Synthesis of mono- and di-esters of phenolic acids from oleaginous meals, and evaluation of their antioxidant activity in emulsion and liposomes
Rapeseed and sunflower meals contain high amounts of phenolic compounds, around 1-2 %DDM (delipidated dry matter) and 1-4 %DDM respectively. In rapeseed meal, 95 % of the total phenolic compounds (TPC) are sinapic acid esters. On the other hand, caffeic acid esters are the main phenolics of sunflower meal, accounting for at least 93 % of the TPC. Both sinapic and caffeic acids can be recovered after chemical or enzymatic hydrolysis of their corresponding esters, either from meals or from extracts. Phenolic acids, and more particularly hydroxycinnamic acids, are known to be bioactive molecules with antioxidant, anti-UV and antimicrobial properties. Their esterification with alcohols of adequate chain length allowed a drastic improvement of their antioxidant activity in liposome suspensions or O/W emulsions. This phenomenon, related to the so-called “cut-off effect”, was attributed to a better location and concentration of esters at the interfacial membrane, where lipid oxidation occur. Knowing this, the aim of this study was to synthetize mono- and di-esters of caffeic, chlorogenic and sinapic acid, the main phenolic acids present in rapeseed and sunflower meal. After direct esterification with diols of increasing alkyl chain length (C2-C16), the antioxidant activity of the resulting mono- and diesters (bearing respectively one and two phenolic moieties) was then studied in O/W emulsion and liposome suspensions as model systems. The compounds having the higher antioxidant capacity among each ester family were finally selected and compared against each other as a function of the model system.
Main Authors: | , , , , |
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Format: | conference_item biblioteca |
Language: | eng |
Published: |
Euro Fed Lipid
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Online Access: | http://agritrop.cirad.fr/597289/ http://agritrop.cirad.fr/597289/2/ID597289.pdf |
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Summary: | Rapeseed and sunflower meals contain high amounts of phenolic compounds, around 1-2 %DDM (delipidated dry matter) and 1-4 %DDM respectively. In rapeseed meal, 95 % of the total phenolic compounds (TPC) are sinapic acid esters. On the other hand, caffeic acid esters are the main phenolics of sunflower meal, accounting for at least 93 % of the TPC. Both sinapic and caffeic acids can be recovered after chemical or enzymatic hydrolysis of their corresponding esters, either from meals or from extracts. Phenolic acids, and more particularly hydroxycinnamic acids, are known to be bioactive molecules with antioxidant, anti-UV and antimicrobial properties. Their esterification with alcohols of adequate chain length allowed a drastic improvement of their antioxidant activity in liposome suspensions or O/W emulsions. This phenomenon, related to the so-called “cut-off effect”, was attributed to a better location and concentration of esters at the interfacial membrane, where lipid oxidation occur. Knowing this, the aim of this study was to synthetize mono- and di-esters of caffeic, chlorogenic and sinapic acid, the main phenolic acids present in rapeseed and sunflower meal. After direct esterification with diols of increasing alkyl chain length (C2-C16), the antioxidant activity of the resulting mono- and diesters (bearing respectively one and two phenolic moieties) was then studied in O/W emulsion and liposome suspensions as model systems. The compounds having the higher antioxidant capacity among each ester family were finally selected and compared against each other as a function of the model system. |
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