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Preharvest circumstances leading to elevated oil acidity in ‘Barnea’ olives
... Though area under olive cultivation is limited by chilling requirements (minimum winter temperatures and rest period), but has the capability to grow in diverse types of soil and conditions. The wild and commercial olive plantation lies round the globe between 30º to 45º North and South of the equator (El-Khashab et al., 2005;Sileshi et al., 2007;Erel et al., 2014;Bustan et al., 2014;Iqbal et al., 2020). Pakistan falls in the same range. ...
... Though olive trees can sustain their growth at relatively less soil fertility and minimal soil moisture levels, research projects indicated that improved soil fertility and provision of ample moisture supply are pre-requisite to achieve high productivity. Olive is cultivated on 9.16 million hectares with production of 15.8 million tons globally with oil production around 3.053 million tons worldwide (FAO, 2019;Bustan et al., 2014;Iqbal et al., 2020). However, currently Pakistan is producing around 1400 tonnes of olive oil production which is expected to increase to 16000 tonnes by the year 2027. ...
... It was found that a favourable medium for fresh weight of leaf of olive seedlings. Our results substantiate findings of Maksoud et al. (2000); El-Khashab et al. (2005); Hegazi et al. (2007); Mustafa et al. (2011);Rehman et al. (2013); Bustan et al. (2014); Zepuri et al. (2015), who inferred that organic matter along with application of NPK and increased fresh weight in olive leaf. ...
... Though area under olive cultivation is limited by chilling requirements (minimum winter temperatures and rest period), but has the capability to grow in diverse types of soil and conditions. The wild and commercial olive plantation lies round the globe between 30º to 45º North and South of the equator (El-Khashab et al., 2005;Sileshi et al., 2007;Erel et al., 2014;Bustan et al., 2014;Iqbal et al., 2020). Pakistan falls in the same range. ...
... Though olive trees can sustain their growth at relatively less soil fertility and minimal soil moisture levels, research projects indicated that improved soil fertility and provision of ample moisture supply are pre-requisite to achieve high productivity. Olive is cultivated on 9.16 million hectares with production of 15.8 million tons globally with oil production around 3.053 million tons worldwide (FAO, 2019;Bustan et al., 2014;Iqbal et al., 2020). However, currently Pakistan is producing around 1400 tonnes of olive oil production which is expected to increase to 16000 tonnes by the year 2027. ...
... It was found that a favourable medium for fresh weight of leaf of olive seedlings. Our results substantiate findings of Maksoud et al. (2000); El-Khashab et al. (2005); Hegazi et al. (2007); Mustafa et al. (2011);Rehman et al. (2013); Bustan et al. (2014); Zepuri et al. (2015), who inferred that organic matter along with application of NPK and increased fresh weight in olive leaf. ...
Olive, chiefly used for high quality edible oil and pickling, is a traditionally an important fruit crop of Mediterranean basin. Its cultivation has expanded to different parts of the world including Pakistan. The ability of olive to thrive on marginal and rocky lands has made it a popular fruit crop in Potohar. The present study was planned to investigate the impact of organic media and NPK levels on growth of olive seedlings. The research material consisted of 150 olive seedlings. The experiment was laid out following Complete Randomized Block Design with three replications at field area of Department of Horticulture, PMAS Arid Agriculture University Rawalpindi, Pakistan during 2018-19. There were 10 treatments of organic media and NPK doses with different combinations. Data were recorded for various traits viz., plant height, number of leaves and primary branches, leaf fresh weight, root length, root fresh weight, chlorophyll and NPK content. Data recorded were analyzed statistically using Statistix 8.1 software to ascertain significance and means were compared using LSD at 5% probability level. Results revealed that treatment T 6 (FYM + Silt + Dose 3 i.e. 7.5 g NPK) was found most ideal growing media for most of traits like number of primary branches, root length, fresh root weight and chlorophyll content in olive seedlings. Hence it is recommended that growth media comprising of silt, FYM and 7.5 g NPK should be used for growing olive seedlings successfully.
... Olive oil quality is the result of genotype, orchard management, time of ripening and olive harvesting, storage and processing operations (Bustan et al., 2014;Di Giovacchino et al., 2002;Manai et al., 2007;Shibasaki, 2005). Particularly olive pests and diseases have an effect on olive oil quality (Bustan et al., 2014;Carvalho et al., 2008;Moral et al., 2014;Torbati et al., 2014;Trapero and Blanco, 2008). ...
... Olive oil quality is the result of genotype, orchard management, time of ripening and olive harvesting, storage and processing operations (Bustan et al., 2014;Di Giovacchino et al., 2002;Manai et al., 2007;Shibasaki, 2005). Particularly olive pests and diseases have an effect on olive oil quality (Bustan et al., 2014;Carvalho et al., 2008;Moral et al., 2014;Torbati et al., 2014;Trapero and Blanco, 2008). Damaged olives negatively affect oil physico-chemical properties like colour, oil free acidity, peroxide value, absorbency in ultraviolet, oxidative stability, phenolic compounds and fatty acids composition. ...
... Olive cultivars have different values for their oil quality attributes, defining particular oil profiles for each cultivar in a particular environment (Feippe et al., 2010;Ferronato et al., 2016;León et al., 2011;Troncoso et al., 2006). Along with cultivar susceptibility to AOR ), oil quality and the impact of the disease may vary with orchard management, harvest and processing management, pathogen population, and environmental conditions -mainly air temperature and relative humidity- (Bustan et al., 2014;Moral et al., 2014). ...
Anthracnose olive rot (AOR) is the main fruit disease of olives, causing direct yield losses and declining oil quality. Fruit infection occurs either in spring during flowering and fruit-set or in summer from the beginning of veraison to harvest. Conducive weather conditions (rain, elevated air relative humidity, air temperature above 20 °C) and the lack of effective chemical control strategies may compromise olive oil production. To quantify AOR effect on olive oil quality and to establish threshold levels, olive oil was extracted from olives with increasing disease incidence (from 0 to 30%), along three consecutive seasons (2012-2014) in two cultivars (cv. Arbeqina and cv. Frantoio) and disease severity index was also determined. The batches were prepared with healthy olives mixed with artificially infested ones, after inoculation with a conidial suspension of Colletotrichum acutatum (1 × 10 6 conidia ml −1) and incubated for 5-7 days at 24 °C. Oil content, water content, and maturity index were determined prior to oil extraction. Then, the obtained cold-pressed oil from each mixture was analyzed for free acidity, peroxide value, absorbance in UV, and total phenolic compounds content. All quality attributes assessed except free acidity qualified for extra virgin olive oil (EVOO) according to International Olive Council Standards. Despite seasonal effects, oil free acidity < 0.8% was obtained when disease incidence was 13% for cv. Arbequina and 50% for cv. Frantoio with AOR severity below 1.5 and 2 respectively. However, these values could be lower if organoleptic attributes are considered. The obtained AOR threshold levels are helpful for orchard and harvest decision management in order to obtain EVOO.
... Both the harvesting time and general condition of the fruit likewise play a crucial factor in determining this feature. These are particularly evident in certain samples, where a large number of exit holes amplify the penetration of air and micro-organisms, leading to an increase in FFAs [34,35]. Furthermore, factors such as extraction technology heavily influence the range of values in these parameters, as reported by the authors Sakar et al. ...
... Both the harvesting time and general condition of the fruit likewise play a crucial factor in determining this feature. These are particularly evident in certain samples, where a large number of exit holes amplify the penetration of air and micro-organisms, leading to an increase in FFAs [34,35]. Furthermore, factors such as extraction technology heavily influence the range of values in these parameters, as reported by the authors Sakar et al. [36], who studied the variations in the physicochemical characteristics of Moroccan olive oil (cv 'Moroccan Picholine') using three extractions systems, namely two-phase, three-phase (3P), and super-pressure (SP) systems, as well as the traditional extraction method. ...
Abstract
This study focuses on evaluating the characteristics of olive oil produced in the Taroudant province (southern Morocco), making this the first comprehensive study focusing on olive oil from the ‘Moroccan Picholine’ cultivar. Our objective was to elucidate the distinctive qualities of olive oil from this region, providing valuable insights into its potential contributions to the country’s olive oil sector. For this purpose, several quality criteria (free fatty acids, moisture content, saponification value, and iodine value), oxidation indices (peroxide value, specific UV extinction coefficients, and oxidizability value), and purity indices (fatty acids and sterol composition) were evaluated. Our results reveal minor-to-significant variations (p < 0.05) in the quality and oxidation parameters. Specifically, our results indicate diverse ranges for free fatty acids (0.33–3.62 g/100 g), peroxide values (0.85–4.01 mEq O2/kg oil), K232 (1.68 to 2.73), and K270 (0.09–0.34). Furthermore, consistently high levels of oleic acid (55.8 to 73.1%) and β-sitosterol (94.2 to 97%) were observed in the studied samples. These outcomes were confirmed through the use principal component analysis and hierarchical cluster analysis. Likewise, important correlations were outlined among the studied parameters. Multidimensional analyses not only highlight inherent variations, but also facilitate the classification of the analyzed olive oils into distinct categories. The results suggest that the Taroudant province exhibits favorable conditions for producing high-quality olive oil.
Keywords: correlation analysis; fatty acids composition; oxidation indices; quality indices; sterol composition; Taroudant region
... In Minas Gerais, in a higher altitude (1,276 m) compared to Chapecó, 'Arbequina' harvesting time starts on January 20 to 25 (40) , later than in Chapecó. The precocity in fruit maturation can be explained by the early flowering, low fruit load (which accelerates the maturation (41) ), and quicker accumulation of degree-days (42) compared to colder regions. ...
... Nevertheless, a long flowering period leads to variability in fruit ripening stage in a same tree. Growers will have to wait to harvest an entire tree when almost all fruits reach a minimum maturity, when others could have reached advanced stages, which is a risk of high acidity and low polyphenol content in the oil, especially in trees with low fruit load (41) . In addition, higher temperatures and solar radiation during oil synthesis and accumulation could cause an undesirable balance in oleic versus linoleic acids, and lower oil accumulation (44)(45) . ...
