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The effect of irrigation level and harvest mechanization on virgin olive oil quality in a traditional rain-fed ‘Souri’ olive orchard
Journal of The Science of Food and Agriculture
Abstract
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
... 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/ ...
... However, as shown in Fig. 4A and Tables 2 and 4, the growers' practices resulted in much lower oil quality that did not meet the quality standards of EVOO. The higher pungency and bitterness of the experimentally extracted oil (Table 4) are probably attributable to the high content of phenolic compounds in this oil (Table 2) (Dag et al. 2008). Three parameters, oil content based on dry weight, FFA values of experimentally and commercially obtained oils, and polyphenol levels in the same oils, indicated that the commercial harvest takes place later than the optimal timing for obtaining high-quality olive oil. ...
... The commercial harvest occurred later than the experimental harvest; therefore, the oil quality could only deteriorate. In 'Souri', the oil content reaches its maximum at an early stage of ripening, and the oil quality begins to deteriorate at a relatively early stage of ripening (Dag et al. 2008). The grower's traditional practice of delaying harvest until late ripening to obtain higher oil yields leads to deterioration in oil quality. ...
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.
... Because of the importance of oil quality and a tendency for quality parameters to benefit from conditions causing water stress to the trees (Ben-Gal et al., 2011a;Dag et al., 2008Dag et al., , 2015, optimization of irrigation of oil olives depends on maintaining at least some level of water deficit. ...
... We found profound improvement in oil quality as a function of lowered seasonal irrigation (Figs. 8 and 9). This is not surprising, as prior studies have indicated the same, including for ' Barnea', 'Koroneiki' and 'Souri' (Ben-Gal et al., 2011a;Dag et al., 2008Dag et al., , 2015. The connection between water stress and higher polyphenols is well established. ...
... They and others (Tovar et al., 2002) indicate that water stress triggers augmented phenol synthesis. The phenomenon where acidity is decreased under increased water stress is less evident in the literature and may be dependent on climate and cultivar since studies reporting the response tend to be based in regions outside of the traditional center of olive production in southwestern Europe (Berenguer et al., 2006;Dag et al., 2008Dag et al., , 2015Ghrab et al., 2014;Toplu et al., 2009). ...
Profits from olive oil production are expected to benefit from regulated deficit irrigation (RDI) regimes designed to optimize yield and oil quality with minimal inputs of water. We evaluated a number of potential strategies for implementing RDI including choosing phenological periods for reduced irrigation, use of midday stem water potential (SWP) for scheduling, considering fruit load, and irrigation to reach optimal fruit water content at harvest. We base our discussion on the potentials and challenges of practical commercial RDI regimes on results from a 6-year orchard experiment on two olive oil cultivars used in intensive orchards ('Barnea' and 'Askal') in Israel, focusing on attempts for long-tern optimization of yield and oil quality. Results showed a general trend of increased water productivity as a function of reduced irrigation but since yields tended to be reduced when irrigation was decreased, there was not a clear benefit of RDI over sustained deficit irrigation. The exception to this was a treatment based on SWP where water application was reduced by some 40% compared to irrigation regimes bringing highest yields, and a non-significant accumulated yield reduction of less than 15% after 6 years in both cultivars. Oil quality, measured in terms of free fatty acids and polyphenol content, was often improved when irrigation was decreased, with no dependence on the seasonal timing of deficit amounts and increased tree water stress.
... Up to now, studies have been carried out to evaluate the effects of different harvesting systems on the basic qualitative parameters of the virgin olive oils (VOOs), such as free acidity, peroxide value and spectrophotometric absorbances in the ultra-violet (Tombesi et al., 1996;Dag et al., 2008;Inglese et al., 2011;Abenavoli and Proto, 2015). However, the results of these studies have been contradictory, indicating the need for further investigation to better understand the effects of mechanization on these parameters. ...
... In a study carried out using the cultivar Souri, oils extracted from olives harvested with hand-held machines showed higher free acidity and peroxide values than those extracted from olives "gently picked manually" (Dag et al., 2008). Tombesi et al. (1996) found no significant differences for these parameters in oils from the cultivar Leccino harvested by hand (with hand-held combs), or by facilitated (hand-held pneumatic combs) and mechanical (trunk shaker) systems. ...
... Some differences regarding oil quality reported in the literature and in our study could be due, at least in part, to the kind of manual harvesting that was used as a reference and to the cultivar. In particular, when olives were gently picked by hand or, in general, by using only hands, manual harvesting tends to give higher quality oils (in terms of free acidity and peroxide values) than those produced from mechanically-harvested olives (Dag et al., 2008;Yousfi et al., 2012;Morales-Sillero and García, 2015). When olives were harvested with hand combs or by beating the canopy with wooden poles, there were no differences between manual harvesting and mechanized harvesting (Tombesi et al., 1996) or the latter (mechanical harvesting) gave a higher quality of the Fig. 4. Relationships between the damaged olive index and contents of some volatile compounds in oils of the cultivars Arbequina (super-intensive grove) and Frantoio (intensive grove) extracted at harvest and after 48 h of olive storage. ...
This study evaluated the effects of different olive harvesting systems and fruit storage durations on quality of oils from both super-intensive (cv. Arbequina) and intensive (cv. Frantoio) olive groves. Four harvesting systems were used: gentle manual harvesting, manual harvesting with hand-held combs, facilitated harvesting with hand-held pneumatic combs, and mechanical harvesting with a straddle machine (in super-intensive grove) or a trunk shaker + reversed umbrella (in intensive grove). Gentle hand harvesting caused the least damage to the fruits, whereas the trunk shaker and the straddle machine caused the greatest damage. The damage increased with olive storage. Total polyphenols and single secoiridoid were all negatively correlated with the degree of fruit damage. Volatile compounds (aldehydes, alcohols, esters and ketones) were strongly affected by both the harvesting system and the olive storage. In both cultivars, increasing the mechanization level (from gentle hand harvest to the straddle machine or the trunk shaker) caused a decrease of total aldehydes and total esters, and an increase of total alcohols and total ketones. Moreover, there were negative relationships between the degree of fruit damage and the total C5 and C6 aldehydes and total esters and positive relationships between the degree of fruit damage and the total ketones. Overall, the results indicate that fruit damage explains most of the worsening of oil quality across harvesting systems and storage duration. This is the first study reporting a clear quantitative/linear correlation between fruit damage and important components of oil quality, such as polyphenols and volatile compounds deriving from the lipoxygenase pathway.
... Various different factors contribute to the reduction of VOO quality along the production chain: orchard management [24]-e.g., high irrigation levels [25] and over-fertilization with nitrogen [26], harvesting-where the method might harm the fruit and reduce oil quality [27], the time elapsed between harvesting and milling [28] and the oil-extraction method [29]. Here, we clearly show good potential for the traditional olive orchards to produce high-quality oil; the FFA and sensory assessment values indicate that the oil can be classified as EVOO. ...
... Using electric combs for harvesting resulted in somewhat better oil quality (Figure 4), but not significantly so because this method also damages the fruit. The negative impact of aggressive olive harvesting on oil quality has been described in the past [27,30]. Regarding fruit storage prior to oil extraction, we evaluated two problems that are prevalent among the traditional growers: one is delayed shipment of the fruit to the mill and the other is storing the fruit in non-ventilated bags. ...
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.
... Water deficit before harvest may increase the concentration of oil phenolic compounds by a reduction of fruit moisture leading to lower losses of fruit phenolic compounds during oil extraction (Dag et al., 2008). Olive fruits have high phenolic concentration. ...
... Few studies have focused on evaluating water deficit strategies carried out before harvest. This can be explained by the fact that pre-harvest water deficit is related to a reduction in fruit oil accumulation (Tognetti et al., 2006;Hueso et al., 2019) and lower efficiency of mechanical harvesting (Dag et al., 2008). In addition, autumn rainfall is frequent in the Mediterranean climate where much of the olive research has been carried out. ...
The effect of pre-harvest deficit irrigation was studied as a tool to reduce fruit moisture and evaluate its influence on fruit characteristics, oil yield extraction, and oil quality. Two regulated deficit irrigation treatments (RDI) were evaluated over two seasons in a cv. Genovesa olive orchard. This study included a Control treatment, irrigated at 100% crop evapotranspiration over the season, and two RDI treatments, irrigated at 50% (RDI1) and 30% (RDI2) of Control. These treatments were applied from the end of pit hardening (mid-January) until harvest (early- April), when oil is accumulated in fruits. Fruit moisture decreased as the deficit irrigation period advanced, being significantly lower in RDI2 and RDI1 than in the Control treatment. Fruits harvested from the RDI2 treatment had lower moisture, dry mass and oil deposition, and higher maturation and pulp flavonoid compounds concentration than in RDI1 and Control. Pooled data across seasons showed that a 1% reduction in fruit moisture produced an increase of 0.16% in oil yield extraction. Phenolic compounds increased consistently with fruit moisture decreasing from 60% to 50%. However, when fruit moisture was as low as 35%, phenolic compounds were the lowest. Additional fruit samples from RDI2 were processed with water addition after malaxation. Water addition led to a general pattern of increases in oil yield extraction, reduction of phenolic compounds, and no influence on acidity, UV indexes, or fatty acids profile.
... [5][6][7][8][9] Although olive is well adapted to the Mediterranean semi-arid conditions, irrigation leads to a substantial increase in fruit and oil yields. [10][11][12][13] Severe scarcity of freshwater in traditional olive growing regions has led to the use of alternative water sources, including saline groundwater 14,15 and reclaimed wastewater (RWW) for irrigation. 16,17 RWW are domestic liquid wastes treated by screening, oxidation, sedimentation and biological digestion; and typically contain high amounts of organic matter, nitrogen (N) and minerals such phosphorus (P) and potassium (K). ...
... 16,30,31 Several studies have focused on effects of irrigation with either fresh or saline water on the composition and quality of olive oils. 13,15,29,[32][33][34] The rising use of RWW for olive irrigation in the Mediterranean calls for intensive study. 25,26,31,35 Here we aimed to determine the effects of long-term RWW irrigation and fertigation on the composition, quality and organoleptic properties of olive oil. ...
BACKGROUND
Irrigation of olives increases fruit and oil yields. Due to scarcity of freshwater, low‐quality water including recycled wastewater (RWW) is utilized in orchards. Here, effects of irrigation with RWW and of fertilization on the composition and quality of olive oil were studied.
RESULTS
Long‐term RWW irrigation of ‘Barnea’ and ‘Leccino’ olive had no significant negative effects on either oil composition or quality parameters, including free fatty acids (FFAs), peroxide value (PV), total phenolics content (TPC), fatty acid profiles and organoleptic characteristics. The average FFA contents for both cultivars were less than 0.8% during most of the experimental period, except the seasons 2009 and 2012–2013 for Barnea where the values were raised up to 1.4%. The measured PV levels were less than 9 and 5 mmol O2 kg‐1 oil for Barnea and Leccino, respectively. In the last season of the experiment for each cultivar, higher TPC were observed in oils obtained from RWW irrigation with reduced fertilization (Re–) as compared to the treatments with the recommended fertilization [freshwater irrigation (Fr) and RWW irrigation (Re+) with standard dose of fertilizers], where the TPC increment exceeded 70% in Barnea and 25% in Leccino. The treatments had only minor effects on the fatty acid profile, reflected in slightly altered levels of C18:2 and C18:3 fatty acids.
