Suchergebnisse

19 Páginas.-- 1 Tabla.-- 5 Figuras ; BACKGROUND The oxidation and polymerization of the phenolic compounds present in black ripe olives give rise to their black shiny colour, which is fixed by the addition of ferrous salts such as ferrous gluconate. Among the many variables that can affect the success of this fixation step, the influence of pH on this process was assessed on fruits of the Hojiblanca cultivar processed at pilot plant scale. Hence the aim of this work was to gain knowledge on the development of this fixation step, in particular on olives that were oxidized with a single alkaline treatment. RESULTS It was found that the penetration of the ferric cation into the olive flesh was an extremely slow process and it led to less‐dark olives. Besides, at a pH higher than 6 the oxidation of the ferrous to the ferric cation was a very rapid reaction, and olives that were processed with initial pH adjusted to 4 units had a darker colour than those without pH correction. Ultrafiltration/nanofiltration of oxidized olive solutions spiked with ferric ions or even pure oxidized ferric solutions through membranes of 10, 3 and 1 kDa revealed that ferric ions formed high‐molecular structures that inhibited the penetration of the ion into the olive flesh and therefore the fixation of the black colour. CONCLUSION The results presented in this study suggest that the formation of ferric ions during the colour fixation step of black ripe olives must be avoided to obtain darker olives. Consequently, the initial pH of the ferrous gluconate solution must be corrected to avoid oxidation of the ferrous to ferric cations during the fixation step. This study will contribute to the improvement of the colour fixation step of black ripe olive processing. © 2018 Society of Chemical Industry ; This work was supported by the Spanish Government Projects AGL2013‐42739‐R and AGL2016‐76820‐R (AEI/FEDER, UE). ; Peer reviewed

16 Páginas.-- 5 Figuras.-- 1 Tabla ; The two‐phase centrifugation system of olive oil extraction produces huge amounts of olive pomace called alperujo that could be a good source of bioactive substances. However, alperujo is currently stored in open air ponds before it is dried and submitted for extraction of the residual oil. The aim of this work is to study the evolution of phenolic and triterpenic acids in alperujo during its storage and extraction processes on an industrial scale. Alperujo is stored in large open air ponds, dried and the residual oil is extracted with hexane over a course of a year for two consecutive olive seasons.The storage of alperujo did not cause great changes in the content of these substances in the paste although the pomace olive oil is enriched in triterpenic compounds, mainly oleanolic acid. By contrast, the drying and extraction steps gives rise to a great reduction in the concentration of phenolic compounds. Likewise, triterpenic acids are very stable during the extraction process, and an enrichment of them is detected in the extracted alperujo that can reach up to 7–8 g kg−1 in these substances, particularly maslinic acid. Practical Applications: There are many studies, methods, and patents to extract bioactive substances from olive by‐products, particularly from the fresh olive pomace called alperujo. However, this study is the first to explore the stored and extracted alperujo as a good source of phenolic and triterpenic substances. Specifically, triterpenic acids were very stable during the storage and drying steps and extracted alperujo was highly enriched in them. This research will contribute to the valorization of olive by‐products. Extracted alperujo is a very good source of triterpenic acids. ; The authors are grateful to San Miguel Arcángel, S. A. for the supply of olive material. This work was supported by the Spanish Government and European Feder funds (project ASOAN, Interconecta ITC‐20111073). The authors thank Alejandra Expósito for technical assistance. ; Peer reviewed

17 Páginas.-- 3 Tablas.-- 3 Figuras ; The aim of this work was to assess the contents of phenolic and triterpenic substances in commercial olives produced in the USA and Spain, which currently use different olive cultivars and elaboration methods The phenolic compounds identified in black ripe olives were hydroxytyrosol, hydroxytyrosol-4-glucoside, hydroxytyrosol acetylated, salidroside, tyrosol, luteolin-7-glucoside, p-coumaric acid and comselogoside.The concentration of these substances in American black ripe olives was lower than 50 mg/kg whereas it was higher than 150 mg/kg in Spanish olives regardless of whether the American processors used the Manzanilla cultivar, which contains higher contents of these substances in the harvested fruit than the Hojiblanca cultivar. Moreover, the concentration of triterpenic acids (oleanolic and maslinic) in American black ripe olives was lower than 200 mg/kg whereas it was higher than 400 mg/kg in the Spanish product. These results indicate that the method used by American processors to elaborate black ripe olives gives rise to lower contents in bioactive substances than the Spanish method, and it must be related to the number of alkali/washing cycles used during processing. Hence, olive processors worldwide must keep in mind the increasing consumer demand for healthy products rich in bioactive substances when developing their elaboration methods. ; This work was partially supported by the Project AGL-2013-42739-R and the European Union FEDER funds. ; Peer reviewed

