Table Olive Cultivars Research Articles

Chemical and Enzymatic Characterization of Leaves from Spanish Table Olive Cultivars

Olive leaves are generated as by-products in the olive industry and contain substances with biological properties that provide health benefits. Although these compounds have been characterized in many leaves from olive cultivars devoted to olive oil extraction, few data are available on leaves from the processing of table olives. In this study, the concentration of polyphenols, triterpenic acids, sugars and enzymatic activities (polyphenol oxidase, peroxidase, β-glucosidase and esterase) were determined in the leaves of the olive tree (Olea europaea L.) of cvs. Aloreña, Cacereña, Empeltre, Hojiblanca, Manzanilla, Verdial, Gordal and Morona. The mean total phenolic content in olive leaves reached 75.58 g/kg fresh weight, and oleuropein was the main polyphenol identified (89.7-96.5%). The main triterpenic acid identified was oleanolic acid, and the main sugar was mannitol, with mean values of 15.83 and 22.31 g/kg, respectively. However, the content of these biocompounds was influenced by the type of cultivar and the orchards of origin. The highest oleuropein content was found in the Manzanilla variety, while the Gordal had the highest triterpene and mannitol content. In particular, the phenolic content could also be affected by endogenous enzymatic activities. High polyphenol oxidase, peroxidase and β-glucosidase activity and low esterase activity were detected, compared to the fruit. Similar to the phenolic compounds, enzymatic activities varied with the harvesting season. The lowest phenolic content corresponded to the highest polyphenol oxidase activity detected during spring. The rest of the enzymatic activities also varied throughout the year, but no common trend was observed.

Growth Development, Physiological Status and Water Footprint Assessment of Nursery Young Olive Trees (Olea europaea L. ‘Konservolea’) Irrigated with Urban Treated Wastewater

Application of urban treated wastewater (TWW) has been practiced globally as an alternative irrigation water source in areas where access to safe and abundant freshwater is limited. Water footprint (WF) has been employed over the last decades as a tool for the assessment of the sustainable management of water resources. In the present study, the suitability of TWW for the irrigation of nursery young olive trees (Olea europaea L. ‘Konservolea’), one of the main table olive cultivars in Greece, the second global table olive exporter, was tested and compared to tap water irrigation and application of zeolite on soil. Plant growth and physiological parameters and stress indicators were measured. Additionally, a WF assessment was performed, distinguishing TWW from freshwater (blue water) resources in order to examine the possibility of minimizing the environmental impact through the limitation of freshwater use. Plants irrigated with TWW performed better in most of the growth and physiological parameters measured compared to the other treatments. Stress indicators revealed that TWW did not induce any additional stress. TWW could be used as an irrigation water source for young olive trees for at least a short period during their growth as a safe and sustainable alternate of blue water resources. Additionally, the WF assessment showed that the application of TWW could be a significant blue water saving measure.

Effects of water scarcity and salinity on the anatomy of the Tunisian table olive cultivar ‘Meski’

The table olive cultivar ‘Meski’ was subjected to two stresses related to water, scarcity, and salinity. Anatomical adaptations of leaves, stems and roots were studied and compared, to value the water use efficiency of the tree. Two stress levels were adopted corresponding to moderate and severe levels. Thus, the trees behaviour was influenced by the stress type and intensity. The aerial part of the trees showed more adaptation modes than the underground part. Under both stresses, plants have fortified the protection of the leaf tissues by developing upper envelope and multiplying the trichomes. Plants reinforced the support tissues by multiplying the collenchyma and sclereids, and have amplified the transport tissues by enhancing vascularity through multiplying the number of conductive vessels. However, different behaviours seemed to be specific to each stress such an enlargement of liber and reduction of wood in the drought stress and a restriction of liber and wood tissues in salt stress. Additionally, a retraction of the palisade parenchyma and an extension of the spongy parenchyma in drought stress inversely to salt stress were noted. In the treated stems and roots, development of stomata, suber, pericyclic fiber and liber, and a restriction of wood especially in severe stress were observed. The plants developed important changes in moderate stresses; however, in the severe, the plants seemed to be stressed, by presenting no significant changes relatively to the control.

