Effect of the operating conditions on a nanofiltration process to separate low-molecular-weight phenolic compounds from the sugars present in olive mill wastewaters

In this study, the cyclic oligomers in the highly chemically resistant polyester polybutylene terephthalate (PBT) were effectively removed using a compressed CO2 antisolvent technique in which 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) was used as the solvent. In addition to the oligomers, tetrahydrofuran was completely removed because of its low molecular weight and liquid state. The effects of the operating variables, including temperature, pressure, and the PBT concentration in HFIP, on the degree of removal of the oligomers were systematically studied using experimental design and the response surface methodology. The most appropriate operating conditions for the purification of PBT were 8.3 MPa and 23.4 °C when using 4.5 wt % PBT in HFIP. Under these conditions, the cyclic trimers and dimers could be removed by up to 81.4% and 95.7%, respectively, in a very short operating time.

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Impact of malolactic fermentation on low molecular weight phenolic compounds

Talanta ◽

10.1016/j.talanta.2007.08.045 ◽

2008 ◽

Vol 74 (5) ◽

pp. 1281-1286 ◽

Cited By ~ 32

Author(s):

M.J. Cabrita ◽

M. Torres ◽

V. Palma ◽

E. Alves ◽

R. Patão ◽

...

Keyword(s):

Molecular Weight ◽

Phenolic Compounds ◽

Malolactic Fermentation ◽

Low Molecular Weight

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Influence of Botanical Species and Geographical Origin on the Content of Low Molecular Weight Phenolic Compounds of Woods Used in Portuguese Cooperage

Holzforschung ◽

10.1515/hf.2000.043 ◽

2000 ◽

Vol 54 (3) ◽

pp. 255-261 ◽

Cited By ~ 29

Author(s):

Sara Canas ◽

M. Conceição Leandro ◽

M. Isabel Spranger ◽

A. Pedro Belchior

Keyword(s):

Molecular Weight ◽

Phenolic Compounds ◽

Geographical Origin ◽

Castanea Sativa ◽

Total Content ◽

Low Molecular Weight ◽

Qualitative And Quantitative ◽

Botanical Species ◽

The Difference ◽

Chestnut Wood

Summary The influence of botanical species (Quercus and Castanea sativa) and geographical origin (Portugal—three different sites, France and North America) on the qualitative and quantitative content of some extractable low molecular weight phenolic compounds was assessed by HPLC. Chestnut wood had the highest total content of low molecular weight phenolic compounds, followed by the Portuguese oaks and the French oaks, whereas the American oak had the lowest content of these compounds. The contents of phenolic acids, phenolic aldehydes, scopoletin and umbelliferone were significantly different among the studied woods. Both the botanical species and the geographical origin affect the content of low molecular weight organic compounds of woods used in Portuguese cooperage. The results also show that the botanical species seem to be more important than the geographical origin to explain the difference in the wood phenolic composition. So, the separation of trees according to their origin is of considerable interest for coopers and winemakers to choose wisely the woods for the ageing of brandies.

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How acetaldehyde reacts with low molecular weight phenolics in white and red wines

European Food Research and Technology ◽

10.1007/s00217-021-03841-8 ◽

2021 ◽

Author(s):

Raffaele Cucciniello ◽

Martino Forino ◽

Luigi Picariello ◽

Francesca Coppola ◽

Luigi Moio ◽

...

Keyword(s):

Molecular Weight ◽

Phenolic Compounds ◽

Low Molecular Weight ◽

Red Wines ◽

Chemical Behavior ◽

White Wines ◽

Red Pigments ◽

Color Properties ◽

Color Evolution ◽

Wine Color

AbstractAcetaldehyde is a key compound in determining wine color evolution and sensory properties. Major wine metabolites reactive to acetaldehyde are phenolic compounds, mainly flavan-3-ols and anthocyanins. Many studies have been conducted with the purpose of investigating acetaldehyde reactivity in model solutions, but very poor are the reports of its fate in real wines. By means of LC-HRESIMS and UV/Vis HPLC, red and white wines exposed to an excess of acetaldehyde were analyzed with a specific focus on low molecular weight phenolics. The chemical behavior of acetaldehyde turned out to be different in white and red wines. In white wines, it mainly mediated the formation of vinyl-flavan-3-ol derivatives, while in red wines it led to the formation of ethylidene-bridged red pigments. These latter positively enhanced the color properties of red wines. Conversely, in white wines, the formation of compounds, such as xanthylium ions, causing the undesired browning effects were not detected.

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ROLE OF LOW MOLECULAR WEIGHT PHENOLIC COMPOUNDS IN THE DIFFERENTIATION OF DRY SHERRY WINES.

Acta Horticulturae ◽

10.17660/actahortic.1995.388.37 ◽

1995 ◽

pp. 245-248 ◽

Cited By ~ 2

Author(s):

M. Palma ◽

C.G. Barroso ◽

J.A. Pérez-Bustamante

Keyword(s):

Molecular Weight ◽

Phenolic Compounds ◽

Low Molecular Weight

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Effect of key operating parameters on the non-catalytic wet oxidation of olive mill wastewaters

Water Science & Technology ◽

10.2166/wst.2009.321 ◽

2009 ◽

Vol 59 (12) ◽

pp. 2509-2518 ◽

Cited By ~ 9

Author(s):

E. Chatzisymeon ◽

E. Diamadopoulos ◽

D. Mantzavinos

Keyword(s):

Reaction Temperature ◽

Treatment Time ◽

Operating Conditions ◽

Total Phenols ◽

Oxidation Reactions ◽

Catalytic Wet Oxidation ◽

Air Oxidation ◽

Experimental Conditions ◽

Olive Mill Wastewaters ◽

Olive Mill

The non-catalytic wet air oxidation (WAO) of olive mill wastewaters was investigated. The effect of operating conditions, such as initial organic loading (1,000 and 4,500 mg/L COD), reaction temperature (140 and 180°C), treatment time (1 and 4 h), initial pH (4.8 and 7) and the use of 500 mg/L H2O2 as an additional oxidant, on treatment efficiency was assessed implementing a factorial experimental design. Of the five parameters tested, the first two had a considerable effect on COD removal, while treatment time was of no significance implying that all oxidation reactions occur during the first hour of treatment. Although the level of mineralization was generally moderate, this was accompanied by nearly complete total phenols and color removal. The analysis was repeated at more intense conditions, i.e. initial COD up to 8,000 mg/L and reaction temperature up to 200°C; at this level, none of the studied effects were important. However, at optimal experimental conditions (i.e. 180°C, 1 h treatment and initial COD of 8,100 mg/L) WAO yielded 34, 94 and 74% removal of COD, total phenols and color respectively. Moreover, ecotoxicity to V. fischeri was slightly reduced after 2 h of treatment at the above conditions.

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