Spanish-style Table Olives Research Articles

LP309 a new strain of Lactiplantibacillus pentosus that improves the lactic fermentation of Spanish-style table olives.

Different varieties of table olives have suitable morphological characteristics that allow them to be processed as Spanish-style green table olives. However, the Campiñesa cultivar presents difficulties when submitted to a lactic fermentation, in spite of being inoculated with dedicated starter cultures such as OleicaStarter. The strategy followed in this study to facilitate the start of lactic fermentation was to reinforce the OleicaStarter culture with the use of the Lactoplantibacillus pentosus Lp309 a strain that enhanced the survival of lactic acid bacteria (LAB) at the beginning of fermentation, reaching final pH values (4.08±0.01), free acidity (1.00±0.01g/100mL of brine), LAB population (6.17±0.09 logCFU/mL), nutrient depletion (0.80±0.09g/kg of pulp), and lactic acid production (11.85±0.72g/L). These values allowed stabilization of the final product, thus complying with the quality and food safety standards established by the Codex Alimentarius for table olives.

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.

Effect of Spanish-Style Table Olive Processing on Fatty Acid Profile: A Compositional Data Analysis (CoDA) Approach.

This manuscript considers that the composition of Manzanilla and Hojiblanca fats are compositional data (CoDa). Thus, the work applies CoDa analysis (CoDA) to investigate the effect of processing and packaging on the fatty acid profiles of these cultivars. To this aim, the values of the fat components in percentages were successively subjected to exploratory CoDA tools and, later, transformed into ilr (isometric log-ratio) coordinates in the Euclidean space, where they were subjected to the standard multivariate techniques. The results from the first approach (bar plots of geometric means, tetrahedral plots, compositional biplots, and balance dendrograms) showed that the effect of processing was limited while most of the variability among the fatty acid (FA) profiles was due to cultivars. The application of the standard multivariate methods (i.e., Canonical variates, Linear Discriminant Analysis (LDA), ANOVA/MANOVA with bootstrapping and n = 1000, and nested General Linear Model (GLM)) to the ilr coordinates transformed data, following Ward's clustering or descending order of variances criteria, showed similar effects to the exploratory analysis but also showed that Hojiblanca was more sensitive to fat modifications than Manzanilla. On the contrary, associating GLM changes in ilr with fatty acids was not straightforward because of the complex deduction of some coordinates. Therefore, according to the CoDA, table olive fatty acid profiles are scarcely affected by Spanish-style processing compared with the differences between cultivars. This work has demonstrated that CoDA could be successfully applied to study the fatty acid profiles of olive fat and olive oils and may represent a model for the statistical analysis of other fats, with the advantage of applying appropriate statistical techniques and preventing misinterpretations.

Application of Digital Olfaction for Table Olive Industry.

The International Olive Council (IOC) established that olives must be free of odors, off-flavors, and absent of abnormal ongoing alterations or fermentations. The use of electronic devices could help when classifying defects in a fast, non-destructive, cheap, and environmentally friendly way. For all of that, table olives were evaluated according to IOC regulation in order to classify the defect predominant perceiving (DPP) of the table olives and their intensity. Abnormal fermentation defects of Spanish-style table olives were assessed previously by an IOC-validated tasting panel. ‘Zapateria’, ‘Putrid’, and ‘Butyric’ were the defects found at different concentrations. Different volatile compounds were identified by gas chromatography in altered table olives. The same samples were measured with an electronic nose device (E-nose). E-nose data combined with chemometrics algorithms, such as PCA and PLS-DA, were able to successfully discriminate between healthy and non-healthy table olives, being this last one also separated between the first and second categories. Volatile compounds obtained with gas chromatography could be related to the E-nose measuring and sensory analysis, being capable of matching the different defects with their correspondents’ volatile compounds.

Determination of the Masking Effect of the 'Zapateria' Defect in Flavoured Stuffed Olives Using E-Nose.

