation to ripening stage was investigated. The parameters of oil extraction by the Abencor system are shown together with mass balances of the products and by products from the olive oil extraction in relation to olive paste. The phenolic compounds in olive paste, pomace, oil and wastewater were identified and measured by HPLC. Throughout the study, the concentrations of simple phenols, secoiridoids and flavonoids were higher in the olive paste and pomace phases than in oil and wastewater phases. High concentrations of 4‐(acetoxyethyl)‐1,2‐dihydroxybenzene (3,4‐DHPEA‐AC) and secoiridoid derivatives such as the dialdehydic form of elenolic acid linked to 3,4‐DHPEA (hydroxytyrosol) or p‐HPEA (tyrosol) (3,4‐DHPEA–EDA, p‐HPEA–EDA, where EDA is elenolic acid dialdehyde) and an isomer of oleuropein aglycone (3,4‐DHPEA–EA, where EA is elenolic acid aldehyde) were found in olive oil, together with lignan compounds. It was observed that 3,4‐DHPEA–EDA was the most abundant polyphenol present in the wastewater phase. This indicates that biotransformation occurred during olive extraction, especially in the crushing and malaxation operations, and reflects the possible chemical changes that lead to the formation of new compounds. Moreover, the distribution of compounds showed their affinities toward different phases. Copyright © 2005 Society of Chemical Industry     

Effect of cultivar and ripening on minor components in Spanish olive fruits and their corresponding virgin olive oils

Phenolics and volatiles are the compounds mainly responsible for the desirable flavour of extra virgin olive oils and therefore to a large extent determine the degree of consumer preference for this highly regarded product. The effect of both (i) the nature of the cultivar and (ii) the degree of ripening of the olive fruit on the biophenolic and volatile profiles of six different Spanish varieties (Arbequina, Cornicabra, Morisca, Picolimón, Picudo and Picual) and their corresponding virgin olive oils was determined in this study. A clear and statistically significant difference was observed for the oleuropein content, the main phenolic component found in the olive varieties studied. Demethyloleuropein was only found in the Arbequina variety and its content doubled during the ripening process. Verbascoside steadily increased throughout fruit maturation and cyanidin 3-O-rutinoside was the most abundant anthocyanin in all the varieties studied. Within the same cultivar a relationship between the oleosides content in the fruit and the presence of secoiridoids in the virgin olive oils was observed; however, the ratio between biophenols content in the olive fruit and in the virgin olive oil varied significantly for each of the cultivars studied (ranging from 2.3 for Picudo and 28 for Picolimon). The major volatile component was the C6 aldehyde fraction whose content varied greatly between the different varieties studied: E-2-hexenal content ranged from 20.5 mg of internal standard (4-methyl-2-pentanol) per kg of oil in the Arbequina variety to 3.1 mg/kg for Cornicabra; the amount of hexanal ranged from 1.75 mg/kg in Morisca to 0.70 mg/kg for Picual samples.     

Seasonal changes in olive fruit characteristics and oil accumulation during ripening process

Olive fruits of three of the most important Spanish and Italian cultivars, ‘Picual’, ‘Hojiblanca’ and ‘Frantoio’, were harvested at bi‐weekly periods during three crop seasons to study their development and ripening process. Fresh and dry weights and ripening index were determined for fruit, while dry matter, oil and moisture contents were determined in both fruit and pulp (flesh). Fruit growth rate and oil accumulation were calculated. Each olive cultivar showed a different ripening pattern, ‘Hojiblanca’ being the last one to maturate. Fruit weight increased, decreasing its growth rate from the middle of November. Dry matter and moisture contents decreased during ripening in pulp and fruit, ‘Hojiblanca’ showing the highest values for both. Oil content, when expressed on a fresh weight basis, increased in all cultivars, although for the last time period showed variations due to climatic conditions. During ripening, oil content on a dry weight basis increased in fruit, but oil biosynthesis in flesh ceased from November. Olive fruits presented lower oil and higher dry matter contents in the year of lowest rainfall. Therefore fruit harvesting should be carried out from the middle of November in order to obtain the highest oil yield and avoid natural fruit drop. Copyright © 2004 Society of Chemical Industry     

Influence of the malaxation time and olive ripening stage on oil quality and phenolic compounds of virgin olive oils

The main objective of this study was to evaluate the influence of the malaxation time (Mt) and ripening stage on oil quality and phenolic compounds of Hojiblanca and Picual virgin olive oils. In both varieties of oil, phenolic content and oxidative stability decreased as ripening progressed. The total level of tocopherols diminished by up to 40% as fruit ripened. The compositions of palmitic, stearic, lignoceric, oleic, linoleic and linolenic acids were significantly influenced by the ripening process. The present work shows that an increased Mt promoted the increase of free acidity (up to 13.3%) and tocopherols (up to 11.6%) and negatively affected the oxidative stability and the concentration of phenols. Further research is required to determine ripening stages and malaxation conditions for all olive oil varieties to achieve a satisfactory balance between the improvement of both oil yield and oil quality and composition.     

