Antioxidant properties of peel and flesh in ‘GoldRush’ and ‘Fiorina’ scab‐resistant apple (Malus domestica) cultivars

Abstract

In the human diet, apples (Malus domestica) are the most consumed fruit worldwide throughout the whole year and are valued for their organoleptic characteristics (aroma, taste, and flavour). Apples are also an important source of phytochemicals, represented by flavonols, flavanols, cinnamic acid, dihydrochalcones, and anthocyanins, which have a known antioxidant activity that can prevent or reduce the insurgence of several chronic and degenerative diseases. These compounds have been found especially in the peel tissue. Apple orchards are often treated chemically against several diseases and particularly against the fungal pathogen Venturia inaequalis. This pathogen causes the growth of small and rough fruits (scab-apples) with black circular lesions on the peel. New resistant genotypes to V. inaequalis have been obtained but until now they have covered restricted markets aimed at organic production. The aim of this study was to evaluate the quality characteristics of two scab-resistant cultivars 'GoldRush' and 'Fiorina', focusing on pomological traits, total antioxidant capacity (TAC), and total phenol (TP) content in the peel and flesh tissues of the fruit. These genotypes were compared with the well-known cultivar 'Golden Delicious' clone B (scab-susceptible). In all the tested cultivars, TAC and TP content were higher in the peel than the flesh. In particular, the highest TAC and TP values were found in the peel of the two scab-resistant cultivars, 'GoldRush' and 'Fiorina', which showed interesting and valuable attributes.

The influence of organic/integrated production on the content of phenolic compounds in apple leaves and fruits in four different varieties over a 2‐year period

“…As reported by several authors,3, 4, 12, 35 peel was richer than pulp in single phenolic compounds as well as in total polyphenolics. Apple peel has a total phenolic content 3–7.5 times higher than pulp.…”

“…The reason for that can probably be found in the great genetic differences between the apple cultivars analysed. That cultivars can also have an influence on the amount of phenolics has been reported by many papers 3, 4, 13, 26, 35. In the case of leaves, year and cultivar were also taken into account, as well as dates, since we obtained data from six different sampling dates (Table 7).…”

Rootstock genotype determines phenol content in apple fruits

“…Several times more phenolic compounds are found in the peel than in apple flesh (Wolfe et al 2003, Drogoudi et al 2008, Leccese et al 2009). High content of phenols was detected in apple juices as well (Lachman et al 2006).…”

Characterization of Grape and Apple Peel Wastes’ Bioactive Compounds and Their Increased Bioavailability After Exposure to Thermal Process

“…There are studies which indicated that 80% of polyphenols are found in apple peel (Leccese et al, 2009), whose total antioxidant capacity is five-to-six-fold higher than that of apple flesh; The health advantages of apple peels, like cardioprotective and anticancer properties, are correlated with the presence of flavonols, anthocyanins, flavan-3-ols, phenolic acids and dihydrochalcones (Boyer and Liu, 2004). Compared with the flesh, the peel contains specific flavonoids, such as quercetin glycosides (Rupasinghe and Kean, 2008).…”