Table Olive Production Research Articles

Current status and future challenges of table olive processing wastewater valorization

Table olive production is expanding worldwide. This production is associated with the generation of enormous amounts of polluting and difficult to handle wastewater streams. Thus, research on different technologies to decompose their organic load is currently needed. The economic benefit of the potential detoxification routes is expected to increase if processes for upgrading Table olive processing wastewaters are designed. This makes biological treatment of particular interest. The current review analyzes a relevant number of scientific studies dealing with promising technologies for biological treatment of table olive processing wastewaters from laboratory to pilot-scale systems. Concise details of the various technologies involved such as anaerobic digestion, lactic acid fermentation and fungal fermentation are determined. The most significant advances in the manufacturing of value-added products (e.g. biogas, platform chemicals, natural antioxidants) from table olive processing wastewaters through different microorganisms, bioreactor design modifications, and operational conditions are critically discussed. Future prospects of valorizing table olive wastewaters are presented.

On-field monitoring of fruit ripening evolution and quality parameters in olive mutants using a portable NIR-AOTF device

This study optimizes the application of portable Near Infrared-Acousto Optically Tunable Filter (NIR) device to meet the increasing demand for cost-effective, non-invasive and easy-to-use methods for measuring physical and chemical properties during olive fruit development. Fruits from different phenotypically cultivars were sampled for firmness, total and specific phenols detection by HPLC, total anthocyanins, chlorophyll and carotenoids detection by spectrophotometry. On the same fruits, a portable NIR device in diffuse reflectance mode was employed for spectral detections. Predictive models for firmness, chlorophyll, anthocyanins, carotenoids and rutin were developed by Partial Least Square analysis. Oleuropein, verbascoside, 3,4-DHPEA-EDA, and total phenols were used to develop a validation model. Internal cross-validation was applied for calibration and predictive models. The standard errors for calibration, cross-validation, prediction, and RPD ratios (SD/SECV) were calculated as references for the model effectiveness. The determination of the optimal harvesting time facilitates the production of high quality extra virgin olive oil and table olives.

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.

Evaluation of Two Lactic Acid Bacteria Starter Cultures for the Fermentation of Natural Black Table Olives (Olea europaea L cv Kalamon)

The production of Greek-style natural black table olives remains an empirical process relying on spontaneous fermentation despite its economic significance. For this reason producers often resort to increased NaCl concentration of the brine to secure quality of the product. In this study we employ two lactic acid bacteria Leuconostoc mesenteroides subsp. mesenteroides Lm139 and Lactobacillus pentosus DSM 16366 as starters in separate laboratory low salinity fermentations of "Kalamon" cultivar olives, processed according to the Greek-style method. L. mesenteroides subsp. mesenteroides Lm139 was previously isolated from Kalamon olives laboratory spontaneous fermentations, while L. pentosus DSM 16366 was isolated from fermenting green olives prepared according to the Spanish-style method. Spontaneous olives fermentation was also performed as a control. Microbiological and physicochemical analyses of the brines revealed that the use of the starters had a significant effect on the olives fermentation, leading to a faster acidification due to the more efficient consumption of soluble sugars in the brines. The final pH value reached by each starter culture used indicates a successful lactic fermentation. The production of lactic acid by the starters and the concomitant drop of the pH value proved to inhibit enterobacteria in a shorter period of time compared to the spontaneous fermentation. Concluding, the use of either of the two lactic acid bacteria as starters in Greek-style Kalamon olives fermentation could lead to a more controllable fermentation at lower salinities. The resulting product could be of higher quality with extended shelf-life while being at the same time safer for the consumer.

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.

Effect of the mechanical harvest of drupes on the quality characteristics of green fermented table olives.

