Phenolics and Antioxidants

Depending on sample freshness, particle size, extraction solvent (ethanol, methanol, acidified methanol, and acetone), reference phenolic compound (catechin vs. gallic acid), and detection method (vanillin vs. Folin Ciocalteu reagent) used for analysis, one may obtain widely varying results for phenolics of the same seed sample [15,21-25], However, the Juglandaceae family pecan and walnut typically contain the highest amount of phenolics per unit weight (Table 2.10), followed by pistachio nuts. 

Vitamin A (international unit) Vitamin A (retinol activity equivalents) Retinol 

Vitamin C (total ascorbic acid) Vitamin E (a-tocopherol) P-Tocopherol y-Tocopherol 5-Tocopherol Vitamin K (phylloquinone) Thiamin (Bj) Riboflavin (Bj) Niacin (B,) Pantothenic acid (B5) Pyridoxine (B ) Cobalamin (B12) Betaine Folate 

Acorn Nut Almond Beechnut Brazil Nut Cashew Chestnut Coconut Hazelnut Hickory Nut Macadamia Pecan Pine Nut Pistachio Walnut  

Source From U.S. Department of Agriculture (USDA), Natioruil Nutrient Database for Standard Reference, Release 19, Published online at http //www.nal.usda.gov/fnic/foodcomp/search/ (accessed February 2007). 

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Kalt, W, Ryan D A, Duy J C, Prior R L, Ehlenfeldt M K, and Vander Kloet S P (2001), Interspecific variation in anthocyanins, phenolics, and antioxidant capacity among genotypes of highbush and lowbush blueberries (Vaccinium section Cyanococcus spp.) , J Agric Food Chem, 49, 4761-4767. 

Turkmen N, Sari F and Velioglu YS. 2005. The effect of cooking methods on total phenolics and antioxidant activity of selected green vegetables. Food Chem 93(4) 713-718. 

Phenolic and antioxidant substances have usually studied in red wines, however, recently, interest has increased in the study of bioactive phenolics in white wines Frega et al. [374] isolated and measured concentration of ethyl caffeoate in Verdicchio white wine by HPLC-tandem-mass spectrometry (HPLC-ESI-MS/MS) and they also determined its effects on hepatic stellate cells and intracellular peroxidation. The resnlts were interesting in the light of other studies demonstrating the relationship between reactive oxygen species, chronic liver injury, and hepatic fibrosis. 

Total endogenous phenols and antioxidants Hypothetical total diet-derived phenols... 

Table 5.6 shows the total phenolic content (determined using the Folin-Ciocalteu assay) and antioxidant activity (ABTS radical scavenging capacity) of extracts from morama bean seed coat and cotyledon prepared with acidified mefhanol. If is clear fhaf morama bean seed coat and cotyledon have appreciable levels of fofal phenolics and antioxidant activity. These phenolics are concentrated in the seed coat. It has been reported that the morama bean cotyledon contains high levels of the amino acid tyrosine (Maruatona et ah, 2010) which is phenolic in nature and can therefore confribufe fo fhe fofal phenolic content of the cotyledon as determined with the Folin-Ciocalteu assay. 

Huang, Z., Wang, B., Eaves, D. H., Shikany, J. M., Pace, R. D. (2007). Total phenolics and antioxidant capacity of indigenous vegetables in the southeast United States Alabama Collaboration for Cardiovascular Equality Project Int. J. Food Sci Nutr., 1-9. 

Moyer, R.A., Hummer, K.E., Finn, C.E., Frie, B., and Wrolstad, R.E., Anthocyanins, phenolics, and antioxidant capacity in diverse small fruits vaccinium, rubus, and ribes, J. Agric. Food Chem., 50, 519-525, 2002. 

TABLE 6.8 Resveratrol, piceid, total phenols, and antioxidant capacity (TEAC) of someTokaji and German botrytized wines. Mean values are in parentheses (adapted from Pour Nikfardjam et al, 2006, and with permission from Elsevier)... 