Olive cultivation has been spread across Brazil subtropical regions, but yields have been variable through years and locations. The objectives of this work were to characterize the reproductive phenology and quantify some productive indexes of three olive cultivars (Arbequina, Arbosana and Koroneiki) in the warm, humid subtropical climate of western
Santa Catarina, Brazil. Shoots of the three cultivars were marked and the quantitative indices of flowering and fruiting were observed periodically. At the same time, the reproductive phenology was evaluated following the BBCH scale, during three seasons, in Chapecó. Reproductive budburst varied from 0 to 32%, which resulted in a relatively low number of flowers per meter of shoot if compared to traditional growing regions, unlike fruit set rates (3.69 to 11.39%), which were similar. Compared to other regions, flowering time was early: inflorescences started to grow from end of June to mid-July, depending on the year. Then maturation was precocious as well, from the end of December to mid-March, and it was later in Koroneiki. The low flowering intensity with risk of frost damages discourages the production initiative in the region.
... The acidity values of the TCP and TCN oils, 3.3 ± 0.5 and 1.9 ± 0.3 mg KOH g − 1 , respectively, were lower than the maximum recommended value, 4.0 mg KOH g − 1 , for virgin fats and oils (Codex Alimentarius, 2001). Several reasons have been proposed for the high levels of acidity in vegetable oils, including fruit yield per tree, ripening stage, nitrogen supplementation and fungal infestation (Bustan et al., 2014). The acidity in the T. catappa oils may likely be related to the ripening stage of the fruits, as they were harvested at the point of maturity. ...
... The acidity in the T. catappa oils may likely be related to the ripening stage of the fruits, as they were harvested at the point of maturity. Bustan et al. (2014) suggested that although the high acidity in extra virgin olive oil can be associated to several factors, the advanced ripening of its olives (Olea europaea L.) presented a substantial risk for degrading its quality. The n-hexane solvent extraction of T. catappa nut oil from Thailand (Janporn et al., 2015) and Nigeria (Menkiti et al., 2015) revealed acidity values of 2.3 and 4.7 mg KOH g − 1 , respectively, which are higher than the values reported in the present study. ...
The aim of this study was to investigate the attributes of the pulp and nut oils from Terminalia catappa fruits obtained by supercritical fluid extraction (SFE) with pressurized CO2. The yield, physico-chemical characterization and fatty acid profiles of both oils were assessed based on their acidity and peroxide indices, thermogravimetric behavior, and infrared spectroscopic and gas chromatographic analyses. The extraction yields were 7.4% and 61.5% for the pulp and nut from T. catappa, respectively. The pulp and nut oils exhibited low levels of acidity, 3.3 and 1.9 mg KOH g-1, and peroxides, 3.8 and 1.7 mEq kg-1, respectively. These values are lower than the maximum recommended levels given by the Codex Alimentarius for virgin oils (4.0 mg KOH g-1 and 15 mEq Kg-1, respectively). Unsaturated fatty acids were a major constituent of the oils (58%), of which omegas 3 and 6 were predominant. The infrared spectroscopy of the nut oil showed high intensity bands between 2912 and 716 cm-1, representative of chemical groups commonly present in unsaturated fatty acids. The pulp oil displayed higher thermal stability than the nut oil, whereby the initial degradation temperatures (Tonset) were 280°C and 230°C, respectively. This difference may be related to a greater amount of saturated fatty acids in the pulp oil compared to the nut oil. Thus, both pulp and nut oils displayed good physicochemical properties, which are desirable in diverse industrial sectors.
... The database was further enriched with relevant information from an ongoing field experiment on 'Barnea' for a total of 1340 'Barnea' trees. N concentration in olive paste and FFA contents were determined according to the method of Bustan et al. (2014). ...
... In 2011, 197 sampled trees out of 753 produced oil with FFA contents above the threshold of 0.6%; in 2012, 184 trees out of 587 had high FFA contents in their oil. The results show that there is a positive correlation between N in fruit and oil FFAs (Table 1) (based on the work of Bustan et al. (2014)). ...
... In each orchard, the fruit yield of sampled trees was recorded and fruit samples were collected close to the commercial harvest time. A detailed description of the survey can be found in Bustan et al. (2014). ...
... This course of OPDW suggests an important role of water stress and recovery in oil biosynthesis and accumulation, particularly in heavy-yielding trees, and reflects the difficulties of such trees to reach their oil yield potential. Noteworthy is the tendency of low-yielding 'Barnea' trees to already have undesirably high oil acidity values ( Figure 4E) early in the season (Bustan et al., 2014), a phenomenon that requires special attention when the harvesting time is determined. ...
In modern oil olive orchards, mechanical harvesting technologies have significantly accelerated harvesting outputs, thereby allowing for careful planning of harvest timing. While optimizing harvest time may have profound effects on oil yield and quality, the necessary tools to precisely determine the best date are rather scarce. For instance, the commonly used indicator, the fruit ripening index, does not necessarily correlate with oil accumulation. Oil content per fruit fresh weight is strongly affected by fruit water content, making the ripening index an unreliable indicator. However, oil in the paste, calculated on a dry weight basis (OPDW), provides a reliable indication of oil accumulation in the fruit. In most cultivars tested here, OPDW never exceeded ca. 0.5 g.g–1 dry weight, making this threshold the best indicator for the completion of oil accumulation and its consequent reduction in quality thereafter. The rates of OPDW and changes in quality parameters strongly depend on local conditions, such as climate, tree water status and fruit load. We therefore propose a fast and easy method to determine and monitor the OPDW in a given orchard. The proposed method is a useful tool for the determination of optimal harvest timing, particularly in large plots under intensive cultivation practices, with the aim of increasing orchard revenues. The results of this research can be directly applied in olive orchards, especially in large-scale operations. By following the proposed method, individual plots can be harvested according to sharp thresholds of oil accumulation status and pre-determined oil quality parameters, thus effectively exploiting the potentials of oil yield and quality. The method can become a powerful tool for scheduling the harvest throughout the season, and at the same time forecasting the flow of olives to the olive mill.
... Various factors contribute to the reduction of VOO quality in the production chain, such as orchard management (e.g., high irrigation levels) (Bustan et al. 2014;Dag et al. 2015), overfertilization with nitrogen (Erel et al. 2013), harvesting time, which might harm the fruit and reduce oil quality (Dag et al. 2008), the time elapsed between harvesting and milling (Dag et al. 2012), and the oil extraction method (Ben-David et al. 2010). Table 4. Intensity of the positive and negative attributes of the sensory assessment of olive oils that originated from commercial and experimental harvesting at 11 traditional orchards (using a scale of 0-10 according to the IOC COI/T.20/ ...
Traditional olive (Olea europaea) orchards have been grown for thousands of years and still occupy most of the world’s cultivated olive areas. To compete with olive oil produced in the higher-yielding intensive orchards, the oil from traditional orchards must be of high quality. We evaluated oil quality—potential and actual (under commercial conditions)—and tested the stages in the production chain that are likely to reduce oil quality in the traditional sector in the Middle East region. Our findings show a clear negative impact of growers’ traditional practices on both the chemical and sensory characteristics of olive oil. The oil originating from the commercial process had higher free fatty acid and lower polyphenol and carotenoid contents, lower stability, lower pungency, lower fruitiness, lower bitterness, and a higher prevalence of organoleptic defects than oil that originated from fruit picked from the same trees during the experimental procedure. The current common harvesting technique of pole beating significantly increased fruit injury and fruit with mold, leading to a reduction in oil polyphenols and an increase in free fatty acid levels compared with those resulting from manual picking. In addition, after harvest, storing the fruit for more than 48 hours in plastic bags dramatically reduced the oil quality. The traditional olive orchard could be a source of high-quality extra virgin olive oil. However, fruit handling—from the trees until the end of the oil extraction process—is performed incorrectly, thus adversely affecting the oil quality.
... Fatty acid composition was determined by gas chromatography following cold methylation according to International Olive Council (IOC) method COI/T.20/Doc. No. 24,2001. Chromatographic analysis was performed using an Agilent 6850 N gas chromatograph equipped with a mass spectrometer (Agilent Technologies, Santa Clara, CA, USA) and DB23 capillary column (60 m long, 0.25 mm diameter, 0.25 µm film thickness; J&W Scientific, Folsom, CA, USA). ...
Traditional olive orchards have been grown for thousands of years and still occupy most of the world’s olive cultivation area. To compete with olive oil produced in the higher-yielding intensive orchards, the oil from traditional orchards must be of high quality. We evaluated oil quali-ty—potential and actual (under commercial conditions)—and identified the stages in the pro-duction chain that reduce oil quality in the traditional sector in the Middle East region. Our findings show a clear negative impact of growers' traditional practices on both chemical and sensorial characteristics of the olive oil. The oil originating from the commercial process had higher free fatty acid and lower polyphenol and carotenoid contents, lower stability, lower pungency, fruitiness and bitterness, and a higher prevalence of organoleptic defects than oil originating from fruit picked from the same trees in the experimental procedure. The current, commonly harvesting technique of pole beating significantly increased fruit injury and fruit with mold, leading to a reduction in oil polyphenols and an increase in free fatty acid level compared to manual picking. After harvest, storing the fruit for more than 48 h in plastic bags reduced oil quality dramatically. The traditional olive orchard could potentially be a source of high-quality Extra Virgin Olive Oil. However, handling of the fruit—from the trees until the end of the oil-extraction process—is done incorrectly, adversely affecting oil quality.
... As found previously, 37 FFA content of olive oil from cv. Barnea fruit was strongly influenced by fruit load (Fig. 1). ...
BACKGROUND
Intensive olive (Olea europaea L.) orchards are fertilized, mostly with the macronutrients nitrogen (N), phosphorus (P) and potassium (K). The effects of different application levels of these nutrients on olive oil composition and quality were studied over 6 years in a commercial intensively cultivated ‘Barnea’ olive orchard in Israel.
RESULTS
Oil quality and composition were affected by N, but not P or K availability. Elevated N levels increased free fatty acid content and reduced polyphenol level in the oil. Peroxide value was not affected by N, P or K levels. The relative concentrations of palmitoleic, linoleic and linolenic fatty acids increased with increasing levels of N application, whereas that of oleic acid, monounsaturated‐to‐polyunsaturated fatty acid ratio and oleic‐to‐linoleic ratio decreased.
CONCLUSION
These results indicate that intensive olive orchard fertilization should be carried out carefully, especially where N application is concerned, to avoid a decrease in oil quality due to over‐fertilization. Informed application of macronutrients requires leaf and fruit analyses to establish good agricultural practices, especially in view of the expansion of olive cultivation to new agricultural regions and soils. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
... Indeed, excessive free fatty acids are associated with large, fully ripened, and fungus-infected drupes obtained from trees with low fruit loads. Even a small amount of such olives can spoil the oil quality [20]. However, different polyphenol content can also affected the acidity value since a higher phenolic concentration inhibits the activity of the lipase-producer yeasts [21]. ...