27 Páginas, 3 Tablas, 5 Figuras ; The development of a method for darkening black ripe olives during the washing step with a single NaOH treatment and preservation liquid was studied. Olives of the Hojiblanca cultivar were darkened at pilot plant scale, packed, sterilized, and analyzed after 2 mo of storage at ambient temperature. It was found that the use of a mixture of preservation liquid:water at a ratio of 1:1 during the first washing gave rise to darker olives with slightly better firmness and no effect on sensory quality. However, care must be taken with the concentration of acetic acid in the preservation solution, as a content of this organic acid higher than 25 g/L can cause adverse effects on olive color due to the low pH that can be reached in the flesh of the fruit. Additionally, the re‐use of the preservation solution in the first washing resulted in enrichment in antioxidant compounds of the packed product. Black ripe olives processed with preservation liquid had a total phenolic content of 629 mg/kg, whereas those with only tap water had 376 mg/kg, in particular hydroxytyrosol and hydroxytyrosol‐4‐glucoside. These findings mean that it is possible to get darker olives with higher contents in bioactive substances by reusing the preservation liquid during the darkening step of black ripe olives. ; This work was supported by the Spanish Government Project AGL‐2013‐42739‐R and the European Union FEDER funds. The authors thank Alejandra Expósito de la Cerda for her assistance with the experimental work. ; Peer reviewed

8 Páginas, 3 Tablas, 2 Figuras ; Harvested olives require further processing to make them edible due to their content in the bitter substance oleuropein. However, some olives of the Erkence cultivar naturally de-bitter on the tree giving rise to the so-called Hurma olives. In this study, the evolution of the chemical characteristics of Erkence and Hurma olives harvested from the northeast and southwest area of trees located in the Karaburun Peninsula was assayed. It was confirmed that the oleuropein content in Hurma olives was much lower (< 2000 mg/kg fresh weight) than Erkence, which reached 35.000 mg/kg fresh weight at the beginning of the season. In addition, no free or polymerized anthocyanins were found in Hurma fruit in contrast to ripened Erkence fruit. The concentration of glucose was also lower in Hurma than Erkence olives. These results suggest that the enzymatic oxidation of oleuropein could be responsible for the natural de-bittering of Hurma olives during their ripening on the tree. ; Una explicación para el desamargado natural de aceitunas Hurma durante su maduración en el árbol. Las aceitunas recién cogidas del árbol necesitan ser procesadas para hacerlas comestibles, debido a su contenido en el compuesto amargo oleuropeína. Sin embargo, algunas aceitunas de la variedad Erkence desamargan de forma natural en el árbol dando lugar a las aceitunas conocidas como Hurma. En este trabajo se han analizado las características químicas de aceitunas Erkence y Hurma recolectadas de la zona noreste y suroeste de árboles situados en la provincia de Karaburun. Se ha confirmado que el contenido en oleuropeína de aceitunas Hurma es muy inferior (< 2000 mg/kg) que Erkence, las cuales alcanzaron una concentración en dicha sustancia hasta de 35.000 mg/kg al principio del periodo de maduración. Además, no se encontraron en aceitunas Hurma antocianinas ni libres ni polimerizadas, a diferencia de Erkence. Estos resultados indican que la oxidación enzimática de la oleuropeína podría ser la responsable de la eliminación del amargor de forma natural en aceitunas Hurma durante su maduración en el árbol. ; This research was supported by the Projects TAGEM/HSGYAD/14/A05/P02/59 (Republic of Turkey, Ministry of Food, Agriculture and Livestock), and AGL-2013-42739-R (Spanish Government and the European Union FEDER funds). ; Peer reviewed

Olives can reduce their bitterness by oleuropein oxidation via an enzymatic reaction. In this study, olives of the Manzanilla and Hojiblanca varieties preserved in acidified brine were submitted to oxidation tests under overpressure of oxygen (0.3 bars) for 3 days. It was found that the oxidation of fruit preserved for more than 3–4 months showed a reduction in the concentration of oleuropein, but with great variability (28–100%). By contrast, when olives were preserved for only one month, the oxidation treatment was able to decrease more than 90% of the content of oleuropein in the fruit. These oxidised olives were stored again in the acidified medium for 6 months and no spoilage or organoleptic problems were detected. Oxidation gave rise to darker olives (L* parameter diminished from 40 to 34). Moreover, the oxidised fruit was enriched with free phenols such as hydroxytyrosol and tyrosol as a consequence of the acid hydrolysis of phenolic glucosides during the preservation step. ; This work was supported by the Project AGL-2013-42739-R and the European Union FEDER funds. ; Peer Reviewed

