Table Olives More than a Fermented Food Perpetuini, Giorgia; Prete, Roberta; Garcia-Gonzalez, Natalia ...
Foods,
02/2020, Letnik:
9, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Table olives are one of the oldest vegetable fermented foods in the Mediterranean area. Beside their economic impact, fermented table olives represent also an important healthy food in the ...Mediterranean diet, because of their high content of bioactive and health-promoting compounds. However, olive fermentation is still craft-based following traditional processes, which can lead to a not fully predictable final product with the risk of spontaneous alterations. Nowadays, food industries have to face consumer demands for safe and healthy products. This review offers an overview about the main technologies used for olive fermentation and the role of lactic acid bacteria and yeasts characterizing this niche during the fermentation. Particular attention is offered to the selection and use of microorganisms as starter cultures to fasten and improve the safety of table olives. The development and implementation of multifunctional starter cultures in order to obtain heath-oriented table olives is also discussed.
Table olives are among the most well-known fermented foods, being a vital part of the Mediterranean pyramid diet. They constitute a noteworthy economic factor for the producing countries since both ...their production and consumption are exponentially increasing year by year, worldwide. Despite its significance, olive's processing is still craft based, not changed since antiquity, leading to the production of an unstable final product with potential risk concerns, especially related to deterioration. However, based on industrial needs and market demands for reproducible, safe, and healthy products, the modernization of olive fermentation processing is the most important challenge of the current decade. In this sense, the reduction of sodium content and more importantly the use of suitable starter cultures, exhibiting both technological and potential probiotic features, to drive the process may extremely contribute to this need. Prior, to achieve in this effort, the full understanding of table olive microbial ecology during fermentation, including an in-depth determination of microbiota presence and/or dominance and its functionality (genes responsible for metabolite production) that shape the sensorial characteristics of the final product, is a pre-requisite. The advent of meta-omics technology could provide a thorough study of this complex ecosystem, opening in parallel new insights in the field, such as the concept of microbial terroir. Herein, we provide an updated overview in the field of olive fermentation, pointing out some important challenges/perspectives that could be the key to the olive sector's advancement and modernization.
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•Industrial-scale production of Spanish-style & natural cv. Chalkidiki green olives.•All products were safe with high nutritional value and desirable sensory attributes.•Metabolite ...profile of polar extracts from olives & brines was processing-depended.•Lye treatment absence maintained the triterpenic acids content in olives.•Reducing NaCl level in processing led to lower Na in flesh.
Table olives are among the most popular fermented foods and cv. Chalkidiki green table olives are particularly popular in both Greek and international markets. This work aimed at comparatively investigating the effect of processing method on the production of Spanish-style and natural cv. Chalkidiki green olives during fermentation and 12-month storage in brines with different chloride salts composition (NaCl, KCl, CaCl2) at industrial scale. All delivered products were safe with satisfactory color and texture characteristics. Employment of UPLC-HRMS revealed differences in metabolites’ profile of polar extracts from olives and brines between the processing methods. Τhe application of alkali treatment drastically decreased the content of hydroxytyrosol and tyrosol in drupes, still an essential amount (1037–2012 and 385–885 mg/kg dry flesh, respectively) of these health-promoting phenolic compounds was retained in all products, even after storage. Noteworthy, fermentation of natural olives in brine (5 % NaCl) yielded in products with significantly lower Na levels in olive flesh (1.7 g/100 g), followed by Spanish-style olives fermented in low (4 %) and high (8 %) NaCl brines (2.7 and 5.2 g Na/100 g, respectively), supporting the efforts toward the establishment of table olives as functional food. Moreover, maslinic and oleanolic acids content was 1.5–2-fold higher in the natural table olives compared to the Spanish-style ones owing to the detrimental effect of alkali treatments. The processing method did not exert a differential effect on α-tocopherol content of olives. Sensory analysis indicated that all the final products were acceptable by consumers, with a slight preference for Spanish-style green olives fermented in brines with 50 % lower NaCl content. Present findings could be beneficial to the ongoing endeavor directed for the establishment of table olives as a source of bioactive compounds that concerns both industrial and scientific communities.
