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In this study, a comprehensive physicochemical characterization of commercial table olives from the Algerian market was conducted, revealing significant discrepancies with international regulations and indicating non-compliance with established standards. Spanish-style green olives and natural turning color olives, for the most part, did not meet the established standards regarding pH and salt concentration. Additionally, samples of oxidized black olives were found, which, due to their high pH, should undergo sterilization but were stored in non-sterilized containers. Microbiological analysis revealed high populations of Enterobacteriaceae and other spoilage microorganisms in the brines, indicating possible deficiencies in hygiene practices during production. The study evaluating the survival of pathogenic microorganisms in the samples indicated that the physicochemical conditions of the product, such as pH and salt concentration, played a crucial role in the non-survival of these pathogens. Furthermore, an antimicrobial effect of certain phenolic compounds present in olives was observed, highlighting the importance of these compounds in food safety. In summary, this study provides a snapshot of the quality of table olives available in the outlets surveyed and underscores the importance of strict microbiological control, quality, and appropriate production practices in the table olive industry in Algeria. The use of preservatives and heat treatments, along with good manufacturing and hygiene practices, are useful tools as control measures to reduce spoilage in table olives. Adhering to established standards in international regulations for table olive processing and implementing effective control measures are essential steps to ensure the quality, safety, and consumer acceptance of this traditionally valued food product.

The presence of acrylamide, a known human carcinogen, in various heated foods raises significant concerns among consumers. Therefore, the development of a good analytical method is of paramount interest to the scientific community. Keeping this in view, a rapid, simple, reliable, and low-cost analytical method was developed and validated for acrylamide quantification in black ripe olives. The method consisted of the water extraction of the compounds from crushed olives with the addition of (13C3)acrylamide as an internal standard. The quantification was performed using high-pressure liquid chromatography and mass detection with positive electrospray ionization. The limits of detection and quantification were determined to be 4 and 11 µg/kg, respectively. The developed method exhibited excellent results in terms of accuracy (98.4-104.8%) and intra- and inter-day precision limits, both less than 20%. This new method was carried out by analyzing 15 samples of Spanish commercial black ripe olives, revealing a wide range of values, from 79 to 1068 µg/kg of fruit. The new protocol reduces the analysis time to just one hour per sample versus the minimum 24 h required by gas chromatography and mass detection, meaning that it could be a good option for the routine analysis of acrylamide in black ripe olives, and may be extendable to the analysis of this compound in other foods.

The phenolic and oleosidic compounds in different components (peel, pulp and seed) and zones of olives during maturation were analyzed. These analyses were also carried out on commercial table olives and olive pomace peel. The profile and concentration of the compounds were very different among the components of the raw fruit; flavonoids were only detected in the peel and their content increased with ripening. Oleuropein was concentrated in the peel and the tissue near the peel, whereas verbascoside, secoxyloganin and oleoside 11-methyl ester were mostly detected near the pit. A close relationship between the maturation area within the fruit and the concentration of phenolic compounds was also found. Although the content of phenolic compounds in the peel and seed of commercial table olives was higher than in the pulp, the phenolic profile was similar for all components. Moreover, the concentration of phenolic compounds was low in commercial olive pomace peel.

Ultrasound-assisted extraction (UAE) is a technique commonly used in combination with solvent extraction and effectively enhances the extraction of polyphenols. This technique has successfully solved the problem of polyphenols in biotechnology. The present study was carried out to optimize the extraction of phenolic compounds (total phenols, flavonoids, orthodiphenols, and flavonols) and the evaluation of antioxidant activities (reducing power and antiradical activity) from oil mill waste (OP, olive pomace). The three independent variables selected were sonication amplitude (20–100%), extraction time (2–20 min), and solvent acetone concentration (40–80%). The optimization study was carried out using the Box-Behnken design. The results revealed that all developed models regarding phenolic contents and antioxidant activities, through experimental design, expressed high levels of significance (F-values = 0.0004–0.0210) with good concordance between predicted and experimental data (R2 = 0.929–0.987). The optimal conditions for phenolic extraction and antioxidant activity were achieved using 57.34% acetone, 83.69% sonication amplitude, and 2 min of extraction. Under these conditions, the obtained contents for TPC, flavonoid, orthodiphenol, and flavonol were 23.43 g GAE/kg, 10.33 g CE/kg, 17.72 g GAE/kg, and 5.43 g QE/kg, respectively, resulting in a global desirability of 84.41%. Moreover, the predicted optimal conditions were experimentally validated. Considering all statistical parameters, it can be concluded that the developed models are suitable for achieving the highest recovery of phenolics from OP.

