Table Olive Processing Research Articles

Abnormal fermentations in table-olive processing: microbial origin and sensory evaluation.

The process of transformation of table olives from tree to table is the result of complex biochemical reactions that are determined by the interactions between the indigenous microflora of the olives, together with a variety of contaminating microrganisms from different sources [fiber-glass fermenters, polyvinyl chloride (PVC) tanks, pipelines, pumps, and water], with the compositional characteristics of the fruit. One of the most important aspects of improving the quality of table olives is the use of selected microorganisms to drive the fermentation. These can supplant the indigenous microflora and, in particular, the complementary microflora that are responsible for spoilage of canned olives. In this context, from a technological point of view, a well-characterized collection of microrganisms (lactic acid bacteria, yeast) that can be isolated from the matrix to be processed (the olive fruit) will provide the basis for the development of starter culture systems. These cultures can be fully compatible with the typical products and will guarantee high quality standards. Inoculation of the brine with such selected starter cultures will reduce the probability of spoilage, and help to achieve an improved and more predictable fermentation process. Control of the fermentation processes can thus occur through chemical, chemico-physical and microbiological approaches, and since 2008, also through organoleptic evaluation (COI/OT/MO/Doc. No 1. Method for the sensory analysis of table olives). This last has established the necessary criteria and procedures for sensory analysis of the negative, gustatory and kinaesthetic sensations of table olives, which can also be attributed to abnormal proliferation of microrganisms. It also sets out the system for commercial classification, through assessment of the median of the defect predominantly perceived.

Evaluating the individual effects of temperature and salt on table olive related microorganisms

Statistical modelling techniques were used in the present study to assess the individual effects of temperature and NaCl concentration on the growth of 10 lactic acid bacteria and 6 yeast strains mostly isolated from different forms of table olive processing and belonging to the species Lactobacillus pentosus, Lactobacillus plantarum, Saccharomyces cerevisiae, Wickerhamomyces anomalus and Candida boidinii. The mathematical models obtained in synthetic laboratory media show that yeasts, except for C. boidinii, were more resistant to a high salt concentration than lactic acid bacteria, with an MIC value ranging from 163.5 (S. cerevisiae) to 166.9 g/L (W. anomalus); while for L. pentosus and L. plantarum this parameter ranged from 110.6 to 117.6 g/L, respectively. With regards to temperature, lactic acid bacteria showed a slight trend towards supporting higher temperature values than yeasts, with the exception of S. cerevisiae. The maximum temperatures for growth of L. pentosus and L. plantarum were 41.9 and 43.0 °C, respectively; while for W. anomalus and C. boidinii they were 38.2 and 36.5 °C. The optimum temperatures for growth were also higher for L. pentosus and L. plantarum (35.5 and 32.9 °C), compared to W. anomalus and C. boidinii (29.3 and 26.9 °C, respectively). Additional experiments carried out in natural olive brines confirmed previous results, showing that high NaCl concentrations clearly favoured yeast growth and that at high temperatures LAB slightly overcame yeasts. Results obtained in this paper could be useful for industry for a better control of both table olive fermentation and packaging.

Defining economic obstacles to the adoption of food safety systems in table olive processing firms

PurposeThe concept of food safety systems is increasing worldwide among farmers, manufactures, and processors and is also affecting consumer perspectives. This trend primarily impacts food businesses and table olive processing firms. The study seeks to explore the major economic obstacles to the adoption of food safety systems in table olive processing firms.Design/methodology/approachAll 59 table olive businesses in the Aydın Province of Turkey were included in the survey. In an effort to remove extraneous items and demonstrate internal consistency, Cronbach's alpha was calculated for each variable. To better specify the economic obstacles to food safety system implementation, data were examined with exploratory factor analysis using principal component extraction and varimax rotation.FindingsMajor economic obstacles that most prominently emerged from analyses may explain several key indicators including difficulties in employing well‐trained personnel required for food safety systems, insufficient training facilities for employees intended to aid in the implementation of food safety systems, deficiency of infrastructure and other physical conditions, and deficient financial support from government and non‐government organizations.Research limitations/implicationsThe study investigated only table olive processors. Future research should include analyses of consumer behaviors.Practical implicationsThe Turkish government must ensure implementation of food safety systems to increase public knowledge and accelerate government funds for the establishment of such systems in the food business industry.Originality/valueThe study contributes to the positive perceptions of managers and their behaviors towards implementation of food safety systems in table olive processing firms. Since the paper is one of only a few dealing with this topic, it provides key clues for dissemination of food safety systems adoption at the firm level.