Spanish-style table olives are one of the most common processed foods in the Mediterranean countries. Lack of control during fermentation can lead to one of the main defects of the olive, called ‘Zapateria’, caused by the combination of volatile fatty acids reminiscent of rotten leather. In this study, table olives altered with ‘Zapateria’ defect were stuffed with a hydrocolloid flavoured with the aroma ‘Mojo picón’ to improve consumer acceptance. Sensory analysis, determination of volatile compounds and electronic nose (E-nose) were used to evaluate the quality of the olives. The control samples had a high concentration of the defect ‘Zapateria’ and were classified in the second commercial category, while higher ‘Mojo picón’ flavour concentrations resulted in these olives being classified as ‘extra category’ (a masking effect). The main volatile compounds in olives with ‘Zapateria’ defect were cyclohexanecarboxylic acid and pentanoic acid. E-nose allowed discrimination between stuffed olives without added flavouring and olives with ‘Mojo picón’ flavouring at different concentrations. Finally, PLS regression allowed a predictive linear model to be established between E-nose and sensory analysis values. The values were 0.74 for perceived defect and 0.86 for perceived aroma. The E-nose was successfully applied for the first time to classify Spanish-style table olives with ‘Zapateria’ defect intensity and with the addition of the ‘Mojo picón’ aroma masking the defect.

Application of Electronic Nose to Discriminate Species of Mold Strains in Synthetic Brines.

The chemical composition of the brine for Spanish-style table olives plays a crucial role during the fermentation process. Traditional laboratory analysis requires a high consumption of reagents, highly qualified personnel, sophisticated equipment, long analysis times, and large amounts of samples. Analysis carried out using an electronic nose (E-nose) offers an alternative, non-destructive technique and is useful in determining alterations in brines caused by microorganisms. In the present research, nine mold strains isolated from spoiled olives were inoculated in synthetic brines to determine the effect of microbial development on sensory quality, volatile profile, and the capacity of E-nose to discriminate altered brines from the healthy ones. The brines inoculated with the mold strains presented negative attributes related to aromas of mold, wood, leather, rancidity and, organic solvents among others. The highest intensity of defect was presented by the brines inoculated with the strains Galactomyces geotricum (G.G.2); three Penicillium expansum (P.E.3, P.E.4, and P.E.20); one Penicillium glabrum (P.G.19); three Aspergillus flavus (A.F.9, A.F.18, and A.F.21); and one Fusarium solani (F.S.11). A total of 19 volatile compounds were identified by gas chromatography. Sensory analysis allowed us to classify the synthetic brines based on the degree of alteration produced by the mold strains used. Also, the E-nose data were able to discriminate the inoculated brines regardless of the intensity of the defect. These results demonstrate the capacity of the E-nose to discriminate alterations in brines produced by molds, thereby making it a useful tool to be applied during the elaboration process to detect early alterations in table olive fermentation.

Effect of High Hydrostatic Pressure in the Storage of Spanish-Style Table Olive Fermented with Olive Leaf Extract and Saccharomyces cerevisiae.

Olives treated according to the Spanish-style are firstly treated with caustic soda and then fermented in brine to reduce phenols. Next, olives are packed and subjected to pasteurization. The effect of different high hydrostatic pressure treatments (400 MPa, 4 and 6 min) was evaluated in Spanish-style table olives fermented with olive leaf extract (OLE) and S. cerevisiae compared with thermal pasteurization (P) at 80 °C for 15 min. HHP and P led to a significant reduction in yeast and aerobic mesophiles after the conservation treatment and during storage (300 days). The physical–chemical properties changed slightly during storage, except for olive hardness; olives treated with HHP presented a higher hardness than pasteurized ones. The CIELAB parameter L* decreased until day 300 in most of the treatments, as well as phenols. The HHP treatment led to significantly higher contents of phenolics (even during storage) than olives submitted to P. Some sensory attributes (colour, aspect, hardness, and overall evaluation) decreased during storage. P treatment caused a decrease in appearance, aroma, hardness, and overall evaluation compared to olives treated with HHP. Thus, the application of HHP in table olives to increase the shelf-life can be considered a valid alternative to P.

Industrial Processing of Algerian Table Olive Cultivars Elaborated as Spanish Style.

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 the washing steps and the time should be reduced to avoid the loss of fermentable matter, with the goal of reaching a pH < 4.0 after the fermentation and preventing the possibility of the growth of spoilage microorganisms and foodborne pathogens.

