More than Just Wine: The Nutritional Benefits of Grapevine Leaves

The domesticated species Vitis vinifera L. harbours many cultivars throughout the world that present distinctive phenology and grape quality. Not only have the grapes been used for human consumption, but the leaves are also used as a source of bioactive compounds and are present in the diets of several Mediterranean countries. We have selected seven different cultivars and performed elemental, fatty acid (FA) and pigment profiling. Total reflection X-ray fluorescence (TXRF) enabled the identification of 21 elements. Among them, Na, Ca and K were highly represented in all the cultivars and Zn was prevalent in V. vinifera cv. 'Pinot noir' and 'Cabernet sauvignon'. Through gas chromatography, six FAs were identified, including omega-3 and omega-6 FA, the most abundant mainly in V. vinifera cv. 'Tinta barroca', 'Pinot noir' and 'Cabernet sauvignon'. FA composition was used to determine nutritional quality parameters, namely atherogenic, thrombogenic, hypocholesterolemic/hypercholesterolemic and peroxidisability indexes as well as oxidability and oxidative susceptibility. Grapevine leaves were highlighted as a suitable source of health-promoting lipids. Given the popularity of "green" diets, we have also performed a leaf pigment analysis. Seventeen pigments including chlorophylls, trans-lutein, b-carotene and zeaxanthins were detected. 'C19' presented the highest content of most of the detected pigments.