CONCLUSION
The use of RWW, combined with the consideration of nutrients arriving with such water to provide appropriate fertilization, was found suitable for olive irrigation to ensure optimal yields while preserving oil quality. © 2019 Society of Chemical Industry
... The levels of polyphenols in extracts were evaluated using the Folin-Ciocalteu method [26]. The extraction (0.1 ml) was added to 3 ml DDW and 0.25 mL of Folin-Ciocalteu Reagent (FCR). ...
... The levels change with relation to the date of harvest (all harvested during April-June). The levels of polyphenols in extracts from S. spinosum were evaluated using the Folin Ciocalteou method [26]. Results ranged in both organs from 100 mg to 376 mg/g dry weight of powder, depending on the date of harvest. ...
Background
Sarcopoterium spinosum (S. spinosum) is used by Bedouin medicinal practitioners for the treatment of diabetes. While the anti-diabetic activity of S. spinosum root extract was validated in previous studies, the activity of aerial parts of the same plants has not been elucidated yet. The aim of this study was to clarify the glucose lowering properties of the aerial parts of the shrub.
Methods
Anti-diabetic properties were evaluated by measuring the activity of carbohydrate digesting enzymes, glucose uptake into 3 T3-L1 adipocytes, and insulin secretion. Insulin signaling cascade was followed in L6 myotubes using Western blot and PathScan analysis.
Results
Activity of α-amylase and α-glucosidase was inhibited by extracts of all S. spinosum organs. Basal and glucose-induced insulin secretion was measured in Min6 cells and found to be enhanced as well. Glucose uptake was induced by all S. spinosum extracts, with roots found to be the most effective and fruits the least.
The effect of S. spinosum on Akt phosphorylation was minor compared to insulin effect. However, GSK3β and PRAS40, which are downstream elements of the insulin cascade, were found to be highly phosphorylated by S. spinosum extracts. Inhibition of PI3K and Akt, but not AMPK and ERK, abrogated the induction of glucose uptake by the aerial parts of the shrub.
Conclusion
The aerial organs of S. spinosum have anti-diabetic properties and may be used as a basis for the development of dietary supplements or to identify new agents for the treatment of type 2 diabetes.
... The time between olive harvest and pressing processes (Dag et al., 2012) and oil extraction methods may cause a decrease in oil quality (Ben-David et al., 2010;Dag et al., 2008). As a result of the interviews and observations made in the field, it was determined that there were deficiencies in this regard. ...
Although olive cultivation has a significant share in economic activities in Milas, productivity is below the national average. The main purpose of the research is to determine the reasons why the productivity of olive farming activities in Milas is lower than the country average and the problems experienced by the producers and to offer solutions. Qualitative research method was adopted in the research and face-to-face interviews were conducted with local people using semi-structured interview technique. The data collected as a result of the interviews were transferred to Maxqda and content analysis was performed. It was concluded that the rugged land structure of Milas, the high average age of people engaged in olive cultivation, the lack of interest of young people in olive cultivation, the lack of qualified personnel, the insufficiency of incentives, the increase in input costs, wrong harvesting methods, etc. are the factors that cause low productivity in olive production in Milas.
... On the other hand, in drupes for olive oil, several studies have been carried out to evaluate the effects of different harvesting systems on the basic qualitative parameters of virgin olive oils, such as free acidity, peroxide value, and spectrophotometric absorptions in ultraviolet [102][103][104][105]. The quality of the oils extracted from the harvested olives met the requirements set by European law for extra virgin olive oils [42,46,74,106], even if, from a sensorial point of view, trunk shakers with a reversed umbrella can be a more efficient solution for mechanical harvesting in southern Italy to avoid the scent of oil obtained from fruits collected with earth. ...
Olive cultivation is still concentrated within the Mediterranean basin, although the last thirty years have seen an expansion into geographical areas outside it. Traditional olive groves, with large planting distances and centuries-old trees, still predominate. However, more and more space is being given over to modern plantations, which allow an ever-increasing degree of mechanisation, although some legal restrictions, often related to the monumental nature of the plantations, make the conversion of old plantations into new ones not always easy. The extreme case is super-intensive olive growing, where the very concept of olive growing has been rethought. In this context, harvesting is the most time-consuming and costly of the cultivation operations. Without it, or rather without a high degree of mechanisation, it is still not possible to produce high-quality oils. A leading role is always played by the trunk shakers, who are still the undisputed protagonists in this sector. This review looks at trunk shakers in olive groves, showing the latest models, and their strengths and weaknesses, based on the research carried out in recent decades.
... Considering the average monthly rainfall, 2014 was characterised by higher average rainfall in July (five times) and September (three times) than in 2013 and 2015 (Supplementary Materials, Figure S1). Results from previous studies on the influence of irrigation indicate lower TPC levels in olive fruits exposed to a greater amount of water [43,44]. It is possible that fruit infestation contributed to the lower TPC levels in 2014. ...
The lipoxygenase pathway has a significant influence on the composition of the volatile components of virgin olive oil (VOO). In this work, the influence of the maturity index (MI) on the activity of the lipoxygenase enzyme (LOX) in the fruits of the autochthonous Dalmatian olive cultivars Oblica, Levantinka and Lastovka was studied. The analysis of the primary oxidation products of linoleic acid in the studied cultivars showed that LOX synthesises a mixture of 9- and 13-hydroperoxides of octadecenoic acid in a ratio of about 1:2, which makes it a non-traditional plant LOX. By processing the fruits of MI~3, we obtained VOOs with the highest concentration of desirable C6 volatile compounds among the cultivars studied. We confirmed a positive correlation between MI, the enzyme activity LOX and the concentration of hexyl acetate and hexanol in cultivars Oblica and Lastovka, while no positive correlation with hexanol was observed in the cultivar Levantinka. A significant negative correlation was found between total phenolic compounds in VOO and LOX enzyme activity, followed by an increase in the MI of fruits. This article contributes to the selection of the optimal harvest time for the production of VOOs with the desired aromatic properties and to the knowledge of the varietal characteristics of VOOs.
... Thus, the very advanced state of the fruit maturity due to the inadequacy of the precautions occurs during the harvesting or storing of olives. Moreover, the noticed high significant temperature during extraction promotes the chemical and enzymatic deterioration of the fruits and consequently increases the content of free fatty acids in the presence of lipases [29,30]. ...
Background:
The present work was conducted to investigate the quality and antioxidant properties of some Algerian extra virgin olive oils (EVOOs).
Objective:
In this paper, the physicochemical characteristics and antioxidant properties of four EVOOs of monovarietal samples (Chemlal) from East Algeria were studied
Methods:
Physicochemical characteristics, which include free acidity, peroxide index, saponification index, specific extinction coefficients, water content, refractive index, relative density, and chemical composition, in addition to their antioxidant activity, were investigated based on DPPH free radical-scavenging activity (DPPH-SA).
Results:
The results of physicochemical and quality parameters proved that all samples are EVOOs with highly nutritious and health benefits for the consumer, as per the recommendation of the International Olive Council (IOC). The results showed that the olive oils from the southern arid region of Algeria (Sahara), have a high antioxidant activity than the samples from the Northern regions.
Conclusion:
These findings revealed a significant influence of geographic location on the chemical characteristics and antioxidant activities of olive oil from the same cultivar (Chemlal). These olive oils from the arid Saharan region may be used as a functional food with great antioxidant potential.
... Other studies showed different patterns of the influence of irrigation on these parameters. For example, Dag et al. [78] found that an increase in irrigation increased FFA, while PV was unaffected. Bedbabis et al. [79] found that irrigation only affected the extinction coefficient (K 232 and K 270 ), while it did not affect FFA and PV. ...
Olive groves in the Mediterranean may lose production sustainability because of their vulnerability to climatic change. Irrigation is an important measure that could significantly affect fruit yield, olive fruit fly infestation, and oil characteristics. The aim of paper was to compare the regulated deficit irrigation with different water management practices, in consecutive years, in two locations in Zadar County (Croatia), affecting fruit morphology, olive fruit fly infestation, and quantity and quality of the extracted Coratina cultivar oil. Treatments, namely C—rainfed, T1—deficit irrigation (produce’s practice), T2—regulated deficit irrigation, and T3—full irrigation (100% ECTO), were established. Irrigated treatments had a positive effect on all morphological characteristics of the fruit. The pulp mass, independently of the year, increased in irrigated treatment (ranging from 1.04 to 1.65 in C to 2.25 and 2.30 in the irrigated treatments) and resulted in a higher oil content on a fresh weight basis (ranging from 16.39% to 17.85% in C to 19.48% to 23.26% in the irrigated treatments). However, fruit yield per tree was only location-dependent. When olive fruit fly presence was high, fruit infestation was greatest in the irrigated compared to the rainfed treatment. According to quality parameters, all oils were classified as EVOO. Individual phenols were influenced by irrigation, while the composition of fatty acids was more influenced by location than treatment. The sensory characteristics of the resulting oil were slightly reduced compared to rainfed treatment. The results indicate that regulated deficit irrigation benefits water use sustainability without compromising the quality of the oil.
... These water-saving measures align with the 31% reduction in water consumption observed in our study. Nevertheless, oil quality is conditioned for both irrigation amount and fruit bruising during harvesting (Dag et al., 2008) along with fruit location within the olive canopy . Complementary measures to control olive vigor in super high-density olive Table 5 Cumulative tree height and trunk diameter growth from April year 1 to November year 3 and average lateral branches growth from April to November. ...
... One option to consider in this situation is deficit irrigation whereby irrigation demand is reduced and crop water use efficiency is enhanced (Mairech et al., 2020). It has also been indicated that optimization of olive oil quantity and quality requires finely tuned water management as increased irrigation, up to a certain level, might result in higher yields but a certain degree of stress is concurrently known to improve oil quality (Ben-Gal, Berenguer et al., 2006;Dag et al., 2008). However, achieving this fine balance between water use and crop yield requires both a comprehensive knowledge of crop response to water stress and an optimized irrigation schedule (Geerts & Raes, 2009). ...
