Olive Flesh Research Articles

Innovative salt replacement for green Spanish-style olives using potassium, calcium, and magnesium chlorides during packaging

This work aimed to enhance green Spanish-style Manzanilla table olives by replacing salt with K, Ca, and Mg chlorides in innovative packaging, utilising Response Surface Methodology (RSM). Both the added replacers and naturally occurring minerals were considered. RSM allowed the development of predictive models for K, Ca, Mg, and Mn (initially present) in olive flesh and their contributions to Reference Daily Intakes (RDI) based on the added salts. The sodium content in the new products decreased from 1.4 g/100 g flesh to 0.68 g/100 g flesh, while K, Ca, and Mg concentrations could increase up to 0.50, 0.45 and 0.15 g/100 g flesh, respectively. Added salt contributions to RDI could reach 25, 60, and 44 % for K, Ca, and Mg. Minimal differences between analytical data-derived minerals and predicted values were minimal, suggesting reliable model performance for nutrition labelling. Results assist the industry in creating nutritionally enhanced table olive products.

Comparative study of Spanish-style and natural cv. Chalkidiki green olives throughout industrial-scale spontaneous fermentation and 12-month storage: safety, nutritional and quality aspects

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.

Relationships between Na, K, and Ca mineral nutrients in brine and table olive flesh. Nutritional labelling implications

The mineral equilibrium between olive flesh/moisture (in-flesh) and the surrounding brines has been studied for the first time. A pseudo-distribution coefficient, Kd, has been defined and applied to fermented Gordal, Manzanilla (green Spanish-style) and packaged Aloreña de Málaga (natural green) olives. Kd had values < 1 for Na and K in the flesh but >1 for Ca, suggesting lower and higher contents in olive flesh than in brine. When the equilibrium for Na and K was referred to the flesh moisture, most Kd approached 1, implying a trend for equilibrium. However, Ca exhibited values above 1, indicating a higher concentration also in the flesh moisture, suggesting that part of this element may also form complexes with soluble olive flesh components. Kd was not significantly related to the concentrations of Na, K, or Ca in brines, although the Na model explained 80% variance. Simple and multiple regressions deduced the mineral nutrients in the flesh as a function of their concentrations in brine, but the second only increased the explained variance (about 10%) in the case of Na. For nutritional labelling purposes in the EU (where sodium must be expressed as salt), both functions can estimate the Na, K, and Ca contents in olive flesh from their concentrations in brine since their variabilities were within tolerance limits, particularly when the initial fermentation/packaging brines were fortified with K or Ca.

Toxicity of Insecticides in the Adult and Larva Olive Fruit Fly, after Estimation of the Dislodgeable Foliar and Fruit Residues in Olive Trees by LC-MS/MS and GC-MS/MS

“Can systemic insecticides be used in bait spots in order to kill the adult olive fly?” Effort was directed toward providing an answer to that question. Both field and laboratory tests were implemented to detect the dislodgeable residues of dimethoate, phosmet and b-cyfluthrin in olive leaves and fruit using the LC-MS/MS and GC-MS/MS chromatographic techniques. Residues of dimethoate declined more over time than those of phosmet, while levels of beta-cyfluthrin remained almost stable, both in leaves and fruit. Additionally, significantly higher and faster toxicity of dimethoate and beta-cyfluthrin (&gt;92%) compared to phosmet (80%) to fly adults was shown, which was reduced significantly after a two-week period. Conversely, 100% mortality of the larval stages within olive flesh was observed at the 2nd day for dimethoate and at the 7th day for phosmet. Although phosmet was not expected to contribute to preventing larval development, its application in bait sprays presented similar toxicity to that of dimethoate. However, no larval toxicity was recorded in beta-cyfluthrin. As a primary conclusion, we recommend the avoidance of the use of systemic insecticides in bait sprays.