Delving into the bacterial diversity of spoiled green Manzanilla Spanish-style table olive fermentations

This work applies metataxonomic, standard statistics, and compositional data (CoDa) techniques to study the bacterial diversity of spoiled and normal Spanish-style table olive fermentations, analysing a total of 10-tons of industrial fermentation containers from two processing yards. Forty percent were affected by butyric, sulfidic, or putrid spoilage, while 60% followed the ordinary fermentation course. The samples were obtained at 30 days of fermentation, determining their 16S rRNA gene Amplicon Sequence Variant compositions (ASVs). The butyric containers showed a bacterial profile strongly associated with the genera Enterococcus, Leuconostoc, and Atlantibacter, but also with Lactiplantibacillus and Melissococcus, and less confident to Raoultella, Enterobacter, Serratia, and Celerinatantimonas. The sulfidic fermentation was linked to Alkalibacterium and, to a lesser extent, Marinilactibacillus and the absence of Lactiplantibacillus. Putrid spoilage was mainly related to Halolactibacillus and Alkalibacterium. Sulfidic/putrid (together) differed from butyric spoilage by the presence of Alkalibacterium/Marinilactibacillus as well as by Halomonas/Halanaerobium. Lactiplantibacillus dominated normal fermentations, but Vibrio was also frequently found (0–46%), apparently not causing any alteration. These results contribute to a better microbial characterisation of non-zapatera spoiled table olive fermentations. They also suggest using several statistical techniques to discriminate normal vs spoiled fermentations adequately.

E-Nose Discrimination of Abnormal Fermentations in Spanish-Style Green Olives.

Current legislation in Spain indicates that table olives must be free of off-odors and off-flavors and without symptoms of ongoing alteration or abnormal fermentations. In this regard, the International Olive Council (IOC) has developed a protocol for the sensory classification of table olives according to the intensity of the predominantly perceived defect (PPD). An electronic nose (e-nose) was used to assess the abnormal fermentation defects of Spanish-style table olives that were previously classified by a tasting panel according to the IOC protocol, namely zapateria, butyric, putrid, and musty or humidity. When olives with different defects were mixed, the putrid defect had the greatest sensory impact on the others, while the butyric defect had the least sensory dominance. A total of 49 volatile compounds were identified by gas chromatography, and each defect was characterized by a specific profile. The e-nose data were analyzed using principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA). The different defects were clearly separated from each other and from the control treatment, independently of PPD intensity. Moreover, the e-nose differentiated control olives from table olives with combined sensory defects despite the dilution effect resulting from the combination. These results demonstrate that e-nose can be used as an olfactory sensor for the organoleptic classification of table olives and can successfully support the tasting panel.

Multi-Statistical Approach for the Study of Volatile Compounds of Industrial Spoiled Manzanilla Spanish-Style Table Olive Fermentations.

Table olives can suffer different types of spoilage during fermentation. In this work, a multi-statistical approach (standard and compositional data analysis) was used for the study of the volatile organic compounds (VOCs) associated with altered (butyric, sulfidic, and putrid) and non-altered (normal) Manzanilla Spanish-style table olive fermentations. Samples were collected from two industrial fermentation yards in Seville (Spain) in the 2019/2020 season. The VOC profiles of altered (n = 4) and non-altered (n = 6) samples were obtained by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Ninety-one VOCs were identified and grouped into alcohols (30), esters (21), carbonyl compounds (12), acids (10), terpenes (6), phenols (6), sulfur compounds (2), and others (4). The association of the VOCs with spoilage samples depended on the standard or compositional statistical methodology used. However, butyric spoilage was strongly linked by several techniques to methyl butanoate, ethyl butanoate, and butanoic acid; sulfidic spoilage with 2-propyl-1-pentanol, dimethyl sulfide, methanol, 2-methylbutanal, 2-methyl-2-butenal, ethanol, 2-methyl-3-buten-2-ol, and isopentanol, while putrid was mainly related to D-limonene and 2-pentanol. Our data contribute to a better characterisation of non-zapatera spoiled table olive fermentations and show the convenience of using diverse statistical techniques for a most robust selection of spoilage VOC markers.

Effects of Different Controlled Temperatures on Spanish-Style Fermentation Processes of Olives.

