Conversion of phenolics to lignans: Sinapic acid to thomasidioic acid

Rubino, Maria; Arntfield, Susan D.; Charlton, James L.

doi:10.1007/bf02577839

Cited by 19 publications

(20 citation statements)

References 19 publications

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“…Rubino et al (27) reported the formation of thomasidioic acid when sinapic acid was exposed to neutral or alkaline conditions. In detailed studies on the conversion of sinapic acid to thomasidioic acid, it was shown that oxygen was necessary for the conversion (27,30). During the storage test, air was introduced occasionally.…”

Section: Resultsmentioning

confidence: 98%

Structural changes of sinapic acid and sinapine bisulfate during autoclaving with respect to the development of colored substances

Cai

Arntfield

Charlton

1999

J Americ Oil Chem Soc

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Structural changes in sinapic acid during autoclaving were studied using spectral analysis, thin-layer chromatography, high-performance liquid chromatography, nuclear magnetic resonance (NMR), and mass spectroscopy. Color properties of sinapic acid and its derivatives were studied by determining the transmittance spectrum, calculating the Commission Internationale de l'Eclairage 1931 tristimulus values and converting to Hunter L a b values. It was found that the colorless sinapic acid aqueous solution (100 µg/mL) turned yellow after 15 min in an autoclave at 121°C and 0.1 MPa. Filtering the yellow aqueous solution through a 0.45-µm filter removed a brown solid consisting of at least three undetermined colored substances and left a yellow liquid. A newly developed yellow substance, syringaldehyde, was identified in the liquid phase by comparing the NMR and mass spectra of the unknown with those of authentic syringaldehyde. Thomasidioic acid was also found in the liquid phase. Under the same autoclaving conditions, sinapine bisulfate showed no evidence of any structural or color changes.Paper no. J8901 in JAOCS 76, 433-441 (April 1999).

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Section: Resultsmentioning

confidence: 98%

Structural changes of sinapic acid and sinapine bisulfate during autoclaving with respect to the development of colored substances

Cai

Arntfield

Charlton

1999

J Americ Oil Chem Soc

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“…Sinapic acid is the predominant free phenolic acid and the principal phenolic acid released from esters and glucosides in canola (Rubino et al 1995). Changes in sinapic acid when exposed to aqueous alkaline conditions results in a conversion to thomasidioic acid (Rubino et al 1995(Rubino et al , 1996a. At pH 4.5, there was binding between sinapic acid and the canola protein through electrostatic interactions whereas at pH 7 and 8.5, a hydrophobic association between thomasidioic acid and the protein occurred (Rubino et al 1996b).…”

Section: Non-covalent Interactions Between Hydroxycinnamates and Protmentioning

confidence: 97%

“…The interaction of quinic acid with the protein suggests predominance of ionic-hydrogen bonding in the interaction process (Suryaprakash et al 2000). Sinapic acid is the predominant free phenolic acid and the principal phenolic acid released from esters and glucosides in canola (Rubino et al 1995). Changes in sinapic acid when exposed to aqueous alkaline conditions results in a conversion to thomasidioic acid (Rubino et al 1995(Rubino et al , 1996a.…”

Section: Non-covalent Interactions Between Hydroxycinnamates and Protmentioning

confidence: 98%

Nature of hydroxycinnamate-protein interactions

2009

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In the context of this review the type and nature of possible interactions between hydroxycinnamates and proteins are discussed. These interactions can be classified in two sub-groups: non-covalent and covalent interactions. A short introduction is given on different sites of possible interactions. The first part of the article then focuses mainly on such reactions of phenolic substances with proteins and enzymes that lead to covalent bonds and thus to their derivatization respectively consequent cross-linking reactions. The corresponding postulated reaction mechanisms in the literature are also described. Effects on physicochemical, structural and techno-functional properties of the modified proteins are discussed, with consequent impact on their digestibility and subsequently on their nutritional quality. The second part incorporates the chemistry behind the (non-covalent) binding potential of the hydroxycinnamates to proteins. The different aspects of the nutritional-physiological consequences of such interactions with focus on their significance to food science and technology are presented. This review finally summarizes the development of potential new research strategies in this field.

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“…Although no relationship has ever been reported between the structural changes of the phenolics and color properties of canola/rapeseed protein, several researchers have observed structural changes of sinapic acid in air-saturated basic conditions (18)(19)(20)(21). Rubino et al (19) reported the formation of thomasidioic acid showing that the conversion was oxygen dependent (20).…”

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confidence: 99%

Structural changes of sinapic acid during alkali‐induced air oxidation and the development of colored substances

Cai

Arntfield

Charlton

1999

J Americ Oil Chem Soc

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Structural changes of sinapic acid were induced by air oxidation in aqueous solutions at pH 7-10 and followed by spectral and high-performance liquid chromatographic (HPLC) analysis. Color properties of the sinapic acid solutions were determined by taking the transmittance spectra, calculating the Commission Internationale de l'Eclairage (CIE) 1931 tristimulus values, and converting to Hunter L a b values. Reaction rate constants for sinapic acid were determined by a kinetic study based on the quantitative results from HPLC analysis. These reactions were first order with respect to sinapic acid and fit the appropriate equation with a coefficient of R 2 > 0.97. Sinapic acid was converted to thomasidioic acid with reaction rate constants (k) of 8.54 × 10 −6 , 2.51 × 10 −5 , and 4.87 × 10 −5 s −1 in phosphate-boric acid buffers of pH 7, 8.5, and 10, respectively. Similar reactions in ammonium bicarbonate buffers were more than 10 times faster. With time, thomasidioic acid further converted to 2,6-dimethoxy-p-benzoquinone and 6-hydroxy-5,7-dimethoxy-2-naphthoic acid. Air oxidation of sinapic acid aqueous solutions caused darkening of the color for the system, with the 2,6-dimethoxy-p-benzoquinone as a major color contributor.Paper no. J9024 in JAOCS 76, 757-764 (June 1999).

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Conversion of phenolics to lignans: Sinapic acid to thomasidioic acid

Cited by 19 publications

References 19 publications

Structural changes of sinapic acid and sinapine bisulfate during autoclaving with respect to the development of colored substances

Structural changes of sinapic acid and sinapine bisulfate during autoclaving with respect to the development of colored substances

Nature of hydroxycinnamate-protein interactions

Structural changes of sinapic acid during alkali‐induced air oxidation and the development of colored substances

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