Bioactive Components in Fruits from different Apple Varieties

Consumption of fruit and vegetables has been shown to be effective in the prevention of chronic diseases. These benefits are often attributed to the high antioxidant content of some plant foods. Apples are commonly eaten in middle Europe during the whole growth period and are large contributors of secondary plant metabolites especially in human diets. The antioxidant activity and the content of ascorbic acid and phenolic compounds of 31 apple varieties were investigated. Of all varieties ascorbic acid was highest in the apple cultivars 'Topaz', 'Berlepsch' followed by a new variety 'AW 93', 'Golden Delicious', 'Rubinette', 'Braeburn' and 'Honeycrisp'; the lowest contents were found in the varieties 'Linsenhofer', 'Kardinal Bea', 'Sternrenette', 'Seestermüher' and 'Gala'. Total phenols (Folin values) were highest in the varieties 'Gehrers Rambour', 'Börtlinger', 'Bohnapfel', 'Dülmener Rosenapfel' commonly used for must production followed by 'Jonagold', 'Linsenhofer', 'AW60', 'AW93' and 'Topaz'. Lowest contents were found in 'Berlepsch', 'Honeycrisp', 'Diwa', 'Fuji', 'AW 105', 'Elstar', 'Rubens', 'Cameo' and 'Pinova'. 'Börtlinger', 'Gehrers Rambour', 'AW 60', 'Bohnapfel', 'Topaz', and 'Jonagold' demonstrated highest antioxidant capacity; the lowest capacity was measured in 'Pinova', 'Rubinette', 'Rubinette Rosso', 'Diwa', 'Braeburn' and 'Berlepsch'. Correlation studies showed that total phenolic compounds (Folin value) contribute strongest to the TEAC antioxidant value of apple while the contribution of ascorbic acid seemed to be low. The high content of secondary metabolites in some varieties, especially in the new developed 'AW' varieties, and the related antioxidative activity indicate that the content of secondary plant ingredients can be enhanced by breeding. These fruits with high contents of phenolic substances may impart health benefits when consumed and should be regarded as a valuable source of antioxidants.