The performance of two innovative packaging materials was investigated on two Sardinian extra-virgin olive oils (Nera di Gonnos and Bosana). In particular, a transparent plastic film loaded with a UV-blocker (packaging B) and a metallized material (packaging C) were compared each other and to brown-amber glass (packaging A). During accelerated shelf-life tests at 40 and 60 °C, the evolution of quality parameters (i.e., acidity, peroxide value, K270, and phenolic content) was monitored, together with the aromatic fingerprint evaluated by electronic nose. Packaging B resulted in the best-performing material in protecting oil from oxidation, due to its lower oxygen transmission rate (0.1 ± 0.02 cm3/m2 24 h) compared to packaging C (0.23 ± 0.04 cm3/m2 24 h). At the end of storage, phenolic reduction was on average 25% for packaging B and 58% for packaging C, and the aromatic fingerprint was better preserved in packaging B. In addition, other factors such as the sanitary status of the olives at harvesting and the storage temperature were demonstrated to have a significant role in the shelf life of packaged extra-virgin olive oil.
... A "second flowering" was mentioned in Hawaii (USA) olives trees of cultivar 'Koroneiki' under warm winter conditions (Miyasaka and Hamasaki, 2016). This lack of synchronization on flowering phenology could led on lack of synchronization of fruit ripening, with a negative impact in both final yield and oil quality (Bustan et al., 2014) and, therefore, should be avoided. ...
Olive flowering phenology is highly affected by climatic conditions. Phenological models have been developed to forecast flowering date on olive mainly based on temperature. These models have used flowering datasets collected from trees growing under Mediterranean climatic conditions. In most of the cases, in those conditions, chilling requirements are rapidly fulfilled. In other cases, artificial modifications of the climatic conditions has been practiced by using growth chambers. In the present work, we compare the flowering phenology of 'Picual' and 'Arbequina' olive cultivars in Mediterranean conditions of Andalucía, Southern Spain, with those in Tenerife, Canary Islands with SubTropical climate. The climatic conditions of Tenerife respect to Andalucía promoted an earlier flowering date but, more importantly, a much longer flowering period. This is mainly produced by an asynchronous flowering bud burst that will generate negative impacts on yield and quality. Quite likely, those differences on flowering phenology between Andalucía and Tenerife climatic conditions are mainly caused by the lack of winter chilling in Tenerife locations. Based on those results, we propose that future works studying the effect of lack of winter chilling on olive should include the length of the flowering period as a parameter to be modeled. Besides, studies on natural climatic conditions with warm winters, as the one here reported, are needed to really assess the effect of winter chilling on olive.
... Furthermore, over-fertilization with N adversely affects oil quality, especially via elevated free fatty acid content and reduced polyphenol levels in the oil [15,46]. Reduced polyphenol levels in the fruit affects fruit health by reducing their resistance to fungal infestation, which further impairs oil quality [47]. Figure 1 provides a schematic illustration of the composite response of olive trees to N fertilization. ...
Intensification of olive orchard management entails increased use of fertilizers, especially nitrogen, phosphorus, and potassium. In this review, plant responses to nutritional aspects, as well as environmental considerations, are discussed. Nutrient deficiency impairs production, whereas over-fertilization may reduce yields and oil quality, and increase environmental hazards and production costs. The effect of irrigation on nutrient availability and uptake is very significant. Application of organic matter (e.g., manure, compost) and cover crops can serve as substitutes for mineral fertilization with additional benefits to soil properties. Recycling of the pruned orchard material, olive pomace and olive mill wastewater, as well as the use of recycled wastewater for irrigation, are all potentially beneficial to olive orchard sustainability, but present the risk of environmental pollution. Some considerations regarding optimization of olive orchard nutrition are discussed.
... Thus, FA is an indicator of how fresh and how well handled the olives were before being milled (Tena, Wang, Aparicio-Ruiz, Garcí;a-Gonzaléz, & Aparicio, 2015). To confirm this, T different studies reported that geographic and environmental factors (Bustan et al., 2014) and the application of specific technological processes (such as filtration or a cooling treatment of olive paste) (Veneziani et al., 2018 a-b) do not affect significantly this parameter. ...
Nutritional and healthy values are well known properties of virgin olive oil (VOO). The product quality, in terms of belonging to a specific quality grade (extra virgin, virgin, lampante), is defined by a set of chemical-physical and sensory measurements. According to the official regulation of the European Union (EU Reg. 1348/2013)the free acidity is the first parameter that has to be determined by analysts; it gives information about the quality of the olives used to produce the VOO as well as the hydrolytic state of VOO just produced and stored. The official procedure is based on an acid-base titration that needs to be carried out in a chemical laboratory. In this paper a portable battery-operated electronic system to measure olive oil free acidity is presented: the system can be used for quick “in situ” tests in a production environment (olive oil mills or packaging centers)by people without particular training. The working principle of the system is based on the creation of an emulsion between oil and a hydroalcoholic solution: the free acidity is estimated on the value of the emulsion electrical conductance. The proposed system has been calibrated and in-house validated showing good results in terms of limit of detection and quantification, precision and accuracy. Moreover, a good correlation (R ²adj = 0.97)with free acidity data obtained applying the official method on 30 olive oil samples belonging to different commercial categories (extra virgin, virgin and lampante olive oil)has been evidenced.
... High fruit load tended to reduce fruit N and subsequently improve oil quality. Bustan et al. (2014) also found a positive relationship between N content in fruit flesh and oil free fatty acid content in a large survey of commercial 'Barnea' orchards in Israel. They also reported a strong effect of fruit load on free fatty acid level. ...
Demand for olive oil has grown dramatically over the past decades. The accompanying increase in production has been largely due to improvement in horticultural practices by means of intensification. Modern intensive olive orchards are characterized by high yielding cultivars, high tree density, mechanization, and micro-irrigation enabling the application of fertilizers via the water distribution system (fertigation). Recent works have provided deeper insight in macronutrient fertilization and olives. Concerning productivity, P availability positively affects flower quality, fruit set and, consequently, oil production. In the case of nitrogen (N), there is an optimal level, since both low and high levels of N fertilization are associated with diminished productivity. Surprisingly, the effect of potassium (K) availability on productivity is relatively small, partially a result of K substitution by Na at low K levels. In modern olive cultivation, beside yield, oil quality also plays an important role. Increasing exposure to N negatively affects major quality parameters of olive oil, whilst P and K levels have minor effects. Increasing irrigation level augments the demand for nutrients on the one hand and their availability on the other. The elevated irrigation volume was found to enhance K and P uptake while N level was not affected. The quality of the irrigation water also plays a major role in olive nutrition. Recycled wastewater may provide a substantial amount of nutrients required by this crop. In a long-term study in a super-intensive olive orchard irrigated with recycled municipal wastewater without additional fertilization, no nutrient deficit or reduction in yield was found in comparison to trees irrigated with fresh water and standard fertilization (N and K). Furthermore, irrigation with recycled water without adjusting the fertilization regime, led to a substantial increase in environmental contamination with N. In conclusion, fertigation systems in intensive olive orchards allow precise control of the amount and timing of nutrient application. This supplies growers with a tool for obtaining high oil yields of high quality, while minimizing environmental contamination. © 2018 International Society for Horticultural Science. All rights reserved.
... Moretto & Fett (1998) argue that free acidity is not a seed constant value; instead, this variable is not much influenced by the genetic characteristics of the plant, but rather by the post-harvest seed management, including storage conditions, particularly high temperature and humidity, known as important causes of and increased oil acidity. On the other hand, it has been observed in olive that a low yield of fruits is associated with a high acidity index of its oil, with a tendency to present low oil acidity in trees with a high fruit yield (Bustan et al., 2014). ...
The castor (Ricinus communis L.) is an oilseed plant whose main features are its drought resistance, and its adaptation to eroded, polluted, and low fertility soils. Its oil has a great demand in the industrial sector and it has recently attracted considerable interest for its use in the production of biodiesel and jet fuel. In this study, morphological, physical and chemical characterizations were performed to ascertain the quality of wild (VQ-1) and under cultivation (VQ-7) oil castor seeds. The results showed that there are differences in the morphological and physicochemical characteristics regarding oil content (44,95 vs 33,84%), ash (3,20 vs 2,42%), and 100-seed-weight (45,87 vs 54,23g); similar behavior was recorded when characterizing the oil: kinematic viscosity (269,67 vs 266,44mm2 /s), density (0,9389 vs 0,9465g/cm3 ), and acidity index (0,9918 vs 0,5440mg KOH/g) for VQ-1 and VQ-7, respectively. Growing conditions to which castor plants were subjected may influence both the final quality of seeds and chemical properties of the oil.
... Studies on the detrimental effects of pests and diseases often do not account for the specific effect of each biotic stress (e.g. Bustan et al., 2014) and, even when focused only on anthracnose, normally do not account for the identity of the pathogen. ...
Control:
The selection of resistant cultivars depends strongly on pathogen diversity and environmental conditions, posing added difficulties to breeding efforts. Chemical disease control is normally achieved with copper-based fungicides, although it may be insufficient under highly favourable disease conditions and causes concern because of the presence of fungicide residues in the oil. In areas where the incidence is high, farmers tend to anticipate harvest, with consequences in yield and oil characteristics. Challenges: Olive production systems, harvest and post-harvest processing are experiencing profound changes in recent years, namely new training systems using specific cultivars, new harvest and processing techniques and new organoleptic market requests. Changes are also occurring both on the geographical distribution of pathogen populations and on the taxonomic framework. Also, stricter rules concerning pesticide use are likely to have a strong impact on control strategies. A detailed knowledge of pathogen diversity, population dynamics and host-pathogen interactions is basal for the deployment of durable and effective disease control strategies, whether based on resistance breeding, agronomic practices or biological or chemical control. This article is protected by copyright. All rights reserved.
... Impact damage disrupts the internal tissues, affecting moisture, fruit density and firmness (Jiménez-Jiménez et al., 2012, 2013Jiménez et al., 2016), and these effects can be observed in the NIR spectra because of changes in light scattering. Damaged olive fruit have higher free acidity due to hydrolytic and lipolytic enzymes activity and/or concurrent freeze injury (Pereira et al., 2004;Mraicha et al., 2010;Vossen, 2013;Bustan et al., 2014). ...