Effect of deficit irrigation on apricot fruit quality at harvest and during storage

The effect of different irrigation strategies on the fruit quality at harvest and during storage at 1 °C of 'Búlida' apricots (Prunus armeniaca L.) was studied. Irrigation treatments consisted of a control irrigated at 100% of crop evapotranspiration (ETc) throughout the season, and two deficit irrigation treatments consisting of continuous irrigation at 50% of control, and regulated deficit irrigation (RDI) at 100% of ETc during the critical periods (second rapid fruit growth and early post‐harvest) and at 25% during the rest of the season. Fruits at harvest from both deficit irrigation treatments showed higher values of total soluble solids (TSS), titratable acidity and hue angle (h°) than control fruits, whereas their diameter, fresh weight, firmness and maturity index values were similar to those in the control. During the first 10 days of the 30‐day chilling storage period, higher TSS and h° values were found in deficit irrigated fruits, whilst the other parameters were similar for all treatments. Weight loss and fungal attacks (mainly Rhizopus sp. and Monilinia sp.) during a subsequent retail sale period of 4 days at 13 °C were the lowest in RDI. Deficit irrigation was demonstrated to be commercially advantageous for keeping fruit quality, saving considerable amounts of water. Copyright © 2007 Society of Chemical Industry     

添加新鲜橄榄叶和复合果胶酶压榨对油橄榄果出油率和初榨橄榄油品质的影响

为提高油橄榄果出油率、改善初榨橄榄油(VOO)品质,以甘肃陇南主栽的成熟度为7的莱星品种油橄榄鲜果为原料,考察压榨过程中新鲜橄榄叶(0、3%、5%)和复合果胶酶(0、0.01%、0.02%)添加量(以油橄榄果质量计)对油橄榄果出油率和VOO色泽、叶绿素含量、基本理化性质、总酚含量、脂肪酸组成及含量的影响。结果表明：添加适量的新鲜橄榄叶可提高出油率及总酚含量,降低酸值,但色泽加深,叶绿素含量和过氧化值升高;添加适量的复合果胶酶在提高出油率的同时,VOO的总酚含量上升,叶绿素含量和过氧化值降低,但酸值升高,色泽加深;压榨过程中添加新鲜橄榄叶和复合果胶酶对VOO脂肪酸组成没有影响,但对油酸、亚油酸、棕榈酸和棕榈烯酸等主要脂肪酸含量有一定影响。在压榨制取VOO时添加适量的新鲜橄榄叶与复合果胶酶可提高出油率,获得富含多酚的VOO。     

陇南两种单品种初榨橄榄油的化学性质和脂肪酸组成随成熟度的变化

分析了陇南2个品种初榨橄榄油的化学性质和脂肪酸组成随成熟度增加的变化规律。结果表明：随着成熟度的增加2个品种的鲜果出油率增加且存在显著性差异。初榨橄榄油风味成分中氮氧化合物、含硫以及烷烃类化合物变化幅度较大,通过电子鼻可以区分不同品种不同成熟度的橄榄油。恩帕特雷和科拉蒂的k232、270值最高分别为1.85和1.91、0.18和0.14,多酚、黄酮含量变化范围分别为2.39～4.53和7.47～10.39、0.07～0.40和0.75～2.84 mg/g。氧化稳定时间在第6（6.28 h）和第5(16.71 h)成熟度为最高。酸价的变化范围分别为0.37～1.02和0.19～0.38 mg/g,过氧化值的变化范围分别为2.92～8.32和2.38～5.19 mmol /kg,油酸含量分别为72.36%～77.76%和59.23%～65.73%,亚油酸含量分别为7.70%～11.81%和9.74%～15.86%,SFA含量分别为11.81%～13.15%和14.25%～20.99%,PUFA含量分别为8.34%～12.36%和10.92%～16.84%,MUFA含量为72.69%～78.50%和62.36%～68.20 %。同一品种的MUFA/PUFA、C18:1/C18:2和MUFA含量变化趋势一致,与PUFA呈相反的变化趋势,2个品种之间各种脂肪酸含量差异明显,上述测定指标完全符合GB 23347—2009中特级初榨橄榄油的标准。科拉蒂的出油率、多酚、黄酮、油酸含量和氧化稳定时间明显大于恩帕特雷,而酸价、过氧化值低于后者。综合考虑认为科拉蒂的初榨橄榄油品质优于恩帕特雷,恩帕特雷和科拉蒂分别在第6和第5成熟度的初榨橄榄油品质最好。     

