Table Olives Research Articles

Path dependencies in Turkish olive production: production arrangements of smallholders, middlemen and cooperatives

ABSTRACT Given the relatively low productivity in the Turkish table olive sector, this article characterizes different production arrangements and interrelationships between smallholders, middlemen (komisyoncus and stockus) and cooperatives to explain existing path-dependences of smallholders. It then identifies barriers for smallholders to upgrade their production methods to achieve higher income. The conceptual backdrop of the article are aspects of global value chains (GVC), which characterize the current organization of olive production and explain their implications for smallholders. The article argues that the combination of weak enforcement of standards as well as strong, one-sided dependencies of smallholders to middlemen (in particular komisyoncus) lead to development paths of high fragmentation, low productivity and low smallholder incomes. These development lock-ins are reinforced by state regulations and existing social networks based on established trust. Farmers’ cooperatives are one option to integrate value chains and improve the bargaining position of smallholders.

Spontaneous and Controlled Fermentation Tests in Industrial Table Olives Production

The process of debittering table olives, known as “natural”, represents the most studied method for its peculiarities. Searching among other studies, very little evidence was found about “outside the lab” tests; this encouraged our research, given the numerous external factors that could influence the whole process. In this study, we followed batch fermentation processes inside an industrial facility, testing both spontaneous and guided processes. The starter selected was a 1:1 ratio of Lactiplantibacillus plantarum B1 strain and Saccharomyces cerevisiae SC24 strain. (108 CFU/mL). Chemical-physical, microbiological, and phenolic parameters of five different barrels were analysed, with a periodic sampling (seven samplings). Results obtained confirmed logical correlations (p < 0.05 Pearson) between chemical-physical parameters (ashes vs. pulp/seed ratio, ashes vs. humidity, salt content vs. pulp/seed ratio, oil content vs. humidity) and showed a good discrimination between samples, especially regarding the phenolic profile of the different barrels (PCA and AHC). Microbiological analysis showed the evolution of microorganisms in the barrels, but the results have an unclear interpretation. No Enterobacter were found, so the safety of both process and product can be confirmed. These results highlight some criticalities of the industrial processes and represent useful data for technicians and production structures in order to improve the quality of the product and minimize losses.

Profile Phenolic Compounds in Spanish-Style and Traditional Brine Black Olives (‘Gemlik’ Cv.) Provided from Different Regions of Türkiye

The aim of this study was to evaluate the effect of growing regions and processing methods on the composition and the quantity of phenolic compounds in ‘Gemlik’ variety table olives. Two different processing methods, Spanish-style and traditional brine (naturally processed) olives, were used in the processing of ‘Gemlik’ table olives. According to the data obtained in this study, the highest concentrations of phenolic compounds were observed for 3-hydroxytyrosol (4.58–168.21 mg/kg), followed by 4-hydroxyphenyl (0.76–97.58 mg/kg), luteolin 7-glucoside (0.32–58.64 mg/kg), tyrosol (1.57–47.24 mg/kg), and luteolin (0.17–53.56 mg/kg) in overall samples. The highest quantity of phenolic compounds was determined in raw olives, and the lowest phenolic compound content was determined in Spanish-style processed olives. Table olives which are produced by the natural process were observed to contain higher concentrations of phenolic compounds compared with the olives, which are produced in the Spanish style. In this sense, statistical results showed that region and processing methods have significant impacts on the phenolic compounds of table olives.

Αpplication of Aspergillus niger for Extracellular Tannase and Gallic Acid Production in Non-sterile Table Olive Processing Wastewaters

