Study of polyphenols, antioxidant capacity and minerals for the valorisation of ancient apple cultivars from Northeast Italy

Nutritional properties and quality of apple fruits can be related to presence of secondary metabolite contents such as phytochemicals and mineral elements. In this paper, eight polyphenols, four major minerals (Na, K, Mg, Ca), total phenolic content and antioxidant capacity were determined in fourteen ancient apple cultivars grown in Friuli Venezia Giulia (Northeast Italy) to highlight their nutraceutical properties. Both apple peel and pulp were examined separately and results were compared to those of six widespread commercial cultivars using principal component analysis. Ancient apples had much higher content in healthful compounds with respect to commercial varieties, particularly in the peel. Ancient cultivars showed a superior antioxidant capacity in peel (3- to 9- fold) and in pulp (2- to 5-fold) compared to commercial cultivars, with a good correlation with total phenolic content (R = 0.83 in peel and 0.69 in pulp). The polyphenols that mostly characterized the ancient apples pulp were catechins and flavonols. Regarding macro elements, K and Mg content were higher in ancient cultivars, while Na and Ca showed no significant differences. In the perspective of a sustainable economic and social development of local agricultural realities, these results contribute to the valorisation of ancient local apple cultivars as invaluable reservoir of genetic biodiversity to be promoted as functional food or exploited in breeding novel apple hybrids with high nutraceutical properties and better resistance to parasites.

Automated summary

Nutritional properties and quality of apple fruits can be influenced by secondary metabolite contents such as phytochemicals and mineral elements. Ancient apple cultivars in Northeast Italy showed higher levels of healthful compounds and antioxidant capacity compared to commercial cultivars, with a strong correlation with total phenolic content. The ancient apples were characterized by higher levels of catechins and flavonols in the pulp, and higher potassium and magnesium content in macro elements. These findings support the valorization of ancient local apple cultivars for their genetic biodiversity and nutraceutical properties.