A rapid, robust, and economical method to detect hailstorm-damaged olive fruit (Olea europaea L.) would benefit both consumers and producers of olives and olive oil. Here, the feasibility of using Near-Infrared (NIR) spectroscopy for olive fruit sorting (cv. Canino) into hailstorm-damaged and undamaged classes is demonstrated. Features selected from the entire spectra by the genetic algorithm (two to six features per model) were input to Linear Discriminant Analysis, Quadratic Discriminant Analysis and k-Nearest Neighbor routines to develop models to classify olive fruit. Spectral pretreatment and feature selection were optimized through an iterative routine developed in R statistical software. Each model was evaluated based on false positive (α-error), false negative (β-error) and total error rates. The most accurate models yielded total error rates of less than five percent. The optimal features corresponded to R[1320 nm], R[∼1460 nm], R[∼1650 nm], R[∼1920 nm], R[∼2080 nm], R[∼2200 nm] and R[∼2220 nm], where R[x] represents the reflectance of light from the sample at a wavelength of x nm. The results indicate that single-point NIR spectroscopy is a feasible basis for hailstorm damage detection in olive fruit with the potential to allow on-line implementation on milling production lines.
... These factors are all responsible for the elevated FFA. 26 The general composition of fatty acids obtained (Table 1) is similar to data presented in previous studies on super-high-density 'Koroneiki' olives in Tunisia. 23,27 In the present study a clear trend of reduction in MUFA/PUFA with increasing water stress was observed. ...
Background
Over the last two decades, the area of cultivated super-high density olive orchards has rapidly increased. Water stress is an important tool in super-high density orchards to reduce tree growth and promote suitability to overhead mechanical harvesters. Little is known regarding the effect of water stress in super-high density orchards on oil quality parameters. In the current study, the effect of irrigation rates on oil quality parameters was studied in a six-year-old super-high density ‘Koreneiki’ olive orchard for five consecutive seasons. Five water status levels, determined by irrigating in order to maintain varied midday stem water potential threshold values (−1.5, −2, −2.5, −3 and −4 Mpa) were applied during the oil accumulation stage.ResultsThe ratio of MUFA/PUFA increased and free fatty acid content generally decreased as a function of increased tree water stress. In most of the seasons, a reduction in polyphenols was found with reduction of irrigation level. Peroxide value was not affected by the water stress level.Conclusion
The current study demonstrates that limiting irrigation and exposure of olive trees to water stress in super-high density, lowers free fatty acid content and therefore benefits oil quality. However, the decreased MUFA/PUFA ratio and the reduction of polyphenol content which were also found under increased water stress negatively influence oil quality.
Jojoba wax is gaining popularity among cosmetics consumers for its skin wound healing and rejuvenation bioactivities, attributed to collagen and hyaluronic acid synthesis. However, information regarding wax phytochemical composition and quality parameters, as well as effect of cultivation practices, and fertilization in particular, on wax quality is limited. The aim of the current work was to study the effect of nitrogen (N) availability to jojoba plants on wax phytochemical composition and beneficial skin-related contents. For this, wax quality from a six-year fertilization experiment with five N application levels was evaluated. The chemical parameters included antioxidant activity, free fatty acid, total tocopherol, total phytosterol and oxidative stability, as well as fatty acid and fatty alcohol profile. Our results reveal that the majority of wax quality traits were affected by N fertilization level, either positively or negatively. Interestingly, while fatty acids were unaffected, fatty alcohol composition was significantly altered by N level. Additionally, fruit load also largely affected wax quality, and, due to jojoba’s biennial alternate bearing cycles, harvest year significantly affected all measured parameters. Results shed light on the effects of N application on various biochemical constituents of jojoba wax, and imply that N availability should be considered part of the entire agricultural management plan to enhance wax quality. Some traits are also suggested as possible chemical quality parameters for jojoba wax.
Oil in fruits and seeds is an important source of calories and essential fatty acids for humans. This specifically holds true for olive oil, which is appreciated for its superior nutritional value. Most olive orchards are cultivated to produce oil, which are the outcome of fruit yield and oil content. Little information is available on the effect of nitrogen (N) on olive fruit oil content. The response of olive trees to different rates of N was therefore studied in soilless culture (3 years) and commercial field (6 years) experiments. In both experiments, fruit N level and oil biosynthesis were negatively associated. Fruit N increased in response to N fertilization level and was inversely related to fruit load. The negative correlation between fruit N and oil content was more pronounced under high fruit load, indicating sink limitation for carbon. These results agree with those reported for oilseed crops for which a trade-off between oil and protein was proposed as the governing mechanism for the negative response to elevated N levels. Our results suggest that the protein/oil trade-off paradigm cannot explain the noticeable decrease in oil biosynthesis in olives, indicating that additional mechanisms are involved in N-induced inhibition of oil production. This inhibition was not related to the soluble carbohydrate levels in the fruit, which were comparable regardless of N level. These results emphasize the importance of balanced N nutrition in oil-olive cultivation to optimize production with oil content.
Yearly yield fluctuations are normal in fruit trees. Yield alternation might be induced by environmental stresses, but in many fruit tree species yield alternation is an inherent characteristic, resulting in perpetual biennial cycling. Endogenous cues are thought to be the major players in determining the phenomenon, although the genetic basis, if it exists, is still enigmatic. In most cases, alternate bearing is due to inhibition of floral induction, following a heavy fruit load ON year. Understanding of flowering control in model plants has made great progress during recent decades. Due to conservation of many molecular components of the flowering‐control pathways among higher plants, there has also been considerable progress in the identification of these components and in the understanding of their role in fruit trees. In this review, flowering control by exogenous and endogenous cues in Arabidopsis along with updated findings in fruit trees are summarized. The effect of fruit load on flowering‐control genes is also examined. Along with these fundamental traits, more practical aspects, namely mitigation strategies of alternate bearing, are also reviewed. Recent developments in mitigation practices of six representative fruit trees are also summarized. Finally, some basic questions, including the genetic and epigenetic background of alternate bearing, an evolutionary perspective, and possible common mechanisms among various fruit trees, are thoroughly discussed.
The effect of bag-in-box (B) packaging material on quality characteristics of extra virgin olive oil (EVOO) was studied as a function of storage time (0–120 days) and temperature (22 °C and 37 °C). Olive oil packaged in tin-plated steel (S) containers served as control. Olive oil sampling was carried out every 20 days, assessing quality deterioration by monitoring multiple quality parameters: acidity, PV, K232, K270, ΔK, color, total phenolic content (TPC), FA composition and volatile compounds’ profile. Based mainly on acidity, PV, K232, and K270 values, samples packaged in S could no longer rank as EVOO after 80 days of storage at 22 °C, and after 60 days at 37 °C. Samples stored in B retained EVOO specifications throughout storage at 22 °C and had a 100 days shelf life at 37 °C. Conclusively, results showed that B packaging proved to be more suitable for all olive oil samples even for those exposed to abuse temperatures.
In order to assess the quality and purity of olive oil, certain physical and chemical characteristics have been recommended. Hydrolysis and oxidation are the most serious quality deteriorations of olive oil. Hydrolysis causes release of fatty acids from the triacylglycerol molecule with consequent increase in total acidity (free fatty acids [FFAs]) and change in flavor. Factors affecting hydrolysis are moisture, temperature, enzymes, and microorganisms. Oxidation of olive oil may occur either in the dark (autoxidation) or in the light (photooxidation). The oxidation products have an unpleasant flavor and odor and may adversely affect the nutritional and functional value of the oil. Research related to the problems of oxidative deterioration has been of interest due to the fact that such a process eliminates the functional compounds of the oil and can cause damage to cell membranes and DNA; thus, it may be involved in the aging process, hypertension, and cancer growth.
Fruit rot is one of the most common diseases of olive in Iran. In a survey on the causal agents of olive fruit rot in Tarom region (Zanjan Province, Iran), olive fruits with anthracnose symptoms were collected from olive orchards. Isolation was made using routine plant pathology methods. The causal agent of the disease was identified as Truncatella angustata based on morphological and cultural characteristics. The identity of the species was further confirmed by sequence data of ITS-rDNA region. Pathogenicity tests performed on olive fruits led to the same symptoms as observed in the field conditions. To the best of our knowledge this is first report on occurrence of T. angustata on O. europaea in any part of the world and is first record for the genus Truncatella in Iran.
A comparative study was conducted to evaluate the influence of seven different levels of irrigation applied to 'Arbequina I-18' olive (Olea europaea L.) trees grown in a super-high-density orchard (1,656 trees/ha) in the Sacramento Valley of California. Water was applied differentially by drip irrigation at rates of 15%, 25%, 40%, 57%, 71%, 89%, and 107% evapotranspiration (ETc) in 2002, and 28%, 33%, 55%, 74%, 93%, 117%, and 140% ETc in 2003. Each treatment was replicated three times. Olives were harvested on two different dates each year from each of 21 plots. Three of four harvest dates showed a decrease in maturity index with increasing irrigation levels. Oils were made from olive samples collected from each plot and analyzed for oil quality parameters. Total polyphenol levels and oxidative stability decreased as the trees received more water, especially for the three lowest irrigation treatment levels in 2002, but few differences were noted between treatments in 2003 when all the trees were irrigated more heavily. Average oxidative stability was correlated very closely with total polyphenol content with r2 = 0.98 in 2002 and 0.94 in 2003. In 2002, free fatty acid levels increased and peroxide levels were unchanged, but in 2003, free fatty acid levels were unchanged and peroxide levels decreased in treatments receiving more water. Saturated fatty acids did not significantly change in 2002, due to tree irrigation level. The mono-unsaturated fatty acid levels and oleic-linoleic relationship declined while poly-unsaturated fatty acid levels increased in 2002 with increased irrigation. In 2003, there was no notable difference in the ratio of mono to poly unsaturated fatty acid levels. The individual fatty acid most consistently affected by more irrigation water was stearic, which decreased in both years. Total sterol content (mg·kg-1), percentages of cholesterol and erythrodiol were significantly influenced by tree irrigation levels, but increased in one year and either decreased or were unchanged the next. Oil sensory properties of fruitiness, bitterness, and pungency all declined in oils made from trees receiving more water. The lowest irrigation levels produced oils that were characterized by excessive bitterness, very high pungency, and woody, herbaceous iavors. Intermediate irrigation levels (33% to 40% ETc) produced oils with balance, complexity, and characteristic artichoke, grass, green apple, and some ripe fruit flavors. Higher irrigation levels lowered oil extractability and produced relatively bland oils with significantly less fruitiness and almost no bitterness or pungency.
