Fatty acid composition, squalene and elements in apple by-products: comparison between ancient cultivars and commercial varieties

The manufacturing of apple-based products leads to high volumes of apple pomace (about 25% of the fresh fruit), whose exploitation would be desirable. The aim of this study was to investigate the content of bioactive substances and elements in this waste material. Fatty acids, squalene content and mineral composition were determined in peel and seeds of the fruits of four commercial varieties and seven ancient cultivars. Peel lipid extract resulted to have optimal n -6/ n -3 polyunsaturated fatty acids ratio (1.5–7.6), encouraging possible exploitations in nutraceutical formulations. Squalene, a triterpene with several bioactivities, showed a content of 1.7–24.7 and 0.9–2.9 mg/100 g in fresh seeds and peels, respectively, with the highest values in commercial varieties. Regarding the mineral content, resulted to be generally higher in ancient varieties, potassium was the most abundant (56.1–91.3 and 80.0–193.1 mg/100 g, in fresh seeds and peels, respectively), followed by phosphorus (26.8–63.8 and 8.7–75.3 mg/100 g, respectively) and magnesium (24.3–47.7 and 5.3–30.8 mg/100 g, respectively). Among micronutrients, apple pomace resulted to be a good source of iron (0.32–0.98 and 0.11–0.78 mg/100 g in fresh seeds and peels, respectively), manganese (0.25–0.60 and 0.05–0.33 mg/100 g, respectively) and zinc (0.15–0.42 and 0.03–0.12 mg/100 g, respectively).