Factors Influencing Phenolic Compounds in Table Olives (Olea europaea)

The Mediterranean diet appears to be associated with a reduced risk of several chronic diseases including cancer and cardiovascular and Alzheimer's diseases. Olive products (mainly olive oil and table olives) are important components of the Mediterranean diet. Olives contain a range of phenolic compounds; these natural antioxidants may contribute to the prevention of these chronic conditions. Consequently, the consumption of table olives and olive oil continues to increase worldwide by health-conscious consumers. There are numerous factors that can affect the phenolics in table olives including the cultivar, degree of ripening, and, importantly, the methods used for curing and processing table olives. The predominant phenolic compound found in fresh olive is the bitter secoiridoid oleuropein. Table olive processing decreases levels of oleuropein with concomitant increases in the hydrolysis products hydroxytyrosol and tyrosol. Many of the health benefits reported for olives are thought to be associated with the levels of hydroxytyrosol. Herein the pre- and post-harvest factors influencing the phenolics in olives, debittering methods, and health benefits of phenolics in table olives are reviewed.

Biofilm formation on abiotic and biotic surfaces during Spanish style green table olive fermentation

In this work, the establishment of polymicrobial communities on the surfaces which come into contact with the brine during Spanish style Gordal cv. green olive fermentation when subjected to spontaneous or controlled processes (inoculated with Lactobacillus pentosus LPCO10 or 128/2) was studied. Scanning electron microscopy showed that L. pentosus and yeast populations were able to form mixed biofilms throughout the fermentation process on both abiotic (glass slide) and biotic (olive skin) surfaces. The biofilm architectures in both supports were completely different: on the glass slides only aggregates of L. pentosus and yeasts without any polymeric matrix surrounding them were found while on the skin of the fruits, true mature biofilms were observed. During fermentation, the lactic acid bacteria (LAB) population on the olives remained similar while that of yeasts increased progressively to reach similar levels at the end of the process (8–9logCFU/cm2). Molecular analysis showed that different populations of L. pentosus and yeasts were the only microbial members of the biofilm formed during fermentation, regardless of inoculation. Hence, the green olive surface provides an appropriate environmental condition for the suitable development and formation of complex biofilms during controlled or natural table olive processing.

Potential benefits of the application of yeast starters in table olive processing.

Yeasts play an important role in the food and beverage industry, especially in products such as bread, wine, and beer, among many others. However, their use as a starter in table olive processing has not yet been studied in detail. The candidate yeast strains should be able to dominate fermentation, together with lactic acid bacteria, but should also provide a number of beneficial advantages. Technologically, yeasts should resist low pH and high salt concentrations, produce desirable aromas, improve lactic acid bacteria growth, and inhibit spoilage microorganisms. Nowadays, they are being considered as probiotic agents because many species are able to resist the passage through the gastrointestinal tract and show favorable effects on the host. In this way, yeasts may improve the health of consumers by means of the degradation of non-assimilated compounds (such as phytate complexes), a decrease in cholesterol levels, the production of vitamins and antioxidants, the inhibition of pathogens, an adhesion to intestinal cell line Caco-2, and the maintenance of epithelial barrier integrity. Many yeast species, usually found in table olive processing (Wickerhamomyces anomalus, Saccharomyces cerevisiae, Pichia membranifaciens, and Kluyveromyces lactis, among others), have exhibited some of these properties. Thus, the selection of the most appropriate strains to be used as starters in this fermented vegetable, alone or in combination with lactic acid bacteria, is a promising research line to develop in the near future.

