The biodiversity of apples hosts remarkable chemodiversity: a study on sixteen 'true-to-type' cultivars from the Laimburg core collection and their vitamin C and E content

The diversity of the thousands of known apple cultivars is remarkable but only a handful of cultivars dominate international markets, with negative consequences for their biodiversity. The cultivars ‘Golden Delicious’, ‘Gala’ and ‘Red Delicious’, for instance, account for more than 65% of the regional production in South Tyrol, Italy. The chemical characterization of relevant nutrients like carbohydrates, polyphenols, dietary fiber, minerals and vitamins, known to be present in apple, can support the valorisation of the underappreciated diversity of apple cultivars. This study is focused on the analysis of the major water- and fat-soluble vitamins present in apples, L-ascorbic acid (AsA) and α-tocopherol, in 16 cultivars certified to be ‘true to type’ using molecular genetic tools during the harvest season 2010. Growth and storage conditions were the same for all cultivars. Old cultivars, including local ones, were chosen, together with commercial and managed ones. Two rapid HPLC-DAD methods were used for the analysis of the two vitamins. Results reveal a remarkable chemodiversity, with values ranging from a minimum AsA content of 0.43±0.13 mg 100 g^‑1 fresh weight (FW) to a maximum of 6.22±1.06 mg 100 g^‑1 FW in the cultivars ‘Gala’ and ‘Freiherr von Berlepsch’, respectively. The lowest amount of α-tocopherol was 0.13±0.02 mg 100 g^‑1 FW in ‘Freiherr von Berlepsch’, while the highest was 0.33±0.04 mg 100 g^‑1 FW in ‘Brixer Plattling’. This work adds valuable data to the existing body of evidence concerning the nutritional value and the biodiversity of apples.