Spectral indices can be used as fast and non-destructive indicators of plant water status or stress. It is the objective of the present study to evaluate the feasibility of using several spectral indices including water index (WI) and normalized spectral water indices 1-5 (NWI 1-5) to estimate water status in olive trees in arid regions in Iran. The experimental treatments involved two olive cultivars (Koroneiki and T2) and four irrigation regimes (irrigated with 100%, 85%, 70%, and 55% estimated crop evapotranspiration [ETc]). The results obtained showed that olive trees subjected to the different irrigation regimes of 85%, 70%, and 55% ETc experienced soil water content (SWC) deficits by 4.5%, 12%, and 20.5% that of the control, respectively. Significant differences were observed among the treatments with respect to measured relative water content (RWC), SWC, and the spectral indices of WI and NWI 1-5. The normalized spectral indices combining NIR and NIR wavelengths were found more effective in tracking changes in RWC and SWC than those that combine NIR and VIS or VIS and VIS wavelengths, respectively. Spectral indices were closely and significantly associated with RWC (.63**<R2<.77**) and SWC (.51**<R2<.67**). Among all the spectral indices investigated, NWI-2 showed the least consistent associations with RWC (ranging from 4-15% lower than the other indices examined) and SWC (ranging from 1-23% lower than the others). Based on the pooled data on spectral indices, RWC, and SWC collected during the study period, WI, NWI-1, NWI-4, and NWI-5 showed stronger correlations with RWC and SWC than did NWI-3 and NWI-2. In conclusion, the spectral indices of WI and NWI 1-5 measured at the leaf level are found useful as fast and non-destructive estimators of plant water stress in arid regions.
... According to [47] the stage of maturity of Chemlali fruits is the most important factor determining the fat content of olives, in relation to the fresh weight. In addition, it has been shown that the irrigation of olive trees is a promoting factor for increasing fruit productivity, by increasing both size, number, and oil content [12,48,49]. ...
The aim of this work was the investigation of the effect of wastewater generated from the poultry meat industry on the irrigation of olive trees, during a short time period, in order to evaluate its impact on pomological criteria and olive oil quality. Olive trees were subjected to irrigation with different water qualities: (i) poultry wastewater (PWW), (ii) poultry wastewater diluted with tap water 50:50 (v/v) (PWTWW), (iii) rain-fed cultivation system (control). The results showed that PWTWW contains the optimal mineral proportions, leading to improved pomological criteria. However, the highest significant pulp oil content was obtained using poultry wastewater irrigation (69.51%), while this was 66.71% using diluted poultry wastewater, and 58.03 % for the control. Poultry wastewater irrigation yielded the best results in oil standard quality indices. In addition, an enrichment in oil total polyphenols content was achieved. The oil fatty acid profile was not affected following irrigation with poultry wastewater. Nevertheless, there was a significant increase in the contents of oleic acid and alcohols, accompanied by a decrease in total sterols. However, heavy metals accumulation was observed in both fruits and olive oil. In conclusion, our results suggest that among the three water qualities, poultry wastewater is the best alternative to improve olive oil quality.
... As discussed by de Falco et al. (2018a) effects of irrigation on the fatty acid composition of plants are controversial, according to growth environment and plant species or phenological stage (Bellaloui et al., 2015). Nevertheless, irrigation has a thermal indirect effect whereby water supply allows water to thermoregulate and keep a lower temperature (Dag et al., 2008). Low temperatures, in turn, increase activity of desaturases which increase the linoleic/oleic acid ratio. ...
Salvia hispanica L., commonly named Chia, is a food plant from Central America and Australia, producing seeds whose consumption has been increasing in the last decade. Several articles analysed the seeds metabolite content. However, few is known about Chia leaves. This work is the first report on the whole metabolite profile of chia leaves, determined by spectroscopic methods including NMR, GC-MS and LC-MS coupled with chemometrics analysis. Additionally, molecular networking has been applied to the LC-MS data to determine the flavonoid composition. Different chia sources were compared: one commercial (black) and three early flowering (G3, G8 and G17) mutant genotypes cultivated at two irrigation regimes (50 and 100%). Organic extracts were mainly composed by saturated and mono- and polyunsaturated fatty acids with palmitic being the most abundant followed by oleic and linolenic acids. Aqueous extracts contained glucose, galactose, and fructose as main sugars. Flavonoids were based on vitexin and orientin and their analogues. Chemical composition of early flowering genotypes was quite similar to commercial black chia with the exception of G8 showing significant differences in the polar phase. A generally highest content of omega-9 fatty acids has been found in the early flowering genotypes along with high content of nutraceuticals suggesting them as a potential source of raw materials for the food/feed industry.
... While Authors agree that UVKs and PV are generally not significantly influenced by irrigation, more controversial is the effect on FFA. In the scientific literature, there are cases where the correlation with increasing seasonal irrigation volume and FFA was found to be positive (Berenguer et al., 2006;Dag et al., 2008Dag et al., , 2015Ben-Gal et al., 2011) or not obvious or significant (Dettori and Russo, 1993;Salas et al., 1997;Patumi et al.,1999). Similarly to this last cases, we have found that not only UVKs and PV but also FFA did not show statistically significant differences among treatments (Table 2; data relative to UVKs are not showed), except for the peroxide number in the on-year of trial 2 were the T0 had a value almost double respect to the irrigated treatments but still indicating a high quality EVOO. ...
Reasons of primary importance in supporting the positive trend of worldwide per capita consumption of EVOO (extra virgin olive oil), begun more than 30 years ago, are quite certainly the numerous benefits on the human health recognized in the EU by three health claims awarded by the EFSA (European Food Safety Authority). In two experimental trials carried on in intensive olive groves with quite different soils, in addition to vegetational, agronomical and physiological parameters reported in another paper, some carpological parameters and qualitative characteristics of oils have been determined and discussed in the present paper. Compared water regimes were a dry control and two irrigated with restitution, 50 and 100%, of the watering volume required to restore the full crop evapotranspiration (TWR). Only for the deeper soil there were also an additional treatment resembling local farmers behaviour in irrigating olive (TF); low frequency and high volumes. Results remark that: (i) the flesh:pit ratio grew passing from the dry control to the restitution of 50 and 100% but the highest value was obtained with TF; (ii) TF, was able to modify the shape of drupes increasing their roundness, interestingly for the table olive industry; (iii) at harvest, irrigation reduced oxidative condition, mainly due to a light reduction of acidity and a significative reduction of oil oxidation indexes; (iv) under increasing seasonal irrigation volumes, the percentages of oleic acid enhanced, while that of stearic, linoleic and linolenic acids decreased; (v) it seems that water deficit conditions may increase the percentage of linolenic acid of olive oils over the maximum allowed under the EU regulations for EVOO although they have excellent quality; (vi) opposite to what was previously reported, we observed an increase of the content of total phenols in the TWR respect to the dry control.
... According to Talhaoui et al. [53], the transfer of phenolic compounds from fruits to oil did not surpass 2% in a study with six cultivars that explains qualitative and quantitative changes in phenolic compounds of olive oil during oil extraction in relation to fruits. Our results show that the content of polyphenols in Arbequina and Frantoio oil increased for the non-irrigated treatment compared with the 100% ETc treatment, as also reported by several authors [51,54,55]. During the 2021 season, Arbequina showed the same tendency but the differences were not statistically significant. ...
The expansion of olive orchards into regions with no tradition of olive production and humid climates, such as Uruguay, with more than 1200 mm of annual rainfall, calls into question the need for irrigation. In these regions, however, years with water deficit during summers are quite common. The vapor pressure deficit during summer is lower than in countries with a Mediterranean climate. The high variability in interannual water availability in the current context of climate change, with a growing tendency for extreme events to occur, emphasizes the need to evaluate the production response of olive trees to irrigation. To achieve this, three irrigation treatments were applied to Arbequina and Frantoio cultivars according to the value of the maximum crop evapotranspiration: a first treatment applying 100% ETc, corresponding to being fully irrigated; a second treatment applying 50% ETc; and a third treatment in which neither irrigation nor rain inputs occurred from the end of the pit hardening period until harvest. Results show the possibility of an increasing fruit weight and pulp/pit ratio through irrigation in the local environmental conditions. The oil content in response to irrigation was different within cultivars. Water restriction conditions did not affect the oil content of olives in Arbequina, while in Frantoio it increased it. Polyphenols in fruit increased under water stress for both cultivars. The technological applicability of the results obtained must be accompanied by an economic analysis. The results obtained highlight the need for better use of irrigation water during the growth and ripening phase of the olive fruit under a humid climate.
... The farm must draw up an adequate irrigation plan based on the water balance of the crop and the use of efficient irrigation distribution techniques. In this sense, while irrigation has a positive effect on yield, as irrigation levels increase, the free acidity of the oil and the emission of suckers increase, while the total phenol content and resistance to lower temperatures decrease (Dag et al., 2008;El Yamani et al., 2020). ...
Italian olive growing must aim at the transition to economically and environmentally sustainable management systems, linked to premium quality production and to a recognized and remunerated context of biodiversity conservation in compliance with the provisions of the European Union New Green Deal and United Nations Agenda 2030. To assist and facilitate companies in this step, a sustainability technical guide for the Italian olive oil supply chain has been developed, with reference to the four pillars of sustainability. The guide, consisting of 42 requirements, was submitted to 18 olive farms from 8 different Italian regions participating in this pilot study, to assess their level of total sustainability and to receive feedbacks throughout the drafting process. Taken as a whole, the companies have proved to be virtuous in meeting the requirements provided, with percentages of compliance ranging from 86 to 96% according to pillar and from 70 to 100% according to company and showed a remarkable spirit of collaboration and involvement in the construction of the guide. In this regard, the text is aimed to represent a participatory standard for Italian institutions and for other olive countries.
... The chemical parameters used to determine olive oil quality are the total polyphenol profile and fatty acid composition. Polyphenol levels decrease during fruit development [76,77], positively corresponding with water restrictions [78,79]. Elevated temperatures lead to a dramatic decrease of up to 65% in the total polyphenol content of most analyzed cultivars [4]. ...
Climate change, with elevated temperatures throughout the year, affects many stages of the reproductive growth and development of olives as well as oil quality at harvest. Although olive (Olea europaea L.) is well adapted to the environmental conditions of the Mediterranean Basin, agricultural techniques and breeding through selection programs will have to adapt to these climate change, threatening to worsen in the near future. Defining the pathways controlling high fruit productivity and oil quantity and quality, despite elevated temperatures and sub-optimal growing conditions, is important for coping with current and predicted climate changes. As breeding programs aiming to address these crucial changes may take several decades, an urgent need to designate specific olive cultivars that are more resistant to high temperatures emerges.
... These data agree with the literature and follow Ivanov's rule: the amount of linoleic acid rises when the temperature decreases, in contrast with oleic acid. 11,31,32 This trend can be ascribed to a thermal effect of water supply, keeping fully irrigated plants at a lower temperature. Minor compounds have been identified in both stem and flower extracts. ...
BACKGROUND
Chia (Salvia hispanica L.) is a functional food from Central America. Interest in it is growing rapidly due to the many health benefits from the seed. However, when chia is grown at high latitudes, seed yield may be low whereas a high stem biomass and immature inflorescences are produced. Little is known about the chemical composition and the properties of stems and flowers. In this work, the metabolite profile, the antioxidant activity, and the total polyphenol content of stems and inflorescences were evaluated in a factorial experiment with different chia populations (commercial black chia and long‐day flowering mutants G3, G8, and G17) and irrigation (100% and 50% of evapotranspiration).
RESULTS
The results show the influence of irrigation and seed source on the antioxidant activity and total polyphenol content of chia flower and stem. Inflorescences exhibit higher antioxidant activity, suggesting their potential use as natural antioxidant. The mutants G3 and G8, at 50% irrigation, contained the highest amounts of compounds with nutraceutical value, especially within the flower. The mutant G17 showed lower antioxidant activity and polyphenol content compared to other seed sources but exhibited high omega 3 content in flowers but low in stems. This indicates that chia varieties should be chosen according to the objective of cultivation.