High adsorption capacity of thermally treated solid olive wastes to treat olive mill wastewater

In this study, solid olive wastes were suggested as adsorbents for olive mill wastewater (OMWW) clean-up. These solid olive wastes underwent thermal treatment by two-step process: carbonization at 300°C and 400°C, then physical activation at 800°C and 1000°C. Characterizations were determined by FTIR, TGA/DTA, and N2 Adsorption-Desorption techniques. The efficiency of these new bio-adsorbents was verified on OMWW. Adsorption kinetics experiments were realized at room temperature and diluted OMWW (1/100 v/v). Evaluation of obtained activated carbons (ash, iodine value, and moisture) shows a good activity and stability in weight according to the thermogravimetric analysis. Moreover, the textural results of BET surface area showed a high area for activated carbons prepared from olive stones at 300°C/800°C (SBET = 208 ± 0.3 m2/g) and olive flesh at 400°C/1000°C (SBET = 77 ± 0.8 m2/g). The adsorption rates of OMWW were 91% after 120 min and 95.3% after 60 min contact time at pH = 2.0, respectively. At the end, the pH increased to neutral value. Thus, these bio-adsorbents from solid waste of olive industry can be efficient adsorbents for their liquid effluent clean-up.

Chemical Profiles of Moroccan Picholine Olives and Its Brines during Spontaneous Fermentation

ABSTRACT Changes in physical and chemical profiles during spontaneous fermentation of olives from the Moroccan Picholine cultivar at two degrees of ripeness (green and purple stages) were investigated in both olive flesh and brine. Purple olives exhibited the highest sugar, total phenolic and flavonoids content. Spontaneous fermentation led to an important loss of total phenolic, flavonoids and sugar content, particularly in green olives with reductions rate of 43%, 65% and 73%, respectively. The loss of phenolic compounds through fermentation was accompanied by a decrease of the antioxidant activity in olive flesh. The chromatographic analysis showed qualitative and quantitative differences among the olive flesh and brine studied. By the end of fermentation, an increase in hydroxytyrosol and caffeic acid concentrations and a decrease of protocatechuic acid, ferulic acid, p-coumaric acid and quercetine amounts were observed in both olive fleshes. The main phenolic compound identified and quantified in both tested brines was hydroxytyrosol. The purple-olive flesh and green olives brine were found to have the highest antioxidant activity after 66 days of natural fermentation.

Table Olives Fermented in Iodized Sea Salt Brines: Nutraceutical/Sensory Properties and Microbial Biodiversity.

This research aimed to study the influence of different brining processes with iodized and noniodized salt on mineral content, microbial biodiversity, sensory evaluation and color change of natural fermented table olives. Fresh olives of Olea europaea Carolea and Leucocarpa cvs. were immersed in different brines prepared with two different types of salt: the PGI “Sale marino di Trapani”, a typical sea salt, well known for its taste and specific microelement content, and the same salt enriched with 0.006% of KIO3. PGI sea salt significantly enriches the olive flesh in macroelements as Na, K and Mg, and microelements such as Fe, Mn, Cu and Zn. Instead, Ca decreases, P remains constant, while iodine is present in trace amounts. In the olives fermented in iodized-PGI sea salt brine, the iodine content reached values of 109 μg/100 g (Carolea cv.) and 38 μg/100 g (Leucocarpa cv.). The relationships between the two varieties and the mineral composition were explained by principal component analysis (PCA) and cluster analysis (CA). Furthermore, analyzing the fermenting brines, iodine significantly reduces the microbial load, represented only by yeasts, both in Carolea cv. and in Leucocarpa cv. Candida is the most representative genus. The sensory and color properties weren’t significantly influenced by iodized brining. Only Carolea cv. showed significative difference for b* parameter and, consequently, for C value. Knowledge of the effects of iodized and noniodized brining on table olives will be useful for developing new functional foods, positively influencing the composition of food products.

In Vitro Bioaccessibility of Ripe Table Olive Mineral Nutrients.