Microbial dynamics and biodiversity in table olive fermentation: culture-dependent and -independent approaches

The microbial ecology of the table olive fermentation process is a complex set of dynamics in which the roles of the lactic acid bacteria (LAB) and yeast populations are closely related, and this synergism is of fundamental importance to obtain high quality products. Several studies on the ecology of table olives, both in spontaneous fermentations and in inoculated ones, have focused on the identification and characterization of yeasts, as they play a key role in the definition of the final organoleptic profiles through the production of volatile compounds. Moreover, these are able to promote the growth of LAB, which is responsible for the stabilization of the final product through the acidification activity and the inhibition of the growth of pathogenic bacteria. The current empirical production process of table olives could be improved through the development of mixed starter cultures. These can only be developed after a deep study of the population dynamics of yeasts and LAB by means of molecular methods. Until now, most studies have exploited culture-dependent approaches to define the natural microbiota of brine and olives. These approaches have identified two main species of LAB, namely Lactobacillus plantarum and L. pentosus, while, as far as yeasts are concerned, the most frequently isolated genera are Candida, Pichia, and Saccharomyces. However, there are a few studies in literature in which a culture-independent approach has been employed. This review summarizes the state of the art of the microbial ecology of table olive fermentations and it focuses on the different approaches and molecular methods that have been applied.

Multivariate analysis to discriminate yeast strains with technological applications in table olive processing

This survey uses a multivariate classification analysis to discriminate yeast strains with interesting biochemical activities for the processing of table olives among a collection of 32 isolates belonging to 16 different yeast species. Lipase, esterase and β-glucosidase activities (desirable characteristics) were quantitatively evaluated in both extracellular and cellular fractions for all isolates in different types of culture media. The study of the quantitative data by cluster and principal component analyses led to the identification of several Wickerhamomyces anomalus, Candida boidinii and Candida diddensiae isolates with promising characteristics (the best global activity levels), clearly differentiated from the rest of the yeasts. The results obtained in this work open up new alternatives to this methodology for the study, classification and selection of the most suitable yeasts to be used as starters, alone or in combination with lactic acid bacteria, during table olive processing.

Isolation and preliminary characterization of Lactobacillus plantarum bacteriophages from table olive fermentation

Nine table olive fermentation brines were analysed to demonstrate the presence of lytic bacteriophages active against Lactobacillus plantarum strains. Five brines, out of the nine studied, were added to selected strains of L. plantarum as starter cultures, while the other four brines were left to ferment spontaneously. Turbidity tests with different host strains inoculated in growth medium with added filter-sterilized brines demonstrated the presence of phages able to lyse the sensitive strains. Phages were isolated from fermented brines and their presence was confirmed by scanning electron microscopy. A subsequent phage characterization based on host range, restriction analysis and protein profiles was performed. This study reported for the first time the isolation and characterization of L. plantarum phages from table olive fermentation. This demonstrated presence of lytic phages active against L. plantarum could represent a serious obstacle in the regular table olive fermentation process. For these reasons, the search for phage-resistant strains, to use as starter cultures, could be important to counteract the development of fermentation problems.

A critical literature review on the processing of table olives

AbstractAbout 20% of the fruits of olive trees are used for producing table olives, but the literature on the lipid composition of extracted table olives is limited and controversial. Although, the composition of olive oils extracted from various sources has been extensively reported, excessive efforts have been devoted on the use of undefined chemometric methods requiring sophisticated statistical techniques. More reliable and sensitive chemical methods are required to analyze oils from different olive preparations, including widely ranging polyunsaturated fatty acids that affect significantly the oxidative stability of the extracted oils.