Olive leaf is a by-product rich in bioactive compounds, such as polyphenols and triterpenic acids, with numerous biological activities for human health. Nowadays, the existence of dry olive leaves marketed for infusion elaboration is lacking. During the elaboration process, the drying and grinding stages are critical for the conservation of bioactive compounds, and, precisely, the existing research on olive leaf production procedures is quite scarce. This work aimed to study and model the dehydration process using a forced-air oven and infrared with air convection systems. In addition, different grinding grades were studied. The kinetic constant and activation energy during dehydration were obtained. Drying temperatures above 50 °C produced a decrease in the phenolic concentration of olive leaves; however, it has been observed that prior storage of 24 h at room temperature considerably reduced the loss of phenols. Likewise, it was observed that the higher the degree of grinding, the greater the diffusion of both bioactive compounds and colored compounds. Therefore, the drying and grinding stages were closely related to the content of beneficial compounds and the appearance of the infusions, and their optimization was of crucial importance to produce dried olive leaves rich in biocompounds for use as healthy infusions.

Changes in the processing of black olives, together with the dehydration of the latter, were investigated in order to develop a new product with similar physicochemical and sensory characteristics to commercial dry-salted olives. Large fruit of the Hojiblanca cultivar (160 fruit/kg), preserved in brine for eight months, were used. It was found that these olives must be elaborated with hot lye (40 °C) to reduce their strong firmness. Moreover, several changes must be introduced during the color fixation stage including the addition of a concentration of NaCl higher than 6 g/100 mL, acidification with lactic acid and a low concentration of ferrous gluconate (<0.5 g/L). In addition, the kinetic constant and activation energy during the dehydration of the olives by infrared heating were obtained. Finally, it must be noted that this new product was assessed without any negative sensation by tasters one year after packing.

Among the many different types of table olives, the production of dehydrated black olives is rather low worldwide, although there is an increasing interest in them from consumers. The physicochemical and microbiological characterization of 20 samples of these olives obtained from different countries and processing methods was studied. The average pH and water activity (aw) values were 4.7 units and 0.85 respectively, although a great variability was found among samples due to the cultivar and the elaboration method used, including oven-dried olives and dry-salted olives obtained from harvested fruit along with oven-dried fruit from fermented black olives. Moreover, the NaCl concentration in many samples was higher than the unique legal requirement for these olives by international standards (>8–10% in the olive juice), which probably implies a reduction of this mineral in the future as demanded by consumers. More precisely, this product must be valorized based on its 40% content of oil rich in monounsaturated fatty acids, and more than 2500 mg/kg of phenolic compounds and 3500 mg/kg of triterpenic acids which make these olives a very attractive product from a nutritional point of view.

Among the benefits which vacuum impregnation (VI) may provide to fruits and vegetables, this study focused on weight and texture changes during the processing of table olives. VI applied to Manzanilla olives led to around 10% weight gain, which was maintained after their packing as black olives. However, this weight gain was only around 4 % for Hojiblanca olives. Likewise, the use of calcium chloride was recommended to maintain the firmness of the olives, in particular those of the softer Manzanilla cultivar. With regard to the Spanish-style, the Hojiblanca cultivar achieved around 4% weight gain during processing but the use of VI for Manzanilla olives was ruled out due to softening of the fruit. In addition, the black and green color of olives and their flavor were not modified by the application of VI. This technology could be very useful to reduce weight loss during table olive processing. Copyright

A high volume of water is needed to produce black ripe olives, which also entails a significant volume of wastewater with a high organic and inorganic contaminant charge. To reduce this problem, the reuse of KOH solutions (lyes) in a new process was studied. Once the lyes were removed from the tanks, KOH was then added for a new darkening process. Reusing the lyes up to four times gave rise to a product with similar physico–chemical and organoleptic characteristics as obtained with fresh solutions. The application of this process reduced coadjutant consumption by 32% and water by 20%, while global wastewater presented a high K content whose concentration could be valorized as a fertilizer by replacing commercial potassium nitrate.