Industrial Processing of Algerian Table Olive Cultivars Elaborated as Spanish Style.

Olives from the Sigoise, Verdale, and Sevillana cultivars were elaborated as Spanish-style table olives by four Algerian factories, and the quality and food safety of the industrial table olives have been studied by the analysis of physicochemical and microbiological parameters. Differences were observed between the treatments carried out by the different factories throughout the manufacturing process, especially during the washing stage, but no significant differences were found between the analyzed samples for the concentration of sugars and polyphenols. The final pH values reached at the end of fermentation ranged between 5.04 and 4.27, and the titratable acidity was above 0.4% for all samples. Lactic and acetic acids were produced in mean concentrations of 0.68% and 0.21% as a result of lactic acid bacteria (LAB) and yeast metabolism, respectively. However, the presence of butyric, isobutyric, and propionic acids was also detected, and was related to the growth of undesirable spoilage microorganisms, responsible for secondary fermentations. The high-throughput sequencing of bacterial DNA suggested the dominance of LAB species belonging to genera Lactiplantibacillus, Leuconostoc, Pediococcus, Oenococcus, or Enterococcus. The Enterobacteriaceae family was detected during the first days of brining and in only one sample after 120 days of fermentation. Other spoilage microorganisms were found, such as Lentilactobacillus buchneri or the Pectinatus and Acetobacter genera, capable of consuming lactic acid and these played an essential role in the onset of spoilage. The Clostridium and Enterobacter genera, producers of butyric and propionic acids, were responsible for the malodorous fermentation present in the industrial samples that were analyzed. The study concluded that the safety of the table olives analyzed was compromised by the presence of undesirable microorganisms and microbial stability was not guaranteed. The elaboration process can be improved by reducing the washing steps and the time should be reduced to avoid the loss of fermentable matter, with the goal of reaching a pH < 4.0 after the fermentation and preventing the possibility of the growth of spoilage microorganisms and foodborne pathogens.

Chemometric characterization of raw olives from important Turkish table olive cultivars Cvs. using HPLC-DAD method based on their biophenolic profiles.

In this study, raw fruits of important olive cultivars mostly used in the Turkish table (and oil) olive sector, Ayvalik, Gemlik, Domat, Memecik and Uslu, were investigated based on their biophenolic profiles by a HPLC-DAD method. Biophenolic compounds have great importance in olive processing (table and oil) technology and human nutrition physiology and are commonly found in natural products obtained from fruits and vegetables, including table olives and olive oil. Raw olive fruits samples, grown in Bornova and Kemapaşa which are the experimantal areas of Olive Research Institute (İzmir-Turkey), were harvested in different maturity stages during two corp years (2007-2008). The total phenolic content (TPC) and the simple biophenolic profile analysis of raw olive samples were carried out using UV/VIS spectroscopic and HPLC-DAD methods, respectively. It was showed that domestic olive cultivars, mostly used in table and oil technologies, exposed great differences in biophenolic profiles due to the cultivar and harvest time according to the results of this study. TPC data for all raw samples varied from1 89.8mg GAE /100g (Domat) to 421mg GAE /100g (Uslu). Hydroxytyrosol (HT) was the major phenolic compound for all raw olive samples and it varied from 58.70mg/100g (Uslu) to 27.53mg/100g (Memecik). The highest amount of tyrosol (TY) compound was found Uslu (21.23mg/100g) while Ayvalik had the lowest amount of this compound (6.13mg/100g). In this study, the raw fruits of the domestic five table cultivars were characterized and classified chemometric methods (Principal Component Analysis, PCA and Hierarchical Cluster Analysis, HCA) based on their simple phenolic compounds. Luteloin (LT) was effective on the characterization of Uslu cultivar while Gemlik was classified with the apigenin (APG). The Hydroxytyrosol (HT) was discriminative in classification of Memecik cultivar whereas the tyrosol (TY) played role in characterization of Ayvalik cultivar.