This study aims to evaluate the use of a multiple-strain cocktail (Lactiplantibacillus plantarum, Candida norvegica, and Wickeramomyces anomalus) as a starter culture for “Peranzana Alta Daunia” ...olives. The effect of the veraison degree of drupes (violet or green) and brine salt concentration (6 or 8%) on the acidification kinetics was analysed by using a 2k Factorial Design. The acidification was affected by all the variables tested with the veraison degree as the most significant one; in fact, neither salt concentration nor the presence of the starter was able to improve the acidification kinetics when unripe fruits were used.
Knowledge of the microbial biodiversity through the different stages of black ripe olive processing is minimal. This study applied a metagenomic approach to evaluate the bacterial and fungal ...communities present in samples of two olive cultivars collected from an industrial producer. High-throughput sequencing and analysis of the V2-V3 region of the bacterial 16S rRNA genes showed that genus Acetobacter and the lactic acid bacteria (LAB) Lactobacillus and Oenococcus were the most abundant during most of the process. Other LAB genera (Enterococcus, Lactococcus, Weisella, Leuconostoc and Streptococcus), as well as Enterobacteriaceae and Vibrio were also detected, increasing their abundance in the last step before packaging. Some genera, such as Pseudoalteromonas, Alteromonas, Marinomonas and Oenococcus, had never been previously detected in table olives. The fungal community was characterized by the presence of Pichia membranifaciens, Kregervanrija fluxuum and members of the family Dispodascaceae. Although black ripe olives are sterilized before trading, the consequences that these findings may have on the quality of this product are discussed.
•Microbiota present in black ripe olive processing determined for the first time.•Microbial diversity increased throughout the successive stages.•High-throughput sequencing found out taxa never before cited in table olives.
The evolution of safety and other quality parameters of the Greek green table olives PDO “Prasines Elies Chalkidikis” that are prepared according to the Spanish style processing is examined ...systematically at the industrial scale and 12 month storage for two consecutive periods for the first time. Evolution of safety parameters (bacteria/yeasts, pH, acidity) during fermentation in brine and on olives upon storage, changes in olive color and texture during storage, and the fate of characteristic hydrophilic and hydrophobic antioxidants (oleuropein, ligstroside, and related compounds, α‐tocopherol, squalene), and sodium content are monitored using appropriate methods. Sensory scores are also provided in certain cases. Findings support that the final product is microbiologically safe and of acceptable characteristics. However, except for compliance with trade quality criteria, attention should be paid to the reduction in phenolic compounds (hydroxytyrosol, tyrosol) content and the important increase in sodium content due to fermentation and storage in brine. This prototype model study indicates loopholes in the efforts to establish table olives as a functional food.
Practical Applications: Industry has to compromise legal safety and nutritional aspects with traditional processing and storage conditions that are applied in PDO table olive production, considering also intrinsic cultivar characteristics of the drupes. Policy makers, regulatory bodies, IOC, and the industry may profit from the substantiation provided by the results of this 2 years study.
A systematic study of the industrial production line of the Greek green table olives PDO “Prasines Elies Chalkidikis” for two consecutive processing periods.
A systematic study of the industrial production line of the Greek green table olives PDO “Prasines Elies Chalkidikis” for two consecutive processing periods.
The intensities of the gustatory attributes of table olives is one of the sensory set of parameters evaluated by trained sensory panels accordingly to the recommendations of the International Olive ...Council. However this is an expensive and time-consuming process that only allows the evaluation of a limited number of samples per day. So, an electronic tongue coupled with multivariate statistical tools, is proposed for assessing the median intensities of acid, bitter and salty tastes perceived in table olives. The results showed that the device, coupled with linear discriminant analysis, could be used as a taste sensor, allowing classifying aqueous standard solutions according to the three basic tastes (repeated K-fold cross-validation: 98% ± 3% of correct classifications) based on the electrochemical signals of 5 sensors. It was demonstrated that the taste sensor with multiple linear regression models, enabled quantifying the median intensities of the three basic tastes (repeated K-fold cross-validation: R2 ≥ 0.96 ± 0.04) perceived in table olives by a trained sensory panel, based on the potentiometric fingerprints (21–25 signal profiles) of aqueous olive pastes and brines. The overall satisfactory results showed the electronic tongue potential to assess the intensities of gustatory attributes of table olives, formerly only achievable by sensory panels.
•Acid, bitter and salty of table olives evaluated by sensory panel according to IOC.•E-tongue potentiometric fingerprints of aqueous olive paste and brines recorded.•Basic tastes standard solutions correctly discriminated by E-tongue-LDA-SA.•Gustatory attributes intensities successfully quantified by E-tongue-MLR-SA.•E-tongue-chemometric device showed to be a powerful taste sensor tool.