Aspergillus niger B60 was screened for the first time toward extracellular tannase and gallic acid production by submerged fermentation using synthetic media supplemented with tannic acid as the sole carbon source at a wide concentration range (5–150 g/L). Maximum tannase (47 IU/mL) and gallic acid production (36 g/L) was obtained at initial tannic acid concentration 100 g/L. For this study, it was of interest to valorize non-sterile table olive processing wastewaters for fungal tannase production. In particular, lye and washing water effluents from Spanish-style green olive processing enriched with 100 g/L tannic acid provided effective alternative substrates for the production of tannase (21 IU/mL and 17 IU/mL, respectively) and gallic acid (22 g/L and 14 g/L, respectively). The fungal growth and tannase production kinetics were described by the Logistic and Luedeking–Piret models, respectively. The maximum dry biomass content and the maximum specific growth rate were more pronounced in the tannic acid-rich effluents (16–18 g/L and 0.5–0.6 1/h, respectively) than in the synthetic medium (11 g/L and 0.4 1/h, respectively) although in all cases tannase production was growth-associated. These novel findings cast a new light on successful biorefinery strategies of the effluents and warrant further investigation via process scaling-up and optimization.Graphical

Effect of elaboration process, crop year and irrigation on acrylamide levels of potential table olive varieties.

Table olives are widely consumed in the Mediterranean diet, and several typical Spanish and Portuguese varieties could potentially be used as such. In order to ensure a good-quality product, the effect of different factors such as elaboration processes, irrigation conditions, crop year and their crossover interaction on acrylamide content and antioxidant compounds needs to be deeply studied. When looking through irrigation, regulated deficit irrigation (RDI) presented lower acrylamide levels than rainfed conditions for 'Cordovil de Elvas', 'Picual' and 'Verdeal Alentejana'. No significant interactions were found between the type of irrigation and elaboration style for 'Arbequina' and 'Koroneiki' varieties. Although RDI had the largest concentration of total phenols, antioxidant activity was also the highest. The table olives harvested in the crop year of 2019 showed lower levels of acrylamide due to a significant relationship between the crop year and irrigation conditions. Novel varieties to be marketed should be taken into consideration for table olive elaboration. The impact of the crop year on the bioactive value of table olives and crossover interactions relies strongly in climatological conditions. Last but not least, the benefit of selecting the best irrigation and elaboration methods is crucial to ensure desirable acrylamide levels. © 2023 Society of Chemical Industry.

Innovative Device for Automated Monitoring of Table Olive Fermentation Parameters: First Experimental Results

The table olive sector is highly important to the Italian agri-food industry. To produce quality table olives without defects in appearance, flavors, or aroma and to meet consumer expectations, special precautions must be taken to limit side effects associated with transformation and storage processes. During these processes, essential to debitter and stabilize the final product, drupes may undergo undesirable fermentations due to changes in the olive-to-brine ratio, temperature changes, and alteration of the brine’s chemico–physical parameters, thus decreasing their commercial and nutritional value. An innovative user-friendly system, equipped with low-cost digital and sensorized devices, has been engineered and realized for step-by-step batch monitoring of table olive storage brines. The main fermentation parameters (i.e., temperature, pH, salinity, free acidity, volatile acidity, and residual sodium hydroxide) of virgin, compliant, and altered brines were analyzed with both the automated prototype and Official reference methods, with the aim of testing the functionality of the prototype device and verifying the reliability and repeatability of the measurements. Good linearity was observed for all parameters examined, with a relatively low mean deviation between the two approaches. It is therefore possible to constantly monitor brine conformity automatically during the processing stages, benefiting product quality and environmental, energy, and economic sustainability.

Use of Artificial Vision during the Lye Treatment of Sevillian-Style Green Olives to Determine the Optimal Time for Terminating the Cooking Process.

This study focuses on characterizing the temporal evolution of the surface affected by industrial treatment with NaOH within the processing tanks during the lye treatment stage of Manzanilla table olives. The lye treatment process is affected by multiple variables, such as ambient temperature, the initial temperature of the olives before lye treatment, the temperature of the NaOH solution, the concentration of the solution, the variety of olives, and their size, which are determinants of the speed of the lye treatment process. Traditionally, an expert, relaying on their subjective judgement, manages the cooking process empirically, leading to variability in the termination timing of the cook. In this study, we introduce a system that, by using an artificial vision system, allows us to know in a deterministic way the percentage of lye treatment achieved at each moment along the cooking process; furthermore, with an interpolator that accumulates values during the lye treatment, it is possible to anticipate the completion of the cooking by indicating the moment when two-thirds, three-fourths, or some other value of the interior surface will be reached with an error of less than 10% relative to the optimal moment. Knowing this moment is crucial for proper processing, as it will affect subsequent stages of the manufacturing process and the quality of the final product.