The black dry olive is a highly regarded product that is mostly elaborated from harvested black fruits subjected to a dry-salting process. The aim of this study was to develop a new dehydrated black table olive product. Fruits of the Gordal and Hojiblanca cultivars were alkali treated and preserved in brine for several months, after which they were dehydrated at 60 °C. Among the variables assessed to avoid lactic acid fermentation of the olives (NaCl concentration, washing, temperature), only maintenance of the fruit under refrigeration (5-6 °C) succeeded in maintaining the pH of the fruit above 6 units for several months. This high pH was crucial to obtaining dark olives after the dehydration process because browning of the fruit was highly dependent on their pH level. Chemical oxidation of phenolic compounds, in particular hydroxytyrosol, was related to the first order kinetic of the darkening rate of olives. Unfermented and dried olives of the Gordal cultivar were packed and assessed by tasters that considered this new dehydrated black table olive product as acceptable for future consumers.

La impregnación al vacío (IV) es una técnica ampliamente conocida en tecnología de alimentos para múltiples aplicaciones tales como la modificación del pH, introducción de compuestos bioactivos, sales, enzimas, etc (Derossi et al., 2012). Se ha estudiado su uso para la introducción de sales de hierro en aceitunas de mesa (Zunin et al., 2017) y acelerar el tratamiento alcalino de aceitunas verdes (Tamer et al., 2013). Sin embargo, nunca se ha investigado en aceitunas de mesa la influencia que pueda tener la aplicación de esta técnica sobre las propiedades físicas de los frutos, en particular su textura y modificaciones en el peso. Por tanto, el objetivo de este trabajo ha sido estudiar a escala industrial la influencia de la impregnación al vacío sobre el peso y textura de las aceitunas durante su elaboración como negras oxidadas.

Gas pocket defect causes substantial losses every season to Spanish-style green table olive processors. This defect has been thought to be caused by microorganisms that are able to produce gaseous compounds that break the flesh and/or the epidermis of olive fruits. This study was focused on the search for the microorganism actually responsible for this spoilage. Metataxonomy analysis of industrial spoiled brines demonstrated the presence of Celerinatantimonas as the most probable source leading to gas pocket formation. Several bacterial isolates were obtained from different industrial spoiled brines whose 16S rRNA sequence closest homologue was Celerinatantimonas diazotrophica (94–96% similarity). Vigorous gas production (H2 and CO2) by these isolates in broth cultures was confirmed. Inoculation of microbial pellets from one of these spoiled brines did indeed provoke gas pocket formation in fresh batches of Spanish-style green olives. Although the species C. diazotrophica has been previously reported in metataxonomy studies in samples of table olives, this is the first time that it was isolated from fermenting table olive samples. In addition, this is the first report that associates this species to the gas pocket defect in table olives. Thus, inoculation with one of the wild-type isolates identified as C. diazotrophica in table olive brines confirmed the involvement of this microorganism in the formation of the gas pocket defect in Spanish-style green olives.