Because of damage caused by mechanical harvesting, the drupes for table olive production are traditionally hand harvested. Until now, no data have been available on the microbiological and chemical features of mechanically harvested drupes during fermentation. Drupes mechanically harvested and inoculated with Lactobacillus pentosus OM13 were characterized by the lowest concentrations of potential spoilage microorganisms. On the other hand, drupes mechanically harvested and subjected to spontaneous fermentation showed the highest concentration of Enterobacteriaceae and pseudomonads during transformation. The lowest decrease of pH (4.20) was registered for the trials inoculated with the starter culture. Differences in terms of volatile organic compounds were estimated among trials. Multivariate analysis showed that the olives processed from the drupes mechanically harvested and inoculated with starter were closely related to control production (drupes manually harvested) in terms of microbiological and pH values. Sensory analysis evidenced negative evaluations only for the uninoculated trials. Drupes mechanically harvested and subjected to a driven fermentation with Lactobacillus pentosus OM13 determined the production of table olives with appreciable organoleptic features. Thus mechanical harvesting performed using a trunk shaker equipped with an inverse umbrella and the addition of starter lactic acid bacteria represents a valuable alternative to manual harvesting for table olive production at the industrial level.

Azeitonas de mesa no Brasil: mercado, tecnologia e aspectos legais

Azeitona de mesa é o produto vegetal fermentado de maior importância no mundo ocidental. Apesar de não possuir produção significativa, o Brasil está entre os dez maiores consumidores de azeitona de mesa do mundo. Para o ano safra 2013/2014 (período entre os dias 01 de outubro até 30 de setembro), estima-se que o país seja o segundo maior importador e o nono maior consumidor do fruto. No entanto, as características do fruto e os principais processos de elaboração de azeitonas de mesa são pouco conhecidos no Brasil. Dessa maneira, este trabalho objetiva realizar um levantamento do mercado, as principais tecnologias utilizadas e os aspectos legais associadas à produção de azeitona de mesa

Debittering of Olives by Semi Drying

It was reported that oleuropein content and bitterness of olives could be reduced with reduction of water content to 15-20% by drying after pretreatment such as keeping in brine, soaking, dry salt folding, drilling and/or drawing. Black table olives have been produced with a traditional method in the name of 'Ferrandina' in Italy during many years. As a result of industry adaptation work of the 'Ferrandina' method, 'Sybaris' method was developed. But researchers reported that industrial production of table olives by drying could not be grown up. In this review, researches on the debittering method of olives by partial drying after pretreatment as a development of new table olive processing method were presented.

Analysis of Consumer Preferences for Table Olives—The Case of Albanian Urban Consumers

The table olive production sector is undergoing rapid changes, as the government is undertaking an ambitious program supporting the expansion of olive grove plantations. Despite the increase in domestic production, imports of table olives are still high, due to constraints in quantity and quality of domestically supplied olives. In the context of import substitution strategy, embraced by producers and policy-makers, it is important to analyze the consumer preferences for table olives. The objective of this paper is to segment the table olive market according to preferences for table olives attributes, and assess willingness to pay for the main product attributes, applying Conjoint Choice Experiment (CCE) and Latent Class Analysis to collect and analyze the data. The research results show a strong consumer preference for domestic table olives whereas preferences for other attributes and willingness to pay vary between consumer groups.

Olive fruit fly adult response to attract-and-kill bait stations in greenhouse cages with weathered bait spray and a commercial table olive orchard

Attract-and-kill bait stations and olive foliage sprayed with insecticidal bait spray and exposed to 0–4weeks of weather were evaluated for efficacy by olive fruit fly, Bactrocera oleae (Rossi), adult mortality. Mortality in greenhouse cage tests was significantly higher after three days than one day of exposure to non-weathered bait spray on bait stations and foliage, and on bait stations exposed to weather for three weeks. Mortality increased with an increase in insect exposure time, and decreased as bait spray weather exposure increased. Mortality was higher on bait stations than on olive foliage, and treated foliage showed little toxicity after 4weeks in weather. In a commercial orchard, bait station efficacy was determined by captures of adults on yellow panel traps. Day temperatures were slightly higher on the underside of the station than top from 2 May to 10 July, similar on the top and underside 11 July to 7 August, and slightly lower on the underside from 8 August to 4 September. Fruit length increased from 0.4 on 16 May to 3cm on 24 September and on 30 May attained 1cm, the minimum size to produce one adult. No larvae or adults emerged from collected fruit. More adults were captured in an untreated row than a row with bait stations until 22 August and significantly so for the period ending on 11 July. Maximum adult captures occurred during 2weeks prior to 19 September. Attract-and-kill bait stations would help reduce insecticidal applications and table olive production costs.