For the first time, the bioaccessibility of the mineral nutrients in ripe table olives and their contributions to the recommended daily intake (RDI), according to digestion methods (Miller’s vs. Crews’ protocols), digestion type (standard vs. modified, standard plus a post-digest re-extraction), and mineralisation system (wet vs. ashing) were studied. Overall, when the standard application was used, Miller’s protocol resulted in higher bioaccessibilities of Na, K, Ca, Mg, and Fe than the Crews’ method. The modified protocols improved most of these values, but the Crews’ results only approximated the Miller’s levels in the case of Na and K. The bioaccessibility of P was hardly affected by the factors studied, except that the modified Miller’s protocol led to higher levels when ashing. No significant effect of the mineralisation system was found. The modified Miller’s protocol, regardless of the mineralisation system, led to the overall highest bioaccessibility values in ripe olives, which were: Na (96%), K (95%), Ca (20%), Mg (73%), Fe (45%), and P (60%). Their potential contributions to the RDI, based on these bioaccessibilities and 100 g olive flesh service size, were then 29, 0.5, 4, 3, 33, and 1% respectively. The investigation has led to the development of a method for assessing the bioaccessibility of the mineral nutrients not only in ripe but also in the remaining table olive presentations and opens a new research line of great interest for producing healthier products.

Effect of olive leaf extract combined with Saccharomyces cerevisiae in the fermentation process of table olives.

Yeasts have a great importance in the table olives quality and have been proved more and more as starter cultures. Moreover, the addition of olive leaf extract (OLE) could enhance the nutritional value of table olives, but there are no studies in which added OLE has been combined with yeasts during fermentation. The aim of this work was to determine if the quality and functional value of table olives increases when OLE and a yeast starter are used during a Spanish-style olive fermentation process. Several combinations were used: (1) fermentations trials with OLE combined with a strain of Saccharomyces cerevisiae; (2) fermentations with OLE; (3) control fermentations, with no extract or starter culture. During fermentation performed with the addition of OLE and yeasts, the yeast number remained stable for most of the time, resulting in a slight decrease of yeasts by the end of the process. The phenolic profile of olive flesh and brines of the trials was analysed during the fermentation. The addition of OLE increased the concentration of phenols in olive flesh and brines at the end of the fermentation; in these fermentations, hydroxytyrosol was the most abundant, at around 1700mg/kg in olive flesh and 3500mg/L in brines olive flesh, whereas in the control fermentation the concentrations were around 900mg/kg and 2500mg/L, respectively. In spite of adding OLE, the fermentation resulted in olives without bitterness. We can conclude that yeast inoculation combined with OLE improves safety, nutritional value and other properties of the final product, without affecting its sensorial qualities.

The Effect of Salinity and Irrigation Regimes on the Level of Fatty Acids in Olive Flesh Oil

&lt;p&gt;Olive trees have the capability of growing under semi-arid regions, where drought and salinity are the major concerns. Two years field experiments were carried out to investigate the interaction effects of natural saline well water and irrigation levels on the quantity and quality of fatty acids in the olive flesh fruits (“Roghani” cultivar). A factorial layout within a randomized complete blocks design with three replications of five irrigation levels (I&lt;sub&gt;1&lt;/sub&gt; to I&lt;sub&gt;5&lt;/sub&gt; as 0.25, 0.5, 0.75, 1 and 1.25 ET&lt;sub&gt;c&lt;/sub&gt;) and three saline water levels (S&lt;sub&gt;1&lt;/sub&gt; to S&lt;sub&gt;3&lt;/sub&gt; as 100%WW, 50%WW+50%FW and 100%FW) were considered. The fresh and brackish irrigation water were withdrawn from two different natural wells (fresh water (FW) and saline water wells (WW)). &lt;em&gt;Results revealed that &lt;strong&gt;increasing salinity and decreasing irrigation water levels caused significant increment in the ratio of unsaturated fatty acids, palmitic acid to the percentage of oil and oil percentage in olive flesh fruit&lt;/strong&gt;&lt;/em&gt;. It is found that as water&lt;em&gt; &lt;/em&gt;salinity increased from lowest to the highest level, the oleic acid trends to its highest value of 23.68% in I&lt;sub&gt;1&lt;/sub&gt;S&lt;sub&gt;1&lt;/sub&gt;. Mean values of palmitic acid in 2013 were 27.52% and decreased to 19% in 2014. &lt;em&gt;It is concluded that highest percentage of oleic, linoleic, linolenic and palmitic acids obtained under high saline and less applied irrigation treatment (S&lt;sub&gt;1&lt;/sub&gt;I&lt;sub&gt;2&lt;/sub&gt;) yielding to improve the olive oil quality.&lt;/em&gt;&lt;/p&gt;