The defect of gas pocket formation still leads to substantial losses of yield and quality of Spanish-style green olives worldwide. This spoilage has recently been associated with the growth of Celerinatantimonas sp., and this study was aimed at investigating the influence of several factors on the growth of Celerinatantimonas, both in synthetic media as well as in the olive brines of the three olive cultivars Gordal, Manzanilla and Hojiblanca. Using synthetic media, it was found that the concentration of NaCl within current industrial levels (3.5–7.0%) did not affect the growth of Celerinatantimonas, whereas the pH was a crucial factor, the range of growth being 4.5–7.5 units. Among the acids tested, lactic acid presented the highest inhibitory action against this microorganism. The assays carried out with olive brines disclosed that the population of Celerinatantimonas and its normal fermentation products (acetic acid and ethanol) increased in all of the inoculated brines, while the reduction of gas pocket defect depended on the combined use of several factors including addition of lactic acid, control of pH and inoculation with a lactic acid bacteria starter. Hence, the maintenance of a pH below 4.5 units at the beginning of fermentation along with the addition of 0.2–0.8% lactic acid was considered necessary to inhibit growth of Celerinatantimonas and to prevent gas pocket defect. The tools proposed as conclusions of this work should be used by table olive processors in the future to reduce the incidence of this olive spoilage.

A large spectrum of beneficial health properties has been attributed to olive leaves. This study was undertaken to characterize the bioactive compounds of commercial olive leaf extracts and olive leaves and their infusions. High variability of bioactive compounds was found among commercial samples. Polyphenol was detected in a range of 44–108 g kg−1 and 7.5–250 g kg−1 for olive leaves and olive leaf extracts, respectively. The main phenol was oleuropein, representing 74–94% of total phenols. However, only 17–26% of polyphenols were diffused to the aqueous phases when olive leaf infusions were prepared. Triterpenic acids were found in a range of 26–37 g kg−1 in olive leaves, but not detected in the infusions. Hence, the absence of the latter substances and the low oleuropein diffusion in olive leaf infusions make new studies necessary to maximize the presence of these bioactive compounds in the final product.

Scope. The postprandial effects of virgin olive oils (VOOs) enriched with phenolic compounds and triterpenes from the olive fruit on plasma glucose and insulin (primary outcomes), and gastrointestinal hormones responses were evaluated in healthy adults. Methods and results: Single doses (30 mL) of three oils were evaluated: optimized polyphenols-rich VOO (OVOO); functional olive oil (FOO): OVOO enriched with triterpene acids; and VOO with low content of polyphenols. Postprandial plasma insulin release was lower after the intake of the FOO compared to VOO, while plasma glucose levels were lower after the intake of the VOO compared to OVOO. Matsuda's index of insulin sensitivity improved after the intake of FOO and OVOO, while the insulinogenic index and gastric inhibitory polypeptide (GIP) tended to improve after the intake of OVOO. Conclusion: The enrichment of VOOs with bioactive compounds from the olive fruit increases its benefits, improving postprandial insulin release and peripheral tissue sensitivity.

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 th

This study was aimed at making progress on the valorisation of table olive wastewater that currently represent a big environmental problem for factories. Concentrates from vacuum evaporation of the wastewater generated during processing of black ripe olives treated with KOH were tested as fertilisers of tomato plants in open field assays for three consecutive crops. Fertilisation was performed by drip irrigation every 15 days; the first treatment being 15 days after transplanting, and a total of five fertilisation treatments were carried out. A phytotoxic effect was not observed on plants or fruit in any case but higher yield (fruit/plant and g/plant) was obtained in comparison to irrigation with only tap water. Moreover, the combined use of the olive concentrate with inorganic nitrogen supply (NH4NO3), in order to comply with the nutrient needs of plants, was also tested. The results demonstrated that the olive concentrates could be a good substitute for inorganic potassium (as KNO3) during the cultivation of tomato plants without any negative effect on the tomato quality (pH, °Brix, sugars, organic acids) or content of bioactive substances (phenolic compounds and carotenoids).

The type of container (airtight and pouches with different O2 permeability) and packing conditions (cover brine, air or N2 atmosphere) has been studied to preserve black ripe olives in acid medium for a year. Unlike the traditional sterilized product, these acidified olives only needed pasteurization to assure its microbial safety, the absence of acrylamide being an additional advantage. Surprisingly, an increase in the oxygen diffusion through the films (i) faded the black color of the olives, (ii) softened the fruit that lost around 33% of its initial firmness in only 6 months, and (iii) produced the lipid́s oxidation forming volatile compounds that transmitted an abnormal flavor which tasters identified as rancid. Therefore, ripe olives in acid medium must be packed in airtight containers such as glass jars, cans o metallic pouches with cover brine or N2 atmosphere. The addition of calcium is recommended to avoid olive softening.