Production of potential probiotic Spanish-style green table olives at pilot plant scale using multifunctional starters

This work evaluates the use of two multifunctional starters of Lactobacillus pentosus species (TOMC LAB2 and TOMC LAB4) during elaboration of Manzanilla olive fruits processed according to the Spanish-style. Data show that the use of inocula at the onset of fermentation led to a proper acidification and sugar consumption of brines compared to the spontaneous process, obtaining in a shorter period of time the maximum population for lactic acid bacteria. Both inoculated L. pentosus strains were recovered at high frequencies at the end of fermentation on the olive surface, which was corroborated by RAPD-PCR analysis. In situ observation of olive epidermis slices by scanning electron microscopy revealed a strong aggregation and adhesion between microorganisms, which reached population levels of approximately 6 and 7 log10 cfu/cm2 for yeasts and lactic acid bacteria, respectively. Enterobacteriaceae on the olive surface were also found at the onset of fermentation (∼9 log10 cfu/cm2), but they declined during the process and were below the detection limit at the end of fermentation. Results obtained in this study show the advantage of using multifunctional starters with the ability to adhere to the olive epidermis because, ultimately, the fruits are the food ingested by consumers.

Transformation of an Ancient Crop: Preparing California ‘Manzanillo’ Table Olives for Mechanical Harvesting

As one of the oldest continuously produced tree crops in the world, it is ironic that table olive (Olea europaea) production has benefitted from few technological innovations, including harvesting. Two harvesting technologies, trunk shaking and canopy contact, have been identified. In a 2013 trial, a prototype canopy contact harvester successfully harvested 92% of a 5.3-ton/acre mechanically pruned crop, vs. 81% for a 12.8-ton/acre hand-pruned control crop in a 19-year-old, 13 × 26-ft grove, spaced at 139 trees/acre and adapted for mechanical harvesting with 6 years of mechanical topping and hedging. About 85% of the hand-pruned olives were cannable vs. 86% of the mechanically pruned olives. Over the 6 years of mechanical pruning, the mechanically pruned trees averaged an annual 4.2 tons/acre vs. 5.3 tons/acre with hand-pruned trees. Again in 2013, this same canopy contact harvester achieved 81% final harvester efficiency with a 5.8-ton/acre crop in a 12-year-old, 12 × 18-ft, 202-tree/acre, mechanically pruned hedgerow grove vs. 80% efficiency for a 5.17-ton/acre crop with hand-pruned hedgerow trees. Similarly, no significant differences in the percentage of cannable olives, fruit size distribution, or value per ton was produced by the pruning treatments. In this trial in which both hand and mechanical pruning were used to produce a hedgerow, the hand-pruned trees averaged 3.7 tons/acre vs. 4.3 tons/acre for mechanically pruned trees. In a commercial trial in 2012, the trunk-shaking harvester achieved 77% average harvester efficiency in a 40-acre, 180-tree/acre grove, with a 4-ton/acre crop prepared with both hand and mechanical pruning. These ongoing trials indicate that adapting groves with mechanical pruning does not decrease average annual yields and can produce table olive groves that can be mechanically harvested at a cost and speed that is competitive with hand harvesting.