Modeling the inhibitory effects of zinc chloride on table olive related yeasts

This survey examines the inhibitory effects of ZnCl2 on 22 yeast strains of the genera Saccharomyces, Wickerhamomyces, Debaryomyces, Issatchenkia, Candida, Pichia, Kluyveromyces and Torulaspora, all of them isolated from diverse table olive processing. The yeasts were first incubated in a laboratory medium supplemented with different ZnCl2 concentrations (0–250 mg/L) and monitored by means of optical density measurements for 100 h in an automated spectrophotometer at 30 °C. Fractional areas were used to estimate the non-inhibitory concentrations, which ranged from 22 mg/L (Debaryomyces etchellsii TOMC Y24) to 178 mg/L (Candida diddensiae TOMC Y1), and minimum inhibitory concentration, which oscillated from 84 mg/L (Wickerhamomyces anomalus TOMC Y11) to 238 mg/L (C. diddensiae TOMC Y1), of the assayed strains to ZnCl2. Time to kill curves were then obtained by spread plating at three ZnCl2 concentrations (250, 500 and 1000 mg/L) above the highest minimum inhibitory concentration obtained. Data showed that, in some cases, the growth was only ceased, but a clear reduction in the initial number of viable cells (well fitted by means of the Weibull’s equation) was always noticed at the highest ZnCl2 concentration. The results obtained in this work open new alternatives to the use of ZnCl2 as a yeast preservative agent in fermented vegetable (olives, cucumber, capers, etc.) which may be spoiled by these microorganisms.

Biochemistry of volatile compounds during the processing of table olives

Biochemistry of volatile compounds during the processing of table olives

Chemometric Classification of the Fat Residues from the Conditioning Operations of Table Olive Processing, Based on their Minor Components

The work characterizes the unsaponifiable matter of fats released in pitting green (GP) and ripe (RP) olives, in pitting/stuffing green olives with vegetable (GPSV) and animal (GPSA) products and in the fat settled at the end of the factory sewer system (W). The unsaponifiable matter ranged from 1.94% (RP) to 5.91% (GPSA); total sterols from 1319 mg/kg fat (GPSV) to 2002 mg/kg fat (RP), with β-sitosterol as the most abundant. Fatty alcohols ranged from 242 mg/kg (GP) to 556 mg/kg (W), with C22 as the most abundant. Triterpene diols were found only in GPSV (erythrodiol + uvaol, 0.80%). Wax was not present in the fats from GP and RP but increased with the general fat degradation in the order GPSV (128 mg/kg), GPSA (171 mg/kg) and W (263 mg/kg). Chemometric analysis was able to detect differences among the diverse fats; sterols + fatty alcohols cluster analysis was useful for fat grouping.

Microbiological quality and biophenol content of hot air‐dried Thassos cv. table olives upon storage

Microbiological quality and biophenol content evolution was studied in minimally processed Thassos cv table olives by hot air dehydration under mild conditions (40°C, 24 h, aw = 0.893) and storage under characteristic packaging conditions (vacuum, 100% N2 and air) at 4 and 20°C over a period of 180 days. No salt was used in the production line or packaging. The undesirable microorganisms (Enterobacteriaceae, Staphylococcus aureus, Bacillus, Clostridium) were undetectable until the end of the storage period. Also, modified atmospheres prevented fungal growth at both temperatures apart from the samples stored in air, in which Penicillium and Aspergillus spp. were identified. At 20°C, a coexistence of mesophilic bacteria and yeasts occurred. At 4°C, yeasts were the predominant microflora. All of the samples analysed were found to be rich sources of the bioactive ingredients, elenolic acid (EA) glycoside and EA. Hydroxytyrosol and derivatives, caffeic acid, luteolin 7-O-glycoside, apigenin derivative and p-coumaric acid derivative assigned as comselogoside were the prevailing phenols in all of the samples. Although the levels of the above compounds decreased upon processing and storage, especially in the samples stored at 4°C, their presence is important for stability because of their high antimicrobial and antioxidant activities. Practical applications: Reducing the amount of salt used in the table olive processing and preservation seems to be an important innovation though this is not a straightforward process, as salt plays an important role in the microbiological quality of the end product. Our study faces such a challenge in the case of minimally processed Thassos cv olives by hot air dehydration under mild conditions (40°C, 24 h, aw = 0.893), which, traditionally, are processed by means of salt. To our knowledge, this is the first report focusing on the evolution of microbiological quality and biophenol content of hot air-dried Thassos olives upon storage under characteristic modified-atmosphere packaging conditions (vacuum and 100% N2). This experimentation provided evidence that this product can be considered as one with a satisfactory microbiological quality and nutritional value with regard to bioactive ingredients and the absence of salt. Assessment of the ‘best before date’ of this product is needed before commercialization.