Table olive wastewaters represent a big problem for factories not yet solved. Some partial solutions are the purification, the reuse or the generation of a smaller volume of these liquids. The purpose of this study was to investigate the possibility of obtaining a concentrate that can be stable over time and that has a biofertilizing capacity on tomato (Solanum lycopersicum L.) plants. In this study, washing waters from Spanish style green and storage liquids from black ripe olive processing were vacuum concentrated up to 10, 13 and 17 times so that they reached total sugar content of up to 700 mmol L−1, 925 mmol L−1 and 1200 mmol L−1 respectively. Interestingly, the evaporation achieved to retain most of the phenolic compounds that ranged from 18 mmol L−1 in the fresh solution to 140 mmol L−1 in the solution concentrated 10 times. Moreover, these concentrates showed in vitro antimicrobial activity against the bacteria Erwinia amylovora and Pseudomonas syringae, and the Oomycota Phytophthora sp. In addition, they increased the strength and cumulative yield of the tomato plants cultivated under greenhouse conditions, even after 12 months of storage at room temperature. It has been demonstrated that it is possible to reduce the large volume of the wastewaters of the table olive industry, and the concentrates have potential application for agricultural uses, even after 1 year of storage, thereby contributing to a more environmentally sustainable industry.

La elaboración de aceitunas de mesa ha generado en España un sector industrial de gran interés económico aunque con un gran problema de gestión de sus aguas residuales. Estudios previos han demostrado que soluciones procedentes de la elaboración de aceitunas verdes estilo español pueden tener un efecto promotor del crecimiento en plantas de tomates. El objetivo de este trabajo fue confirmar con nuevas experiencias en diferentes campañas los resultados observados inicialmente. En un primer ensayo(campaña 2015) se emplearon dos aguas de lavado de variedades de aceitunas diferentes ('Manzanilla'y 'Hojiblanca'), que fueron aplicadas por riego en dos dosis (20 y 50%). Los resultados indicaron que la aplicación de estas soluciones no tenía efecto fitotóxico y la evaluación de los parámetros asociados al vigor de la planta, la producción y la calidad de los frutos mostraron que la solución más efectiva fue el agua procedente de la elaboración de aceitunas 'Hojiblanca'aplicada a dosis alta. En un segundo ensayo (campaña 2016) se empleó una nueva solución de la variedad 'Hojiblanca'que fue concentrada diez veces y se aplicó recién preparada o una vez transcurrido seis meses de almacenamiento. Además, en esta ocasión, sólo se realizó riego a dosis alta (50%) y se ensayaron con variedades diferentes de tomate ('Optima'y 'Carmello'). La evaluación de los mismos parámetros que en la campaña anterior nos indicaron que el efecto fortificante de estas soluciones fue independiente de la variedad de tomate y deltiempo de almacenamiento de la solución concentrada. En conclusión, la utilización de estas soluciones procedentes de la elaboración de aceitunas de mesa como fertilizante natural puede ser una alternativa para la agricultura ecológica y, además, podría reducir el volumen de vertidos en ese sector industrial.

A new aeration treatment of black ripe olive streams prior to their vacuum evaporation was studied. It was found that the aeration for two days of these solutions reduced the chemical oxygen demand (COD) of the distillate phase (>80%) generated during their vacuum evaporation; although the temperature (14–38 °C) and the air flow rate (10–50 L air/h/L) had a great influence on this reduction. Moreover, the COD in the distillate was mainly associated with the presence of acetic acid (~400 mg/L) and ethanol (~500 mg/L), the later substance being eliminated by strong aeration. Additionally, the growth of native aerobic microorganisms, mainly Acetobacter, increased the pH of the wastewater to 7–8 units, thus avoiding evaporation of the acetic acid salt formed. These results make the use of the distillate for plant irrigation viable and its discharge into municipal depuration plants possible, given the low COD (<500 mg/L) reached with this new method.