Table olives are one of the main fermented vegetables in the world. Olives can be processed as treated or natural. Both have to be fermented but treated green olives have to undergo an alkaline ...treatment before they are placed in brine to start their fermentation. It has been generally established that lactic acid bacteria (LAB) are responsible for the fermentation of treated olives. However, LAB and yeasts compete for the fermentation of natural olives. Yeasts play a minor role in some cases, contributing to the flavour and aroma of table olives and in LAB development.
The main microbial genus isolated in table olives is Lactobacillus. Other genera of LAB have also been isolated but to a lesser extent. Lactobacillus plantarum and Lactobacillus pentosus are the predominant species in most fermentations. Factors influencing the correct development of fermentation and LAB, such as pH, temperature, the amount of NaCl, the polyphenol content or the availability of nutrients are also reviewed. Finally, current research topics on LAB from table olives are reviewed, such as using starters, methods of detection and identification of LAB, their production of bacteriocins, and the possibility of using table olives as probiotics.
► This is a review of the presence and role of lactic acid bacteria in the fermentation of table olives. ► Lactobacillus plantarum and Lactobacillus pentosus are the predominant species. ► Several factors (pH, temperature, NaCl, polyphenols, nutrients) influencing the correct LAB fermentation are reviewed. ► Current topics such as starters, molecular detection and bacteriocins are also reviewed.
Written by experts in the field of table olives, this book is a source of recent research advances on the characterization and processing of table olives. Research papers are provided relating to the ...characterization of their composition of volatiles and the sensory profile; mineral composition and bioavailability; changes in bioactive components (chlorophylls) by processing; and new strategies to reduce sodium and additives for stabilizing the organoleptic properties and avoiding defects in table olives. Other research papers are included in relation to microbiological and chemical changes in table olives during spontaneous or controlled fermentation employing different cultivars, and the optimized use of starter cultures for the improvement of the different fermentative processes. In addition, this book includes an overview of the main technologies used for olive fermentation, including the role of lactic acid bacteria and yeasts characterizing this process, and of the processing and storage effects on the nutritional and sensory properties of table olives.
Foodomics employs advanced analytical techniques to provide answers regarding food composition, authenticity control, marker identification and issues related to food quality and safety. Nuclear ...magnetic resonance (NMR) spectroscopy and chromatography hyphenated to mass spectrometry (MS) are the main analytical platforms used in this field. Nevertheless, they are rarely employed in an integrated manner, and even then, the contribution of each technique remains vague. Table olives (Olea europaea L.) are a food commodity of high economic and nutritional value with an increasing production tendency over the last two decades, which, however, suffers from extensive fraud incidents and quality determination uncertainties. Thus, the current attempt aims towards two axes with the first being the multilevel integration of LC-HRMS and NMR data of the same samples and table olives being the selected matrix. In more detail, UPLC-HRMS/MS-based analysis was compared at different stages within an untargeted metabolomics workflow with an NMR-based study and the complementarity of the two platforms was evaluated. Furthermore, statistical heterospectroscopy (SHY), rarely employed in foodomics, combining the spectroscopic with spectrometric datasets and aiming to increase the confidence level of annotated biomarkers was applied. Amongst these lines, the second parallel axis of this study was the detailed characterization of table olives' metabolome in search for quality markers considering the impact of geographical (from Northern to Southern Greece) and botanical origin (Kalamon, Konservolia, Chalkidikis cultivars), as well as processing parameters (Spanish, Greek). To that end, using deep dereplication tools including statistical methods, with SHY employed for the first time in table olives, different biomarkers, belonging to the classes of phenyl alcohols, phenylpropanoids, flavonoids, secoiridoids and triterpenoids were identified as responsible for the observed classifications. The current binary pipeline, focusing on biomarkers’ identification confidence, could be suggested as a meaningful workflow not only in olive-based products, but also in food quality control and foodomics in general.
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•In-depth characterization of table olives via untargeted UPLC-HRMS/MS and chemometrics.•Quality markers correlated to geographical/botanical origin and processing parameters.•Step-by-step integration of LC-HRMS/MS and NMR data in a multilevel approach.•Statistical heterospectroscopy (SHY) methods rarely employed in foodomics.•Suggestion of a binary and detailed workflow for the food quality assessment.
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