Ultrasound-accelerated debittering of olive fruits

Abstract Effects of ultrasound-accelerated debittering (UAD) at different NaOH concentrations (1.50, 1.75, and 2.00% w/v) and temperatures (25, 30 and 35 °C) on physicochemical and textural properties of olive fruits were investigated and compared with conventional debittering (CD). In UAD, processing time decreased up to 48% in comparison with CD method. During debittering, increasing moisture and decreasing nitrogen and ash contents of the samples were observed. In UAD, reduction rate of phenolic compounds and as a result the speed of debittering process increased in comparison with CD method. UAD was able to reduce textural hardness at a higher rate than CD method. Fatty acid compositions of UAD and CD samples were similar. Both UAD and CD methods similarly caused considerable damages to the structure of olives as observed on micrographs. Overall, UAD method was able to debitter olive fruits at a higher rate without causing any undesirable changes. This can have practical implications in reducing NaOH and water usage for olive processing. Industrial relevance In this research, the efficacy of ultrasound-assisted debittering (UAD) of olive fruit was evaluated. UAD increased the rate of sodium hydroxide penetration into the olive flesh, leading to a higher rate of oleuropein hydrolysis and significant reduction of processing time of up to 48% in comparison with CD method. Therefore, ultrasound-assisted debittering was found to be a suitable and applicable technique in minimizing debittering time of olive fruits and reducing NaOH concentration. It is also possible to reduce the number of wash-cycles required for the completion of debittering resulting in substantial reduction in water usage.

The phytoprostane content in green table olives is influenced by Spanish-style processing and regulated deficit irrigation

No previous information exists on the effect of deficit irrigation during pit hardening and the processing of Manzanilla de Sevilla Spanish style green table olives on the phytoprostanes (PhytoPs) contents in the fruit flesh. In this paper, the influence of different irrigation treatments during pit hardening on the PhytoPs content of raw and processed olive flesh was studied. PhytoPs profile in the raw olive flesh was characterized by the presence of 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, 16-B1-PhytoP and 9-L1-PhytyoP.Fruit yield and fruit size was not affected by deficit irrigation, but PhytoPs content in the raw and processed olive flesh was enhanced. After olive fruit processing only 9-F1t-PhytoP and 9-epi-9-F1t-PhytoP were detected, which enhanced their contents. Consequently, table olive tree culture under deficit irrigation conditions during pit hardening and the processing of its fruits to obtain Spanish-style olives can be considered as complementary actions to enhancing the PhytoP content and hence their potential beneficial effects on human health.

Changes in phenolic compounds during ripening in Gemlik variety olive fruits obtained from different locations

The phenolic compounds, total phenolic content, and antioxidant activity of Gemlik variety olive fruits obtained from four different locations in Turkey on five different harvesting dates (HDs) were investigated. The determination of phenolic compounds in olive flesh methanolic extracts was done by high performance liquid chromatography (HPLC) analysis. The total phenolic content and antioxidant activity values were estimated using Folin–Ciocalteu reagent and 2,2-diphenyl-1-picodrylhydrazyl reagent methods, respectively. Among 11 phenolic compounds identified, vanillic acid and hydroxytyrosol are the most abundant ones. In general, olive fruits from the Umurbey location had higher levels of phenolic compounds. The antioxidant activities of the olives were related to their phenolic content, and the olive fruits from the Umurbey location had a mean antioxidant activity 66.52% higher than that of other olives. There were differences among the quantities of phenolic compounds, the total phenolic contents, and the antioxidant activities of the olive fruits depending on HDs and location.