Table olive wastewaters are seriously polluting and a difficult to treat effluent worldwide, mainly due to their high content in sodium. An alternative approach could be the treatment of the olives with KOH instead of NaOH, in order to reuse the olive streams as biofertilizers. In this study, the debittering of olives with KOH was investigated at pilot plant scale in two olive seasons. The results indicated that a concentration between 1.7 and 2.0% of KOH (similar to that employed with NaOH) led to a fermented product with the same physicochemical and organoleptic characteristics than the traditional one. The spent lyes and washing waters from the KOH treatments were gathered and vacuum evaporated, giving rise to a concentrated solution rich in potassium (52 g/L) that was tested as biofertilizer in open tomato fields. Furthermore, the drip irrigation of the tomato plants with a combined olive solution and mineral fertilizer (NH4NO3) produced similar tomato yield and quality than the irrigation with only mineral fertilizer (NH4NO3 + KNO3). Overall, it has been demonstrated that Spanish-style green olives can be processed with KOH and the effluents valorized to be used as biofertilizer.

The preservation of olives intended for processing as black ripe olives must be done in a salt‐free environment although it involves the use of calcium addition to retard olive softening. Calcium chloride and calcium lactate were added by up to 1600 mg Ca L−1 (i) in the preservation liquid of olives before darkening and (ii) in the cover packing brine. The highest texture and calcium absorption were found in the latter case. In addition, the sensory characteristics of the final product were not affected by the use of any of the calcium salts studied at concentrations of up to 1600 mg Ca L−1. Calcium chloride and calcium lactate can be employed to obtain higher texture and calcium content in black ripe olives, although it is advisable to add the cation to the cover packing brine of pitted olives rather than to the preservation liquid.

The darkening process of black ripe olives produces a high volume of wastewater that is phytotoxic due to its high sodium content. The substitution of NaOH by KOH to produce ripe olives was investigated at pilot plant scale with olives of the Hojiblanca, Manzanilla and Cacereña cultivars. No significant differences were observed in this step due to the type of alkali used, although a higher weight increase was found when using KOH instead of NaOH. Furthermore, the final canned product had a similar superficial color, firmness, content of bioactive substances and flavor regardless of the alkali used; the difference with the traditional product was a slightly lower content in Na and six times more K content. Moreover, the concentration of potassium ranged from 6200 to 7500 mg/L in the overall wastewater discharged during the oxidation process with KOH, therefore these solutions could be used as biofertilizer for agriculture purposes.

The debittering of natural table olives is a very slow process. The effect of acetic, lactic and citric acids on the hydrolysis rate of oleuropein was studied in vitro and at pilot plant scale. The acid hydrolysis of oleuropein was faster with lactic and citric acids than acetic acid, running the experiments at the same pH of 3.8–4.0 units. The temperature exerted a high effect of the hydrolysis of oleuropein in a range of 10–30 °C and the concentration of the organic acid did not show a significant trend. Moreover, the in vitro results were confirmed with three lots of olives that presented a higher content of oleuropein after 3–7 months of preservation when they were processed with acetic acid rather than lactic acid and the opposite for hydroxytyrosol. These results open the possibility of accelerating the debittering of natural olives by preserving them with lactic acid instead of acetic acid

Recently, the potential use as fertilizer of some wastewaters from table olive factories has been reported but the cause of this activity has not been disclosed up to now. In this study, a huge number of table olive waste solutions were analyzed from three consecutive seasons. Sugars, phenolic and mineral compounds were the main chemical groups identified. The individual effect of these components was tested on the growth of tomato plants and the quality of their fruits. Two factorial designs were assayed (24 and 23), in which the individual groups of chemical substances were sugars, minerals (nitrogen, potassium and phosphor), simple and polymeric phenols. Also, fresh wash water from Spanish-style green table olive processing was tested. The main conclusion was that no one individual group caused the fertilizer activity but a synergetic action of all of them was efficient and the fresh waste solution tested was the most effective.