Metal Status of Olive Trees Grown in Southeastern Marmara Region of Turkey

Black table olive production is concentrated in the southeastern Marmara Region of Turkey, which is one of the most important agricultural areas of the country with highly fertile soils. Soil pollution has become an important concern for arable lands as a result of intensive agriculture and urban-industrial expansion in the region. This study was conducted to characterize the metal accumulation in the soils, fruits, and leaves of Oleaeuropea L. in the orchards located in southeastern Marmara Region. The research was performed in 64 orchards with cv. Gemlik table olive trees in the towns of İznik, Orhangazi, Gemlik, Mudanya, and Nilüfer of Bursa Province in the region. To determine levels of pollution, soils and aboveground parts of the trees were sampled and analyzed for iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), cobalt (Co), nickel (Ni), chromium (Cr), lead (Pb), and cadmium (Cd). Total amounts of Ni and Cr were found to be excessive in soils. Cadmium, Co, and Cu concentrations were slightly greater than the permissible ranges in a minority of the soils tested The concentrations of these elements, however, were not at the toxic levels in the different plant parts. Because of lack of standard concentrations indicating excessive concentrations of extractable elements, statuses of extractable elements in the soils were not evaluated. Except for Zn in some fruit samples and Cu in some fruit and leaf samples, metal accumulation in the trees were not estimated by both leaf and fruit analysis. Concentration of total and diethylenetriaminepentaacetic acid (DTPA)–extractable metals in the soils did not correlate with the plant content of the metals. Therefore, total and DTPA-extractable metal concentrations were not reliable and descriptive in estimating metal concentrations in olive trees. As a result, the appearance of metals in soils might be due to agricultural activities and parent material. Continuous monitoring and future studies of the olive orchards are recommended to ascertain long-term impacts of pollution on the trees.

Isolation of Megaritolactones and Other Bioactive Metabolites from ‘Megaritiki’ Table Olives and Debittering Water

'Megaritiki' is an olive cultivar widely used in Greece for the production of low polyphenol olive oil and table olives. To investigate possible metabolic differentiation in comparison with other varieties, the composition of 'Megaritiki' olive fruits and wastewaters from the debittering procedure was studied. Moreover, the recovery of bioactive metabolites from wastewater using adsorption resin was studied to exploit this byproduct. Metabolites in fruits and wastewaters were monitored using NMR spectroscopy. The major constituents of wastewater were hydroxytyrosol-4-O-glucoside, 11-methyl-oleoside, hydroxytyrosol, and tyrosol but not oleuropein. Furthermore, wastewater afforded rengyoxide and rengyoside B, which are for the first time isolated from olives. The final edible olives, besides hydroxytyrosol and tyrosol, contained rengyoxide and cleroindicin C, which are the first isolated from the species, haleridone for the first time isolated from edible olives, and four metabolites, which are the first reported as natural products, megaritodilactone, megaritolactonic acid, methyl ester of megaritolactonic acid B, and megaritolactonol.

The Historical Development and Nutritional Importance of Olive and Olive Oil Constituted an Important Part of the Mediterranean Diet

The olive tree (Olea europaea) is widely cultivated for the production of both oil and table olives and very significant because of its economic value. Olive and olive oil, a traditional food product with thousands of years of history, are the essential components of the Mediterranean diet and are largely consumed in the world. Beside of their economical contribution to national economy, these are an important food in terms of their nutritional value. Olive and olive oil may have a role in the prevention of coronary heart disease and certain cancers because of their high levels of monosaturated fatty acids and phenolic compounds. In addition, olives (Olea europaea L.) and olive oils provide a rich source of natural antioxidants. These make them both fairly stable against auto-oxidation and suitable for human health. The aim of this paper is to define the historical development and nutritional importance of olive and olive oil constituted an important part of the Mediterranean diet.

Understanding the Characteristics of Oleuropein for Table Olive Processing

Phenolic compounds make up 2-3% (w/w) of olive flesh, whose most abundant part is oleuropein which is responsible for the characteristic bitter taste of olive fruits. Oleuropein is a heterosidic ester of elenolic acid and hydroxytyrosol and possesses beneficial effects on human health. But most fundamental and important step of table olive processing is to reduce level of oleuropein because olive fruits can only be consumed after de-bittering procedures. Oleuropein accumulates during fruit growth and is slowly converted to elenolic acid glucoside and demethyloleuropein as the fruit ripens. Harvest maturation affects the table olive processing factors, according to change on oleuropein content of olive fruits. More severe applications are required for processing of olive which has high oleuropein content. Also oleuropein and its hydrolysis end products (elenolic acid and aglycone) inhibit the activity of a number of microorganisms involved in the lactic fermentation of olives. Oleuropein was significantly affected by both acid and base treatment, resulted in the liberation of hydroxytyrosol. Bitter taste of olive fruit can be eliminated by removing the oleuropein out of the olive or chemical or enzymatic hydrolysis of oleuropein in table olive processes. Understanding the characteristics of oleuropein for table olive processing helps manufacturer to produce high quality table olives and researchers to develop innovative methods for table olive production. So that this research was aimed to explore the characteristics of oleuropein and its effects on table olive processes.

