Apples polyphenolics extraction

The product quality has been analyzed with respect to the retention of the antioxidant activity of the spray-dried powder. Polyphenolic compounds present in several extracts (grape seed, apple polyphenolic extract, or olive-leaf) were also encapsnlated by SD in protein-lipid emulsions (Kosaraju et al, 2008) and chitosan (Kosaraju et al., 2006). 

Annurca apple polyphenol extract (APE) HaCaT cells keratinocytes Antiproliferative action [104]... 

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-... 

LDL-C oxidation is unquestionably an important contributor to atherogenesis. However, although the extent to which LDL-C can be oxidized ex vivo has been extensively investigated, its impact in vivo is contentious. The potential inhibition of LDL-C oxidation was tested for six commercial apple juices and the peel, flesh and whole fresh Red Delicious apples. All the tested products inhibited LDL-C oxidation assessed by an in vitro copper catalyzed human LDL-C oxidation system. The inhibition of the test products was 21, 34 and 38% for flesh, whole apple and peel, respectively, and 9—34% for the juices. Apple peel extract rich in quercetin also inhibited LDL-(Z oxidation in vitroP Moreover, apple polyphenols have been shown to increase the excretion of cholesterol oxidation products and protect against peroxidation in rats. ... 

Chalcones and dihydrochalcones have been reported in a restricted number of foods (Robards and others 1999 Tomas-Barbcran and Clifford 2000). Chalconaringenin occurs in tomato skin, but the acid extraction conditions of the usual polyphenol analyses convert the chalcone to the corresponding flavanone (naringenin) in the tomato. The most common dihydrochalcones found in foods are phloretin glucoside (phloridzin) and phloretin xylogalactoside, which are characteristic of apples (see Table 2.2) and derived products such as apple juice, cider, and pomace (Robards and others 1999 Tomas-Barbcran and Clifford 2000). 

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. 

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. 

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. 

To solubilize the hemicelluloses, we prefer a two- or three-stage extraction of the depectinated residue because some fractionation of the hemicelluloses could be effected. Thus with CWM from immature cabbage leaves, and parenchymatous tissues of apples and runner beans, 1 M KOH solubilized the bulk of the polysaccharide-protein or polysac-charide-protein-polyphenol complexes, some of which precipitated on neutralization. The stronger alkali, on the other hand, solubilized the bulk of the strongly hydrogen-bonded xyloglucans and glucomannans. 

Pancreatic lipase is a key enzyme for TAG absorption and many studies have associated polyphenols with lipase inhibition. Sugiyama et al. (2007) showed that oligomeric apple procyanidins had an inhibitory effect on pancreatic lipase activity in vitro which was higher than other polyphenolic compounds of an apple extract. These results were also confirmed in both an animal and a human study where oligomeric apple procyanidins inhibited postprandial TAG absorption. ... 

Angeletti, M. and Sparapani, L., Process for producing a grape seed extract having a low content of monomeric polyphenols, PCT Int. AppL, 2005. 

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