Olive (Olea europaea subsp. europaea var. europaea) is one of the first domesticated and cultivated trees that is widely distributed in the Mediterranean regions. The Anthracnose, caused by the two complex fungal species Colletotrichum acutatum and C. gloeosporioides, is the most important disease adversely affecting the olive oil quality. Even so, the effect of Anthracnose on oil quality is largely unknown and many questions remain unanswered. This offers a unique opportunity to study how Colletotrichum species, cultivars, infection type (latent or visible) and severity, and other factors that may affect different parameters of oil quality, such us acidity, peroxide value, K232, K270, phenolic compounds, or alkyl esters. This review focuses on the current knowledge of the biology, epidemiology, and management of Anthracnose and its effect on olive oil quality.El olivo (Olea europaea subsp. europaea var. europaea) es uno de los primeros cultivos leñosos domesticados. Actualmente el olivo se encuentra ampliamente distribuido por todas las regiones de clima mediterráneo. La Antracnosis, causada por las especies complejas Colletotrichum acutatum y C. gloeosporioides, es la enfermedad del olivo que más afecta a la calidad del aceite. Aun así, el efecto de la Antracnosis en la calidad del aceite es ampliamente desconocido. Por lo que creemos esencial que se afronten estudios encaminados a dilucidar el efecto de las especies del patógeno, el cultivar de olivo y el tipo (latente o visible) y severidad de las infecciones de la aceituna en los distintos parámetros de calidad del aceite como la acidez, índice de peróxidos, K232, K270, compuestos fenólicos o ésteres alquílicos. Esta revisión presenta los conocimientos actuales sobre la biología, epidemiología, control, y efecto en la calidad del aceite de la Antracnosis del olivo.
Most newly planted olive (Olea europaea L.) orchards are irrigated and
harvested mechanically. We assessed the effects of olive storage temperature and
duration on the resultant oil’s quality in three cultivars from modern orchards. Oil
acidity increased with storage temperature and time, most markedly in ‘Barnea’ and
least in ‘Koroneiki’. In ‘Koroneiki’, after 9 days in cool storage (4 and 10 �C), free
fatty acid (FFA) level remained constant. Polyphenol (PP) content behaved
differently among cultivars: in ‘Picual’, it was relatively invariable; in ‘Barnea’, it
decreased moderately; and in ‘Koroneiki’, it decreased sharply to half of its initial
value in 4 �Cstorage and one-sixth its initial value in room temperature storage after
23 days. Peroxide value (PV) did not increase during the storage period and did not
appear to be affected by temperature. Thus, different cultivars show different
responses to storage, and fruit originated from modern orchards are not necessarily
more sensitive to storage than those from traditional orchards.
Olive (Olea europaea subsp. europaea var. europaea) is one of the first domesticated and cultivated trees that is widely distributed in the Mediterranean regions. The Anthracnose, caused by the two complex fungal species Colletotrichum acutatum and C. gloeosporioides, is the most important disease adversely affecting the olive oil quality. Even so, the effect of Anthracnose on oil quality is largely unknown and many questions remain unanswered. This offers a unique opportunity to study how Colletotrichum species, cultivars, infection type(latent or visible) and severity, and other factors that may affect different parameters of oil quality, such us acidity, peroxide value, K232, K270, phenolic compounds, or alkyl esters. This review focuses on the current knowledge of the biology, epidemiology, and management of Anthracnose and its effect on olive oil quality.
Global climate change leads to the exposure of olive orchards to higher temperatures than in the past. We followed yield and quality parameters of olive oils from Barnea, Coratina, and Picual, under hot climatic conditions through different levels of ripeness. Oil yield per tree increased throughout the monitoring period due to continuous oil accumulation. Toward the last harvest date, significant fruit drop occurred, which resulted in substantial loss in oil yield. Maximal oil yield was obtained in Barnea at a maturity index of 2.1–2.5, in Coratina at 2.3 and in Picual at 3.2. A reduction in quality parameters was found with delay of harvest date: free fatty acid content increased and the ratio of monounsaturated to polyunsaturated fatty acid declined, but only in one season. Nevertheless, all parameters remained within the trade standard for extra virgin olive oil (EVOO). In contrast to most previous studies, no consistent reduction was observed in total polar phenol content in the oils. Hence, maximizing oil yield should be the main criterion for the determination of harvest date under these conditions. It is therefore suggested that olives exposed to hot climate be harvested earlier than those in typical Mediterranean climate areas.
Harvesting plays a major role in the virgin olive oil production line, being the most expensive single component, but also due to its significant effect on the whole year's produce. Previous studies have focused on the effects of harvest timing on either oil yield or quality. Here we determined the separate and combined effects of harvesting date, fruit maturation, cultivar and fruit load on olive oil quality and quantity. Cultivars typical to the Middle East region were selected: the traditional cv. Souri and the newer cv. Barnea, grown under intensive conditions. The results demonstrate fundamental differences between the two cultivars with respect to harvest strategy. In high-yielding ‘Barnea’, oil accumulation continued throughout the ripening season resulting in increasing yield of oil with time while maintaining high quality. Hence, exploiting the production potential in ‘Barnea’ requires late harvest and advanced fruit maturity. However, in heavily loaded ‘Souri’, oil accumulation was accompanied by early massive shedding of fruits. Furthermore, late harvest and advanced maturation in ‘Souri’ were associated with a sharp increase in free fatty acids combined with a rapid decline in polyphenol content, and in MUFA to PUFA and saturated to unsaturated fatty acid ratios, all resulting in loss of oil quality. Rapid decline in oil yield coupled with deterioration of oil quality call for early harvesting at low maturity index in ‘Souri’. In medium-yielding trees of both cultivars, maturation progressed more rapidly, resulting in earlier harvest to utilize optimal oil potential.
The effects of olive fly damage, olive storage, harvest date, olive grove plot and their interactions on the microflora associated with olive paste and oil acidity were studied. Microflora and oil acidity were significantly affected by the four studied factors and by several interactions between them. Fly damage and olive storage interacted sinergically increasing oil acidity. The relationship between fly damage and oil acidity was lineal although sometimes it was not significant depending on microflora populations. The relationship between microflora populations and oil acidity fitted to a logarithmic model. Major microorganisms in olive paste were bacteria (Xanthomonas), yeasts (mostly Torulopsis and Candida) and in a smaller measure moulds (mainly Fusarium and Penicillium). Results overall suggest that a qualitative damage threshold based on the percentage of damaged fruits in order to infer oil acidity may be unfeasible in most instances.
Detached olive (Olea europaea) fruit inoculated with isolates of Colletotrichum acutatum, causal agent of olive anthracnose, were used to study host-pathogen interactions. Fruit susceptibility increased with increasing fruit maturity. Wounded fruit were more severely affected than nonwounded fruits however, the wound effect depended on cultivar and inoculation method. Severity of fruit infection increased with inoculum density, although this effect also depended on fruit maturity and cultivar susceptibility. The susceptibility of selected olive cultivars to anthracnose under field conditions correlated well with the response of immature fruit under controlled conditions. As fruit matured, there were fewer differences among cultivars. Based on these results, an inoculation method using immature green fruit and high inoculum densities (10(5) to 10(6) conidia/ml) sprayed on the fruit has been proposed to evaluate Olive cultivars for anthracnose resistance under controlled conditions.
Biennial bearing is a major horticultural and economic drawback of olive (Olea europaea L.) cultivation, which particularly affects the olive oil industry under intensive production systems. The number of fruits per tree in an on-year is a primary determinant of the biennial cycle. While fruit thinning using NAA shortly after full bloom is commonly practiced to increase fruit size in table olives, the extent of its influence on biennial bearing is unknown. In the present study, the ability of that common naphthaleneacetic acid (NAA) treatment (100 mg/L, 10 days after full bloom) to alleviate biennial bearing in two oil olive cultivars, Picual and Barnea, was poor, although significant influence on the number of fruit was evident solely in Barnea. Picual seemed less susceptible than Barnea to biennial bearing. Consequently, the effect of a broad range of NAA concentrations (0–320 mg/L, 10 days after full bloom) on various yield parameters was investigated during a biennial cycle of Barnea trees. There was a gradual proportional decline in the on-year number of fruits from ~50 000 to 10 000/tree in response to increasing NAA concentrations. The number of return fruits in the off-year was reciprocal to the on-year fruit load, but remained relatively small, below 15 000/tree. The dynamic relationship between fruit load and fruit size in both on- and off-years was a significant compensation factor in fruit and oil yields. In both cultivars, an on-year fruit load smaller than 20 000/tree is likely to provide consistent yearly oil yields ranging from 10 to 12 kg/tree. The results demonstrate the possibility of using NAA post-bloom spraying to balance biennial bearing in oil olives.
Olive has been widely grown around the Mediterranean Basin for around 5000 years, where productivity and survival of this long-lived evergreen tree in environments of low and variable rainfall depend on physiological characteristics but also on management. The tree exercises effective control of water loss by transpiration and can also withstand intense internal water deficit that in turn increases extraction of water from soil. Critical aspects of management that maintain, albeit limited, transpiration and metabolic activity during hot dry summer months, are directed at both crop and understorey. Strategic decisions are selection of cultivar, tree density, and canopy size, together with surface management as tilled soil or as cover crop of selected species. Tactical adjustments are seen in extra pruning of olives and timing of tillage, or of grazing, mowing, or herbicides to restrict growth and water use of the understorey, especially following dry winters and during dry summers. Survival of olive orchards in low-rainfall climates requires that canopies intercept a small proportion of incident radiation, depending upon rainfall amount, distribution, and soil water storage capacity. Crop water balance models can assist in defining optimum canopy size for productivity and survival. New olive production in the Mediterranean and now extending widely in the ‘New World’, including in Australia, deviates widely from traditional practice. Orchards are planted at higher density, are generally irrigated, and trees are formed to suit mechanical pruning and harvesting. The environmental adaptation and understanding of water relations of olive in traditional systems are of limited applicability to these new production systems. Rather, there are now new emphases on nutrition, irrigation, canopy management, assimilate relationships, and fruiting performance to add to the existing questions of the suitability of cultivars to new environments in terms of productivity and oil quality.