Black ripe olive processing produces large volumes of salty wastewater that may be reduced by using a salt-free solution during the preservation stage. In this study, the employment of calcium chloride and calcium lactate during this stage to improve the texture of olives of the Manzanilla, Hojiblanca and Cacereña cultivars was assessed. Neither calcium salt affected the preservation of the olives under aerobic conditions, with yeasts and acetic acid bacteria being the predominant microorganisms during this stage, whereas lactic acid bacteria were detected after several months of preservation with the increase of the ambient temperature, including Oenoccocus sp., which has not been isolated from olives until now. Moreover, both calcium salts at 20 mM concentration were equally effective in delaying the softening of olives during all processing stages regardless of the olive cultivar. In addition, the color and flavor of the olives were not affected by either of the calcium salts. Hence, these results revealed that both calcium salts must be used for the preservation stage of black ripe olives in salt-free solution without any preference for either of them from a technical point of view.

The fermentation of natural black olives is currently carried out under anaerobic conditions. This work investigates the aerobic fermentation of this product in tanks containing 16 000 kg of Empeltre olives during two seasons. The microorganisms in brines were yeasts in all cases, whereas lactic acid bacteria growth was only observed in some tanks. Consequently, the pH during fermentation was in most cases higher than recommended 4.3 units. However, the Empeltre olive brines displayed bactericidal effect against Salmonella enterica, Sthapylococcus aureus, Escherichia coli and Listeria monocytogenes, with a 5 log population drop in one or 24 h depending on the brine age so that these olive brines are a harsh environment for the growth of these pathogens. It was found HyEDA as the major phenolic compound in both brine and olive pulp at the beginning of fermentation that slowly hydrolysed into hydroxytyrosol that reached a concentration up to 1500 mg kg.

Harvested olives require further processing to make them edible due to their content in the bitter substance oleuropein. However, some olives of the Erkence cultivar naturally de-bitter on the tree giving rise to the so-called Hurma olives. In this study, the evolution of the chemical characteristics of Erkence and Hurma olives harvested from the northeast and southwest area of trees located in the Karaburun Peninsula was assayed. It was confirmed that the oleuropein content in Hurma olives was much lower (< 2000 mg/kg fresh weight) than Erkence, which reached 35.000 mg/kg fresh weight at the beginning of the season. In addition, no free or polymerized anthocyanins were found in Hurma fruit in contrast to ripened Erkence fruit. The concentration of glucose was also lower in Hurma than Erkence olives. These results suggest that the enzymatic oxidation of oleuropein could be responsible for the natural de-bittering of Hurma olives during their ripening on the tree., Una explicación para el desamargado natural de aceitunas Hurma durante su maduración en el árbol. Las aceitunas recién cogidas del árbol necesitan ser procesadas para hacerlas comestibles, debido a su contenido en el compuesto amargo oleuropeína. Sin embargo, algunas aceitunas de la variedad Erkence desamargan de forma natural en el árbol dando lugar a las aceitunas conocidas como Hurma. En este trabajo se han analizado las características químicas de aceitunas Erkence y Hurma recolectadas de la zona noreste y suroeste de árboles situados en la provincia de Karaburun. Se ha confirmado que el contenido en oleuropeína de aceitunas Hurma es muy inferior (< 2000 mg/kg) que Erkence, las cuales alcanzaron una concentración en dicha sustancia hasta de 35.000 mg/kg al principio del periodo de maduración. Además, no se encontraron en aceitunas Hurma antocianinas ni libres ni polimerizadas, a diferencia de Erkence. Estos resultados indican que la oxidación enzimática de la oleuropeína podría ser la responsable de la eliminación del amargor de forma natural en aceitunas Hurma durante su maduración en el árbol.

The types of retortable pouches with different O2 permeability and packing conditions (liquid, air or N2 atmosphere), and processed with and without iron addition, have been studied. In all cases, consumption of oxygen and production of CO2 were found during the first months of storage. Moreover, oxygen caused discoloration of the olives. Consequently, a loss of black color was observed during shelf-life of fruits packed under air atmosphere, particularly as the permeability of the pouch increased. Hence, the use of nitrogen atmosphere has been disclosed as a good method for packing ripe olives, especially in those pouches with high oxygen permeability. Likewise, the type of container and packing conditions did not influence the firmness of the olives but only the use of iron gave rise to firmer olives.

