Apple Peel as a Contributor to Whole Fruit Quantity of Potentially Healthful Bioactive Compounds. Cultivar and Year Implication

Abstract

On the basis of the fresh weight of apple fruit and its peel and the concentration of bioactive compounds, the total quantity of L-cysteine, glutathione, ascorbate, flavonols, and anthocyanins as well as phenolics was evaluated in a wide range of cultivars and two growing seasons. Apple peel as a contributor to the entire apple quantity of the examined components considerably differed in relation to the investigated compounds and was also highly cultivar dependent. A great amount of flavonols was found in apple peel (approximately 40%), followed by ascorbate (approximately 30%) and total phenolics (approximately 20%), while the lowest contribution was assessed for thiols (approximately 11% and 14% for L-cysteine and total quantity of glutathione, respectively), based on average values for both years. Seasonal variations in the quantity of antioxidants was more pronounced in apple peel, whereas the contribution of apple peel to the whole fruit was predominantly affected by the genotype. A very high positive correlation existed between apple peel and the whole fruit quantity of antioxidants.

Sunlight Differentially Affects the Fruit Skin, Flesh, and Core Coloration of the Type 2 Red-fleshed Apple ‘Kurenainoyume’: Optimization of Fruit Bagging Treatment

“…It is generally known that the contents and compositions of secondary metabolites including anthocyanins show annual variations (Lata, 2007;Lata and Tomala, 2007). Indeed, annual and/or locational differences in the levels of red coloration of 'Kurenainoyume' flesh have been reported (Matsumoto, 2017).…”

Annual variation in sensory characteristics of seventeen apple cultivars

“…Literature confirms that the annual effects on agricultural produce can be manifold and are usually year and cultivar specific (Wolfe et al 2003, Łata and Tomala 2007, Belviso et al 2013, Guan et al 2015. Bizjak et al (2013) concluded that polyphenol content in the apples is strongly dependent upon their growth conditions.…”

“…In addition to the lessened yield, reduced photosynthesis may cause less flavonoids and other phenolic and bioactive compounds to be synthesised. The quantity of these compounds can vary manifold between cultivars and harvest years (Wolfe et al 2003, Łata and Tomala 2007,Belviso et al 2013. Sugiura et al (2013) observed that anthocyanin level, responsible for the redness of apple peel, decreased in 'Fuji' apples, when temperature was over 25 °C.…”

“…Juiciness, crispiness and low mealiness along with agreeable taste are important indicators of freshness (Peneau et al 2006(Peneau et al , 2007 and key parameters in determining consumer quality. If these characteristics remain stable over the years the cultivar has a promise of success.Literature confirms that the annual effects on agricultural produce can be manifold and are usually year and cultivar specific (Wolfe et al 2003, Łata and Tomala 2007, Belviso et al 2013, Guan et al 2015. Bizjak et al (2013) concluded that polyphenol content in the apples is strongly dependent upon their growth conditions.…”

“…Bizjak et al (2013) concluded that polyphenol content in the apples is strongly dependent upon their growth conditions. Astringency is related to the quantity and quality of phenolic compounds, which are greatly affected by the harvest year (Łata and Tomala 2007, Belviso et al 2013). Corollaro et al (2014) showed that astringency is difficult to predict with instrumental data, but it highly correlates with perceived sourness, an association also observed in the present study.…”