Autochthonous Microbes to Produce Ligurian Taggiasca Olives (Imperia, Liguria, NW Italy) in Brine

Table olives are considered high-quality food, and Italy has a wealth of varieties and typical features that are truly unique in the world (about eighty cultivars of table olives or dual-purpose olives, four of which are protected by the protected designation of origin—PDO), and it is the second largest European consumer, behind Spain. The Taggiasca olive does not have a PDO, but it is very appreciated not only in the region of production (Liguria), but also in all the Italian regions and abroad. Autochthonous microbes (bacteria, yeasts, and filamentous fungi) are essential in the fermentative processes for brine olive production. However, these microbial communities that colonised the olive drupes are affected by the environmental conditions and the fermentation treatments. Hence the importance of studying and comparing olive microbes from different farms and investigating the relationships between bacteria, yeasts, and filamentous fungi to speed up the deamarisation process. Our results showed that yeasts are dominant relative to lactobacteria in all three brines studied, and Wickerhamomyces anomalus was the most performant fungus for the oleuropein degradation. The latter represents the best candidate for the realisation of a microbial starter.

Inquiring Quality Assurance of the Table Olive Products

Table olives are the healthy fruit of the varieties of cultivated olive trees (Olea europaea), selected for the production of olives whose characteristics make them particularly suitable for processing. The processing of the olive is necessary, aiming mainly at the degradation of the phenolic glycoside oleuropein, a compound that gives a bitter taste to the fruit, making it impossible to consume immediately. Also, the various treatments aim to ensure the preservation of the product through the action of lactic acid bacteria (reducing the pH), to improve the quality of the final product (affecting the aroma, taste, texture, etc.). Olive varieties around the world are estimated to reach six hundred. Yet, there are three types of table olives in the market: natural black olives of the Greek type, black olives of California and green olives of the Spanish type. Table olive can be processed according to the method for natural black olives. Natural black olive is a natural product, i.e., the addition of chemicals is minimal. Its processing through the traditional method is simple and requires low energy consumption. The table olive processing plant must implement a healthy food production assurance system to protect the consumers from chemical hazards. This system is the HACCP (Hazard Analysis Critical Control Points) system, which is described by Codex Alimentarius. HACCP and ISO certification are a necessary step for most modern businesses, recognizing that a food business has developed, documented and implemented the right food production, standardization and packaging systems, according to these certifications.

Effect of Glucose and Inactivated Yeast Additions on the Fermentation Performances of Lactiplantibacillus pentosus OM13 during the Production of Nocellara del Belice Table Olives

The use of selected strains of lactic acid bacteria is necessary to produce fermented table olives with high hygiene and quality standards at the industrial level. A current tendency is the use of fermentation adjuvants (nutrients and activators) that can satisfy the nutritional needs of starter strains. In this study, five experimental protocols, different for nutrient and activator presence and addition of Lactiplantibacillus pentosus OM13 in freeze-dried form and after acclimatisation, were tested with the aim of improving the fermentation performances of the commercial starter. The trial inoculated with the starter strain acclimatised in the presence of nutrients and activator showed the most rapid acidification during the first phase of fermentation (third to ninth day), registering a pH loss of 3.40 units. The addition of adjuvants positively influences starter dominance (>89%) and rapid colonisation (>7 Log CFU/mL from third d) by indirectly limiting the presence of undesirable microorganisms. The analysis of volatile organic compounds revealed the presence of 32 chemicals distributed differently in each trial. Sensory evaluation showed that table olives produced with the different treatments were characterised by low bitterness, acidity, and absence of unpleasant odours/flavours. Control production showed slower acidification kinetics and lower sensory pleasantness than the other trials.