Effect of postharvest treatments of mechanically harvested 'Manzanilla' table olives on product quality

'Manzanilla', today's main table olive cultivar, is traditionally harvested manually. However, manual harvesting is becoming less economically feasible due to increasing labor costs and a shortage of workers. Consequently, we examined options for mechanical harvesting of these table olives. The 'Manzanilla' fruit skin is sensitive to bruising and damage caused by mechanical harvesting. Therefore, postharvest field (PHF) treatments were studied, to reduce the percentage of damaged fruit in the final product. The effect of PHF treatments on final product quality of mechanically harvested 'Manzanilla' table olives was studied over 6 consecutive years (2011–2016). In the first part of the study (2011–2013), a wide range of treatments was tested in 2 L containers; the most promising one seemed to be immersing the fruit in a 1 % NaOH solution immediately after harvest. Later in the study, this treatment was also tested in commercial-scale containers, with acceptable results, although there was a certain variability between years and even between different olive batches in the same year. Although the grower wishing to apply such a treatment is faced with a certain logistical challenge, it allows for the possibility of applying mechanical harvesting to 'Manzanilla', a procedure which, until now, has been considered unsuitable for this table olive cultivar.

Green Olive Browning Differ Between Cultivars.

Currently, table olives, unlike oil olives, are harvested manually. Shortage of manpower and increasing labor costs are the main incentives to mechanizing the harvesting of table olives. One of the major limiting factors in adopting mechanical harvest of table olives is the injury to fruit during mechanical harvest, which lowers the quality of the final product. In this study, we used the Israeli germplasm collection of olive cultivars at the Volcani Institute to screen the sensitivity of many olive cultivars to browning in response to injury. The browning process after induced mechanical injury was characterized in 106 olive cultivars. The proportional area of brown coloring after injury, compared to the total fruit surface area, ranged from 0 to 83.61%. Fourteen cultivars were found to be resistant to browning and did not show any brown spot 3 h after application of pressure. Among them, there are some cultivars that can serve as table olives. The different response to mechanical damage shown by the cultivars could be mainly due to genetic differences. Mesocarp cells in the fruits of the sensitive cultivars were damaged and missing the cell wall as a result of the applied pressure. The cuticles of resistant cultivars were thicker compared to those of susceptible cultivars. Finally, we showed that the browning process is enzymatic. We suggest cuticle thickness as an indicator of table olive cultivars suitable for mechanical harvest. A shift to browning-resistant cultivars in place of the popular cultivars currently in use will enable the mechanical harvest of table olive without affecting fruit quality.

Flowering, Fruiting of Two Table Olive Cultivars “Olea europaea L.” Grown in Southern Egypt

Flowering, Fruiting of Two Table Olive Cultivars “Olea europaea L.” Grown in Southern Egypt

Tunisian Table Olive Oil Traceability and Quality Using SNP Genotyping and Bioinformatics Tools.

To enhance and highlight the authentication and traceability of table olive oil, we considered the analysis of 11 Tunisian table olive cultivars based on seven SNP molecular markers (SOD, CALC, FAD2.1, FAD2.3, PAL70, ANTHO3, and SAD.1) localized in six different genes. Accordingly, we assessed the potential genotype-phenotypes links between the seven SNPs, on the one hand, and the quantitative and qualitative parameters, on the other. The obtained genotypes were analyzed with computational biology tools based on bivariate analysis, multinomial logistic regression, and the Bayesian networks modeling. Obtained results showed that PAL70 SNP marker was negatively influenced by the phenol rate (r = -0.886; p <0.001), the oxidative stability (r = -0.884; p <0.001), traducing a direct effect of the PAL70 genotype deviations on the proportion of total phenol for each variety. Additionally, we revealed a significant association of SAD.1 marker with the content of the linolenic unsaturated fatty acids (C18:3; p=0.046). Moreover, SAD.1 was positively correlated with the saturated stearic acid C18:0 (r = 0.644; p = 0.032) based on multinomial logistic regression and Bayesian networks modeling, respectively. This research work provides better understanding and characterization of the quality of Tunisian table olive and supplies a significant knowledge and data information for table olive traceability and breeding.