Application of ultrafiltration for olive processing wastewaters treatment

Abstract Reducing environmental impacts and getting economic benefits, based on by-product recovery, was the aim of applying the ultrafiltration (UF) process for the treatment of olive processing wastewaters, namely olive mill wastewater (OMW) and table olive wastewaters, the main pollutants of olive oil and table olive production industries. Magnetically stirred unit and polyethersulfone membrane of a molecular weight cut-off of 50,000 Da were used. The effectiveness of the different operating conditions was evaluated using rejection coefficients of: chemical oxygen demand, color, total solids and total phenolic content (TPC). The effects of pH on the permeate fluxes and OMW depollution were evaluated. A substantial reduction of the aforementioned parameters was obtained excluding the TPC which was intentionally kept as high as possible. The obtained results show that the UF can be used as an efficient pretreatment for olive processing wastewaters at acidic pH. Such a pretreatment may enhance efficiently a subsequent extraction process of phenolic compounds from permeate and improve the effectiveness of any further secondary treatment. Therefore, a sustainable and cleaner production of olive oil and table olives can be achieved.

Phenolics profile of a naturally debittering olive in comparison to regular olive varieties

Hurma, an olive variety that grows in a specific area in Turkey, loses its bitterness before harvesting, and therefore does not need further processing steps for the production of table olives. The total phenol content and phenolic profiles of (1) this naturally debittered olive type, Hurma; (2) the same olive variety, but not a naturally debittered type, Erkence; and (3) another variety, Gemlik, which is commonly consumed as table olive, were determined during their maturation period for two harvest years. The total phenol content of Hurma is the lowest compared to the other types regardless of harvest year, which has a significant effect on the phenolic content and composition of individual components for all olive types. All three olive types can be differentiated from each other especially during the late phase of maturation using the phenolics profile in combination with principal component analysis. The natural debittering phenomenon of Hurma olive on the tree involves a decrease in phenol content and a change in phenol composition. The differentiation in phenol composition especially becomes very significant in the late of period of maturation.

Quality Improvement of Green Table Olive cv. ‘Domat’ (Olea europaea L.) Grown in Turkey Using Different De-Bittering Methods

The most basic step in table olive production is de-bittering. Olives contain bitter flavor compounds such as oleuropein, and their presence precludes the consumption of fresh fruits. Oleuropein can be removed by natural methods (e.g., using tap water) or by applying various chemicals (e.g., lye). Chemicals affect the organoleptic and nutritional qualities of the olive fruit. The aim of this study was to improve the quality of naturally fermented ‘Domat’ cultivar green table olives using different de-bittering methods (by scratching, using 1% lye and using tap water). The lye pre-treatment negatively affected the nutritional, organoleptic and color qualities of the olives. In all of applications, the best color stability was obtained in the olives that were de-bittered using the scratching method.

Effect of Regulated Deficit Irrigation on Productivity, Quality and Water Use in Olive cv “Manzanilla”

The objective of this experiment was to determine the effect of different regulated deficit irrigation (RDI) strategies on productivity, oil quality and water-use efficiency on olive grown in the Sonoran Desert. The experiments were carried out in 2009 and 2010, and in a ten years old traditional (10 × 5 m) “Manzanilla” olive orchard. The control treatment was irrigated at 100% ETc during the whole season while RDI treatments were applied at 75% ETc or 50% ETc. The two RDI were applied during two phenological stages: at postharvest to evaluate the effect on table olive or from pit hardening to harvest to evaluate the effect on oil olive. Our results indicated that RDI applying 50% ETc during postharvest period reduced significantly fruit set and table olive yield, while applied during pit hardening to harvest period, it decreased oil yield but increased oil content. The RDI applying an ETc of 75% during the postharvest period gave similar table olive yield to the control, and applied form of pit hardening to harvest also gave similar oil yield to the control. The RDI using an ETc of 75% resulted in the highest water-use efficiency for oil or table olive production.