Phenolic and oleosidic compounds in different parts of Spanish olive cultivars: Influence of maturation and processing

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.

Supramolecular-solvent based extraction of hydroxytyrosol from brines of the processing of table olives

The recovery of bioactive compounds from agri-food waste is a growing sector and in line with the principles of green chemistry. In the last two decades, the development of processes for the extraction and purification of bioactive compounds that are cheaper, faster, simple, efficient, safe and ecological has been investigated. In this study, we develop for the first time a simple liquid–liquid extraction method of hydroxytyrosol from brines of the processing of table olives, an abundant and underutilized waste of the olive industry as alternative to nanofiltration and sorption onto resins. Brines contain a high concentration of phenolic compounds with beneficial health properties, the major compound being hydroxytyrosol. For the extraction of hydroxytyrosol from brines, green supramolecular solvents (SUPRASs) made up of 1,2-hexanediol and water and induced by salts (Na2SO4 and sodium citrate) were used, all innocuous and authorized ingredients for use in the cosmetic industry. The extraction process of hydroxytyrosol from brines was optimized (in terms of the amount of 1,2-hexanediol and salt for the synthesis of SUPRAS). The highest concentrations of hydroxytyrosol in the SUPRAS extracts (∼0.5–0.9% w/w) were obtained with 4.8% v/v of 1,2-hexanediol and 1 M of Na2SO4 for synthesis (equivalent to a SUPRAS:sample ratio of 1:20 v/v in the extraction process). The final extracts were further analyzed by liquid chromatography and high resolution mass spectrometry to identify other compounds of interest.

Table Olives: A Nutritional Approach to Health

Olea europaea L. is the botanical name for olive tree; it is usually produced in the Mediterranean countries. The by-products are table olives and olive oil; they undergo many processes in order to become edible for consumers. Table olives are affected by various agronomical factors; this affects the structure of nutritional and non-nutritional components. Some of the most significant nutrients include monounsaturated fatty acids (MUFAs), vitamin E and a substantial amount of phytochemicals. The primary aim of this review is to study the various bioactive compounds found in the table olives, it also comprehensively explained the numerous health benefits associated with the regular intake of olive oil.

Microbial and Chemical Characterization of Natural-Style Green Table Olives from the Gordal, Hojiblanca and Manzanilla Cultivars.

Microbial and biochemical changes in the brine during the spontaneous fermentation of Gordal, Hojiblanca and Manzanilla olive cultivars processed according to the natural style were monitored. The microbial composition was assessed through a metagenomic study. Sugars, ethanol, glycerol, organic acids and phenolic compounds were quantified by standard methods. In addition, the volatile profiles, contents of phenolic compounds in the olives and quality parameters of the final products were compared. Fermentation in Gordal brines was conducted by lactic acid bacteria (mainly Lactobacillus and Pediococcus) and yeasts (mainly Candida boidinii, Candida tropicalis and Wickerhamomyces anomalus). In Hojiblanca and Manzanilla brines, halophilic Gram-negative bacteria (e.g., Halomonas, Allidiomarina and Marinobacter) along with yeasts (mainly, Saccharomyces) were responsible for the fermentation. Higher acidity and lower pH values were reached in Gordal brines compared to Hojiblanca and Manzanilla. After 30 days of fermentation, no sugars were detected in Gordal brine, but residual amounts were found in the brines from Hojiblanca (<0.2 g/L glucose) and Manzanilla (2.9 g/L glucose and 0.2 g/L fructose). Lactic acid was the main acid product in Gordal fermentation, whereas citric acid was the predominant organic acid in the Hojiblanca and Manzanilla brines. Manzanilla brine samples showed a greater concentration of phenolic compounds than Hojiblanca and Gordal brines. After a 6-month fermentation, Gordal olives were superior compared to the Hojiblanca and Manzanilla varieties regarding product safety (lower final pH and absence of Enterobacteriaceae), content of volatile compounds (richer aroma), content of bitter phenolics (lower content of oleuropein, which resulted in less perceived bitterness) and color parameters (more yellow and lighter color, indicating a higher visual appraisal). The results of the present study will contribute to a better understanding of each fermentation process and could help to promote natural-style elaborations using the above-mentioned olive cultivars.