New evidence is provided for early asymptomatic infection of flowers of olive varieties Barnea and Manzanillo byColletotrichum acutatum andC. gloeosporioides. Asymptomatic infection of olive flowers by these species ofColletotrichum and the likely quiescent behaviour of the pathogens resulting in symptomatic disease expression of mature fruits has not
been recorded anywhere previously.
BACKGROUND: Macronutrients play fundamental roles in processes affecting olive oil productivity and are expected to influence oil composition. A necessary step in optimal nutrient application management for olives is an understanding of the relationship between olive tree nutritional status and oil quality parameters. We studied the independent effects of N, P and K concentrations in irrigation solution on the oil quality of ‘Barnea’ olives by applying a wide range of macronutrient concentrations under highly controlled conditions.
RESULTS: Oil composition was significantly influenced by P and N levels, while K levels had only a minor effect. Unsaturation levels were unaffected by the treatments but, within the unsaturated fatty acids, the levels of PUFA increased compared to those of MUFA. Specifically, levels of the MUFA C18:1, polyphenol content and peroxide values decreased while levels of the PUFA C18:3 increased in response to higher doses of N and P.
CONCLUSION: Decreased MUFA and polyphenol levels coupled with increased omega‐3 levels demonstrated a potential negative influence on oil profile alongside increased nutritional benefits. The sum effects on oil yield and composition should be considered in designing of nutrient application management strategies for olive orchards. Copyright © 2009 Society of Chemical Industry
Studying the composition of olive oil requires cold-press olive oil extraction. One of the most common laboratorial mills is the Abencor system. However, its operation protocol was formulated decades ago for Spanish olive varieties from traditionally rain-fed orchards. We modified this protocol for use with “Barnea” and “Picual” olives from irrigated orchards that are characterized by high water content. Independent effects of malaxation time, temperature, water addition and talc addition on extraction efficiency, and major quality indices of virgin olive oil were studied. Overall, addition of talc to the fruit paste was the most significant treatment in terms of yield and quality of the oil although its effect was cultivar dependent. Improved oil yield was particularly significant for “Picual.” Extended malaxation time was also effective in improving oil extractability. Addition of talc generally improved oil-quality parameters, while water addition had the opposite effect. Yet, quality parameters remained within the extra virgin level. Temperature increments reduced oil quality. The need to adapt a modified protocol for use with fruits from irrigated orchards that will facilitate critical comparison of results obtained from different agronomic theses and different laboratories is highlighted. It is recommended that each laboratory develops an appropriate protocol for the operation of the Abencor system in accordance to the characteristics of the olive fruit they are working with.
Anthracnose is an important disease affecting mature olive fruits, causing significant yield losses, and poor fruit and oil quality. In Portugal, high anthracnose incidence was recorded during 2003–2007 with 41% of 908 orchards surveyed displaying disease symptoms. In another 14% of the orchards, the pathogen was recorded in symptomless plants. Disease severity was on average 36%, frequently reaching 100%. In Portugal, anthracnose is endemic to neglected orchards of susceptible cultivars, but under favourable conditions it can also severely affect less susceptible cultivars. Pathogens were genetically heterogeneous, with Colletotrichum acutatum genetic group A2 as the most frequent (80%), followed by group A4 (12%) and group A5 along with C. gloeosporioides (3–4%), while groups A3 and A6 of C. acutatum were sporadic. Important geographic variations were observed in the frequencies of these populations, accompanied by year-to-year populational shifts. Epidemiology and histopathology studies showed the presence of the pathogens on vegetative organs year-round, particularly on olive leaves and branches, and on weeds. These represent inoculum reservoirs where secondary conidiation occurs, and conidia are then dispersed by spring rains reaching flowers and young fruits or by autumn rains reaching pre-mature fruits. Unripe fruits were colonized without showing symptoms up to penetration of the cuticle, but further colonization and symptom production was completed only as fruits matured. These findings challenge current control practices, particularly the timing of fungicide treatment, and contribute to improved disease management.
This study evaluated the effect of regulated deficit irrigation (RDI) strategies applied to olive trees (Arbequina cv) during the fruit ripening and harvest periods on oil yield and oil composition. Fatty acid composition, pigments, colour, polyphenol content and stability of oils were evaluated. The results indicate that regulated deficit irrigation induces fruit ripening; at harvest, oil yield increased when water supply was decreased, probably as a consequence of lower water content in the olive. Acidic composition was not affected by irrigation treatments. Irrigation affected pigment content and oil colour primarily during the early stages of olive ripening. RDI increased polyphenol concentration and stability of oils at all picking dates, especially during the first stages of the ripening period, probably owing to water stress.
© 2000 Society of Chemical Industry
The pattern of oil accumulation in the olive fruit during its development was studied in 15 cultivars under various levels of orchard intensification. While yield, fruit size and final oil content are dependent on both genetical and environmental conditions, the basic pattern of oil accumulation is determined only by the cultural and environmental conditions and is not cultivar dependent. Under irrigated intensive growing conditions oil accumulation is linear during most of the fruits’ growing period. The oil accumulation pattern will change considerably under limiting environmental or stress conditions.
The olive commodity spread in ancient times hand in hand with western civilization in the Mediterranean basin. It was till recently and in many regions still is a highly traditionally cultivated commodity. Table olives were subjected about 200 years ago to irrigation and intensification. This was unacceptable in olive cultivation for oil extraction. During the last century the economy of the olive industry declined and became questionable. A drastic increase in efficiency of the olive oil industry was obligatory for its survival. In the nineteen fifties, an approach to intensify the olive oil industry was initiated using irrigation and modern nutrition. The initial results indicated a significant increase in production without reducing oil quality. Slight changes in taste occurred occasionally due to quantitative changes of some oil constituents but oil quality was not affected. Some of these oils gained high prizes in international competitions. Some cultivars responded to irrigation better than others regarding growth, fruit yield and relative oil content. Thus, selection and breeding of responsive cultivars to intensification was initiated. Once responsive cultivars were identified and planted commercially in pioneering orchards, a revolution of the olive oil industry was initiated. An increase in both fruit and oil yield up to more than five times that in traditional orchards was achieved. This increased production and tree uniformity initiated the development of new orchard systems, advanced mechanization and oil mill technologies reducing manual labor. This attracted large scale orchard development in traditional, new and marginal regions. Basis on this development it can be concluded that the introduction of irrigation revolutionized the world's olive oil industry from a traditional barely economic one to a thriving modern economical developing industry.
Irrigation is one of the most important means of increasing olive oil production but little information exists on the responses of olive to variable water supply. Five different irrigation strategies, full irrigation, rain fed, and three deficit irrigation treatments were compared from 1996 to 1999, in Cordoba, southern Spain, to characterize the response of a mature olive (Olea europaea L. 'Picual') orchard to irrigation. Crop evapotranspiration (ETC) varied from less than 500 mm in the rain fed to ≈900 mm under full irrigation. The deficit irrigation treatments had ETC values that ranged from 60% to 80% of full ETC depending on the year and treatment. Water relations, and oil content and trunk growth measurements allowed for the interpretation of yield responses to water deficits. In a deficit irrigation treatment that concentrated all its ETC deficit in the summer, stem water potential (ψx) decreased to -7 MPa but recovered quickly in the fall, while in the treatment that applied the same ET deficit progressively, ψx was never below -3.8 MPa. Minimum ψx in the rain fed treatment reached -8 MPa. Yield (Y) responses as a function of ETC were calculated for biennial yield data, given the alternate bearing habit of the olive; the equation are: Y = -16.84 + 0.063 ET -0.035 × 10-3 ET2, and Y = -2.78 + 0.011 ET - 0.006 × 10-3 ET2, for fruit and oil production respectively, with responses to ET deficits being similar for sustained and regulated deficit irrigation. The yield response to a deficit treatment that was fully irrigated during the bearing year and rain fed in the nonbearing year, was less favorable than that observed in the other two deficit treatments.
The aim of the present study was to evaluate the qualitative and quantitative yield response to irrigation of olive in southern Italy. The olive cvs Kalamata, Ascolana Tenera, and Nocellara del Belice were tested in a-factorial combination with four irrigation levels: a rain-fed control (T0) and three treatments (T1, T2 and T3) irrigated daily with an amount of 33%, 66% and 100%, respectively of crop evapotranspiration. Soil water content remained near field capacity in treatment T3 with no difference with respect to treatment T2. In T0 and T1 the soil moisture decreased during the summer with the lowest value (20.8%) found in T0 on 12 August, after which rainfall restored the soil moisture to field capacity. During the season the relative water content in the leaves was higher in the irrigated treatments than in the rain-fed control. Yields were higher in all the cultivars with irrigated treatments than in the rain-fed control. The yield increase with treatment T1 in 'Nocellara del Belice' was 200% compared with the rain-fed control and with T2 in 'Ascolana tenera' and 'Kalamata' the yield was 233% and 47% greater than in the control. The higher oil yield obtained in the irrigated treatments was mainly due to the increase in fruit yield, since the pulp-stone ratio and the quantity of triglycerides accumulating in the fruits were similar for all treatments. The fatty acid composition of the oils was not affected by irrigation, while there was a decrease in the content of polyphenolic substances with irrigation. This decrease could be attributed to different enzymatic activity, caused by the water deficit, rather than to different degrees of fruit ripening. The decrease of polyphenols did not influence the oil quality in terms of organoleptic parameters or oil shelf-life.
The amount and composition of tocopherols and phenols, two of the main natural antioxidants in virgin olive oil, have been studied in seven varieties of Tunisian olive oil. Results showed that phenol and tocopherol amounts vary according to cultivars. Among the studied varieties, the oil of Chetoui presents the highest amounts of total phenols (925.7 +/- 24.3 mg/kg) and tocopherols (490.7 +/- 2.2 mg/kg). The prevalent phenols in studied oils were secoiridoids such as dialdehydic form of oleuropein aglycon (DFOA), dialdehydic form of ligstroside aglycon (DFLA), aldehydic form of oleuropein aglycon (AFOA), and aldehydic form of ligstroside aglycon (AFLA). Moreover, phenolic acids, mainly p-coumaric acid, are well represented. Flavonoids (apigenin and luteolin) and lignans (pinoresinol and acetoxypinoresinol) were also detected in our samples. As reported by some authors, total phenols, o-diphenols, secoiridoids and hydroxytyrosol amounts show a good correlation with stability measured by Rancimat. There is a lower influence of tocopherols and lignans. Nevertheless, the stability of Sayali oil seems due to its high oleic/linoleic ratio rather than to its phenol content.
