Changes in Texture and Cell Wall Polysaccharides of Olive Fruit during "Spanish Green Olive" Processing

Jiménez, Ana; Guillén, Rafael; Sánchez, Clara I.; Fernández‐Bolaños, Juan; Heredia, Antonia

doi:10.1021/jf00056a051

Cited by 47 publications

(52 citation statements)

References 16 publications

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“…The chemical composition (g/100 g of dry weight ± SD, n = 3) of milled olive cake was as follows: Moisture, 5 Olive cake contains a large amount of fiber, approximately 60% of the dry matter, the cell walls being mainly polysaccharides (cellulose 18-28%, hemicellulose 14%) and lignin (17-20%). Since the type of parenchymal cell of the olive fruit pulp is scarcely lignified (18), the lignin data seem to be overestimated. It is composed mostly of condensed tannin and other polymers.…”

Section: Resultsmentioning

confidence: 99%

Steam‐explosion pretreatment of olive cake

Felizón

Fernández‐Bolaños

Heredia

et al. 2000

J Americ Oil Chem Soc

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Olive cake was processed by steam-explosion under different steam conditions, followed by fractionation to separate the main components. In the water-soluble fraction, the main compounds were carbohydrates. Glucose represented a significant part of the total monosaccharide content, especially under conditions of mild severity, followed by arabinose, but the solubilization of sugars occurred predominantly in the oligomeric fraction. Mannitol was also found in significant amounts (1.5%), similar to that in the initial material. In the ethyl acetate extract, low molecular weight phenols were identified, the most abundant being hydroxytyrosol, which is present in the olive pulp. Hydroxytyrosol is abundant and has great antioxidant activity, reaching 149 mg/100 g of dry olive cake. The procedure used in this study obtained all the hydroxytyrosol residual present in the by-product. The constitutive polymers were quantified in the insoluble fraction, and the sugar composition showed that cellulose was associated with a high proportion of xylans and other polysaccharides rich in arabinose and galactose. This cellulose was nearly amorphous, as it was highly susceptible to hydrolytic enzymes. The extractables in dilute alkali (not true lignins) increased as steaming became more severe; the residual "lignin" in this fraction decreased. Enzymatic hydrolysis of the insoluble fraction using a cellulolytic complex was also studied. The slight increase in the extent of saccharification was not proportional to the high alkaline delignification. However, when the residues were efficiently delignified with chlorite treatment, the susceptibility to enzymatic hydrolysis greatly increased.Paper no. J9149 in JAOCS 77, 15-22 (January 2000).Olive cake is a by-product derived from the olive oil extraction industry. It is obtained by pressing the fruit, leaving a residue of seed husks (fragmented olive stones), seed, pulp and peel (olive cake). Olive-mill wastewater and/or vegetation water is also obtained. Olive cake has been utilized as an energy source, fertilizer, and animal feed (1). In spite of its high fiber and protein contents, this by-product has low nutritional value owing to phenolic compounds inhibiting digestive enzymes. During oil extraction, polymers are formed among the phenolic substances themselves and/or protein and cellulose so that they are unavailable for ruminant digestion. Consequently, these polymers constitute an integral part of the cell wall component and show physical and chemical properties very similar to lignin (2). By way of certain pretreatments, it is possible to reduce the degree of lignification of the olive cake, thus enhancing its nutritional value.High-pressure steaming followed by rapid decompression is called steam-explosion. Recently, steam-explosion has been considered an effective pretreament (3) of waste cellulosic materials for further processing, including olive stones (4,5). The resultant material is finely divided; and the main components-cellulose, hemicelluloses, and lignin-are separated...

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Section: Resultsmentioning

confidence: 99%

Steam‐explosion pretreatment of olive cake

Felizón

Fernández‐Bolaños

Heredia

et al. 2000

J Americ Oil Chem Soc

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“…The changes in texture and solubilization of cell wall polysaccharides during the processing of Spanish green olives have been extensively studied by different researchers (Jiménez et al, 1995(Jiménez et al, , 1996(Jiménez et al, , 1998Coimbra et al, 1996). They observed a marked decrease in texture during lye treatment and washing and a noticeable increase after soaking the olives in brine.…”