CONCLUSION
These findings, indicating a close relation of metabolite content with irrigation and seed source, may provide the basis for the use of chia flower and stem for their nutraceutical value in the food, feed, and supplement industries. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
... Many research studies that have been developed with fruit trees and correlated different water regimes and productive performance have shown that the application of greater irrigation depths does not always lead to a significant increase in fruit quality or productivity (Dag et al. 2008;Kiggundu et al. 2012;Dinc et al. 2018). The reason is that the higher the levels of water applied to the soil, the greater the chances of nutrients leaching out of reach from the root system. ...
The acai palm (Euterpe oleracea Mart.) is a fruit from the Amazon that is originally found in flooded areas. Over recent years, its marketability has gained significant interest in Brazil and abroad because of its agronomic, nutritional and economic potential. However, there is a lack of technical-scientific information about crop water requirements for irrigation management during the reproductive phase of acai palm. Therefore, the aim of this research was to estimate the water requirements (crop evapotranspiration (ETc), single (Kc) and dual (Kcb + Ke) crop coefficients) of acai palm in the Eastern Amazon (Brazil) using the Bowen ratio system. A micrometeorological tower was installed in the center of an experimental area to monitor ETc and meteorological variables. Phenological development was monitored during two growing seasons. Soil water evaporation was determined on a daily scale using weighing microlysimeters. Ke and Kcb values were calculated by the ratio of soil surface evaporation and transpiration to reference evapotranspiration (ETo), respectively. Total water requirements of the acai palms were 1165 mm, with a daily average of 3.49 mm day⁻¹ for the growing season. The average values of Kc, Ke and Kcb for the acai palm were 1.08; 0.21 and 0.84, respectively. The findings will assist the design of irrigation management protocols for acai trees that are better tailored to satisfy crop water requirements. This will allow improved water use efficiency, ensuring tree crop sustainability.
... The changes in these substances regarding the mentioned factors confirmed the results obtained by Motilva et al. (2000) and Rufat et al. (2018). In the same way, it was indicated that higher levels of irrigation reduced the total phenols content in olive oils (Salas et al., 1997;Tovar et al., 2001;Romero et al., 2004;Gómez-Rico et al., 2007;Servili et al., 2007;Dag et al., 2008); while the highest concentrations were recorded at deficit-irrigated, and severely stressed trees or those grown under rainfed conditions (Motilva et al., 2000;Caruso et al., 2014;Gucci et al., 2019). Moreover, differences in total phenols amounts were related to many environmental conditions, especially the amount of water applied Chehab et al., 2013;Marra et al., 2016;Sastre et al., 2016). ...
The purpose of this work is to evidence the effects of ripening index and water regime on the quantity and quality indices of “Moroccan Picholine” virgin olive oil (VOO) produced in northern Morocco. Olive trees were subjected to full irrigation and rainfed conditions, and olive fruits were collected at different ripening times. Results showed that the extracted volume of VOO increased during ripening, and decreased when full irrigation was applied. In regard to VOO quality, the statistical analysis revealed the predominant effect of ripening index on the majority of the considered parameters, except total phenols content that was strongly influenced by water regime. At more advanced stages of maturity, lower values of peroxide value, K232, carotenoids, chlorophylls and total phenols were registered while more free fatty acids were accumulated. Moreover, full irrigation reduced total phenols and increased free fatty acids, even if a great amount of pigment content was scored. Correlation studies showed significant relationships between pigments content and oxidation indices (peroxide value and K232).
... Studies show that final fruit quality is also highly influenced by the optimality of harvesting time (Muhtaseb, 2007;Kviklienė and Valiuškaitė, 2009). Management of irrigation coupled with the method and timing of harvest is reported to have an important bearing on final oil quality of olive trees (Dag et al., 2008). Promisingly, developments in Information and Communication Technologies (ICT) including sensors and robotics provide the potential for precise measurement of crop water status for irrigation management and precise estimation of optimal harvest timing, among others. ...
Precision management has become vital in agriculture with possibilities growing alongside developments in information and communication, robotics and sensor technologies. On the other side of expected benefits of precision management in terms of environmental friendliness, yield margin, input efficiency, etc., is the upfront expensiveness of such technologies. There is hence a need to quantitatively assess expected net benefits and provide useful information for farmers and stakeholders to enable informed choice on the potential adoption of precision technologies and management practices. This study presents economic assessment of precision irrigation and harvest management system with integrated use of sensor technologies and Farm Management Information System (FMIS) as compared to conventional practice applying partial budgeting as a tool. Relevant scenarios are defined based on data from an experimental apple orchard field situated in Prangins, Switzerland. The precision management system is found to be economically justifiable in situations of high demand for irrigation characterized by limited rainfall and considerable variabilities in weather conditions. Its economic feasibility is found to be sensitive to changes in fruit price and capital cost.
... Numerous environmental and inherited factors may alter olive oil quality, the most acknowledged of which being: variety, climate, water availability, fruit maturity level, pest damage, harvest method, and oil extraction method (Aparicio and Luna, 2002). Enhanced irrigation caused a decrease in polyphenol content and thus a decrease in oil stability and bitterness (Dag et al., 2008a. Until recently, mineral nutrition was not thought to play a major role oil quality. ...
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.
... Although a number of studies have reported the effects of irrigation on yield parameters under conditions and varieties, there is a shortage of the influence of the harvesting method on oil quality. The effect of irrigation on the oil quality of the fruit obtained from both the mechanical and hand harvesting methods in addition to the yield parameters was also researched [4]. They found that when fruit was picked carefully by hand so that no injuries were inflicted, free fatty acids levels were substantially reduced, peroxide was reduced and the total polyphenol content was increased. ...
The aim of this paper is to determine how different harvesting methods of olives and the waiting period before the extraction of the extra virgin olive oil affect the viscosity and some thermal properties, namely thermal conductivity and thermal resistivity. Olive trees in the Aegean region of the western part of Turkey were harvested by using six different harvesting methods: by hand, harvesting by a beating pole on a synthetic fabric, harvesting by a beating pole on a platform, harvesting by machine on a synthetic fabric, harvesting by machine on a platform and direct collecting of dropped olives by hand. Olive oil samples were obtained in certain intervals between the harvesting and processing that was made by using a laboratory type system. The viscosity values of oil samples were measured by using a vibro-viscometer. The thermal conductivity and thermal resistivity of oil samples were measured simultaneously by using the KD2 Thermal properties analyzer. As a result, viscosity, thermal conductivity and thermal resistivity values changed related to the harvesting method and the waiting period after harvesting to obtain olive oil. While viscosity (dynamic) and thermal conductivity values increased with the increase of the waiting time, thermal resistivity values decreased. The lowest viscosity and thermal conductivity values and the highest resistivity values were found for oils that were obtained from olives harvested by hand.
... Continuous mechanical harvesting is a key management practice in intensive and superintensive groves. Some studies have shown that this mechanical operation may cause internal fruit damage, leading to a fast reduction of quality in several varieties (Dag et al., 2008;Morales-Sillero and Garc ıa, 2015;Yousfi et al., 2012). However, other researchers have reported that early harvesting and improving fruit management through mechanization result in a better oil quality (Camposeo et al., 2013). ...
This study describes the effects of mechanical harvesting and irrigation on quality in ‘Arbequina’ olive oil (Olea europaea L.). Irrigation treatments included a control, deficit irrigation (DI) during pit hardening, and subsurface deficit irrigation (SDI). Results showed that mechanical harvesting damaged the olives and reduced olive oil quality by increasing free fatty acids (FFAs) and peroxide value,
and by decreasing fruitiness, stability, bitterness, and pungency. DI resulted in increased fruit dry weight and oil content, which could be explained by their reduced crop load (9.3% of crop reduction for DI and 23.9% for SDI). DI did not affect olive oil characteristics, whereas SDI increased stability, fruitiness, and bitterness, and decreased polyunsaturated fatty acid (PUFAs). In conclusion, mechanical harvesting tended to damage the fruit, resulting in lower quality
olive oil, the DI strategy neither affected fruit nor olive oil characteristics, whereas the SDI strategy positively affected oil quality when greater water restrictions were applied.
... Palese et al. (2010) found a significant decrease in total phenol content of olive oils from irrigated trees. On the other hand, Greven et al. (2009) found that the olive trees deprived from irrigation yielded oils with lower phenol levels compared to irrigated trees (a 33% decrease), while Dag et al. (2008) suggest that moderate water stress would be beneficial to olive oil quality. ...
This study aims to evaluate the variations in the quality and composition of extra virgin olive oils of Spanish (Arbequina, Arbosana) and Greek (Koroneiki) varieties produced over two crop seasons in the Oriental region of Morocco, taking into consideration the influence of climatic conditions. To this end, serval parameters were evaluated, such as quality indices, fatty acids, triacylglycerols, minor compounds (phytosterols, phenolic compounds, tocopherols and pigments) and oxidative stability. The results obtained in this study indicate that the majority of the studied parameters, with the exception of phytosterols, are influenced by climatic conditions of the crop season (p < 0.05). Additionally, the majority of the studied parameters were also influenced by the cultivar factor (p < 0.05). However, the studied varieties produce an excellent oil quality with a chemical composition respecting the requirements recommended by the International Olive Council. The main variations observed on the analyzed olive oils between the two crop seasons are those of antioxidant parameters, such as phenols and oxidative stability. Triacylglycerols and fatty acids are also influenced by the crop season's climatic conditions. Nonetheless, the behavior of the studied varieties towards climatic conditions is different.
... Differently from what reported in the literature (Caruso et al., 2014;García et al., 2016;Dag et al., 2008;Bucelli et al., 2011;Del Campo et al., 2013), the oil obtained from irrigated trees showed a concentration of phenols statistically higher than that obtained from not irrigated olive trees adding or not carbonic snow during oil extraction. ...
To highlight the effects induced by the direct addition of solid carbon dioxide to olive fruits on oil production and phenol accumulation, olive fruits from the same cultivar with different ripening degrees were used. A part of the olives were obtained from irrigated plants, while the other fraction derived from not irrigated olive trees. The yield of oil extracted from olive fruits belonging the same cultivar and coming from the same orchard increased with the ripening degree of the milled fruits. Furthermore, the olives harvested on the same date from irrigated plants produced more oil than those coming from not irrigated trees. In addition, the addition of carbonic snow to fruits characterized by the same ripening index increased both the yield of oil and the concentration of total phenols dissolved in the extra-virgin olive oils.
... Therefore, the new methodologies used to increase production need to be assessed for their impact on oil quality parameters. Our previous studies explored the effect of harvest timing , fruit storage prior to oil extraction (Dag et al., 2012), irrigation (Ben-Gal et al., 2011;Dag et al., 2015), harvesting method (Dag et al., 2008) and oil extraction protocol (Ben-David et al., 2010) on virgin olive oil quality. In the current study, we explore the effect of tree nutrition, focusing on nitrogen (N), which was found in our earlier study to be a key macro-element having a pronounced effect on oil quality parameters. ...
