Ethanol in Olive Fruit. Changes during Ripening

Beltrán, Gabriel; Bejaoui, Mohamed Aymen; Jiménez, Antonio; Sánchez‐Ortíz, Araceli

doi:10.1021/acs.jafc.5b01453

Cited by 30 publications

(49 citation statements)

References 10 publications

(22 reference statements)

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“…Acetaldehyde increased in reduction capacity in the fermentation pathway. Beltrán, et al [63] observed the accumulation of both ethanol and acetaldehyde in olive fruit during maturation, although ethanol showed a more rapid increase.…”

Section: Resultsmentioning

confidence: 99%

Changes in Volatile and Non-Volatile Flavor Chemicals of “Valencia” Orange Juice over the Harvest Seasons

Bai

Baldwin

McCollum

et al. 2016

Foods

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Florida “Valencia” oranges have a wide harvest window, covering four months after first reaching the commercial maturity. However, the influence of harvest time on juice flavor chemicals is not well documented, with the exception of sugars and acids. Therefore, we investigated the major flavor chemicals, volatile (aroma), non-volatile (taste) and mouth feel attributes, in the two harvest seasons (March to June in 2007 and February to May in 2012). Bitter limonoid compounds, limonin and nomilin, decreased gradually. Out of a total of 94 volatiles, 32 increased, 47 peaked mid to late season, and 15 decreased. Juice insoluble solids and pectin content increased over the season; however, pectin methylesterase activity remained unchanged. Fruit harvested in the earlier months had lower flavor quality. Juice from later harvests had a higher sugar/acid ratio with less bitterness, while, many important aroma compounds occurred at the highest concentrations in the middle to late season, but occurred at lower concentrations at the end of the season. The results provide information to the orange juice processing industry for selection of optimal harvest time and for setting of precise blending strategy.

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Section: Resultsmentioning

confidence: 99%

Changes in Volatile and Non-Volatile Flavor Chemicals of “Valencia” Orange Juice over the Harvest Seasons

Bai

Baldwin

McCollum

et al. 2016

Foods

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“…However, Beltran et al showed that the origin of ethanol is unclear, and the olive fruit itself is a possible source. According to the latter study, ethanol accumulates in olive fruit during ripening due to the activity of the enzyme alcohol dehydrogenase during the synthesis of anaerobic metabolites (including ethanol).…”

Section: Introductionmentioning

confidence: 99%

“…Earlier work has found that, in these conditions, oxygen in the headspace is naturally consumed by the paste and, at the same time, a huge amount of carbon dioxide accumulates in the sealed chamber . Following the work of Beltran et al and the hypothesis that ethanol formation in olive fruit is due to enzymatic activity, the accumulation of headspace ethanol during malaxation in sealed conditions is investigated in a series of trials, in an attempt to better understand the olive/ethanol association.…”

Section: Introductionmentioning

confidence: 99%

Ethanol From Olive Paste During Malaxation, Exploratory Experiments

Masella¹,

Guerrini²,

Angeloni³

et al. 2018

Euro J Lipid Sci & Tech

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Ethanol is a precursor of ethyl esters in olive oil. Its presence is generally ascribed to microbial degradation of damaged olives. At the same time, it is an anaerobic metabolite that naturally accumulates in olive fruit during ripening. As the possible link with olive processing is poorly studied, this laboratory‐scale experiment measures gaseous ethanol in the headspace above olive paste malaxated in sealed conditions. Malaxation take place in the presence or absence of oxygen, using sanitized or untreated olives. The findings show that ethanol accumulates in the headspace in oxygenated trials, reaching roughly 80 μmol kg−1 of olive paste. Under anoxic conditions ethanol accumulation is ten times higher, while olive treatment is not significant. Ethanol kinetics during malaxation are modeled as a biexponential system in which two components are simultaneously present, originating from parallel reactions at different constant rates. The first is the ethanol present in the olives and gradually released in the headspace. The second is ethanol neoformation under anoxic conditions. Under oxygenated conditions, the first component predominates, while under anoxic conditions, the opposite holds. Practical Application: Online monitoring of gaseous ethanol above olive paste during malaxation could easily be implemented in olive oil processing plants. Ethanol kinetics could indicate the presence of unwanted anoxic conditions and help in setting appropriate oxygen levels in the kneaded paste. Future studies may find a link between ethanol kinetics in the malaxation headspace, and the occurrence of ethyl esters in oils. If this is the case, operators would be able to fine‐tune the process to avoid unwanted effects. Ethanol is an anaerobic metabolite that naturally accumulates in olive fruit during ripening. Gaseous ethanol is found to be released from the olive paste during malaxation (sealed conditions). Furthermore, under anoxicity, the ethanol release is roughly ten times higher in response to the absence of oxygen, that is, cell anaerobic respiration take place.

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“…Conte et al described the formation of ethyl esters during oil conservation. Ethyl esters can be formed by direct esterification of free fatty acids or by transesterification of fatty acids from triacylglycerides as described by Biedermann et al Their alcoholic precursor – ethanol – may be synthesized in the own olive fruit whereas it remains on the tree, but any alteration of the fruit can result in fruit enzyme activation or attack by microorganisms because of the loss of fruit integrity during its period on the ground. Furthermore, an increase in ethanol content and free acidity, although values were always below the regulated limits, may induce the synthesis of ethyl esters in VOO.…”

Section: Introductionmentioning

confidence: 99%