Morphological and histological characterization of bruising of ‘Gordal Sevillana’ table olives

'Gordal Sevillana' is one of the most important table olive cultivars. It is appreciated for its large size, and fruits are mainly intended for green processing. During harvesting, fruits can be damaged causing important losses in the final product quality. This damage known as “bruising” is characterized by darkening of both the surface and the mesocarp of the fruit due to cell rupture and enzymatic oxidation of phenolic compounds. Our group has developed a methodology to characterize and localize this damage based on morphological and histological studies after an induced impact in fruits of different table olive cultivars. This paper presents the results of the location and evolution over time of bruising damage in the cultivar 'Gordal Sevillana' using this methodology. The total damaged area was quantified in portions of mesocarp tissue of the bruised fruit by image analysis. Later, different quantitative parameters related to the number and location of the tissue ruptures were determined in histological sections of the damaged fruit mesocarp. To observe the progress over time, measurements were made at 0.5, 2 and 24 h after the impact. Our results revealed that the distribution and extent of the damaged area (bruising) in 'Gordal Sevillana' vary with respect to other previously studied cultivars. Furthermore, it was confirmed that the extent of damage increased over time.

Fruit, mesocarp, and endocarp responses to crop load and to different estimates of source: sink ratio in olive (cv. Arauco) at final harvest

Abstract The annual fluctuations in olive crop load due to alternate bearing and other factors often lead to large differences in fruit size and oil content between years at harvest. A better understanding of how fruit parameters respond to the different leaf: fruit (i.e., source: sink) ratios that occur with contrasting crop loads would provide important information for crop management. Thus, the primary objectives of this study conducted with the cv. Arauco in three growing seasons were to: 1) determine the weight and size responses of the fruit and its main tissues, mesocarp (pulp) and endocarp (pit), to crop load; and 2) obtain relationships between different estimates of the source: sink ratio versus various fruit and oil parameters. Fruit thinning was performed by hand on uniform trees with high initial crop loads four weeks after full bloom the first season to obtain different crop loads at harvest. The thinning percentages the first season were 24%, 48% and 87%, along with an unthinned control. The same trees were then monitored the following two seasons without any further thinning. Fruit were sampled at harvest each season to determine fruit and tissue weights and diameters, oil weight per fruit, and oil concentration (%). Fruit weight was reduced 30–40% by high crop loads in each growing season with the mesocarp being much more affected than the endocarp. Oil weight per fruit (−50%) showed a somewhat greater reduction than fruit weight to crop load due to both fruit diameters and fruit oil concentration being decreased at high crop loads. Fruit and tissue weights and oil weight per fruit all displayed bilinear functions versus source: sink ratio when the source was expressed as canopy volume (a surrogate for leaf area) and sink on both a fruit number and glucose equivalent (GE) basis. Source limited fruit growth at both medium and high crop loads due to limited photoassimilate availability based on the bilinear functions, and the slope of the endocarp response to source: sink ratio was 15 times less than that of the mesocarp when expressed on a GE basis. A quantitative comparison with previously published studies indicated that maximum fruit weight appears to be obtained in olive between 1–2 m2 of leaf area per kg of GE. The bilinear relationships of source: sink ratio versus fruit weight observed in this study could contribute to crop modelling, and further research concerning how and when the mesocarp and endocarp respond to crop load is needed to aid crop management in obtaining sufficient fruit size and quality for table olive cultivars.

Internal fruit damage in table olive cultivars under superhigh-density hedgerows

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 24h 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.

Changes in Total Phenol Content and Antioxidant Activity of Greek Table Olive Cultivar Amfissis during Maturation

Changes in Total Phenol Content and Antioxidant Activity of Greek Table Olive Cultivar Amfissis during Maturation

Bayesian and Phylogenic Approaches for Studying Relationships among Table Olive Cultivars.