... Despite the fact that mechanical harvesting of the olives for oil mill extraction is now a reality in many countries, studies of the effect of this method on oil quality are very scarce, probably because the production of EVOO is usually feasible in these conditions. However, losses of natural antioxidants and flavor components, and in some cases, increased free acidity, have been observed with different types of harvesters, either hand-vibrating combs (Dag et al., 2008) or grape straddle harvesters (Yousfi et al., 2013). This is probably a response to fruit internal damage caused by harvesters and to physiological alterations to the fruit, such as increases in respiration rate and, mainly, ethylene production (Morales-Sillero and García, 2015;Yousfi et al., 2013). ...
... Although in many cases values were lower in irrigated treatments, differences were statistically significant (p < 0.01) only for the commercial variety at 2 min, and sample variability did not allow significance to be reached in the other instances. The general trend of our data agrees with literature reports of a negative effect of irrigation on TPC for different species (Dag et al., 2008;Esteban et al., 2001). ...
Chia (Salvia hispanica L.) is an emerging crop with a high content of α-linolenic acid and metabolites of industrial and pharmaceutical interest but information on metabolome variations in response to agricultural management is scarce. We investigated the yield and metabolic profile of the seeds of two chia populations, one commercial black (B) and one long-day flowering genotype (G8), in response to two irrigation levels: replacement of 100% ET0 (I) or rainfed (NI). Seed yield was higher in irrigated plots in G8 only (0.255 kgm−2 for I vs 0.184 kgm−2 for NI) while it was very low regardless of irrigation in B due to late flowering. Ultrasound assisted extraction (UAE) of seeds followed by gas chromatography-mass spectrometry (GC/MS) analysis showed differences in fatty acids and the major classes of organic compounds due to both genotype and irrigation, especially in the non-polar phase where irrigated samples showed a higher content of α-linolenic and other fatty acids and a lower oleic/
linoleic ratio (47.4 in NI vs. 39.6 in I). The antioxidant activity, expressed as trolox equivalent antioxidant capacity (TEAC), ranged from 1.317 ± 0.027 to 2.174 ± 0.010 mmol TEAC/g of defatted chia seed after 2 and 40 min respectively, and was negatively affected by irrigation. The total polyphenolic content (TPC) measured with the Folin-Ciocalteu method, also decreased with irrigation. According to our results irrigation can affect chia yield, metabolome and antioxidant behavior but some of the effects are genotype-dependent.
... Although in many cases values were lower in irrigated treatments, differences were statistically significant (p < 0.01) only for the commercial variety at 2 min, and sample variability did not allow significance to be reached in the other instances. The general trend of our data agrees with literature reports of a negative effect of irrigation on TPC for different species (Dag et al., 2008;Esteban et al., 2001). ...
Chia (Salvia hispanica L.) is an emerging crop with a high content of α-linolenic acid and metabolites of industrial and pharmaceutical interest but information on metabolome variations in response to agricultural management is scarce. We investigated the yield and metabolic profile of the seeds of two chia populations, one commercial black (B) and one long-day flowering genotype (G8), in response to two irrigation levels: replacement of 100% ET0 (I) or rainfed (NI). Seed yield was higher in irrigated plots in G8 only (0.255 kg m⁻² for I vs 0.184 kg m⁻² for NI) while it was very low regardless of irrigation in B due to late flowering. Ultrasound assisted extraction (UAE) of seeds followed by gas chromatography-mass spectrometry (GC/MS) analysis showed differences in fatty acids and the major classes of organic compounds due to both genotype and irrigation, especially in the non-polar phase where irrigated samples showed a higher content of α-linolenic and other fatty acids and a lower oleic/linoleic ratio (47.4 in NI vs. 39.6 in I). The antioxidant activity, expressed as trolox equivalent antioxidant capacity (TEAC), ranged from 1.317 ± 0.027 to 2.174 ± 0.010 mmol TEAC/g of defatted chia seed after 2 and 40 min respectively, and was negatively affected by irrigation. The total polyphenolic content (TPC) measured with the Folin-Ciocalteu method, also decreased with irrigation. According to our results irrigation can affect chia yield, metabolome and antioxidant behavior but some of the effects are genotype-dependent.
... The first is based on the stage of maturity at which the olive fruits have been harvested, it could be obtained from green fruits, which was not accomplished in this experiment, where the phenol content is higher than in black fruits as has been reported by several authors (Conde et al., 2008;Dag et al., 2011). The second one can be attributed to the water availability where several studies have highlighted that the amount of phenolic compounds is higher in oils obtained from non-irrigated or drought-stressed trees than in those from irrigated trees (Dag et al., 2008;Gomez-Rico et al., 2007). For Fouji variety, no study has been published describing the total phenol content. ...
Here we evaluate the olive oil antiradical and anti-inflammatory potential through its polyphenols extracts and examine the influence of olive maturity on olive oil quality properties, polyphenols composition and biological potentials. Samples have been obtained from minor Tunisian olive cultivars (Chemchali, Fouji and Zarrazi) at different maturity indices. Principal quality properties were evaluated and polyphenols analysis was carried out by Folin Ciocalteu reagent and HPLC-UV-MS. Antiradical activity was examined by DPPH and FRAP scavenging assays while J774A.1 murine macrophages were used to evaluate anti-inflammatory potential by analyzing NO production with Griess reagent method and iNOS and COX-2 expression by cytofluorimetric analysis. Our results revealed that quality characteristics, total phenol content, as well as phenolic compound concentrations were significantly affected by the olive maturity levels. On the other hand, the polyphenols extracts showed an interesting radical scavenging capacity and a potential ability to inhibit inflammatory markers at 90% for NO release and 75% for iNOS expression. Thus, our study establishes that olive oil through its polyphenols extracts has a substantial antiradical and anti-inflammatory potential. Likewise a lot of attention should be attributed to olive ripening level in order to decide the optimum harvesting time.
... An important use of irrigation is to improve the olive fruit yield. Irrigation can markedly influence the physical properties of olives (Bacelar et al., 2007;Fernandes-Silva et al., 2010;G omez del Campo, 2007;Moriana et al., 2002), the growth and production of fruits (d' Andria et al., 2004;Grattan et al., 2006;Gucci et al., 2007), the oil content of the fruits, and the oil quality (Dag et al., 2008;Fernandes-Silva et al., 2013;Lavee et al., 2007;Ramos and Santos, 2010). Fernandes-Silva et al. (2016) found olive trees have a near-isohydric behavior with a tendency to maintain a constant root-toleaf water gradient. ...
Under field conditions, this study investigated the influence of the irrigation amount on olive root morphology and spatial distribution. Soil samples were taken with an auger at distances of 30, 60, and 90 cm from the tree trunks in four directions. The roots were analyzed using an Epson Twain Pro root scanning system. The results indicated that under different irrigation treatments, the indicators of root morphology of different varieties showed different responses to the irrigation amount. The root length density (RLD), root surface area (RSA), and root volume (RV) of Arbosana first increased with increasing irrigation amount but then decreased; however, those of Arbequina monotonically increased with increasing irrigation amount. The root average diameter of the two varieties was inversely proportional to the irrigation amount. In the vertical dimension, the RLD and RSA of each treatment decreased with increasing soil depth and were mainly distributed in the surface soil (0–20 cm in depth). The RLD and RSA in the vertical direction (VD) of the drip irrigation belt were higher than those of the belt in the parallel direction (PD), and the range was 12% to 86%. Compared with the roots of the 0- to 20-cm soil layer, the roots of the 20- to 40-cm and 40- to 60-cm soil layers were more influenced by the irrigation amount. Horizontally, the RLD and RSA decreased with increasing radial distance. The 30-cm radial area contained most roots, the proportion of roots in this region increased with increasing irrigation capacity. The influence of irrigation quantity in the PD of the drip irrigation belt was greater than that in the VD. The results suggest that irrigation does not change the root spatial distribution pattern but does promote root growth. The two varieties had different responses to irrigation. In terms of soil moisture levels after irrigation, 75% of field capacity is appropriate for ‘Arbosana’, whereas 100% is advisable for ‘Arbequina’. To improve water use efficiency, moisture should be irrigated within the 30-cm radial distance from the trunk, and irrigation depth is not easy to more than 20 cm. This study provides a scientific basis for the efficient water management of olive trees. © 2017, American Society for Horticultural Science. All rights reserved.
... These sensorial properties are very intense in the oil produced from drought-stressed trees, and they are generally found to be unpleasant by consumers. Irrigation can influence the content of biophenols in olive oil, and consequently its sensory properties (Motilva et al. 2000;Tovar et al. 2001;Romero et al. 2002;Gómez-Rico et al. 2007;Dag et al. 2008). ...
Due to increased occurrence and intensity of agricultural droughts in humid Mediterranean regions, monitored irrigation is becoming an increasingly inevitable element of agricultural practice. To determine the impact of different irrigation regimes on olive tree (Olea europaea L.) growth and crop yield, and of the olive oil production and biophenol content, a 3-year study was conducted in an olive grove located in a relatively humid region of southwestern Slovenia. The mean olive production from trees under full irrigation (replacement of 100% crop evapotranspiration) was significantly higher than those that were only rain fed or were under deficit irrigation (replacement of 33 and 66% crop evapotranspiration). There were no significant differences in total biophenol contents of the olive oil across these irrigation treatments. These irrigation effects can be explained according to the levels of precipitation throughout the growing season. Despite the positive effects of rainfall on these parameters, the mean olive oil yield of the rain-fed olives was about 30% lower than that for the deficit irrigation treatments.
... On the other hand, it has been suggested that internal damage, and also the loss of quality in the extracted oils, may be explained by different physiological responses of fruits after harvest by grape straddle machines (Yousfi et al., 2012;Morales-Sillero et al., 2015;Morales-Sillero and García, 2015). Internal damage in fruits could also explain the loss of quality in oils from fruits harvested by trunk-shakers in intensive conditions (Dag et al., 2008). However, to our knowledge no study has described internal damage in fruits harvested by any type of harvester. ...
This study describes fruit damage of the Manzanilla de Sevilla and Manzanilla Cacereña cultivars under super high-density conditions at morphological and histological levels. Fruits were harvested both manually and by a grape straddle harvester. Dark spots and tissue ruptures were found throughout the mesocarp of both cultivars, particularly after mechanical harvesting. Quantitative traits previously described by our group were used to evaluate internal damage. ‘Manzanilla de Sevilla’ always showed the highest total damaged area in the mesocarp, as well as the highest sum of the areas of all of the tissue ruptures, and number of tissue ruptures intersected by the second circumferential arc. Tissue ruptures in the exocarp were also observed in this cultivar as well as a general increase in this type of damage over time (from 2 to 24 h after harvesting). Investigation of the cuticle and epidermal cell dimensions in undamaged fruits shows that ‘Manzanilla Cacereña’ presents a thicker cuticle and a greater cuticle area per epidermal cell than ‘Manzanilla de Sevilla’. The relationship between these results and the different bruising susceptibilities of the two cultivars studied is discussed.