Estimating the bioremediation of green table olive processing wastewater using a selected strain of Aspergillus niger

Green table olive processing wastewater (TOPW) constitutes a notoriously polluting and difficult to treat wastewater, mainly due to its high polyphenol and organic content. This study reports on the laboratory development of an aerobic biological treatment method for TOPW, using a selected strain of Aspergillus niger . Two duplicated treatments from a single green table olive producing plant were examined in order to assess the bioremediation potential of the selected strain of Aspergillus niger. The wastewater arising from two different production processes was examined: (a) the typical debittering protocol, using dilute NaOH solution, and (b) an alternative protocol, using dilute KOH solution. Trials were carried out using cultures in flasks, and were monitored for changes in the pH values, electrical conductivity, oxygen uptake rate, chemical oxygen demand (COD), total solids, and total phenols, for 118 hours. A total of 5 dilutions (100%, 85%, 70%, 55%, and 40%) of wastewater were inoculated with Aspe...

Life Cycle Assessment (LCA) used to compare two different methods of ripe table olive processing

The aim of the present study is to analyze the most common method used for processing ripe table olives: the “California style”. Life Cycle Assessment (LCA) was applied to detect the “hot spots” of the system under examination. The LCA results also allowed us to compare the traditional “California style”, here called “method A”, with another “California style”, here called “method B”. We were interested in this latter method, because the European Union is considering introducing it into the product specification of the Protected Denomination of Origin (PDO) “La Bella della Daunia”. It was also possible to compare the environmental impacts of the two “California style” methods with those of the “Spanish style” method. From the comparison it is clear that “method B” has a greater environmental impact than “method A” because greater amounts of water and electricity are required, whereas “Spanish style” processing has a lower environmental impact than the ”California style” methods.

Fermentation profiles of Manzanilla-Aloreña cracked green table olives in different chloride salt mixtures

NaCl plays an important role in table olive processing affecting the flavour and microbiological stability of the final product. However, consumers demand foods low in sodium, which makes necessary to decrease levels of this mineral in fruits. In this work, the effects of diverse mixtures of NaCl, CaCl 2 and KCl on the fermentation profiles of cracked directly brined Manzanilla-Aloreña olives, were studied by means of response surface methodology based in a simplex lattice mixture design with constrains. All salt combinations led to lactic acid processes. The growth of Enterobacteriaceae populations was always limited and partially inhibited by the presence of CaCl 2. Only time to reach half maximum populations and decline rates of yeasts, which were higher as concentrations of NaCl or KCl increased, were affected, and correspondingly modelled, as a function of salt mixtures. However, lactic acid bacteria growth parameters could not be related to initial environmental conditions. They had a longer lag phase, slower growth and higher population levels than yeasts. Overall, the presence of CaCl 2 led to a slower Enterobacteriaceae and lactic acid bacteria growth than the traditional NaCl brine but to higher yeast activity. The presence of CaCl 2 in the fermentation brines also led to higher water activity, lower pH and combined acidity as well as a faster acidification while NaCl and KCl had fairly similar behaviours. Apparently, NaCl may be substituted in diverse proportions with KCl or CaCl 2 without substantially disturbing water activity or the usual fermentation profiles while producing olives with lower salt content.