Chemical composition changes in four green olive cultivars during spontaneous fermentation

Changes in some physico-chemical characteristics (pH and free acidity) and chemical composition (sugars, total phenolic and flavonoid contents) of four olive cultivars during spontaneous fermentation in brine were investigated. The cultivars were typical of the Moroccan market: “Moroccan Picholine”, “Languedoc Picholine”, “Ascolana” and “Sevillana”. The physico-chemical changes of olives and brines during fermentation process were monitored. A similar pattern of pH was noticed for the “Moroccan Picholine”, “Languedoc Picholine” and “Ascolana” cultivars with a final pH ranging between 4.4 and 4.6. The profile of free acidity measured throughout fermentation period in brines was in agreement with the pH trend. The concentration of sugars, total phenolic and flavonoids contents in olives flesh and brines during fermentation is reported. The loss of flavonoids, sugars and total phenolic contents in the olive flesh by the end of fermentation process was up to 60%, 63% and 79% in “Languedoc Picholine”, “Sevillana” and “Moroccan Picholine”, respectively. The main phenols identified and quantified in the different brines at the end of brining process were hydroxytyrosol, tyrosol, (+)-catechin and quercetine. The highest total phenolic content and antioxidant activity were obtained in Moroccan Picholine brine after 71 days of fermentation.

Understanding the Characteristics of Oleuropein for Table Olive Processing

Phenolic compounds make up 2-3% (w/w) of olive flesh, whose most abundant part is oleuropein which is responsible for the characteristic bitter taste of olive fruits. Oleuropein is a heterosidic ester of elenolic acid and hydroxytyrosol and possesses beneficial effects on human health. But most fundamental and important step of table olive processing is to reduce level of oleuropein because olive fruits can only be consumed after de-bittering procedures. Oleuropein accumulates during fruit growth and is slowly converted to elenolic acid glucoside and demethyloleuropein as the fruit ripens. Harvest maturation affects the table olive processing factors, according to change on oleuropein content of olive fruits. More severe applications are required for processing of olive which has high oleuropein content. Also oleuropein and its hydrolysis end products (elenolic acid and aglycone) inhibit the activity of a number of microorganisms involved in the lactic fermentation of olives. Oleuropein was significantly affected by both acid and base treatment, resulted in the liberation of hydroxytyrosol. Bitter taste of olive fruit can be eliminated by removing the oleuropein out of the olive or chemical or enzymatic hydrolysis of oleuropein in table olive processes. Understanding the characteristics of oleuropein for table olive processing helps manufacturer to produce high quality table olives and researchers to develop innovative methods for table olive production. So that this research was aimed to explore the characteristics of oleuropein and its effects on table olive processes.

Performance of two potential probiotic Lactobacillus strains from the olive microbiota as starters in the fermentation of heat shocked green olives

The performance of two potential probiotic Lactobacillus strains from olive microbiota, namely L. pentosus B281 and L. plantarum B282 was assessed as starter cultures in Spanish-style fermentation of heat shocked green olives cv. Halkidiki. Two different initial salt levels were studied, 10% (w/v) and 8% (w/v) NaCl, and the brines were inoculated with (a) L. pentosus B281, (b) L. plantarum B282, and (c) a mixture of both strains. A spontaneous fermentation was also taken into account as control treatment. Prior to brining, olives were heat shocked at 80°C for 10min to reduce the level of the indigenous microbiota on olive drupes and facilitate the dominance of the inoculated cultures. Microbiological, physicochemical and sensory analyses were conducted throughout fermentation. The composition of LAB population and the evolution of added inocula were assessed by Pulsed Field Gel Electrophoresis (PFGE). The final population of LAB was maintained above 6log cycles in olive flesh. Both L. pentosus B281 and L. plantarum B282 were able to dominate over indigenous LAB, albeit strain B281 exhibited higher recovery percentages (100 or 94.7% for B281 and 58.8% or 55.0% for B282 in 10% or 8% NaCl, respectively). L. pentosus B281 also dominated over L. plantarum B282, when the two strains were co-inoculated in olive fermentations. The sensory assessment showed higher preference for inoculated fermentations of L. pentosus and L. plantarum separately in 8% NaCl, followed by the L. plantarum in 10% NaCl. The present study showed that probiotic strains L. pentosus B281 and L. plantarum B282, may offer a great potential for use as functional starter cultures in olive fermentation and deliver a promising probiotic food to the consumer.

