Phenolic acids, in foods

Knowledge of the identity of phenolic compounds in food facilitates the analysis and discussion of potential antioxidant effects. Thus studies of phenolic compounds as antioxidants in food should usually by accompanied by the identification and quantification of the phenols. Reversed-phase HPLC combined with UV-VIS or electrochemical detection is the most common method for quantification of individual flavonoids and phenolic acids in foods (Merken and Beecher, 2000 Mattila and Kumpulainen, 2002), whereas HPLC combined with mass spectrometry has been used for identification of phenolic compounds (Justesen et al, 1998). Normal-phase HPLC combined with mass spectrometry has been used to identify monomeric and dimeric proanthocyanidins (Lazarus et al, 1999). Flavonoids are usually quantified as aglycones by HPLC, and samples containing flavonoid glycosides are therefore hydrolysed before analysis (Nuutila et al, 2002). 

Robbins RJ. 2003. Phenolic acids in foods An overview of analytical methodology. J Agric Food Chem 51(10) 2866-2887. 

The determination of the free phenolic acids in foods requires hydrolysis, because the phenolics are usually found in the conjugated form and rarely in the free state. When the separation... 

Robbins, R. J. 2003. Phenolic acids in foods an overview of analytieal methodology. J. Agric. Food Chem. 51 2866-2887. 

Phenolic acids occur naturally in higher plants, usually as free adds, glycosides, esters, or in insoluble-bound form in a complex mixture of other phenolic compounds. The presence of phenolic acids in food products has been associated with astringency, discoloration, inhibition of enzyme activity, and antioxidant properties, among others [15]. A major portion of phenohc acids present in almond was found in the form of soluble esters. Wijeratne et al. [16] reported that the total amounts of identified free phenolic acids were 16.3, 14[ig/g and a trace amount in skin, shell, and whole seed extracts, respectively, whereas the amounts for total esterified phenolic acids were 279.6,967.1, and 40.3 [ig/g, respectively. 

Phenolic acids in foods occur in the fi ee, esterified, glycosidic, and insoluble-bound forms [3]. Free phenolic acids are known to contribute to the taste of foods. 

MATTILA p and KUMPULAINEN J (2002) Determination of free and total phenolic acids in plant-derived foods by HPLC with diode-array detection, JAgric Food Chem, 50, 3660-67. 

Hakkinen S H and Torronen A R (2000), Content of flavonols and selected phenolic acids in strawberries and vaccinium species influence of cultivar, cultivation site and technique , Food Res Int, 33, 517-524. 

Floridi S, Montanari L, Marconi O and Fantozzi P. 2003. Determination of free phenolic acids in wort and beer by coulometric array detection. J Agric Food Chem 51(6) 1548—1554. 

Mattila P, Hellstrom J and Torronen R. 2006. Phenolic acids in berries, fruits, and beverages. J Agric Food Chem 54(19) 7193—7199. 

L. Yao, Y. Jiang, N. Datta, R. Singanusong, X. Liu, J.Duan, K. Raymont, A. Lisle and Y. Xu, HPLC analyses of flavanols and phenolic acids in the fresh shoots of tea (Camellia sinensis) grown in Australia. Food Chem. 84 (2004) 253-263. 

Torronen, R. et al., Flavonoids and phenolic acids in selected berries. Cancer Lett., 114, 191, 1997. Arts, I.C.W., van de Putte, B., and Hollman, P.C.H., Catechin contents of foods commonly consumed in The Netherlands. 2. Tea, wine, fruit juices, and chocolate milk, J. Agric. Food Chem., 48, 1752, 2000. 

Nardini, M., Cirillo, E., Natella, F., and Scaccini, C., Absorption of phenolic acids in humans after coffee consumption, J. Agric. Food Chem., 50, 5735, 2002. 

Mattila, P., Hellstrom, J. (2007). Phenolic acids in potatoes, vegetables, and some of their products. J. Food Compos. Anal., 20, 152-160. 

Lewis, C. E., Walker, J. R. L., Lancaster, J. E., Sutton, K. H. (1998). Determination of anthocyanins, flavonoids and phenolic acids in potatoes. I. Coloured cultivars of Solanum tuberosum L. Journal of the Science of Food and Agriculture, 77,45-57. 

C Regnault-Roger, R Hadidane, JF Biard, K Boukef. High performance liquid and thin layer chromatographic determination of phenolic acids in palm (Phoenix dactilifera) product. Food Chem 25 61-71, 1987. 

Yu J, Vasanthan T, Temelli F. 2001. Analysis of phenolic acids in barley by high-performance liquid chromatography. J Agric Food Chem 49 4352-4358. 

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