© 2014 American Chemical Society. The main Spanish table olive varieties supplied by different olive cooperatives were investigated for their polyphenol compositions and the endogenous enzymes involved in their transformations during two growing seasons. Olives of the Manzanilla variety had the highest concentration in total polyphenols, followed by the Hojiblanca and Gordal varieties. The Gordal and Manzanilla cultivars showed the highest polyphenol oxidase activities. The Gordal cultivar presented a greater β-glucosidase and esterase activity than the others. An important influence of pH and temperature on the optimal activity of these enzymes was also observed. The polyphenol oxidase activity increased with temperature, and peroxidase activity was optimal at 35 °C. The β-glucosidase and esterase activities were at their maximum at 30 and 55°C, respectively. The oxidase and β-glucosidase activities were at their maximum at the pH of the raw fruit. These results will contribute to the knowledge of the enzyme transformation of oleuropein in natural table olives. ; This work was supported by Project AGL 2009-07512 from the Spanish government and European Union (European Regional Development Funds). E.R. thanks MINECO for her FPI fellowship. ; Peer Reviewed

The aim of this work was to obtain ripe olives enriched in bioactive compounds of phenolic nature. For this, two partially purified solutions rich in phenols from the table olive processes were used as cover in the packaging: washing waters of Spanish-style green olives or previous preservation acid solutions of ripe olives. Both solutions were nano-filtered through a 4000 Da membrane and vacuum evaporated at pilot plant scale. Regenerated liquids were employed at 50% and 100% in the packing brine. Results demonstrated that it is possible to achieve a >3-fold higher concentration of phenolic compounds in olives than with the traditional method when using the regenerated washing water at 100% to enrich the packing brine. Moreover, a <2-fold higher concentration was found in olives enriched with the regenerated preservation solution at 100%. It must also be noted that the color, texture and flavor of the olives were not affected by the use of regenerated washing water as packing solution. Industrial relevance: Among the different types of commercial table olives, black ripe have the lowest content in phenolic compounds. The methodology developed in this work will allow the enrichment of black olives in these bioactive substances, in particular hydroxytyrosol, which has been attributed to many beneficial properties for human health. The methodology is simple and easy to implement by processors. Hence, these results will contribute to the nutritional valorization of black ripe olives. ; This work was supported by the Spanish Government Projects AGL2013-42739-R and AGL2016-76820-R (AEI/FEDER, UE), and the Junta de Andalucía through financial support to group AGR-125. The authors thank Alejandra Expósito for her assistance with the experimental work. ; Peer Reviewed

24 Páginas.-- 6 Figuras.-- 2 Figuras suplementarias ; BACKGROUND Olive oil extraction generates a large amount of residue consisting mainly of the pomace and leaves when using a two‐phase centrifugation system. The aim of this study was to assess the content of phenolic and triterpene compounds in the by‐products produced in Spanish olive oil mills. RESULTS Olive pomace had concentrations of phenolic and triterpene substances lower than 2 and 3 g kg−1, respectively. The leaves contained a high concentration of these substances, although those collected from ground‐picked olives had lost most of their phenolic compounds. Moreover, the sediment from the bottom of the olive oil storage tanks did not have a significant amount of these substances. By contrast, a new by‐product called olive pomace skin has been revealed as a very rich source of triterpenic acids, the content of which can reach up to 120 g kg−1 in this waste product, maslinic acid comprising around 70% of total triterpenics. CONCLUSION Among the by‐products generated during extraction of olive oil, olive pomace skin has been discovered to be a very rich source of triterpenic acids, which can reach up to 120 g kg−1 of the waste. These results will contribute to the valorization of olive oil by‐products. © 2017 Society of Chemical Industry ; We are grateful to the Cooperatives of the Jaencoop SCA group for the supply of olive material. This work was supported by the Spanish Government and European FEDER funds (project ASOAN, Interconecta ITC‐20111073). We thank Alejandra Expósito and Juan Antonio Espejo for technical assistance. ; Peer reviewed