This work aimed to determine the effect of applying different temperatures during the fermentation process of Spanish-style table olives. ‘Manzanilla de Sevilla’ (southwest of Spain, Badajoz) and ‘Manzanilla Cacereña’ (northwest of Spain, Caceres) olives were processed at an industrial scale in table olive fermenters whose brine was subjected to different thermal treatments. One of the three conducted experiments found that maintaining brine at 20–24 °C over a 3-month period led to optimum firmness, better color indices, and greater free acidity and lactic acid bacteria populations in comparison to an unheated control. Furthermore, raising the temperature of the fermenter to 20–24 °C accelerated the fermentation process, provoking better lactic bacteria and yeast growth without affecting olive firmness. The higher fermentation rate (shorter time to completion) associated with temperature-controlled olives also reduced the marketing time of the final product. Controlling brine temperature led to a better aspect and color, higher acidity, lower bitterness, and better overall assessment of processed olives. In addition, ‘Manzanilla de Sevilla’ olives presented a higher phenolic content than ‘Manzanilla Cacereña’ olives. Preliminary evidence is presented suggesting that ‘Manzanilla Cacereña’ olives appear highly amenable to Sevillian-style processing. The present innovative work demonstrates the importance of applying different thermal treatments to brine to control the temperature during the industrial fermentation of table olives during the cold season.

Proposal for technological adaptation of small-sized green olives to Spanish-STYLE processing

In this study, small-sized green olives were assessed for processing as Spanish-style table olives. Technological adaptations included the selection of three lye treatments, combined with a 3 h washing, a subsequent fermentation for 105 days in brine (12% NaCl (w/v) acidified with hydrochloric acid, 2.3 mL/L of brine) using a starter culture (OleicaStarter®) and preservation for 7 months in the fermentation brine fortified with NaCl up to 9%. Different physicochemical (pH, titratable, combined acidity, sodium chloride, sugars, fermentable matter, colour and firmness of fruits), and microbiological (yeasts, lactic acid bacteria and Enterobacteriaceae) and parameters were monitored during processing of the olives. The results showed that lye treatment with 3.4% sodium hydroxide was the most suitable treatment since it presented the highest values of titratable acidity. At the end of fermentation, all treatments presented physicochemical and microbiological parameters compatible with the production of Spanish-style table olives. Likewise, high levels of lactic acid bacteria present on the fruit epidermis could make these olives suitable as carriers of functional bacteria after ingestion (6.8–6.9 log CFU/g). Finally, preservation can maintain the stability and quality of table olives. All the results highlight that small-sized green olives can be successfully processed as Spanish-style table olives.

Effects of different preservation methods and storage on Spanish‐style domat olives fermented with different chloride salts

In this study, Domat olives were fermented with different chloride salts (NaCl, KCl, and CaCl2) then preserved with different preservation methods (pasteurization, potassium sorbate, and ozone treatment). The effects of preservation methods on the main physicochemical and microbiological characteristics related to these table olives were evaluated during the storage period (up to 240 days). The results showed that preservation and storage affect the characteristics of table olives. Preservation methods applied reduced the hardness of the olives, pasteurized olives were found the hardest, and ozone-treated olives were the softest at the end of storage. Preservation techniques have significantly affected the pH of olive brine and statistically found to be different from pasteurized olives, potassium sorbate used, and ozonated olives (p < .05). In particular, the a* values of olives with potassium sorbate changed from the green region (negative values) to the red region (positive values) during storage. The lowest a* value was determined in olives using potassium sorbate and the highest a* value was determined in pasteurized olives. While potassium sorbate was effective in yeast-mold inhibition, it was not effective on lactic acid bacteria (LAB) and total mesophilic aerobic bacteria count (TMAB), and approximately 1 logarithmic unit reduction was observed in LAB and TMAB numbers at the end of storage. Although there was a decrease of approximately 3–4 logarithmic units in the number of yeast-mold at the beginning of the storage (day 0) after the ozonation process, a sudden increase was observed on the 15th day of the storage, and then, it tended to decrease generally by following a fluctuating course. The hardness of olives produced using KCl (3.5% NaCl + 3.5% KCl) decreased significantly after the 6-month storage period that caused a lower acceptability. Practical applications The aim of this article was to find the effects of preservation methods and storage time on some quality parameters of Spanish-style table olives processed with different chloride salts. The findings are guided by the choice of preservation technique and storage time for the table olive industry. The study provides the industry to choose the preservation technique of table olives processed with different salts. Therefore, this paper provides information about Na, K, and Ca contents in the flesh of fermented Domat green table olives as well as their physicochemical characteristics and satisfy consumer demand for low Na with K and Ca fortified table olive.

Impact of Processing and Extraction on the Minor Components of Green Spanish-Style Gordal Table Olive Fat, as Assessed by Innovative Approaches.