To enhance table olive tree authentication, relationship, and productivity, we consider the analysis of 18 worldwide table olive cultivars (Olea europaea L.) based on morphological, biological, and physicochemical markers analyzed by bioinformatic and biostatistic tools. Accordingly, we assess the relationships between the studied varieties, on the one hand, and the potential productivity-quantitative parameter links on the other hand. The bioinformatic analysis based on the graphical representation of the matrix of Euclidean distances, the principal components analysis, unweighted pair group method with arithmetic mean, and principal coordinate analysis (PCoA) revealed three major clusters which were not correlated with the geographic origin. The statistical analysis based on Kendall's and Spearman correlation coefficients suggests two highly significant associations with both fruit color and pollinization and the productivity character. These results are confirmed by the multiple linear regression prediction models. In fact, based on the coefficient of determination (R 2) value, the best model demonstrated the power of the pollinization on the tree productivity (R 2=0.846). Moreover, the derived directed acyclic graph showed that only two direct influences are detected: effect of tolerance on fruit and stone symmetry on side and effect of tolerance on stone form and oil content on the other side. This work provides better understanding of the diversity available in worldwide table olive cultivars and supplies an important contribution for olive breeding and authenticity.

The influence of Zn, Fe and B applications on leaf and fruit absorption of table olive “Gemlik” based on phonological stages

Four field experiments were established at different locations to study the influence of Zn alone and combined Zn+Fe, Zn+B and Zn+Fe+B applications on leaf and fruit absorption levels by “Gemlik” table olive cultivar (Olea europea L.) trees. The treatments of every experiment were consisted of control, soil and foliar applications. Soil applied Zn did not have an effect on Zn contents of either the leaves or the fruit in each year of the experiments. Every treatments of foliar applied Zn elevated sufficiently Zn contents of the leaves. Four times foliar application of each dose should be conducted due to more evident increases in the fruit Zn contents. Foliar applications of double and triple combinations of Zn with Fe and B increased significantly Zn, Fe and B concentrations in the olive trees.

New process for production of fermented black table olives using selected autochthonous microbial resources.

Table olives represent one important fermented product in Europe and, in the world, their demand is constantly increasing. At the present time, no systems are available to control black table olives spontaneous fermentation by the Greek method. During this study, a new protocol for the production of black table olives belonging to two Italian (Cellina di Nardò and Leccino) and two Greek (Kalamàta and Conservolea) cultivars has been developed: for each table olive cultivar, starter-driven fermentations were performed inoculating, firstly, one selected autochthonous yeast starter and, subsequently, one selected autochthonous LAB starter. All starters formulation were able to dominate fermentation process. The olive fermentation was monitored using specific chemical descriptors able to identify a first stage (30 days) mainly characterized by aldehydes; a second period (60 days) mainly characterized by higher alcohols, styrene and terpenes; a third fermentation stage represented by acetate esters, esters and acids. A significant decrease of fermentation time (from 8 to 12 months to a maximum of 3 months) and an significant improvement in organoleptic characteristics of the final product were obtained. This study, for the first time, describes the employment of selected autochthonous microbial resources optimized to mimic the microbial evolution already recorded during spontaneous fermentations.

Distribution and timing of cell damage associated with olive fruit bruising and its use in analyzing susceptibility

Bruising, damage caused by impact on the fruit during harvesting, is a major limiting factor in the production of table olives and currently restricts the applicability of mechanical harvesting. Bruising is characterized by darkening of the olive fruit surface and softening of the mesocarp or pulp. It decreases final product quality and may cause consumer rejection. This paper describes and quantifies anatomical changes in the olive mesocarp (pulp) related to bruising in fresh olive fruits after an induced impact. The study assessed two harvested table olive cultivars differing in bruise susceptibility (‘Manzanilla de Sevilla’ and ‘Hojiblanca’) at two different times (4 and 24h after induced impact). Qualitative observations of tissue bruising prior and after histological analysis revealed changes in the damaged mesocarp including ruptured cells, loss of cell wall thickness, and discoloration in the damaged areas. These changes appeared greater in ‘Manzanilla de Sevilla’ than ‘Hojiblanca’, and more evident 24h after the impact. Bruising damage was quantified using eleven parameters related to the area of the damaged zone, and incidence and position of tissue ruptures. Nine of these parameters changed significantly with time, and significant differences were observed between the two cultivars studied in seven of the parameters. Three of these, the total damaged area (TDA) measured in mesocarp portions prior to histological procedure, the number of tissue ruptures in the mesocarp intersected by circumferential arc2 (located at one-fourth of the pulp thickness from the fruit exterior; Brk-arc2), and the distance from the fruit exterior) to the first found tissue rupture (D-min)), measured in histological preparations, were the most discriminating and easy to assess parameters, and are thus recommended for the evaluation of susceptibility to bruising among harvested table olive cultivars.