The influence of macronutrient status on olive oil properties was studied for three years. Data were analyzed by a multivariate model considering N, P, K, and fruiting year as explanatory factors. Oil quality parameters were primarily associated with N concentration in leaves and fruits which increased with N in irrigation solution. The effect of P on oil quality was mainly indirect since increased P availability increased N accumulation. The potassium level had negligible effects. The oil phenolic content decreased linearly as a function of increased leaf N, indicating protein-phenol competition in leaves. The overall saturation level of the fatty acids decreased with fruit N, resulting in increased polyunsaturated fatty acids. Free fatty acids increased with increased levels of fruit N. High fruit load tended to reduce fruit N and subsequently improve oil quality. The effect of N on oil properties depended solely on its concentration in leaves or fruits, regardless of the cause.
An interpretation is given of a number of observations on the chemiotropic behavior ofBactrocera oleae in connection with olive maceration water and the fly's return to the olive groves after the first summer rains. To this end, the headspace of both maceration water and leaf leaching water, simulating rainfall, were examined. In both cases, the presence of ammonia, which is generally known to attract fruit flies (Diptera, Tephritidae), was detected and, for the first time, in addition to other compounds that are inert for the fly, the presence of styrene was also detected. This aromatic hydrocarbon was found to be a strong attractant. It is shown that both ammonia and styrene are products of the metabolism of microbial flora present on the olive and leaf surface.
This is a review of water use by the olive tree, in which the most-relevant knowledge from the literature is combined with key results from experiments just finished or currently in progress. We describe the plant characteristics and mechanisms conferring drought tolerance on the olive tree. The root system functionality, hydraulic characteristics of the conductive system, leaf water relations, and transpiration behavior are considered. We explain the most-advanced techniques for optimizing irrigation, based on a more accurate calculation of the crop water needs. The crop responses to deficit irrigation strategies and to the use of wastewater for irrigation are also included.
The true origin of the olive is not known but is speculated to be Syria or possibly sub-Saharan Africa. For more than 6000 years, the cultivated olive has developed alongside Mediterranean civilizations and is now commercially produced on more than 23 million acres (9.4 million ha) in the Mediterranean basin. New plantings also exist in California, Chile, Argentina, South Africa, and Australia. Various nonscientific selection processes created a multitude of different cultivars. Many villages in Europe, the Middle East, and North Africa feature distinct varieties. However, it is also common to see the same cultivars with different names and, in some cases, different cultivars with the same name. This is currently being sorted out with DNA identification. The olive tree requires some chilling; tolerates hot, dry conditions; does not like moisture during bloom, and actually produces better with some stress. As a result, olives were traditionally relegated to lands where little else would survive. For thousands of years olives were grown primarily for lamp oil, with little regard for culinary flavor. World production of table olives is now about 1.5 million t/year. The ''California Style'' black table olive is virtually unknown outside the United States, and this very mild-flavored olive is largely used on pizzas. Elsewhere, table olive recipes are as varied as the villages in the Mediterranean region. Oil styles are also varied, and most olive fruit (' '16 million t/year) is processed into oil. There are about 19 classic styles of olive oil produced in the world, primarily based on specific varieties grown in different regions. In some cases oils are made with a blend of regional varieties. Defective olive oil is common worldwide. The author discusses six of the world's most influential olive oil varieties 'Picual', 'Coratina', 'Koroneiki', 'Arbequina', 'Frantoio', and 'Leccino'; covers some horticultural history of oil olive cultivation and processing; and describes the most current trends toward superhigh-density plantings and automated continuous oil processing. along the eastern Mediterranean Coast in what are now southern Turkey, Syria, Leb- anon, Palestine, and Israel based on written tablets, olive pits, and wood fragments found in ancient tombs. Ancient documents in Syria indicate that around 2000 BCE the value of olive oil was five times that of wine and two and a half times that of seed oils. The spread of the olive tree probably coincided with the vegetative propagation and trade of superior wine grape, date palms, and fig selections. Propagation of olive trees by seed is very frus- trating, because the juvenile nonbearing phase is so long (10-15 years) and the progeny very often do not even resemble the original mother tree. These first nurserymen and agriculturists probably also selected for vari- eties that came into bearing early, produced heavy yields every year, grew on poor soils in arid areas, and were easy to harvest. The spread of the olive tree in commerce is well documented. The primary movement, how- ever, was to the west.
The interactions between irrigation rates applied during the oil accumulation stage and crop load were studied in a six-year-old very-high-density Koroneiki (Olea europaea L.) orchard. Five irrigation rates, determined as thresholds of midday stem water potential, were applied from July 1st until harvest in 2008 and 2009 and from July 1st to the end of September in 2010. Oil yield increased with increasing crop load in all the irrigation treatments. Oil yield did not respond to increasing irrigation at very low crop load and the higher the crop load the higher the response to irrigation. There was no response to irrigation at the lowest crop loads, but the higher the irrigation rate the higher the oil yield at high crop loads. The predicted commercial oil yield at common fruit counts increased from 1.99 t/ha at the lowest irrigation rate to 3.06 t/ha at the highest irrigation rate. Stomatal conductance decreased with decreasing stem water potential but leveled off at 30–60 mmol m−2 s−1 at stem water potential values lower than −4.0 MPa. High crop load increased stomatal conductance and decreased stem water potential relative to low crop load at low and medium irrigation rates. The effect of crop load on water relations became evident by the end of August and was well pronounced at the beginning of October. Physiological and irrigation water management implications related to the interactions between tree water status and crop load are discussed.
Olives (Olea europaea cv. Arbequina, Blanqueta, Lechín, Villalonga, and Verdial) used for oil production were harvested and distributed in four successive stages of ripening according to their skin color (green, spotted, purple, and black). The firmness of the fruits and the quality of the oils extracted from these fruits were analyzed. The resistance to postharvest handling measured by fruit firmness decreased during fruit ripening. The total oil content, the total oil extracted, and the α-tocopherol content did not change appreciably during this process. In general, the parameters which measure the oxidation of the oils extracted (K230, K270, and stability to oxidation) indicated a progressive deterioration of oil quality as fruit ripening progressed. Moreover, in this process bitterness indices decreased in the oils. The stage of ripening mainly affected the sensory quality of the oils obtained from the Verdial and Blanqueta varieties, which clearly decreased during fruit ripening. Keywords: Olea europaea; maturity; postharvest; oil quality; analytical determinations
Olive oil yield and its components (fruit number, average fruit weight and fruit oil concentration) depend on crop load and source–sink ratios as affected by environmental conditions, management and the alternate bearing typical of the species. The aims of this work were to: (i) establish quantitative relationships between oil yield and its components as affected by fruit load in a high-yielding production system, (ii) analyse the dynamics of fruit weight and fruit oil concentration in terms of rates and durations, and (iii) explore the relationships between the dynamics of oil and water in fruit. In a fully irrigated olive orchard in Mendoza (32° S), Argentina, cv. Arbequina trees with similar crown volume and three fruit loads (3-fold range) were monitored during two seasons. Oil yield was positively associated with both fruit number and fruit fresh weight, but not with fruit oil concentration. Across seasons and fruit loads, fruit yield increased linearly with fruit number at ∼1.5kg per thousand fruit and reached a maximum ∼60kgtree−1 (or 25tha−1) at a fruit load of 32,700 fruit tree−1. The fruit filling rate was affected by fruit load, while the duration of fruit growth and the dynamics of oil and water concentration were unaffected by fruit load. Fruit water concentration reached a minimum at the onset of Stage III of fruit growth, which was marked by a rapid increase in oil concentration. Fruit fresh weight and oil weight increased with source–sink ratio from ∼0.5 up to a threshold ∼2m3 crown per thousand fruit. In contrast, a 8-fold range of source–sink ratio did not affect fruit oil concentration.
The crop loss which is directly attributable to D. oleae larvae is assessed for the two major oil varieties, Tsounati and Koroneiki, in Crete, Greece at harvest time and following different periods of outdoor storage of the harvested olives before milling. Loss through preharvest fruit drop is not considered here.
The amount of pulp directly consumed by a larva in the field is calculated, taking into account that the female fly chooses the bigger fruit for oviposition, and that the attacked fruit desiccate faster. Larval consumption of fresh pulp in Tsounati olives amounts to about 50 mg, which is confirmed by direct observation in the laboratory. For Koroneiki olives a less precise estimate gives a larval consumption of 150 mg. The reduction in fresh pulp is then translated into an oil loss of 3% for Tsounati and 20% for the smaller Koroneiki olives. This quantitative loss is not affected by storage.
In addition Dacus infestation and storage of the fruit before milling have a cumulatively adverse effect on oil quality, which is measured by the increased acidity of the oil. Log acidity increases directly with the proportion of exit holes in the fruit to be processed, while larvae which may be present in the olives at the same time do not have any appreciable influence. In batches where all olives had exit holes, acidity increased four-fold in Tsounati and two-fold in Koroneiki olives when compared with uninfested fruit. Storage on the other hand caused acidity levels to rise three times within two weeks, and six to twelve times within four weeks. After translating these findings into loss of revenue (according to the Greek oil prices for 1976/77) it is concluded that, unless damage is magnified through prolonged storage of the olives, infestation levels of up to 30% exits at harvest do not reduce the value of the oil.
Der Befall von Dacus oleae (Gmel.) zur Erntezeit und sein Einfluß auf Ertrag und Qualität des Olivenöls auf Kreta (Griechenland)
Für die zwei wichtigsten Olivenvarietäten auf Kreta, Tsounati und Koroneiki, wurde der Verlust ermittelt, welchen D. oleae-Larven zur Erntezeit im Anschluß an verschiedene Lagerungszeiten der Oliven verursachen. Der Verlust an Früchten, die schon vor der Ernte zu Boden fallen, wurde dabei nicht berücksichtigt.
Die Menge des von Larven im Feld verzehrten Fruchtfleisches wird unter Berücksichtigung der Beobachtungen, daß Fliegenweibchen die größeren Früchte zur Eiablage vorzie hen, und daß befallene Oliven rascher austrocknen als unbefallene, berechnet. In Tsounati-Oliven fressen Larven etwa 50 mg frisches Fruchtfleisch, was durch direkte Beobachtungen im Labor bestätigt wurde. Für Koroneiki-Oliven ergeben weniger genaue Schätzungen etwa 150 mg. Dieser Verlust an frischem Fruchtfleisch entspricht einem Ölverlust von 3% für Tsounati-und von 20% für die kleineren Koroneiki-Oliven und ist unabhängig von der Lagerungsdauer.