... In olive trees of cultivar ' Arbequina' subjected to four irrigation management approaches, at different stages of fruit development, the highest content of total phenols, hydroxytyrosol acetate, 3,4-DHPEA-EDA, p-HPEA-EDA, 3,4-DHPEA-EA, o-diphenols, tyrosyl elenolate (p-HPEA-EA), and total secoiridoids was detected in trees stressed from the end of fruit drop to the end of July (Del Campo and García, 2013). Fruit ripening and irrigation treatments have been also found to induce considerable variation in the concentrations of secoiridoid derivatives of hydroxytyrosol and tyrosol in VOO of cultivars 'Cornicabra' (Gümez-Rico et al., 2006), 'Souri' (Dag et al., 2008), and 'Cipressino' (Martinelli et al., 2013). Similar results were found in trees of cultivar 'Leccino, ' where the highest content of phenolic compounds was detected in rain-fed (RF) trees, although the transcript level of the PAL gene did not differ among the water regimes (Martinelli et al., 2012). ...
Olive fruits and oils contain an array of compounds that contribute to their sensory and nutritional properties. Phenolic compounds in virgin oil and olive-derived products have been proven to be highly beneficial for human health, eliciting increasing attention from the food industry and consumers. Although phenolic compounds in olive fruit and oil have been extensively investigated, allowing the identification of the main classes of metabolites and their accumulation patterns, knowledge of the molecular and biochemical mechanisms regulating phenolic metabolism remains scarce. We focused on the role of polyphenoloxidase (PPO), peroxidase (PRX) and β-glucosidase (β-GLU) gene families and their enzyme activities in the accumulation of phenolic compounds during olive fruit development (35–146 days after full bloom), under either full irrigation (FI) or rain-fed (RF) conditions. The irrigation regime affected yield, maturation index, mesocarp oil content, fruit size, and pulp-to-pit ratio. Accumulation of fruit phenolics was higher in RF drupes than in FI ones. Members of each gene family were developmentally regulated, affected by water regime, and their transcript levels were correlated with the respective enzyme activities. During the early phase of drupe growth (35–43 days after full bloom), phenolic composition appeared to be linked to β-GLU and PRX activities, probably through their effects on oleuropein catabolism. Interestingly, a higher β-GLU activity was measured in immature RF drupes, as well as a higher content of the oleuropein derivate 3,4-DHPEA-EDA and verbascoside. Activity of PPO enzymes was slightly affected by the water status of trees during ripening (from 120 days after full bloom), but was not correlated with phenolics content. Overall, the main changes in phenolics content appeared soon after the supply of irrigation water and remained thereafter almost unchanged until maturity, despite fruit growth and the progressive decrease in pre-dawn leaf water potential. We suggest that enzymes involved in phenolic catabolism in the olive fruit have a differential sensitivity to soil water availability depending on fruit developmental stage.
... Apparently conflicting results also emerged concerning the effect of water availability, confirming the results obtained in previous studies. 29,40 In the first year of the present study, higher values of peroxide were measured in oils obtained from FI trees, although any differences disappeared during the second year. Other studies observed differences in peroxide values of oils obtained from trees subjected to different irrigation treatments, although the results were not consistent between the 2 years of study. ...
Background:
Fruit development and oil quality in Olea europaea L. are strongly influenced by both light and water availability. In this study the simultaneous effects of light environment and irrigation on fruit characteristics and oil quality were studied in a high-density orchard over two consecutive years. Olive fruits were harvested from three canopy positions (intercepting about 64%, 42% and 30% of above canopy radiation) of fully-productive trees subjected to full, deficit or complementary irrigation.
Results:
Fruits receiving 61-67% of above canopy radiation showed the highest fruit weight, mesocarp oil content and maturation index, whereas those intercepting only 27-33% showed the lowest values. Palmitoleic and linoleic acids increased in oils obtained from fruits exposed to high light levels, whereas oleic acid and the oleic-linoleic acid ratio decreased. Neither canopy position nor irrigation affected the K232 , K270 , ∆K, and lignans concentration in virgin olive oils (VOOs). Total phenols, 3,4-DHPEA-EDA and p-HPEA-EDA increased in VOOs produced from fruits harvested from the top of the canopy, whereas full irrigation decreased total phenols and 3,4-DHPEA-EDA concentrations with respect to the complementary irrigation treatment.
Conclusion:
Light and water availability are not only crucial for tree productivity, but they also clearly affect olive oil quality.
... Production geographic area, marked by soil factors, altitude and latitude, and climatic conditions during the year, has a significant impact on the properties and chemical composition of virgin olive oils [7,17,[20][21][22][23]. Studies of environmental factors impact on VOOs chemical composition have quite different results, due to the fact that all these factors together interact and as result varieties behave differently in different agroclimatic conditions. ...
Virgin olive oil (VOO) represents a rich source of natural antioxidants, with tocopherols as the most effective group of lipophilic, phenolic antioxidants. α-Tocopherol represents more than 95% of the total tocopherols in virgin olive oil, and it possesses the highest biological activity among members of the vitamin E family. Content and composition of the tocopherols of virgin olive oil depend on several agronomic factors, as well as olive processing and oil storage conditions.
In this chapter, the tocopherol homologue activity in virgin olive oil and the biological importance are discussed. Research work is reported on the tocopherol content and composition variability in virgin olive oils of the most widespread Croatian cultivar “Oblica” and Italian cultivar “Leccino.” Factors studied such as year, growing area and olive fruit ripening and their influence on the tocopherol content and composition of virgin olive oils are discussed. The effect of filtration of the oil and storage conditions on tocopherols are also examined.
... High irrigation rates are associated with decreased oil quality Ben-Gal et al. 2008;Dag et al. 2008). Collectively, these earlier studies suggest moderate water stress results in maximum yields of high-quality oil while limiting vegetative growth. ...
The effects of multiple irrigation regimes, on the relationships among tree water status, vegetative growth and productivity within a super-high density (SHD) ‘Arbequina’ olive grove (1950 tree/ha) were studied for three seasons (2008-2010). Five different irrigation levels calculated as percentage of Crop Irrigation Requirement (CIR) using FAO procedures (Allen et al. 1998) were imposed during the growing season.
Periodically during the growing season, daytime stem water potential (ΨSTEM), inflorescences per branch, fruits per inflorescence and shoot absolute growth rate were measured. Crop yield, fruit average fresh weight and oil polyphenol content were measured after harvest.
The midday ΨSTEM ranged from -7 to -1.5 MPa and correlated well enough with yield efficiency, crop density and fruit fresh weight to demonstrate its utility as a precise method for determining water status in SHD olive orchards.
The relationships between midday ΨSTEM and the horticultural parameters suggest maintaining ΨSTEM values between −3.5 and −2.5 MPa are optimal for moderate annual yields of good quality oil. Values below -3.5 MPa reduced current season productivity while values over -2.5 MPa were less effective in increasing productivity, reduced oil quality and produced excessive crop set that strongly affected vegetative growth and fruit production the following season.
On the basis of the result given here irrigation scheduling in the new SHD orchards should be planned on a two-year basis, and corrected annually based on crop load. Collectively these results suggest that deficit irrigation management is a viable strategy for SHD olive orchards.
... It is possible to adopt different growing practices during olive production or to employ different working conditions during oil extraction to enhance the content of volatile and/or phenolic components and also to determine the quality of the oil. In fact, a sufficient irrigation of the grove, an early harvest of the fruits, a non-stressful olive pressing, a reduced temperature and a more prolonged kneading phase should be adopted to produce an oil characterized by a high content of volatile components and by a more pronounced aroma as well (Dag et al., 2008). To increase the phenolic fraction and then to produce an oil characterized by greater bitterness and stability, it is necessary to ensure a reduced irrigation of the olive trees, the utilization of less ripe fruits, the use of more efficient crushers able to break also the pit and a kneading phase carried on at a higher temperature for a reduced time. ...
The use of solid carbon dioxide (dry ice) as a cryogen is widespread in the food industry to produce high quality wines, rich in color and perfumes. The direct addition of carbon dioxide to olives in the solid state before milling represents a fundamental step which characterizes this innovative extraction system. At room temperature conditions solid carbon dioxide evolves directly into the air phase (sublimation), and the direct contact between the cryogen and the olives induces a partial solidification of the cellular water inside the fruits. Since the volume occupied by water in the solid state is higher than that in the liquid state, the ice crystals formed are incompatible with the cellular structure and induce the collapse of the cells, besides promoting the diffusion of the cellular substances in the extracted oil, which is thus enriched with cellular metabolites characterized by a high nutraceutical value. Furthermore, a layer of CO2 remains over the olive paste to preserve it from oxidative degradation. The addition of solid carbon dioxide to processed olives induced a statistically significant increase in oil yield and promoted the accumulation of tocopherols in the lipid phase, whereas a not significant increase in the phenolic fraction of the oil occurred.
Sarcopoterium spinosum is a medicinal plant, presenting glucose-lowering properties. The study aimed to identify the active components and their mechanisms of action. Bioguided fractionation was utilized to isolate the active molecules, followed by NMR and HRESI MS for their identification and structural elucidation. Binding to the insulin receptor (IR) and activation of the receptor were measured in vitro. Glucose-lowering effects were validated in vivo. A novel procyanidin trimer, named sarcocyanidin A (1, catechin-(4α-8)-epicatechin-(4β-8)-epicatechin), was identified. Sarcocyanidin A (1) activated insulin signaling in CHO-IR and L6 myotubes, while the IR inhibitor abolished this effect. IR autofluorescence and cell-based thermal shift assays indicate a direct interaction of sarcocyanidin A (1) with IR. Sarcocyanidin A (1) also activated insulin signaling and reduced blood glucose in mice. Sarcocyanidin A, a novel procyanidin trimer, mediates at least part of the antidiabetic properties of SSE, through activation of IR.
Ürün verim tahmini, ürün hasadı ve pazarlama stratejilerinin oluşturulması için çok önemli bir rol oynamaktadır. Son yıllarda , birçok tarımsal üründe verimi tahmin etmek için bilgisayarla görme ve derin öğrenme teknikleri çalışmaları yapılmaktadır. Ürünlerin dal üzerinden tam olarak ayrılması ürün verim tahminini doğrudan etkilemektedir. Bu çalışmada ağaç veya fide üzerinde ürünlerin yerlerini tespit ederek ürün verim tahminini kolaylaştıracak derin öğrenme modeli gerçekleştirilmiştir. Materyal olarak zeytin seçilmiştir. Derin öğrenme tabanlı zeytin tespiti yapılmıştır. Modelin algoritması, zeytin tespiti için olive adlı nesne sınıfından oluşmaktadır. Eğitim ve test omurgası YOLOv5(nano-small-medium ve large) modelleridir. Oluşturan modellerin tüm metrik değerleri incelenmiştir. En başarılı model YOLOv5s algoritmasıyla, 640x640 boyutundaki görsellerin 15 Batch, 115 Epoch ile eğitilmiş model olduğu görülmüştür. Model değerleri sonuçları “metrics/precision”, “metrics/recall”, “metrics/mAP_0.5” ve “metrics/mAP_0.5:0.95” olarak incelenmiştir. “YOLOv5 small” modelinin metrik verilerinin diğer modellerle kıyaslandığında daha yüksek olduğu tespit edilmiştir. Başarı oranı 115 epoch için F1 score %85.18,presicion %95.63,recall %84.24, mAP %72.8’dir. Buradan “Model 2”nin robotik zeytin hasadında zeytinin toplanmasında kullanılacak en iyi tespit modeli olduğu anlaşılmıştır.