BACKGROUND: Olive leaves and fruit possess bioactive substances such as phenolic compounds and triterpenic acids that can be obtained from olive by-products generated during olive oil extraction. The aim of the present study was the characterization and quantification of these compounds in Picual and Arbequina cultivars from different locations and throughout two seasons in both olive leaves and fruit. RESULTS: The major phenolic compound identified in the leaves was oleuropein, and the total content of phenolic compounds in this material reached 70 g kg fresh weight. The leaves were also rich in triterpenic acids (20 g kg fresh weight), with oleanolic acid being the most concentrated among them. With regard to olives, oleuropein and demethyloleuropein were the main phenolic compounds in the pulp of Picual and Arbequina cultivars, and the total concentration of these phenolic compounds reached 3.5% fresh weight. Olives can also be an important source of triterpenic acids, although this is mainly the skin part, where the maslinic and oleanolic acids are concentrated. CONCLUSION: Olive leaves can contain up to 70 g kg phenolic compounds and 20 g kg triterpenic acids, and olive fruit can contain up to 35 g kg of the former and 3 g kg of the latter. It must also be noted that this level was constant both between seasons and orchard locations. © 2016 Society of Chemical Industry. ; We are grateful to the Cooperatives of the Jaencoop SCA group for the supply of olive material. This work was supported by the Spanish Government and European Feder funds (project ASOAN, Interconecta ITC-20111073). We thank Alejandra Expósito and Juan Antonio Espejo for technical assistance. ; Peer Reviewed

11 Páginas.-- 3 Tablas.-- 2 Figuras ; A chemical characterization of turning color table olives of the Sigoise variety was made through their processing as natural-style. Polyphenols, sugars, tocopherols, fatty acids, and antioxidant activity in the olives were monitored throughout the elaboration process. Oleuropein, salidroside, hydroxytyrosol 4-glucoside, rutin, ligustroside and verbascoside showed a decrease of 16.90-83.34%, while hydroxytyrosol increased during the first months of brining. Glucose was consumed by 90% due to the metabolism of the fermentative microbiota. The tocopherol content remained stable during the process and only the α-tocopherol decreased. The fatty acids were not affected. The loss in antioxidant compounds resulted in a decrease in the percentage of DPPH radical inhibition from 75.91% in the raw fruit to 44.20% after 150 days of brining. Therefore, the turning color natural table olives of the Sigoise variety are a good source of bioactive compounds. ; La caracterización química de las aceitunas en salmuera de color cambiante de la variedad Sigoise se ha estudiado durante el proceso de elaboración, en particular la concentración de fenoles, azúcares, tocoferoles, ácidos grasos y la actividad antioxidante. La concentración de oleuropeína, salidrósido, hidroxitirosol 4-glucósido, rutina, ligustrósido y verbascósido disminuyó un 16,90-83,34% durante el primer mes en salmuera. El 90% de la glucosa fue consumida debido al metabolismo de la microbiota fermentativa. El contenido en tocoferoles se mantuvo constante durante el proceso y solo disminuyó el α-tocoferol. Los ácidos grasos no se vieron afectados. La pérdida de actividad antioxidante se tradujo en una disminución del porcentaje de inhibición del radical DPPH de un 75,91% del fruto fresco a 44,20% después de 150 días en salmuera. A pesar de todo, la aceituna color cambiante de la variedad Sigoise en salmuera es una buena fuente de compuestos bioactivos. ; We want to thank the Algerian Ministry of Higher Education and Scientific Research for sponsoring this work. The authors are grateful to the staff of the company KHODJA & CO Seddouk (Bejaia, Algeria) for providing the samples. This work was also supported by the Spanish Government (Project RTI2018-093994-J-I00, AEI/FEDER, UE and Ramón y Cajal Programme RyC2018-024752-I). ; Peer reviewed

9 Páginas; 3 Tablas; 3 Figuras ; This study investigated the changes in the flavonoid profile and antioxidant capacity of five olive cultivars after dry salting. The antioxidant activity was determined using ferric reducing ability power (FRAP), oxygen radical absorbance capacity (ORAC), and β-carotene bleaching assays. The results showed that the effects of dry salting on the analyzed parameters were significant (P<0.05). It caused a decrease in total flavonoids with a loss rate of 55%. The HPLC analysis of extracts revealed the presence of four flavonoids: rutin, luteolin-7-glucoside, cyanidin-3-glucoside and cyanidin-3-rutinoside. Among the studied cultivars, Azeradj was characterized by high levels of flavonoids. Concerning the antioxidant activity, diverging results were obtained using different antioxidant assays. Overall, the dry salting induced a reduction in the antioxidant activity with variable values depending on the cultivar. Among the used methods, high correlations were found between flavonoid contents and the FRAP assay. ; Efecto de la salazón en seco sobre el perfil de flavonoides y la capacidad antioxidante de cultivares Argelinos. En este estudio se investigó los cambios en el perfil de flavonoides y la capacidad antioxidante de cinco cultivares de olivo después de una salazón en seco. La actividad antioxidante se determinó mediante los métodos FRAP (Ferric ion Reducing Antioxidant Power), ORAC (capacidad de absorción de radicales de oxígeno) y ensayos de blanqueo de β-caroteno. Los resultados mostraron que los efectos de la salazón en seco en los parámetros analizados fueron significativos (P<0,05). Esto causó una disminución en los flavonoides totales con una tasa de pérdida del 55%. El análisis por HPLC de los extractos reveló la presencia de cuatro flavonoides: rutina, luteolina-7-glucósido, cianidina-3-glucósido y cianidina-3-rutinósido. Entre los cultivares estudiados, Azeradj se caracteriza por altos niveles de flavonoides. En cuanto a la actividad antioxidante, se obtuvieron resultados divergentes utilizando diferentes ensayos antioxidantes. En general, la salazón en seco indujo una reducción en la actividad. ; Thanks are due to Ifri-Olive, Mr Ait Kheddache S. and all those who have harvested the olive samples used in this study, and to the Algerian Ministry of Higher Education and scientific Research who funded this work. This work was also supported by project AGL 2009–07512 from the Spanish Government and The European Union (European Regional Development Funds). ; Peer reviewed