This work aims to study the effect of the green Spanish-style table olive processing and extraction method of fat on its minor components. For this purpose, it uses standard multivariate analysis (developed for Euclidean space), Compositional Data (CoDa) analysis (for data in the simplex) and Multiple Factor analysis (MFA). Overall, processing had a scarce effect on most of the minor components except ethyl and methyl esters and diacylglycerols, which markedly increased during fermentation; however, these compounds in table olive do not have the negative connotations that those in olive oil do since they are normal metabolites from the yeast microflora habitually present during the process. The work also showed that the quantification of minor components in table olive fat was an extraction-dependent method since Soxhlet increased the concentrations of fatty alcohols, triterpene dialcohols, sterols, waxes and polar compounds. Regarding statistical methods, CoDa analysis strategies were successfully applied to produce more appropriate clustering and Principal Component Analysis (PCA) segregation than standard tools. Moreover, MFA allowed for study of the components individually and by groups; the relationships among groups led to the most appropriate clustering and PCA segregation of samples and revealed the effect of the chemical groups’ evolution on the similarity/dissimilarity between samples. Therefore, MFA was the statistical analysis that led to the most information on the effect of processing and extraction methods. Its combination with appropriate CoDa logratios could be an exciting challenge.

Relating starter cultures to volatile profile and potential markers in green Spanish-style table olives by compositional data analysis

This work relates native lactic acid bacteria (LAB) (Lactobacillus pentosus LPG1, L. pentosus Lp13, and Lactobacillus plantarum Lpl15) and yeast (Wickerhamomyces anomalus Y12) starters to the volatile components (VOCs) produced in green Spanish-style table olives. For this aim, the VOC profile was considered as compositional data (CoDa). The CoDa analysis generated new information on the relationship among inocula and VOCs through the tetrahedral plot, CoDa-biplot, variation array matrix, and CoDa dendrogram. The ilr (which includes pivot) coordinates (Euclidean space) from VOCs produced more reliable starters’ clustering than the original data. The potential VOC markers, identified by a test based on the pairwise comparison of the logratio variation arrays from the whole data set and the individual groups, were (starters in the parenthesis): 2-phenylethyl acetate (LPG1, Y12, Y12 + LAB), methanol (Lpl15), cis-2-penten-1-ol (LPG1, Y12, Y12 + LAB), 2-methyl-3-hexanol (LPG1, Y12), U (non-identified) C (m/z 83-112-97) (Y12) and UF (m/z 95-154-110) (LPG1, Y12 + LAB). Besides, some VOCs were partial/totally inhibited by specific starters: 2-methyl-1-propanol (Lp13, Y12 + LAB), 2-phenyl ethanol (Lp13), furfuryl methyl ether (Y12 + LAB), purpurocatechol (Y12, Y12 + LAB), 4-ethyl guaiacol (Lp13, Lpl15), 4-ethyl phenol (Lpl15), 5-tert-butylpyrogallol (Lp13, Lpl15), and UE (m/z 111–198) (Lp13). A better understanding of the relationship between starters and their VOC may facilitate modelling the flavour and quality of Spanish-style green table olive fermentations.

The use of multifunctional yeast-lactobacilli starter cultures improves fermentation performance of Spanish-style green table olives

In this work, Lactobacillus pentosus LPG1, Lactobacillus pentosus Lp13, Lactobacillus plantarum Lpl15, and Wickerhanomyces anomalous Y12, all of them previously isolated from fermented table olive biofilms, were used (alone or in combination) as multifunctional starters for Manzanilla Spanish-style green table olive fermentations. Their performances were evaluated through the changes in the key physico-chemical and microbiological parameters, correlation between AI-2 production and biofilm formation, inoculum imposition, metataxonomic analysis and sensory characteristics of the finished products. Inoculation only with lactic acid bacteria (LAB) strains led to higher titratable acidities and lower pH values than the spontaneous fermentation (non-inoculated control), mainly during the first steps of processing. However, the sequential inoculation of the yeast and then the combination of the 3 LAB strains showed the most favourable evolution. LPG1 strain and, particularly Lp13, were excellent biofilms former and showed the major imposition on the fruit epidermis, as corroborated by rep-PCR analysis. Production of AI-2 was lower in the treatment inoculated exclusively with yeast Y12 but had the highest presence in the sequential yeast-LAB inoculum, with its maximum concentration and maximum LAB population on fruits (19th days) strongly related. Metataxonomic analysis of the biofilms at the end of the fermentation revealed, in addition to Lactobacillus, high proportions of sequences from genera Marinilactobacillus, Alkalibacterium, Halolactobacillus, and low levels of Halomonas and Aerococcus. Compositional data analysis of the omics data revealed that Lpl15 was scarcely efficient for controlling the spontaneous microbiota since its treatment presented the highest proportions of Aerococcus genus. Finally, the sensory analysis showed similar characteristics for the treatment inoculated with LPG1 and the spontaneous process, with olives inoculated with the yeast (alone or in combination with Lactobacillus strains) showing attractive scores. Then, inoculation of Spanish-style table olive fermentations with a sequential yeast and LAB combination could be an advisable practice.