Debittering of black dry‐salted olives

The objective of this work was to investigate the debittering process of dry‐salted olives. Fruits of the Manzanilla cultivar were put into layers of coarse salt and their physicochemical and microbiological parameters were assessed during the dehydration step. A correlation between the content in salt of the olive juice and the ratio salt/olives was found: the lower the ratio, the higher the concentration of salt in the dry‐salted olives. The population of lactic acid bacteria on the olive surface was not significant while yeasts, molds and Enterobacteriaceae were the predominant microbiota. In addition, the analyses of phenolic compounds in the olive flesh revealed that most of them disappeared during the dehydration process, in particular the bitter glucoside oleuropein. Likewise, freshly harvested olives were pasteurized and submitted for dehydration but in this case the degradation of oleuropein and the rest of polyphenols did not occur. All these findings suggest that olive debitter during the dry‐salting process due to the enzymatic oxidation of oleuropein in the olive flesh resulting in no leaching of the phenolic glucoside in the generated brine.Practical applications: This is the first report focusing on the debittering process of dry‐salted olives. An enzymatic pathway for oleuropein degradation has been found, and it opens up the possibility to optimize this reaction taking into consideration the variables involved such as phenolic compounds, oxidative enzyme, and oxygen. The ratio salt/olives must be as low as 0.4 to reach a high concentration of salt in the juice of dehydrated olives needed for the chemical and microbial stability of the product.

Changes in squalene and sterols associated with olive maturation

Squalene and sterols are biologically active compounds of great relevance for olive oil quality. The objective of this research was to study the dynamics of squalene and sterols accumulation during olive maturation. Fruits of cultivars ‘Picual’ and ‘Arbequina’ and two breeding selections derived from crosses between them were harvested monthly from September to December in Córdoba, Spain. Squalene and sterols contents were measured directly in olive flesh by gas chromatography. The fresh fruit weight, oil content, and ripening index were also determined. Oil content reached a maximum in November (19.4%) and maintained similar levels in December (19.8%). Squalene content in the fruit flesh increased significantly from September (4102mgkg−1) to November (4673mgkg−1), showing no significant difference between November and December. Sterol content increased significantly every harvest date, from 723mgkg−1 in September to 1188mgkg−1 in December, though no significant differences were observed between November and December in three out of four genotypes. The concentration of β-sitosterol was reduced from 87.3% in September to 75.9% in November, whereas Δ5-avenasterol concentration concomitantly increased from 7.2% in September to 18.6% in November, remaining unaltered in December. As only very small differences were found for oil, squalene and sterols contents between samples collected in November and December, it can be concluded that early harvest in November will not affect the fruit and oil composition for squalene and sterols.

Analysis of the Olive Fruit Fly Bactrocera oleae Transcriptome and Phylogenetic Classification of the Major Detoxification Gene Families

The olive fruit fly Bactrocera oleae has a unique ability to cope with olive flesh, and is the most destructive pest of olives worldwide. Its control has been largely based on the use of chemical insecticides, however, the selection of insecticide resistance against several insecticides has evolved. The study of detoxification mechanisms, which allow the olive fruit fly to defend against insecticides, and/or phytotoxins possibly present in the mesocarp, has been hampered by the lack of genomic information in this species. In the NCBI database less than 1,000 nucleotide sequences have been deposited, with less than 10 detoxification gene homologues in total. We used 454 pyrosequencing to produce, for the first time, a large transcriptome dataset for B. oleae. A total of 482,790 reads were assembled into 14,204 contigs. More than 60% of those contigs (8,630) were larger than 500 base pairs, and almost half of them matched with genes of the order of the Diptera. Analysis of the Gene Ontology (GO) distribution of unique contigs, suggests that, compared to other insects, the assembly is broadly representative for the B. oleae transcriptome. Furthermore, the transcriptome was found to contain 55 P450, 43 GST-, 15 CCE- and 18 ABC transporter-genes. Several of those detoxification genes, may putatively be involved in the ability of the olive fruit fly to deal with xenobiotics, such as plant phytotoxins and insecticides. In summary, our study has generated new data and genomic resources, which will substantially facilitate molecular studies in B. oleae, including elucidation of detoxification mechanisms of xenobiotic, as well as other important aspects of olive fruit fly biology.

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