Section: Samplingmentioning

confidence: 99%

“…The firmness decreased from 375 gf to 235 gf in 7 and 1/2 hours of processing. The decrease in firmness of the olive flesh takes place in as much as the Na + diffusing into the flesh reacts with the pectins and dislodges the ion Ca 2+ (Jiménez et al, 1995. Although the olives experienced a significant softening, the concentration of calcium increased during the debittering process due to the higher Ca 2+ concentration in the lye than in the olive flesh.…”

Section: Theoretical Considerationsmentioning

confidence: 99%

A simple model of the diffusion phenomena taking place during the debittering process of green table olives

Maldonado¹,

Zuritz²,

Wuilloud³

et al. 2011

Grasas y Aceites

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RESUMENUn modelo simple del fenómeno de difusión que tiene lugar durante el proceso de desamarizado de aceitunas verdes de mesa.Se ha cuantificado el cambio en la concentración de sodio y calcio en la pulpa y en la lejía durante el tratamiento alcalino de aceitunas. La concentración promedio de sodio en la pulpa aumentó de 0,0045 a 0,395 meq Na/g mientras que la de calcio creció de 0,018 a 0,0252 meq Ca/g. La textura de las aceitunas disminuyó casi linealmente de 375 gf a 235 gf durante el tratamiento alcalino. Las aceitunas sufrieron una perdida de azúcares reductores del 25.9%. Se ha propuesto una hipotética y simplificada descripción de la dinámica de los cambios de carga iónica y el desenrrollamiento de las pectinas durante el desamarizado de las aceitunas. También se calculó el coeficiente efectivo de difusión para sodio y calcio usando un modelo de difusión para una placa compuesta. Los coeficientes resultaron en el orden de 10 -12 m 2 /s para la piel y 10 -10 m 2 /s para pulpa. En ambos casos el coeficiente de difusión de Na fue mayor que el de Ca. PALABRAS CLAVE: Calcio -Carga iónica -Difusión -Sodio -Tratamiento alcalino de aceitunas verdes. SUMMARYA simple model of the diffusion phenomena taking place during the debittering process of green table olives.The change in the concentration of sodium and calcium ions in the olive flesh and in the lye during the debittering process was quantified. The average concentration of Na increased from 0.0045 to 0,395 meq Na/g of olive flesh and the concentration of Ca increased from 0.018 to 0.0252 meq Ca/g of olive flesh. The firmness of the olives decreased almost linearly from 375 gf to 235 gf during the alkali treatment. The olives also suffered a 25.9% loss in their initial content of reducing sugars. A hypothetical simplified description of the dynamic of ionic charge changes and unwinding of the pectinic structure during the debittering process of green olives has been proposed. In addition, the A simple model of the diffusion phenomena taking place during the debittering process of green /s for the flesh. In both cases, the diffusion coefficients of Na were larger than the diffusion coefficients of Ca.

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“…3 The majority of the bibliographic data on this subject concerns olives in brine, usually produced by maintaining the fruits in a solution of 40-120 g L −1 sodium chloride for several months. In this context, Jiménez et al 4 showed that green Spanish olives had a significant texture increase when brining was performed after lye treatment (pH of flesh [11][12], but this effect was minimal when brining was carried out after the fermentation of the fruit (pH 3-4). For black olives, texture improvement after brining has been reported for the Hojiblanca variety undergoing the Californian process.…”

Section: Introductionmentioning

confidence: 99%

Effect of dry‐salt processing on the textural properties and cell wall polysaccharides of cv. Thasos black olives

Cardoso¹,

Mafra²,

Reis³

et al. 2008

J Sci Food Agric

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BACKGROUND: Thasos is an olive variety cultivated mainly in Greece used to produce 'naturally black dry-salted olives'. This process consists in placing the olives in disposed layers with coarse sodium chloride. The loss of water and other solutes gradually debitters and wrinkles the fruits. In this study, the effect of dry-salt processing on the texture and cell wall polysaccharide composition was investigated.

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Changes in Texture and Cell Wall Polysaccharides of Olive Fruit during "Spanish Green Olive" Processing

Cited by 47 publications

References 16 publications

Steam‐explosion pretreatment of olive cake

Steam‐explosion pretreatment of olive cake

A simple model of the diffusion phenomena taking place during the debittering process of green table olives

Effect of dry‐salt processing on the textural properties and cell wall polysaccharides of cv. Thasos black olives

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