Effect of ozone treatment on the physical, microbiological and sensorial properties of Spanish-style table olives

Ozone has been widely used in the food industry as an effective antimicrobial agent. In this study the possibilities of using ozone in table olive preservation was investigated for the first time. For this purpose, the Domat variety of table olives was processed according to the Spanish style and treated with aqueous ozone for 5, 10, and 20 minutes at 0.5, 1, 2 and 4 ppm. The effects of ozonation on the microbiological, physical and sensory characteristics of the table olives were evaluated during the storage period (up to 180 days). The pH, color and firmness of the ozone treated table olives showed higher stability. Statistically significant reductions in the total bacteria and yeast/mould counts were obtained (p &lt; 0.05). Enterobacteriaceae and Escherichia coli were not found in the samples. After 60 days of storage the control samples (ozone untreated olives) obtained low values for sensory analysis, and did not meet market requirements. The results indicate that treating green table olive with ozon (1 ppm concentration) for 10 min in aqueous form reduces the microbial population without any negative effects on the firmness, color (L*, a* b*) or sensory attributes of the table olives.

Quality of lipid fraction during Spanish-style table olives processing of Sigoise and Azzeradj cultivars

This work aimed to study the effect of different steps of Spanish-style processing (raw olives, lye treatment, washing, and fermentation) on the oil quality index (Acidity, peroxide value (PV) and extinction coefficient UV at 232 nm and 270), fatty acids, phenols, tocopherols, hexanal and nonanal compounds, and antioxidant activity of the lipid fraction of green Sigoise and Azzeradj cultivar. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) was used to discriminate the samples according to cultivars and elaboration phases. Most of the variance of the quality parameters and fatty acids was due to cultivars and less for processing.After processing, a substantial loss in the total and individual phenolic compounds was recorded (79.25% and 67.58% for Azzeradj and Sigoise, respectively), but the most significant reduction occurred at lye treatment and washing step rather than the fermentation. Tocopherols were less affected than the phenolic compounds. The antioxidant activity against DPPH radicals of the total lipid fraction of olives was less affected than that of its methanolic extract alone.

Effect of regulated deficit irrigation on the quality of raw and table olives

Fresh water scarcity is a major worldwide issue. There is a need to reduce water use whereas preserving the quality of food products. Regulated deficit irrigation (RDI) is a strategy to reduce fresh water consumption. The aim of this work was to study the effect of RDI on olives when applied before harvesting, without a rehydration period, on the quality of table olives. The experiment was performed in “La Hampa”, the experimental farm of IRNAS-CSIC at Coria del Río (Seville, Spain) during 2015 and 2016. Two deficit irrigation treatments were compared with a full irrigated control. Treatment 1 (T1) reduced irrigation from early September, about 2 weeks before harvest, until values of midday stem water potential were around −2 MPa. Treatment 2 (T2) reduced irrigation from mid-August, about 4 weeks before harvest, with a similar water stress level. The duration and level of water stress was described with the stress integral (SI). Fruit features were studied, before and after the industrial process to obtain Spanish-style table olives, in order to evaluate differences due to irrigation on raw olives and due to processing on table olives. Water stress conditions slightly changed olive characteristics, affecting size and composition. The industrial processing to table olives masked differences between irrigation treatments, though some features such as total polyphenols content (TPC) were still different. SI was significantly related with fruit weight, pit weight, equatorial diameter, linolenic acid and MUFAs content and (MUFA/PUFA)/SFA ratio.