Zusätzlich haben Lagerungsdauer der Früchte vor der Ölverarbeitung und Dacus-Befall noch eine sich gegenseitig steigernde schlechte Wirkung aud die Ölqualität, welche an Hand des steigenden Säuregehaltes ermittelt wird. Der Logarithmus dieses Säregehaltes nimmt direkt proportional zum Anteil der Schlupflöcher der Dacus-Larven zu, während Larven selbst, welche gleichzeitig noch in den Oliven lebel, keinen meßbaren Einfluß zeigten. In Proben, in denen alle Früchte Ausschlupflöcher hatten, stieg der Säuregehalt gegenüber den unbefallenen Früchten auf das 4fache bei Tsounati-und auf das 2fache bei Koroneiki-Oliver. Lagerung andererseits ergab 3mal höhere Säuregehalte nach 2 Wochen und 6-bis 12fache Werte nach 4 Wochen. Der diesen Werten entsprechende Geldverlust (an Hand der offiziellen griechischen Ölpreise für 1976/77) zeigt, daß Befallsdichten bis zu 30% Ausschlupflöchern zur Erntezeit den Wert des Öls nicht verringern, es sei denn, der Säuregehalt werde durch eine längere Lagerungszeit erhöht.
Species of Botryosphaeria and Neofusicoccum are well known as pathogens of woody hosts. In this study the species that occur on rotting olive drupes in the main production areas of southern Italy were studied. Species were identified from the morphology of their conidial states in culture and from sequence data of the ITS rDNA operon and partial sequence of the translation elongation factor 1-α gene. Botryosphaeria and Neofusicoccum species were isolated from more than 60% of the affected drupes, suggesting that they are the main contributors to this disease. The most common species was B. dothidea, which was isolated from 34% of the drupes. However, N. australe and N. vitifusiforme were also common and were isolated from 16 and 12%, respectively. Two other species (N. parvum and N. mediterraneum) were uncommon and occurred on less than 1% of the drupes. All five species were pathogenic on the two cultivars of olive tested. The most aggressive species was N. vitifusiforme, followed by N. australe and B. dothidea. The two olive cultivars differed in their susceptibility to the pathogens. The results show that B. dothidea, N. vitifusiforme and N. australe are important pathogens of olives.
Harvest time plays a key role in the quality and oxidative stability of olive oil. Olive producers can control oil quality by using appropriate harvest times. Fruits from three olive cultivars, Corregiolla, Mission and Paragon growing in the southwestern region of New South Wales, Australia, were harvested at six different times during the season, over 3 years and immediately processed in a laboratory scale mill. The oils were then analyzed for total polyphenol content, induction time, chlorophyll content and fatty acid profile. The maturity index of the fruit was also determined. Most parameters measured, including polyphenols, induction time and fatty acids, showed a significant year effect. Cultivar effects were also apparent with total polyphenols content in cv. Mission being consistently higher than in the other cultivars studied. There was a strong interaction between the parameters studied, particularly between total polyphenol content and induction time, with high polyphenol content increasing oil oxidative stability. The fatty acid profiles of the oils were found to be strongly influenced by the growing season. Generally, as the fruit matured, the oil became less stable due to decreasing total polyphenol content, increasing polyunsaturates (mainly linoleic acid), and decreasing chlorophyll content.
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
Black-ripe olives (Olea europaea cv. Ascolano, Manzanillo, Mission, and Sevillano), intended for oil extraction, were stored at 5 °C for 6-8 weeks to evaluate their postharvest physiology and quality changes. Also, samples of olives were placed at 20 °C for 2 weeks to determine the deterioration rate of four cultivars at ambient temperature. Fruit quality evaluations included color, visual quality, fruit firmness, mass loss, and water and oil content. Decay incidence, physiological disorders, and respiration and ethylene production rates of the olives were also recorded. Olive oil quality was determined by analysis of titratable acidity, peroxide value, K 232 and K 270 coefficients, and fatty acid composition of the olives. Fruit and oil quality of Ascolano and Manzanillo cultivars deteriorated more rapidly than that of Mission and Sevillano olives. Black-ripe Manzanillo and Ascolano olives could be stored with good air circulation at 5 °C for 2 and 4 weeks, respectively, whereas Mission and Sevillano cultivars could be stored for 6-8 weeks at 5 °C with maintenance of good fruit and oil quality.
Black-ripe olives (Olea europaea cv. 'Manzanillo'), used for processing into canned olives or oil were stored at 0, 2.2 and 5°C in air or 2 kPa O 2 (balance N 2). Olive samples were analyzed initially, and after 2, 4 and 6 weeks for fruit quality based on color, visual quality and fruit firmness, weight loss, water and oil content. Respiration rate, ethylene production and incidence of physiological disorders and decay were determined. Olive oil quality was evaluated based on titratable acidity, peroxide value, K 232 and K 270 coefficients, and fatty acid composition. Decay incidence increased with storage temperature and duration but it was lower in black-ripe olives kept in 2 kPa O 2 than in those kept in air. Fruit decay after 4 weeks storage in 2 kPa O 2 was 9.2, 8.2, and 7.7% in olives kept at 0, 2.2, and 5°C, respectively. No visual chilling injury symptoms were observed in any of the storage treatments. Storage time and atmospheres had no significant effect on olive color but visual quality scores of olives stored in 2 kPa O 2 at 0°C were generally higher than other treatments. Ethylene production and respiration rates were considerably higher at 5°C than at 0 or 2.2°C and in air than 2 kPa O 2 . Fruit firmness declined markedly after 4 weeks storage in both the air and 2 kPa O 2 treatments, irrespective of storage temperature. There was no significant difference between the air and 2 kPa O 2 stored fruit. There were no significant differences in water and oil content among treatments. Oil obtained from olives stored at 0°C, was within the limit of 'extra' virgin quality in terms of acidity, irrespective of storage atmosphere after 4 weeks storage, whereas oils extracted from olives stored at 2.2°C in air and 2 kPa O 2 and olives stored at 5°C in 2 kPa O 2 were qualified as 'fine' virgin quality. K 232 and K 270 values were not surpassed in any of the treatments except oil obtained from olives stored at 20°C. Fatty acid composition was within the range required for 'extra' virgin olive oil, except for slightly higher linolenic acid. In conclusion, black-ripe 'Manzanillo' olives can be stored at 0–5°C in air or in 2 kPa O 2 for up to 4 weeks between harvesting and processing while maintaining fruit and oil quality. © 1999 Elsevier Science B.V. All rights reserved.
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
Characterization of virgin olive oils from two new olive cultivars obtained through controlled crossings on Meski variety was investigated. These two olive varieties have been selected among a progeny of 30 olive descendants after an evaluation of oil fatty acid composition and the content of their fruits. The study was achieved during the crop years 2001/2002 and 2002/2003. These two new cultivars (9D and 6H) had an improved oil composition compared to that of Chemlali, the dominant Tunisian olive oil variety; the latter is characterized by low rate of oleic acid and high rates of linoleic and palmitic acids. New cultivars are distinguished by: (1) good content of total phenols and oil yield; (2) a balanced fatty acid composition; and (3) a good content of OOO and a relatively low ΔECN42 as compared to that of Chemlali.
This study evaluated the effect of regulated deficit irrigation (RDI) strategies applied to olive trees (Arbequina cv) during the fruit ripening and harvest periods on oil yield and oil composition. Fatty acid composition, pigments, colour, polyphenol content and stability of oils were evaluated. The results indicate that regulated deficit irrigation induces fruit ripening; at harvest, oil yield increased when water supply was decreased, probably as a consequence of lower water content in the olive. Acidic composition was not affected by irrigation treatments. Irrigation affected pigment content and oil colour primarily during the early stages of olive ripening. RDI increased polyphenol concentration and stability of oils at all picking dates, especially during the first stages of the ripening period, probably owing to water stress.© 2000 Society of Chemical Industry
The olive tree is a traditionally nonirrigated crop that occupies quite an extensive agricultural area in Mediterranean-type agroecosystems. Improvements in water-use efficiency of crops are essential under the scenarios of water scarcity predicted by global change models for the Mediterranean region. Recently, irrigation has been introduced to increase the low land productivity, but there is little information on ecophysiological aspects and quality features intended for a sagacious use of water, while being of major importance for the achievement of high-quality products as olive oil. Therefore, deficit irrigation programmes were developed to improve water-use efficiency, crop productivity and quality in a subhumid zone of Southern Italy with good winter–spring precipitation. The response of mature olive trees to deficit irrigation in deep soils was studied on cultivars Frantoio and Leccino by examining atmospheric environment and soil moisture, gas exchange and plant water status, as well as oil yield and chemical analysis. Trees were not irrigated (rainfed) or subjected to irrigation at 66% and 100% of crop evapotranspiration (ETC), starting from pit hardening to early fruit veraison. Improvements in the photosynthetic capacity induced by increasing soil water availability were only of minor importance. However, plant water status was positively influenced by deficit irrigation, with 66% and 100% of ETC treatments hardly differing from one another though consistently diverging from rainfed plants. The effect of water stress on photosynthesis was mainly dependent on diffusion resistances in response to soil moisture. Leccino showed higher instantaneous water-use efficiency than Frantoio. Crop yield increased proportionally to the amount of seasonal water volume, confirming differences between cultivars in water-use efficiency. The unsaturated/saturated and the monounsaturated/polyunsaturated fatty acid ratios of the oil also differed between cultivars, while the watering regime had minor effects. Although irrigation can modify the fatty acid profile, polyphenol contents were scarcely affected by the water supply. Irrigation to 100% of ETC in the period August–September might be advisable to achieve high-quality yields, while saving consistent amounts of water.
Chétoui is the second main olive variety cultivated in the north of Tunisia and shows a high capacity of adaptation to various pedoclimatic conditions. The aim of this work was to study changes in oil composition of such variety according to origin of plantation. Thus, olives at the same stage of maturation were harvested from seven regions in the north of the country for oil extraction and analysis. Three consecutive crops from years 2000, 2001 and 2002 were considered. The analytical parameters studied were fatty acid composition, triacylglycerol molecular species and amounts of polyphenols and o-diphenols. The results showed considerable variability in oil composition because of the effect of cultivar–environment interaction.