Research has shown that moderate regulated deficit irrigation (RDI) can enhance the fruit and oil yield of olive trees in Mediterranean conditions. However, there is limited research on the effects of deficit irrigation on olive trees in marginal regions. To address this, a study was conducted on the Zard olive cultivar over two consecutive years. Six irrigation regimes were tested, including control (C) (100% ETc) during the growing season, sustained deficit irrigation (SDI1) at 75% ETc throughout the growing season, regulated deficit irrigation (RDI1) at 75% ETc from 4 to 9 weeks after full bloom, sustained deficit irrigation (SDI2) at 50% ETc throughout the growing season, regulated deficit irrigation (RDI2) at 50% ETc from 4 to 9 weeks after full bloom, and regulated deficit irrigation (RDI3) at 50% ETc 2 weeks before harvest. The results showed that sustained and regulated deficit irrigation negatively impacted flower number and perfect flowers in inflorescence, except for RDI3. The study found that the fruit set was not significantly impacted by the irrigation treatments RDI1 and RDI3 compared to the control. However, the irrigation treatment of SDI2 resulted in the most significant reduction in both fruit weight and pulp-to-pit ratio. Fruit yield and oil content did show significant differences among all treatments. Overall, the study showed a 25% reduction in water usage during the 4 to 9 weeks after flowering or 2 weeks before harvesting did not significantly affect fruit yield compared to the control treatment. A minor reduction in applied water (RDI1 and RDI3) is recommended for semiarid regions (excluding Mediterranean regions) to achieve high fruit and oil content.
The advancement of computer science has encouraged engineers and researchers to use simulation techniques for the design and evaluation of agricultural machinery and food industry equipment. The finite element method (FEM) is a numerical method used to solve complex problems, such as impact phenomena, in harvest and post-harvest processes. In this paper, the FEM procedure, elastic-plastic and viscoelastic properties of agricultural products, quasistatic and dynamic tests, and the stress generated during the post-harvest process has been reviewed. In addition, the application of FEM for the analysis of bruise volume and susceptibility is described. Finite element analysis is an appropriate method to reduce negative effects on agriculture products caused by harvesting and post-harvesting machines. This paper is intended for researchers interested in the design, optimisation, and development of harvesting or post-harvesting equipment for achieving the best final quality of the fruit.
This study was carried out during two successive seasons of 2008 and 2009 on mature olive trees cv. Manzanillo. In this study, nine irrigation treatments were used during five months from May to December in an expected "On" year (2008) and an expected "Off" year (2009).The treatments were: No irrigation (rain fed), 60mm once /month, 80mm once/ month, 100mm once/ month, 120mm once/ month, 30 mm twice/ month, 40 mm twice /month, 50 mm twice /month and 60 mm twice/ month. The rainfall in the experimental region recorded 92.0 and 115.0 mm/year in 2008 and 2009, respectively. The result showed that the higher level of irrigation water (60 mm twice/month) during May to September was more effective in increasing the productivity and fruit quality of Manzanillo olive in both seasons. Also leaf nitrogen, potassium, calcium and iron content were increased under such conditions.
Global warming is predicted to have a negative effect on plant growth due to the damaging effect of high temperatures. In order to address the effect of high temperature environments on olive oil yield and quality, we compared its effect on the fruit development of five olive cultivars placed in a region noted for its high summer temperatures, with trees of the same cultivars placed in a region of relatively mild summers. We found that the effects of a high temperature environment are genotype dependent and in general, high temperatures during fruit development affected three important traits: fruit weight, oil concentration and oil quality. None of the tested cultivars exhibited complete heat stress tolerance. Final dry fruit weight at harvest of the 'Barnea' cultivar was not affected by the high temperature environment, whereas the 'Koroneiki', 'Coratina', 'Souri' and 'Picholine' cultivars exhibited decreased dry fruit weight at harvest in response to higher temperatures by 0.2, 1, 0.4 and 0.2 g respectively. The pattern of final oil concentration was also cultivar dependent, 'Barnea', 'Coratina' and 'Picholine' not being affected by the high temperature environment, whereas the 'Koroneiki' and 'Souri' cultivars showed a decreased dry fruit oil concentration at harvest under the same conditions by 15 and 8% respectively. Regarding the quality of oil produced, the 'Souri' cultivar proved more tolerant to a high temperature environment than any other of the cultivars analyzed in this study. These results suggest that different olive cultivars have developed a variety of mechanisms in dealing with high temperatures. Elucidation of the mechanism of each of these responses may open the way to development of a variety of olives broadly adapted to conditions of high temperatures.
An increase in olive oil consumption has occurred worldwide in the last decades and has resulted in more land area being dedicated to olive orchards in several southern hemisphere countries. In order to achieve sustainable productivity under the increasing water scarcity, optimal water use is essential. Thus, a field experiment was conducted during four consecutive growing seasons (2010–2011 to 2013–2014) to evaluate olive oil quality in response to irrigation cut-off strategies applied after fruit set using midday stem water potential (Ψstem) thresholds in a super-high density olive orchard (cv. Arbequina) located in the Pencahue Valley, Maule Region, Chile. The experimental design was completely randomized with four treatments and four replicates. In treatment T1 (control), Ψstem was between −1.4 and −2.2 MPa (100% of actual evapotranspiration) throughout the season, while the T2, T3 and T4 treatments did not receive irrigation from fruit set until they reached a Ψstem threshold of approximately −3.5, −5.0, and −6.0 MPa, respectively. Once these thresholds were reached, irrigation was reestablished and maintained as T1 in all treatments until olives were harvested. Fruit oil and water content (%) at harvest were not affected by the different treatments. Free acidity was also not affected, while peroxide and extinction coefficients only showed minor differences between treatments that were within the limits established for commercial extra virgin oil quality. Total polyphenols at harvest were much higher in the water deficit treatments and showed a significant linear relationship each year with the water stress integral. The percentages of the main fatty acids were not affected by the treatments. However, they were significantly different between seasons. Sensory tests indicated that the higher total polyphenol content positively contributed to more pronounced bitter and pungent attributes of olive oil from trees with higher water deficit. Thus, the irrigation cut-off strategies evaluated at our four-year study can be an excellent management tool to both improve the oil quality of cv. Arbequina and reduce water use in super-high density orchard.
BackgroundA previous multi-locus lineage (MLL) analysis of SSR-microsatellite data of old olive trees in the southeast Mediterranean area had shown the predominance of the Souri cultivar (MLL1) among grafted trees. The MLL analysis had also identified an MLL (MLL7) that was more common among rootstocks than other MLLs. We here present a comparison of the MLL combinations MLL1 (scion)/MLL7 (rootstock) and MLL1/MLL1 in order to investigate the possible influence of rootstock on scion phenotype. ResultsA linear regression analysis demonstrated that the abundance of MLL1/MLL7 trees decreases and of MLL1/MLL1 trees increases along a gradient of increasing aridity. Hypothesizing that grafting on MLL7 provides an advantage under certain conditions, Akaike information criterion (AIC) model selection procedure was used to assess the influence of different environmental conditions on phenotypic characteristics of the fruits and oil of the two MLL combinations. The most parsimonious models indicated differential influences of environmental conditions on parameters of olive oil quality in trees belonging to the MLL1/MLL7 and MLL1/MLL1 combinations, but a similar influence on fruit characteristics and oil content. These results suggest that in certain environments grafting of the local Souri cultivar on MLL7 rootstocks and the MLL1/MLL1 combination result in improved oil quality. The decreasing number of MLL1/MLL7 trees along an aridity gradient suggests that use of this genotype combination in arid sites was not favoured because of sensitivity of MLL7 to drought. Conclusions
Our results thus suggest that MLL1/MLL7 and MLL1/MLL1 combinations were selected by growers in traditional rain-fed cultivation under Mediterranean climate conditions in the southeast Mediterranean area.
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.
Phenolic compounds of peel, pulp and seed of olive fruit, their distribution in oil and byproducts during oil mechanical extraction and the endogenous enzymes that can catalyse phenolic modifications during processing were studied. All the constitutive parts of the fruit contained secoiridoids and phenyl-acids, while luteolin-7-glucoside and rutin were found only in the peel. Crushing led to a strong decrease of secoiridoids glucoside and increase of aglycon derivatives. Verbascoside did not vary significantly. A noticeable amount of paste phenols (>96%) was found in by-products, oil did not contain either secoiridoid glycosides or verbascoside but showed high concentration of secoiridoid aglycons. Malaxation reduced phenols concentration in oil and in by-products. High levels of glycosidase and oxidoreductase activities were observed in pulp and seed.
The main objective of this research was to determine the extent to which irrigation practices affect the partitioning of phenolic compounds between olive paste, pomace, olive oil and wastewater. The current paper also aimed to study the effect of technological natural micro-talc (NMT) addition during the oil extraction process on the partitioning of the phenolic compounds between solid and liquid phases. The results obtained in this study showed that irrigation applied to olive trees let to a considerable decrease in the phenol content of the olive paste. The water status of the trees affected the phenol synthesis in the olive fruit, and consequently the phenol content of the olive paste, more than the partitioning of the phenolic compounds during the olive oil extraction process. The most remarkable point of the phenol partitioning was related to the simple phenols. While in the samples from non-irrigated trees the greater proportion of these phenols partitioned into the pomace, in samples from irrigated trees most of them were lost in the wastewater. After comparison of the results obtained from the experiments with and without NMT addition, it was concluded that the use of that co-adjuvant did not significantly alter either the phenolic profile of the oil phase obtained or the content of the individual phenolic compounds.
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 main objective of this research was to determine the extent to which irrigation practices affect the partitioning of phenolic compounds between olive paste, pomace, olive oil and wastewater. The current paper also aimed to study the effect of technological natural micro-talc (NMT) addition during the oil extraction process on the partitioning of the phenolic compounds between solid and liquid phases. The results obtained in this study showed that irrigation applied to olive trees let to a considerable decrease in the phenol content of the olive paste. The water status of the trees affected the phenol synthesis in the olive fruit, and consequently the phenol content of the olive paste, more than the partitioning of the phenolic compounds during the olive oil extraction process. The most remarkable point of the phenol partitioning was related to the simple phenols. While in the samples from non-irrigated trees the greater proportion of these phenols partitioned into the pomace, in samples from irrigated trees most of them were lost in the wastewater. After comparison of the results obtained from the experiments with and without NMT addition, it was concluded that the use of that co-adjuvant did not significantly alter either the phenolic profile of the oil phase obtained or the content of the individual phenolic compounds.