The Desalting Process for Table Olives and Its Effect on Their Physicochemical Characteristics and Nutrient Mineral Content.

The desalting process is critical for packaging table olives in brine with reduced NaCl or fortified mineral nutrients. In this study, the effect of desalting on the physicochemical characteristics and mineral content of green Manzanilla Spanish-style (plain and stuffed with pepper paste) and DOP Aloreña de Málaga table olives was investigated for the first time. The surface colour of the fruits turned slightly brownish, and the olives became somewhat softer. The lactic acid, the mineral macronutrients (mainly) and micronutrient contents decreased, while flesh moisture increased. The kinetic parameters of the minerals' losses depended on the presentation, with the estimated values for plain olives being the lowest (slowest desalting). Overall, the desalting process resulted in slight quality damage and a moderated decrease in the mineral concentration in the flesh, leading to some product degradation. This study provides quantitative information on these changes that may affect the commercial value of the final products and offers information for viable designs.

Simultaneous Trunk and Canopy Shaking Improves Table Olive Harvester Efficiency versus Trunk Shaking Alone

Production of California table olives has declined significantly in recent years due to hand harvesting costs, often over 60% of gross return. Mechanical harvesting could sharply decrease harvest costs, increasing economic viability. Mechanical harvester efficiency is a combination of the percentage of the total fruit on a tree removed by a harvester, and the time required to do so. A comparison between an experimental canopy contact shaker and a commercial trunk shaker demonstrated low harvest efficiencies and no significant differences in harvester efficiency between the two, averaging no more than 8%. However, simultaneously combining both shaking methods increased fruit removal to an economically feasible 75% and produced better fruit quality. Combining both shaking methods increased the price per ton by 63% versus trunk shaking and 35% versus canopy shaking. These results suggest a mechanical olive harvester that simultaneously combines trunk and canopy shaking is more efficient than either shaking method alone, and, has potential for economically feasible mechanical table olive harvesting.

The Fate of the Chlorophyll Derivatives in Olives Preserved and/or Packaged in Presence of Exogenous Copper.

Chlorophyll pigments are thought to be responsible for the highly appreciated green color of unfermented Castelvetrano-style table olives, but no studies have considered the effects of a controlled addition of copper during storage or packaging at the industrial level. For this purpose, chlorophyll derivatives were analyzed in Nocellara cultivar table olives debittered industrially using the Castelvetrano method, via means of HPLC and MS analyses, following the addition of copper in alkaline brines stored at 4 °C for 3 months in 220 L barrels, and during the subsequent storage in acid brines in commercial 400 g packages at 4 °C for up to 18 months. The presence of copper in storage or in packaging brines both contributed significantly to maintaining the green color of the olives, which was associated with a specific pattern of chlorophyll derivatives, as evidenced by principal component analysis. Notably, re-greening was rapidly achievable also for olives that had yellowed for 18 months at a copper concentration below the limit of EU legislation. Finally, by means of PCA, we also demonstrated that a short-term thermic treatment can work as an accelerated predictive tool in determining the fate of chlorophyll derivatives.

The Ancient Olive Trees (Olea europaea L.) of the Maltese Islands: A Rich and Unexplored Patrimony to Enhance Oliviculture.

