Radical Scavenging Activities of Peels and Pulps from cv. Golden Delicious Apples as Related to Their Phenolic Composition

Abstract

The relationship between phenolic composition and radical scavenging activity of apple peel and pulp was investigated in fruit produced according to both organic and integrated agricultural methods. Apple tissue extracts were subjected to high-performance liquid chromatography separation, which showed that as compared with pulps, peels are richer in almost all of the quantified phenolics. Flavonols, flavanols, procyanidins, dihydrochalcones, and hydroxycinnamates were the identified phenolic classes in peel tissue, and the most abundant compounds were epicatechin, procyanidin B2, and phloridzin. Pulps were poorer in phytochemicals. Their major phenolics were procyanidins and hydroxycinnamates. Flavonols in amounts <20 mg kg(-1) fresh weight (fw) were also found. In both peels and pulps, integrated production samples were richer in polyphenols. Among the 14 compounds identified, only phloridzin had a tendency to appear higher in organic peels. The total antioxidant capacities (TAC) of extracts were evaluated using the 1,1-diphenyl-2-picrylhydrazyl radical assay and were expressed as Trolox equivalents. Integrated peels gave the highest TAC (18.56 mM kg(-1) fw), followed by organic peels (TAC = 14.96), integrated pulps (TAC = 7.12), and organic pulps (TAC = 6.28). In peels, the top contributors to the antioxidant activity were found to be flavonols, flavanols, and procyanidins, which accounted for about 90% of the total calculated activity whereas in pulps, the TAC was primarily derived from flavanols (monomers and polymers) together with hydroxycinnamates. A good correlation between the sum of polyphenols and the radical scavenging activities was found. Among the single classes of compounds, procyanidins (in peels and pulps) and flavonols (in peels) were statistically correlated to the TAC.

Analysis of selected primary metabolites and phenolic profile of ‘Golden Delicious’ apples from four production systems

“…In contrast, Chinnici et al measured higher concentrations of hydroxycinnamic acids in apple cv. 'Golden Delicious' grown in integrated production than in apple from organic production [24].…”

“…In apple pulp, contents of flavonols were essentially lower than in peel and, moreover, organically produced apples contained higher levels in comparison with the other three treatments. However, Chinnini et al, who compared contents of phenolic compounds in apple peel and pulp in regard to the applied management system, detected higher concentrations of flavonols in apples of integrated production compared with those produced organically, both in apple peel and pulp [24]. On the other hand, Slatnar et al reported that the concentration of flavonols was not dependent on infection with apple scab [25] and Mikulic Petkovsek et al determined that cultivars resistant to apple scab contained lower contents of quercetin 3-rhamonoside [19]; flavonols may not play a key role in the defense against apple scab.…”

Avaliação da atividade antioxidante e identificação dos ácidos fenólicos presentes no bagaço de maçã cv. Gala

“…Chinnici et al (2004) encontraram valores totais de flavanóis (equivalente à catequina) de 223 ± 26,4 e 46,1 ± 9,22 mg.kg -1 em peso fresco, para maçã descascada e polpa de maçã, respectivamente. Esses valores são superiores aos encontrados em nosso estudo.…”

Liquid chromatographic method for quantifying polyphenols in ciders by direct injection

“…During the past decade the apple polyphenols have been subjected to a number of investigations due to their presence in human diet and their biological properties and benefit effects on health. Phenolic compounds seem to protect against cardiovascular disease and have certain potential anticarcinogenic properties due to their antioxidant activity and their function as free radical scavengers [6][7][8][9].…”