Debittering of black dry‐salted olives

Ramírez, Eva; García-García, Pilar; Castro, Antonio de; Romero, Concepción; Brenes, Manuel

doi:10.1002/ejlt.201300167

Cited by 29 publications

(24 citation statements)

References 20 publications

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“…These pigments therefore are not involved in the dark color of Hurma olives but polymers formed during the enzymatic oxidation of oleuropein must be responsible for this dark-brown color. Therefore, Hurma olives lose their bitterness during maturation on the tree due to the enzymatic oxidation of oleuropein, which gives rise to non-bitter substances, as it has also been demonstrated for the de-bittering of black dry-salted and dried green olives (Ramírez et al, 2013;Piscopo et al, 2014).…”

Section: Discussionmentioning

confidence: 93%

“…The results presented in Table 2 indicate the absence of these substances either free or polymerized in Hurma olives so that their dark brown color could be formed from the oxidation of o-diphenols, particularly oleuropein. The oxidation of the latter substance gives rise to nonbitter substances (García et al, 2008), and it has been proposed as the explanation for the de-bittering of black dry-salted and dried green olives (Ramírez et al, 2013;Piscopo et al, 2014).…”

Section: Resultsmentioning

confidence: 99%

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An explanation for the natural de-bittering of Hurma olives during ripening on the tree

Susamci¹,

Romero

Tuncay

et al. 2017

Grasas y Aceites

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SUMMARY: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. KEYWORDS:Anthocyanin; Bitterness; Olive; Phenolic compounds; Sugar RESUMEN: 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.

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Section: Discussionmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

An explanation for the natural de-bittering of Hurma olives during ripening on the tree

Susamci¹,

Romero

Tuncay

et al. 2017

Grasas y Aceites

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“…However, loss of polyphenols has been reported by Devic et al (2010) during osmotic dehydration of apples in 60°Brix solutions at 45 and 60°C. Otherwise, diffusion of oleuropein, bitter glycoside, from dark olives has been demonstrated by Ramírez et al (2013) during dry-salting for long period. The relative bitterness to sweetness ratio decreased significantly from 4.9 (±0.5) for fresh peels to 1.8 (±0.3) for peels treated with dry sugar and to 1 (±0.1), 0.9 (±0.1), and 0.7 (±0.1), respectively, for peels immersed at 25°C in 40 and 60°Brix sucrose solutions and at 50°C in 60°Brix sucrose solution.…”

Section: Kinetics Of Bitter Glycosides Flavanones Lossmentioning

confidence: 99%

Effects of Osmotic Treatments on Modulating Bitter Flavanones Glycosides Contents and Microstructure of Citrus aurantium Peels

Zid

Dhuique-Mayer

Lartaud

et al. 2015

Food Bioprocess Technol

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This study investigated the use of wet and dry osmotic dehydration for modulating the bitter taste of Citrus aurantium peels, imparted by the predominance of flavanones glycosides in their albedo; namely naringin, neohesperidin, and neoeriocitrin. For this purpose, the peels were subjected to dehydration-impregnation by soaking (DIS) in 40°Brix sucrose solution at 25°C and in 60°Brix sucrose solutions at 25 and 50°C and to dry osmotic dehydration (DOD) at 25°C for 6 h. The peels had not shown the immediate dewatering phenomena in the DIS process but rather an imbibition of sucrose solution, reflected in water and sugar gains. Such a tendency has shown to be ascribed to the porous structure of the albedo which fostered the capillary inflow of external liquid. The imbibition was observed during 6 h of treatment in low concentrated sucrose solution whereas in high concentrated ones, it was followed by the dewatering phenomenon thereby inducing an increase of pore volume together with a decrease of cells size. Conversely, in the DOD process, the expected cross transfers of water and sugar were markedly observed. The water was removed from both albedo and flavedo. Indeed, the essential oil cavities exhibited elongation of their shape in line with shrinkage of the peel. The two techniques allowed loss of bitter compounds and gain of sucrose. Nonetheless, The DIS gave rise to higher gain of sucrose and losses of flavanones glycosides than DOD.

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“…Dry salt debittering is one of the oldest methods which consist of placing the olive fruits in disposed layers with dry salt [23,34]. In olive debittering during the dry-salt process, due to the enzymatic oxidation of oleuropein in the olive flesh resulting in no leaching of the phenolic glucoside in the generated brine.…”

Section: Degradation Of Oleuropeinmentioning

confidence: 99%

“…In olive debittering during the dry-salt process, due to the enzymatic oxidation of oleuropein in the olive flesh resulting in no leaching of the phenolic glucoside in the generated brine. The osmotic pressure provoked by the salt on the olives gave rise to the rupture of the tissues thereby putting polyphenols into contact with polyphenoloxidase [34].…”

Section: Degradation Of Oleuropeinmentioning

confidence: 99%

Understanding the Characteristics of Oleuropein for Table Olive Processing

Öztürk¹

2014

J Food Process Technol

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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.

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Debittering of black dry‐salted olives

Cited by 29 publications

References 20 publications

An explanation for the natural de-bittering of Hurma olives during ripening on the tree

An explanation for the natural de-bittering of Hurma olives during ripening on the tree

Effects of Osmotic Treatments on Modulating Bitter Flavanones Glycosides Contents and Microstructure of Citrus aurantium Peels

Understanding the Characteristics of Oleuropein for Table Olive Processing

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