Polyphenols in apple

Suarez B, Picinelli A and Mangas JJ. 1996. Solid-phase extraction and high-performance liquid chromatographic determination of polyphenols in apple musts and ciders. J Chromatogr A 727(2) 203-209. 

Y Lu, LY Foo. Identification and quantification of major polyphenols in apple pomace. Food Chem 59 187-194, 1997. 

Alonso-Salces R.M. Korta E. Barranco A. Berrueta L.A. Gallo B. Vicente F. 2001. Pressurized liquid extraction for the determination of polyphenols in apple. J. Chromatogr. 933 37-43. 

Determination of phenols in other matrices like food samples must also be mentioned. Capillary liquid chromatography was evaluated as an alternative to conventional HRLC to analyze complex phenolics and polyphenols in apple juice. Determination of polyphenols is of very high importance because of their biological properties, like... 

Cao XL, Wang C, Pei HR, Sun BG (2009) Separation and identification of polyphenols in apple pomace by high-speed counter-current chromatography and high-performance liquid chromatography coupled with mass spectrometry. J Chromatogr A 1216 4268-4274... 

Bureau S, Scibisz I, Le Bourvellec C, Renard CMGC (2012) Effect of sample preparation on the measurement of sugars, organic acids and polyphenols in apple fruit by mid-infrared spectroscopy. Agric Food Chem 60 3551 3563... 

Table 16.1 Mean content (mg/g DM) of polyphenols in organically produced Golden Delicious apples in three successive years (analyses were carried out at the beginning of the storage period in December). The percentage differences compared to conventional fruit from the same production unit, the level of significance between conventional and organic fruit ( = P > 0.01 = p > 0.05) or trends (exactp-value listed if 0.05 < p < 0.13) are indicated...

This method is also used to measure ex vivo low-density lipoprotein (LDL) oxidation. LDL is isolated fresh from blood samples, oxidation is initiated by Cu(II) or AAPH, and peroxidation of the lipid components is followed at 234 nm for conjugated dienes (Prior and others 2005). In this specific case the procedure can be used to assess the interaction of certain antioxidant compounds, such as vitamin E, carotenoids, and retinyl stearate, exerting a protective effect on LDL (Esterbauer and others 1989). Hence, Viana and others (1996) studied the in vitro antioxidative effects of an extract rich in flavonoids. Similarly, Pearson and others (1999) assessed the ability of compounds in apple juices and extracts from fresh apple to protect LDL. Wang and Goodman (1999) examined the antioxidant properties of 26 common dietary phenolic agents in an ex vivo LDL oxidation model. Salleh and others (2002) screened 12 edible plant extracts rich in polyphenols for their potential to inhibit oxidation of LDL in vitro. Gongalves and others (2004) observed that phenolic extracts from cherry inhibited LDL oxidation in vitro in a dose-dependent manner. Yildirin and others (2007) demonstrated that grapes inhibited oxidation of human LDL at a level comparable to wine. Coinu and others (2007) studied the antioxidant properties of extracts obtained from artichoke leaves and outer bracts measured on human oxidized LDL. Milde and others (2007) showed that many phenolics, as well as carotenoids, enhance resistance to LDL oxidation. 

In general, beer tends to be rich in HA protein and poor in HA polyphenol, while apple juice tends to have the opposite pattern (Siebert et al., 1996a). Grape juice is fairly low in HA protein and variable in HA polyphenol. 

Vrhovsek, U. et al., Quantitation of polyphenols in different apple varieties, J. Agric. Food Chem., 52, 6532, 2004. 

For phenolics in fruit by-products such as apple seed, peel, cortex, and pomace, an HPLC method was also utilized. Apple waste is considered a potential source of specialty chemicals (58,62), and its quantitative polyphenol profile may be useful in apple cultivars for classification and identification. Chlorogenic acid and coumaroylquinic acids and phloridzin are known to be major phenolics in apple juice (53). However, in contrast to apple polyphenolics, HPLC with a 70% aqueous acetone extract of apple seeds showed that phloridzin alone accounts for ca. 75% of the total apple seed polyphenolics (62). Besides phloridzin, 13 other phenolics were identified by gradient HPLC/PDA on LiChrospher 100 RP-18 from apple seed (62). The HPLC technique was also able to provide polyphenol profiles in the peel and cortex of the apple to be used to characterize apple cultivars by multivariate statistical techniques (63). Phenolic compounds in the epidermis zone, parenchyma zone, core zone, and seeds of French cider apple varieties are also determined by HPLC (56). Three successive solvent extractions (hexane, methanol, aqueous acetone), binary HPLC gradient using (a) aqueous acetic acid, 2.5%, v/v, and (b) acetonitrile fol-... 

The lag time effect probably results from the inhibition of copper-containing oxidases and other copper-catalyzed oxidative processes in apple by Sporix. These oxidative reactions normally would bring about the rapid loss of AA and permit browning to occur once the added AA was depleted (18). Sporix also would inhibit PPO directly by chelation of its copper (3), thereby decreasing the rate of polyphenol oxidation and subsequent browning. The ability of Sporix to exert its effect on enzymatic browning by these two independent mechanisms probably accounts for the apparent synergism obtained with Sporix-AA combinations. 

Catechins Epigallocatechin, epicatechin gallate. and epicatechin. They are the main polyphenols in green tea. Other sources are apples, cherries, and pears. Down regulation of mutagenic signalling [841. 10-300... 

Bayindirli et al. (2006) studied the effectiveness of treating polyphenol oxidase activity in apple juice by applying high hydrostatic pressure with mild heat treatment (350 MPa at 40 °Q. 

Dietary fat appears to enhance the absorption of polyphenol flavonoids, which may explain why the phenolic compounds in olive oil are especially bioavailable. Pectin, a type of fiber found in apples, appears to enhance the bioavailability of an abundant polyphenol known as quercetin. Finally, there appears to be significant individual genetic variability in the ability of individuals to produce the active metabolites of some phenols. Whether this can be overcome has yet to be established. Until more is known about the complex factors involved with the bioavailability of these powerful plant-based health-promoting compounds, your best bet is to consume them as food, not supplements, in as fresh a form as possible, and to limit the use of processing and cooking methods like boiling or frying. 

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