橄榄油中甾醇组成及总量测定方法的探讨

介绍了甾醇组成及总量测定在橄榄油评价中的意义,比较了3种甾醇测定方法优缺点,详细探讨了COI/T.20/Doc.no.10《气相色谱法测定甾醇组成及甾醇含量》测定方法中影响测定结果的操作要点等,以求通过对方法探讨和分析,提高COI/T.20/Doc.no.10方法的可操作性.通过对实例样品的分析可以看出,橄榄油理事会制定的COI/T.20/Doc.no.10方法是一种值得推荐的可行的分析方法.     

油橄榄鲜果中主要化合物随成熟度的变化

为阐明油橄榄果实成熟过程中主要化合物的变化,探索最佳成熟度,本试验以不同成熟度的皮瓜尔鲜果为材料,测定其蛋白质、还原糖、粗脂肪、总多酚的含量,以及果油中主要的脂肪酸和角鲨烯的相对含量。结果表明,随着成熟度的增加,蛋白质含量无较大差异,还原糖先降低后略有升高,粗脂肪先升高后趋于平稳,总多酚先降低后趋于平稳;各种脂肪酸相对含量在整个成熟过程中变化不一致;油酸、棕榈酸、亚油酸、亚麻酸、硬脂酸是橄榄油中含量较高的脂肪酸;角鲨烯先升高后降低。利用主成分分析对油橄榄果实品质进行综合评价,第四成熟度为油橄榄果的最佳成熟度。     

Influence of some environmental factors on drupe maturation and olive oil composition

BACKGROUND: Understanding the relationships between olive cultivars and the cultivation environment as well as optimising cultivation choices can lead to maximum expression of oil production in terms of both quantity and quality. For this purpose, samples of the Ortice olive cultivar grown in two different environments in southern Italy at altitudes of 500 and 50 m above sea level (a.s.l.) were harvested on various dates to monitor drupe maturation and determine the nutritional and chemical characteristics of the oils. RESULTS: Fruits grown at 50 m a.s.l. ripened about 10–15 days earlier than those grown at 500 m a.s.l. The oil obtained at 500 m a.s.l. was characterised by a higher content of total polyphenols and a higher content of oleic and stearic acids. CONCLUSION: The different heat accumulation related to the environment affected drupe development as well as the colouring trend and oil content. Consequently, the growth environment changed the content of Ortice oil fatty acids and polyphenols, while the flavour profile remained fairly stable in both environments, with the cultivar effect prevailing over the environment factor. © 2012 Society of Chemical Industry     

The effect of irrigation level and harvest mechanization on virgin olive oil quality in a traditional rain‐fed ‘Souri’ olive orchard converted to irrigation

BACKGROUND: Olive trees are generally grown under rain‐fed conditions. Since yield response to application of water in the growing season may be considerable, irrigation is increasingly introduced to existing, mature orchards. An additional feature of modernization of olive cultivation is mechanical harvesting. To investigate the effect of irrigation level on the quality of virgin olive oil (VOO) produced from cv. Souri, six regimes, ranging from deficit to excess, were applied to trees in a mature, traditional orchard as it was converted to irrigation. Furthermore, in order to investigate the effect of damage incurred during harvest, oil quality of hand‐picked fruit was compared to that of mechanically harvested olives. RESULTS: Data were collected from two consecutive growing seasons. Increased irrigation quantity increased the free acidity level of the oil and decreased the total phenol content of VOO, while the peroxide level of the oil was not affected. Oil of hand‐picked fruits had lower free acidity, higher polyphenol content and slightly lower peroxide level compared to the oil of mechanically harvested olives. CONCLUSION: Fruits from irrigated trees demonstrated an apparent sensitivity to mechanical wounding that subsequently led to increased free acidity, increased peroxide level and decreased total phenol content in oil. Management of irrigated orchards including method and timing of harvest and oil extraction techniques should consider these results in order to optimize production of high‐quality oil. Copyright © 2008 Society of Chemical Industry