The health benefits explain the growth in interest concerning the characterization and evaluation of phenolics and antioxidant capacity in food-related products. The chemical structures of the main polyphenols found in Madeira table wines are summarized in Fig. 7.13. 

Some studies have shown that MAE may be superior to other extraction methods. Total phenolics and antioxidant activity were found to be higher in spice samples extracted by MAE than by UAE (Gallo et ah, 2010). In extracting anthraquinones from Morinda citrifolia, commonly known as noni, optimized MAE conditions were found to be 80% ethanol, 60 °C extraction temperature, and 30 min extraction time. MAE was shown to require less extraction time while achieving higher yields when compared to Soxhlet, maceration and UAE methods (Hemwimon et ah, 2007). 

Chiou A. Karathanos V.T. Mylona A. Salta F.N. Prevent F. Andrikopoulos N.K. 2007. Currants Vitis vinifera L.) content of simple phenolics and antioxidant activity. Food Chem. 102 516-522. 

Leaf samples from Ghana contained lower levels of total phenols and antioxidant activity (Table VII). The sample from the Volta Dam only contained 3.3% of total phenols and the sample from Dodowa was even lower at 2.6%. The antioxidant activity not surprisingly was also lower than the majority of the samples from Zambia (Tables V-VII). The sample from Volta Dam had an antioxidant activity of 5.7% while the sample from Dodowa s had a little lower activity of 5.0% (Table VII). 

In this study, we found that phenolic compounds are the major contributors to the antioxidant activity, since total phenolics and antioxidant activity showed a good correlation with a correlation coefficient of R2=0.9208. However, we note that the trunk barks of A. leiocarpus exhibit a high antioxidant activity and a low level of total phenol antioxidant. The value of correlation coefficient between total flavonoids and antioxidant activity was R2 = 0.752 only. 

Finally, practical suspension formulations may contain a number of other additives that are included to provide features, not all of which are directly related to suspension stability. Viscosity-enhancing additives are an obvious example, but other formulation agents may relate to the preservation of suspension stabilizing agent, such as antimicrobial agents (e.g. benzoic acid, aldehydes and phenolics) and antioxidants (reducing agents). 

Picinelli Lobo A, Dineiro Garcia Y, Sanchez JM, Rodriguez Madrera R, Suarez Valles B (2009) Phenolic and antioxidant composition of cider. J Food Comp Anal 22 644-648... 

Kalt, W., MacDonald, J.E., and Donnor, H., 2000. Anthocyanins, phenolics, and antioxidant capacity of processed lowbush blueberry products. J. Food Sci., 65, 390—393. 

When antioxidant capacities of the lichens are compared with their phenolic constituents, it could be concluded that antioxidative nature of the lichens might depend on their phenolics. There are many reports which correlate the total phenolic content of lichens and their antioxidant activity. For example, for the methanol extract of Lobaria pulmonaria, there was a strong correlation between antioxidant activity and total phenolic content (Odabasoglu et al. 2004). Kekuda et al. (2012) found highly positive relationship between total phenols and antioxidant activity in methanol extract of a foliose macrolichen Everniastrum cirrhatum. 

Ramful, D., Bahorun, T., Bomdon, E., Tamus, E. and Aruoma, O.I., 2010a. Bioactive phenolics and antioxidant propensity of flavedo extracts of Mauritian citrus fruits Potential prophylactic ingredients for functional foods application. Toxicology 278(1), 75-87. 

The addition of antioxidants can alleviate the photodegradation of both wood fiber and thermoplastics. Peng et al. [125] combined two kinds of antioxidants, namely antioxidant 1010 (AO-lOlO, hindered phenols) and antioxidant 168 (AO-168, phosphite), and then made WF/PP composites at different compound proportions. The chemical structures of the two antioxidants are given in Fig. 24. The compound systems showed a synergistic effect on maintaining the surface color and flexural properties of the composites, especially at the ratio of 1 5 (AO-lOlO AO-168). 

Dykes L, Rooney LW. 2006. Sorghum and Millet Phenols and Antioxidants. Journal of Cereal Science 44(3) 236-251. 

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