In Mediterranean countries the table olive industry produces a huge volume of wastewaters that are phytotoxic due to their high sodium content. Olives intended for Spanish-style green olives are currently debittered with NaOH that generates lyes and washing waters that cannot be used for agronomic purposes. In this study, the substitution of NaOH with KOH during the debittering of Manzanilla and Hojiblanca cultivars was assessed as well as the vacuum evaporation of the olive wastewaters to comply with fertilizer requirements. Typical lactic acid fermentation occurred in brines of olives treated with KOH and a final product with similar color and flavor characteristics to those treated with NaOH was achieved. However, lower texture was found in olives debittered with KOH than those with NaOH, using them at the same molar concentration. Furthermore, the lyes and washing waters from the KOH treatment were concentrated up to 10% of their initial volume and they complied with Spanish requirements to be considered as organo-mineral fertilizers (Corganic > 4%, K2O > 2%, Ntotal + K20 > 6%) although an external source of nitrogen would be needed. They also had a high content in phenolic compounds, particularly hydroxytyrosol. This research demonstrates that table olives can be processed with KOH and the generated waste streams could have potential applications in agriculture or being a source of bioactive substances.

This article gives an overview of the current use of the European system of protected designation of origin (PDO) and protected geographical indication (PGI) for Spanish table olives. To date, there have been two PDOs recognized by the European Commission, the PDO “Aceituna Aloreña de Málaga” (2012) and the PDO “Aceituna de Mallorca/Mallorquina” (2014). In both cases, olives are debittered in brine without the use of alkali, although they may be crushed to accelerate the process. Therefore, they can be sold as natural olives according to the standards of the International Olive Council. Moreover, most of these protected olives are seasoned with fennel, garlic, pepper, and thyme. However, the production of these protected olives is very low. In fact, they represent less than 1% of the total Spanish production of table olives. Nevertheless, the new PGI “Aceituna Manzanilla Sevillana/Aceituna Gordal Sevillana” can significantly increase the production of Spanish protected olives in the near future as its application is in its final phase. These are olives elaborated following the Spanish style and have been highly esteemed by consumers for centuries. Practical Applications: The European system of PDO and PGI tries to protect farmers and processors against faked imitations of agricultural products intended for human consumption. Although it has not been used extensively by Spanish table olive processors, this protection system could help farmers to valorize their table olives in the future. This article gives an overview of the current use of the European system of protected designation of origin (PDO) and protected geographical indication (PGI) for Spanish table olives. This review hopes to address the effectiveness of these systems in preventing faked imitations of agricultural products intended for human consumption.

The table olive factory generates a large amount of wastewaters and this is a big environmental problem. The aim of this study was to look for a solution of this issue, using table olive waste as irrigation water during the growth of four Mediterranean crops: tomato (Solanum lycopersicum L.), strawberry (Fragaria x ananassa L.), cucumber (Cucumis sativus L.) and pepper (Capsicum annuum L.). These solutions were rich in sugars (17–85 mmoles L−1) and polyphenolic compounds (13–21 mmoles L−1), being hydroxytyrosol the main component (5.5–14.5 mmoles L−1). Also, some minerals were identified (carbon, nitrogen, sodium, potassium and phosphorus). The solutions were free of sodium chloride and no phytotoxic effect was detected, neither on the fruits or the leaves. The irrigation with the tested solutions originated an increase of the plant growth, fruit size and cumulative yield by at least 20% compared to the dipping and spraying applications mode. Also, it was observed a decrease of the powdery mildew disease in strawberry plants. Particularly, the fruit medium weight of cucumbers treated with table olive solutions was 40 g higher that the untreated fruits. Among the wastewaters generated during table olive processing, the wash water solution from Spanish-style green olives and the acidified storage liquids from black ripe olive processing could be employed as natural fertilizers and fungicide in substitution of synthetic products.