Influence of Ripe Table Olive Processing on Oil Characteristics and Composition As Determined by Chemometrics

The changes in ripe olive fat produced by processing were studied according to cultivars using the general linear model, principal component analysis (PCA), predictive discriminant analysis (DA), and hierarchical clustering. Acidity, peroxide value, K(270), and DeltaK increased during storage. Acidity also increased after sterilization, whereas K(270) decreased after darkening; K(232) showed a progressive decrease during processing. Fatty acids (except C17:0, C18:0, and C24:0), triacylglycerols (except PLLn, OOLn+PoOL, PLL+PoPoO, SOO, and POS+SLS), polar compounds, diacylglycerol, and monoacylglycerols also suffered statistically significant changes during processing. A PCA discriminated between cultivars and, within the same cultivar, among the raw materials from the rest of the treatments. Using fatty acid and triacylglycerol compositions, predictive DA discriminated between cultivars (100% correct), but high discriminant capacity among processing steps (95% correct assignation and 87% in cross-validation) was achieved only with fatty acids. A hierarchical clustering analysis successfully grouped cultivars and processing steps according to overall olive oil composition and quality.

Study of green Sicilian table olive fermentations through microbiological, chemical and sensory analyses

The production of five different green table olive cultivars was studied by a combined strategy consisting of chemical, microbiological and sensory analyses. Cultivable microflora of samples collected during processing was monitored by plate counts on seven synthetic culture media. In all samples Enterobacteriaceae, Pseudomonaceae, staphylococci, lactic acid bacteria and spore-forming bacteria were undetectable. Yeasts and moulds were countable from the day 42 (2 log CFU/ml) till the end of fermentation (6 log CFU/ml). The use of three different approaches for microorganism detection, including a culture-independent methodology, revealed the presence of barely three yeast species during the entire fermentation period: Candida parapsilosis, Pichia guilliermondii and Pichia kluyveri. Biochemical features of technological interest were evaluated for 94 strains in order to investigate their potential role in fermentation of green Sicilian table olives. Olive drupes sampled at picking and periodically during fermentation were also carpologically analyzed, revealing that all the cultivars were suitable for table olive fermentation process. After 120 days of fermentation all products met acceptable commercial standards, although GC–MS analysis evidenced several differences among varieties in terms of aroma components. Results from sensory evaluation led to the conclusion that a revision of technological procedures may improve the final quality of product.

EFFECT OF THE USE OF DIFFERENT LACTIC STARTERS ON THE MICROBIOLOGICAL AND PHYSICOCHEMICAL CHARACTERISTICS OF NATURALLY BLACK TABLE OLIVES OF GEMLIK CULTIVAR

ABSTRACT The effect of different lactic acid bacteria cultures on the physicochemical and microbiological characteristics of brined black olives of Gemlik cultivar at low fermentation temperature was studied. Fermentation was carried out according to the traditional Gemlik method with modifications like low salt concentration and lactic starter addition. The brines with 7% salt concentration were inoculated with lactic acid bacteria (Lactobacillus brevis, Leuconostoc cremoris and L. paramesenteroides), which were previously isolated from olive fruits at low temperatures and a commercial strain of Lb. plantarum. Fermentation procedures were carried out at controlled temperatures (between 10–12C). Lactic acid bacteria survival was accompanied by yeast development, no Pseudomonas and Enterobacter species were detected in all treatments during fermentation. The highest total titratable acidity, lowest pH and least yeast growth were determined at the brines and fermentation products, which were inoculated with L. cremoris. PRACTICAL APPLICATIONS The use of suitable starter cultures is necessary to improve the microbiological control of the naturally black table olive process, help to standardize the fermentation, increase the lactic acid yield and accordingly provide the production of olives with high quality. The requirements mentioned for starter cultures include a rapid and predominant growth, homofermentative metabolism, tolerance to salt, acid and polyphenols, and few growth factor requirements. Especially at the regions where olives were picked later when environmental temperatures are lower, the use of a starter culture that has the ability to grow at low temperatures may be necessary. Use of such starter cultures may help to increase acidification, to control some types of spoilage and to shorten the fermentation process.