Olives can debitter naturally without the use of NaOH but it is a very slow process. The purpose of this work was to evaluate the influence of both temperature and chemical characteristics of brine on the oleuropein hydrolysis rate in natural table olives. Two different phases were established for natural debittering. During the first 1–2 months of brining, a low concentration of NaCl (60 g/L) and acetic acid (2 g/L) together with a low storage temperature (10 °C) were the processing conditions that promoted a rapid hydrolysis of the bitter phenol because these mild conditions facilitated the action of endogenous enzymes (β-glucosidase and esterase). Thereafter, higher concentrations and temperature of storage (140 g/L NaCl, 16 g/L acetic acid and 40 °C) favored the chemical hydrolysis of oleuropein during long term (a few months) storage. These results will contribute to the knowledge of the natural debittering of table olives and they will help processors to accelerate their elaboration methods. ; This work was supported by projects AGL 2009-07512 and AGL 2013-42739-R from the Spanish Government and European Union (European Regional Development Funds). Eva Ramírez thanks MINECO for her FPI fellowship. Thanks also to Alejandra Expósito for technical assistance ; Peer Reviewed

The bitter taste of olives is mainly caused by the phenolic compound named oleuropein and the mechanism of its hydrolysis during the processing of natural green olives was studied. First, a rapid chemical hydrolysis of oleuropein takes place at a high temperature of 40 °C and at a low pH value of 2.8, but the chemical hydrolysis of the bitter compound is slow at the common range of pH for these olives (3.8-4.2). However, decarboxymethyl elenolic acid linked to hydroxytyrosol and hydroxytyrosol have been found in a high concentration during the elaboration of natural green olives. When olives were heated at 90 °C for 10 min before brining, these compounds are not formed. Hence, the debittering process in natural green olives is due to the activity of β-glucosidase and esterase during the first months of storage and then a slow chemical hydrolysis of oleuropein happens throughout storage time. ; This work was supported by projects AGL 2009-07512 and AGL-2013-42739-R from the Spanish Government and European Union (European Regional Development Funds). Eva Ramírez wishes to thank MINECO for her FPI fellowship. Thanks also to Alejandra Expósito for technical assistance. ; Peer Reviewed

29 Páginas; 4 Tablas; 3 Figuras ; The presence of phenolic compounds in raw olives, particularly the bitter glucoside oleuropein, requires transforming this substance into other non-bitter to make the fruit palatable. An alkali treatment is currently carried out to hydrolyze the oleuropein but a high volume of wastewater is generated. The aim of this study was to develop a natural product without an alkali treatment and with appropriate organoleptic characteristics similar to those of Spanish-style green olives. Mild heat treatments (60 °C for 10 min) were sufficient to inactivate the β-glucosidase activity which prevented the formation of antimicrobial compounds and thereby the growth of lactic acid bacteria was promoted. By contrast, heating released a high concentration of oleuropein in fruits that remained at a very high level even after 6 months of fermentation. The inoculation of the brines of Manzanilla olives with selected lactic acid bacteria with oleuropeinolytic activity was insufficient for reducing the high concentration of the bitter glucoside. However, favorable results were obtained with varieties such as Gordal and Aloreña, which have lower oleuropein contents. The product obtained showed a very attractive color, similar to that of Spanish-style green olives and lighter than natural green olives, which is a positive aspect for consumer acceptability. ; This work was supported by Project AGL 2009-07512 from the Spanish government and European Union (European Regional Development Funds). E.R. thanks MINECO for her FPI fellowship. ; Peer reviewed