Behaviour of some olive accessions resulting from an olive improvement program

The olive (Olea europaea) is one of the most important oleaginous crops of the Mediterranean basin. Increased demand for olive oil creates a need for new olive varieties to help meet the requirements of the global market. Rapid technological changes in olive growing have increased interest in breeding programs and new cultivars. A breeding program aimed at selecting new dual purpose (i.e. oil and table olive) cultivars, began in Egypt in 1994. A three successive years evolution (2011, 2012 and 2013) was conducted on progenies resulted from crosses between (Koronaki x Hamed), (Manzanello x Hamed) (Picual x Hamed) and (Arbquine x Hamed). The progenies have been analyzed for some tree growth traits, growth, blooming, fruiting, fruit quality and rootability. The obtained data, concluded that some valuable selections have resulted from this study progenies No. 73, 91 and 100 for table olive, whereas progenies No. 42, 47, 71, 89 and 98 for oil besides, progenies No. 57 and 59 for dual purpose. Thereupon, it is preferable to propagate all the best selected progenies and planted in three locations, in order to evaluate their performance (i.e., tree growth, yield, fruit characteristics, oil content and oil compositions in fatty acids) in different geographical areas. It remains necessary to study quantities and qualitative traits of olive production in more detail, for the most interesting selections.

Chemical thinning of ‘Barouni’ and ‘Manzanilla’ olives with naphthalene acetic acid under South African conditions

Table olives grown in the Mediterranean-type climate of Western Cape province of South Africa are prone to alternate bearing, as elsewhere in the world. To date, South African producers have tolerated the negative effects of alternate bearing, but due to increased olive production costs, profit margins are decreasing and producers have to reduce alternate bearing. Trials were conducted to evaluate the use of naphthalene acetic acid (NAA) on ‘Barouni’ and ‘Manzanilla’, the most important green table olive cultivars grown in South Africa. NAA is used elsewhere in the world, but local research is required since the efficacy of NAA is modulated by environmental conditions and genotype. NAA decreased the fruit number per tree, thereby improving fruit size in both cultivars. Thinning did not affect return bloom in ‘Barouni’, possibly due to the low level of thinning achieved, whereas adverse climatic conditions during flower development may be to blame for the lack of return bloom in ‘Manzanilla’. Although NAA application did not affect the income per hectare, profitability may increase as harvesting costs account for roughly 50% of the input costs. Based on these results, 200 mg L−1 NAA, applied 10–15 d after full bloom, is recommended for local conditions.

Physico-chemical and microbiological characterization of spontaneous fermentation of Cellina di Nardò and Leccino table olives.

Table olives are one of the most important traditional fermented vegetables in Europe and their world consumption is constantly increasing. In the Greek style, table olives are obtained by spontaneous fermentations, without any chemical debittering treatment. Evolution of sugars, organic acids, alcohols, mono, and polyphenol compounds and volatile compounds associated with the fermentative metabolism of yeasts and bacteria throughout the natural fermentation process of the two Italian olive cultivars Cellina di Nardò and Leccino were determined. A protocol was developed and applied aimed at the technological characterization of lactic acid bacteria (LAB) and yeast strains as possible candidate autochthonous starters for table olive fermentation from Cellina di Nardò and Leccino cultivars. The study of the main physic-chemical parameters and volatile compounds during fermentation helped to determine chemical descriptors that may be suitable for monitoring olive fermentation. In both the analyzed table olive cultivars, aldehydes proved to be closely related to the first stage of fermentation (30 days), while higher alcohols (2-methyl-1-propanol; 3-methyl-1-butanol), styrene, and o-cymene were associated with the middle stage of fermentation (90 days) and acetate esters with the final step of olive fermentation (180 days).