A prospecting campaign in the Maltese Islands has ensured the survival of several ancient olive trees (Olea europaea L.), genetically distant from known cultivars. Most of these plants were abandoned or partially cultivated. A two-year evaluation of fruit characteristics and compositions was performed on samples collected from the main representatives of these indigenous genotypes. Analyses were carried out using Gas Chromatography, High-Performance Liquid Chromatography and Near Infrared Spectrometry. Among the fruit samples, a wide range of variations was observed. Some of the genotypes showed fruit traits suitable for table olive production. This is the case of samples with a pulp/pit ratio higher than four, such as 1Wardija, 1Caritas, 1Plattini, 1Bingemma Malta and 3Loretu, whilst 1Bidni, 1Mellieha, 2Qnotta, 3Loretu, 1Bingemma Malta and 1Caritas were suitable for dual purpose. The total phenol content ranged from 6.3 (1Wardija) to 117.9 (2Mtarfa) g/kg of fresh pulp. The average percentage of MUFA was quite low for most of the varieties. These genotypes, which presumably originated in the Maltese Islands and are well adapted to the local pedo-climatic conditions, are being propagated for the following evaluation of their bio-agronomical performance (production, suitability to intensive cultivation, environmental sustainability, product quality, etc.). The purpose is to select, among these local genotypes, the most outstanding varieties, in terms of phenolic and FA profile and agronomical potential, to spread into cultivation, thereby contributing to an increase in the quality of the local table and olive oil production, strongly linked to the territory.

Concentration of phenolic compounds from olive washing wastewater by forward osmosis using table olive fermentation brine as draw solution

The olive industry has a considerable amount of process water consumption. As a result of the process, a large volume of oil mill wastewater (OMW) and table olive wastewater (TOW), both of them with high concentrations of organic matter, phenolic compounds and conductivity, are released. The appropriate management of these wastewaters is of paramount importance due to their toxic impacts on the environment. In this work, forward osmosis (FO) process is presented as an option to concentrate phenolic compounds for their further recovery. Two membranes, OsmoF2OTM (FTS, USA) and HFFO.6 (Aquaporin, Denmark) were evaluated with NaCl as draw solution (DS) and olive oil washing wastewater (OOWW) filtered at 5μm (5F) as feed solution (FS). Both membranes were able to concentrate the phenolic compounds with acceptable volume reduction (VR) values. The HFFO.6 membrane, which presented the lowest passage of phenolic compounds (TPhC) to the DS, was tested with fermentation brine from table olive processing (FTOP) as DS. As FS the same 5F-OOWW as well as an OOWW ultrafiltration permeate (UF-OOWW) were considered. Interestingly, greater percentages of TPhC concentration were observed compared to the tests with NaCl as DS (74.13–76.93% versus 62.6%, respectively). Although the tests with UF-OOWW presented greater flux, the recovery percentages of TPhC were similar, even slightly lower than those obtained with 5F-OOWW. Therefore, FO appears as a promising option to concentrate TPhC from OOWW and as well as to dilute FTOP. Thus both wastewaters from the olive industry could be treated at the same time.

Machine olfaction discrimination of Spanish-style green olives inoculated with spoilage mold species

As an alternative to traditional sensory analysis evaluation, machine olfaction represents a valuable tool for detecting incipient defects caused by microorganisms. For this purpose, different strains of spoilage molds were inoculated into Spanish-style table olives and the effect on their sensory quality and volatile profile were analyzed using an electronic nose (E-nose). The main defects obtained for the different inoculated microorganisms associated with abnormal fermentation were mold and humidity. A total of 36 volatile compounds were identified and classified into phenolics, alcohols and carboxylic acids, while minor ones included derivatives of acids and oxygenated compounds. In general, a decrease in the concentrations of acetic acid, phenolic compounds and creosol was observed in olives inoculated with mould strains. However, propanoic acid, 2-methoxy-phenol, 2,4-dimethyl-heptane, among others, increased after mold inoculation. Sensorial and volatile compound analysis showed the table olives inoculated with the strains of Aspergillus flavus A.F.18 and Penicillium expansum P.E.20 to be the most altered. The E-nose data were able to classify the inoculated olives into different categories and distinguish them from the control treatment, regardless the intensity of the defect. The principal component analysis (PCA) of table olives inoculated showed that 70.23% of the total variance of data was explained by PC1 and 23.27% by PC. The sum of the elements of the diagonal of the confusion matrix gives the percentage of success in discrimination of 95.5%. Therefore, these results show the capacity and precision of E-nose to discriminate between the alterations caused by different mold strains.