The tissues of the Victoria plum tree (Prunus domestica var. Victoria) were analysed for total phenols, leuco-anthocyanins and flavanols at intervals during the growing season. At all times, the methanol extracts from the smaller leaves contained smaller amounts of phenolic constituents although the changes paralleled those in the larger leaves. The proportions of leuco-anthocyanins and flavanols to total phenols were less in the smaller leaves. The amounts of the three phenolic constituents increased rapidly until the leaves reached maximum size and then decreased. Leaves taken from the shady side of the tree contained less phenolic constituents and a lower proportion of leuco-anthocyanins. The analysis of shaded leaves suggested that the synthesis and metabolism of leuco-anthocyanins were influenced by light. Leaves from unhealthy trees contained smaller amounts of phenolic constituents and the leuco-anthocyanins were a much smaller fraction. The amount of the phenols in a plum fruit increased with its growth and the Zeuco-anthocyanins in the skin decreased when it reddened. The phenolic constituents in the woody tissues showed a much smaller variation than the leaves, and the outer bark, phloem and cambium contained more of them than the outer and inner sapwoods and the heartwood.
This study evaluated the effects of different regulated deficit irrigation (RDI) strategies applied to olive ( Arbequina cultivar) trees on the qualitative and quantitative parameters of the resulting oil during the maximum evaporative demand period for three consecutive crop seasons. Quality indices, fatty acid composition, pigments, colour, α‐tocopherol and phenolic contents, bitter index, oxidative stability and organoleptic properties of the oil were determined. Irrigation did not affect those parameters used as criteria for classifying olive oil in its commercial grades. Only polyphenol and o ‐diphenol contents and, consequently, the bitter index and oxidative stability were affected by the RDI strategy, with increasing values as the water applied decreased. Regulated deficit irrigation resulted in important savings in irrigation requirements without detriment to oil quality.
© 2002 Society of Chemical Industry
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
Methods for the quantitative analysis of anthocyanins, leuco-anthocyanins, flavanols and total phenols in plant tissue extracts are critically examined and suitable modifications of existing methods are described.
The response of cv. Muhasan trees and its fruit characteristics to a 50% regulated deficit irrigation (RDI) was studied. The general response to the reduced irrigation was relatively small. However, the schedule of water application was very significant for various fruit characteristics. In the best schedule the 50% reduction in annual irrigation water reduced the oil yield over 4 years by only 12.2% and that of the fruit yield by 18.5%. The most efficient schedule was based on applying all the irrigation water after stone hardening. In lighter soils however, with lower water holding capacity or in regions with a lower rainfall diverting some of the water to the pre-bloom and fruit set period might be needed. The fruit mesocarp/endocarp (flesh/pit) ratio was dependent on the water availability during the stone hardening period. This ratio was significantly improved when water availability during the stone hardening period was reduced. The rate of oil accumulation was also affected by the irrigation schedule but was about the same in ‘on’ and ‘off’ years. Fruit growth was less affected by the irrigation schedule but most significantly by the yield load. All the affects of the irrigation schedules were more expressed in the ‘on’ years than in the ‘off’ years. No clear cut differences or consistent effects of the irrigation schedule were found on the degree of alternant bearing and mineral content of the leaves.
Research has been carried out to ascertai the effects of different processing systems on olive oil quality. Tests were performed
in industrial oil mills that were equipped with both pressure and centrifugation systems. Results show that oils extracted
from good-quality olives do not differ in free fatty acids, peroxide value, ultraviolet absorption and organoleptic properties.
Polyphenols ando-diphenols contents and induction times are higher in oils obtained from good-quality olives by the pressure system because
it does not require addition of water to the olive paste. The centrifugation system requires the addition of warm water to
the olive paste and helps to obtain oils with a lower content of natural antioxidants. Oils obtained from poorquality or from
ripe olives in continuous centrifugal plants are lower in free fatty acids than those obtained by the pressure system.
The oil content in olive fruits of different sizes from irrigated high (‘on’) and low (‘off’) yielding olive trees of cvs. Barnea and Manzanillo were determined at different stages of fruit maturation. The fruit size range at all stages of maturation is significantly higher on low yielding ‘off’ trees than on high yielding ‘on’ trees. The oil content in the mesocarp of olive fruits is not yield or fruit size dependent. Only in young fruit at early stages of green maturation is the oil content in the fruit’s mesocarp higher in the low yielding ‘off’ trees than in the high yielding ‘on’ ones. At full black maturation, the relative oil content in the mesocarp is uniform in all fruits regardless of size and level of yield. The final oil content in the fruits is dependent on the interaction between the growing conditions and the genetic potential of the variety. The amount of oil produced by an olive tree seems to be regulated mainly by the amount of mesocarp available for oil biosynthesis. The ratio of mesocarp/endocarp (flesh/pit) within each cultivar is strongly related to fruit size, and thus affected by high and low yields.
The olive tree is generally grown under rain-fed conditions. However, since the yield response to irrigation, even with low amounts of water, is great there is increasing interest in irrigated agriculture. The main goal of this study was therefore to optimize sustainable irrigation conditions in the Cornicabra olive cultivar grown in Castilla-La Mancha, a region where the aquifers are over-exploited, and to study the effect of different irrigation strategies on the composition and quality of Cornicabra virgin olive oil. Different irrigation treatments, based on regulated deficit irrigation (RDI), 100% ETc, 125% ETc, and rain-fed as control, were applied to a traditional olive orchard (cv Cornicabra) in a randomized complete-block design with four replications. The average olive production of the trees grown under rain-fed conditions was much lower, about 35%, than that obtained by applying the different irrigation treatments studied, between which practically no difference were observed. The total phenol content, which affected the sensory bitterness in the oils, decreased significantly as the amount of supplied water increased. This is very relevant, as high levels of phenols, typical of Cornicabra virgin olive oils, may decrease consumer preference. Notably, one of the RDI strategies produced olive oil similar in composition and quality to that obtained by 100% ETc but with reduced water usage.
This work reports the results of a study carried out in an intensive monocone orchard of Olea europaea L. cv. Kalamata, a dual purpose (olive oil and table olives) variety, to investigate the influence of different irrigation regimes on productivity and quality of olives and olive oil. Irrigation regimes did not affect the sugar composition of the fruit, while the content of the phenolic compounds varied. In the water stress condition, olive fruit showed an higher cuticular thickness to prevent the loss of water and nutrients. Olive oil composition did not change with irrigation, except for the total phenols, which decreased. A restitution of 66% of crop evapotranspiration (ETc) was sufficient to achieve good yields, while higher water volumes (100% of ETc) gave little additional yield increases.
An experiment was performed in a low-density olive orchard (69 trees ha−1) to study the recovery from water stress of olive trees under different irrigation managements. The effect of water stress on oil quality was also examined. The trees were subjected to one of four irrigation treatments: rain-fed conditions, irrigation with either 100% or 125% of the crop evapotranspiration (ETc) level, or a deficit treatment in which only 60 mm of water were provided (at different times depending on the weather and phenological stage of the crop). The irrigation water in the deficit treatment was some 43% of the water applied in the 125% treatment. Plant water relations were determined periodically by measuring the water potential of covered leaves and the stomatal conductance at midday. The trees in the water deficit and rain-fed treatments rapidly recovered from water stress after receiving irrigation water or autumn rainwater, respectively, reaching the condition of the fully irrigated trees. However, stomatal conductance took longer to recover. Recovery at mid-summer in the deficit treatment was related to the amount of water in the soil; in autumn, however, this relationship was not so clear in rain-fed trees. The effect on oil quality was recorded in terms of the total concentration of phenolic compounds (TP). This was strongly related to the water stress integral, suggesting that the effect of irrigation on this variable occurs year-round and not just during the oil accumulation phase. Thus, even with low doses of water it should be possible to significantly reduce the TP concentration. Since recovery from water stress is rapid when irrigation is concentrated in the second half of summer, such an irrigation regimen might allow efficient use of the limited amounts of water available in central Spain.
To review the evidence that the traditional Mediterranean diet is associated with longevity.
Elderly persons of both genders in Greece, Spain, Denmark and Australia studied by different groups of investigators.
Adherence to the principles of the Mediterranean diet was operationalised through a score devised a priori, and study participants were followed up until death or the end of the study. Proportional hazard models were used.
Closer adherence to the Mediterranean diet was associated with a significant decrease in general mortality among the elderly persons studied.
The Mediterranean diet is positively associated with longevity among the elderly. If the assumption holds that there is no interaction between age and diet with respect to general mortality, it can be inferred that the traditional Mediterranean diet represents a healthy nutritional pattern.
This study investigated the effect of both the degree of ripening of the olive fruit and irrigation management-rain-fed, two different regulated deficit irrigations (RDI), the method proposed by the Food and Agriculture Organization of the United Nations (known as FAO), and 125 FAO (125% FAO)-on the phenolic and volatile composition of Cornicabra virgin olive oils obtained during two crop seasons. Secoiridoid phenolic derivatives greatly decreased upon increase of both irrigation and ripening, for example, the 3,4-DHPEA-EDA content decreased from 770 to 450 mg/kg through fruit ripening under rain-fed conditions and from 676 to 388 mg/kg from rain-fed conditions to FAO irrigation treatment (at a ripeness index of approximately 4). Moreover, secoiridoid derivatives of hydroxytyrosol decreased more than those of tyrosol. The levels of major volatile components decreased in the course of ripening but were higher in irrigated olive oils: for example, the E-2-hexenal content ranged between 4.2 and 2.6 mg/kg (expressed as 4-methyl-2-pentanol) over fruit maturation under rain-fed conditions and between 8.0 and 3.5 mg/kg under FAO scheduling. It is important to note that where water was applied only from the beginning of August (RDI-2), when oil begins to accumulate in the fruit, the resulting virgin olive oil presented a phenol and volatile profile similar to those of the FAO and 125 FAO methods, but with a considerable reduction in the amount of water supplied to the olive orchard.
The article reviews the available information on the start of fruit tree cultivation in the Old World. On the basis of (i) evaluation of the available archeological remains and (ii) examination of the wild relatives of the cultivated crops, it was concluded that olive, grape, date, and fig were the first important horticultural additions to the Mediterranean grain agriculture. They were most likely domesticated in the Near East in protohistoric time (fourth and third millennia B.C.) and they emerge as important food elements in the early Bronze Age.
Domestication of all four fruit trees was based on a shift from sexual reproduction (in the wild) to vegetative propagation of clones (under domestication). Olive, grape, date, and fig can be vegetatively propagated by simple techniques (cuttings, basal knobs, suckers) and were thus preadapted for domestication early in the development of agriculture.
The shift to clonal propagation placed serious limitations on selection and on fruit set under cultivation. We have examined the consequences of this shift in terms of the genetic makeup of the cultivars and traced the various countermeasures that evolved to ensure fruit set.
Finally, it was pointed out that in each of these classic fruit trees we are confronted with a variable complex of genuinely wild types, secondary weedy derivatives and feral plants, and groups of the domesticated clones, which are all interfertile and interconnected by occasional hybridization. It was concluded that introgression from the diversified wild gene pool facilitated the rapid buildup of variation in the domesticated crops.
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