Effect of grape (Vitis vinifera L.) varieties and harvest periods on bioactive compounds, antioxidant activity, phenolic composition, mineral contents, and fatty acid compositions of Vitis leave and oils

Total phenolic contents of immature and mature vine leaves changed between 38.45 (Cabernet Sauvignon) and 78.66 mg GAE/g (Michele Palieri) to 19.49 (Cabernet sauvignon) and 47.76 mg GAE/g (Michele Palieri), respectively. In addition, antioxidant values (DPPH) of immature and mature vine leaves changed between 17.24 µmolTE/g (Chairette) and 30.24 µmol TE/g dw (Trakya İlkeren) to 14.54 µmol TE/gdw (Gamay) and 23.65 µmolTE/g dw (Narince), respectively. Immature and mature vine leaves contained 11.20 g/kg (Michele Palieri) and 34.90 g/kg (Gamay); 24.18 g/kg (Hamburg Misketi) and 60.76 g/kg (Gamay) fructose, respectively. The highest 3,4-dihydroxybenzoic acid and (+)-catechin contents of immature and mature leaves were found in Trakya İlkeren and Michele Parieri (14.15 mg/kg and 387.86 mg/kg) and Cincaut and Hamburg misketi (11.30 mg/kg and 168.73 mg/kg) vine leaves, respectively. The major fatty acids of vine leave oils were palmitic, linoleic, arachidic, and linolenic acids. Therefore, the results obtained will create a detailed database of these materials. Practical applications: Stuffed grape leaf picked fresh from the vine has been a famous dish of Turkish, Balkan, and Middle East Nations cuisine for centuries. Vine leaves are rich in sugars, organic acids, and phenolic compounds. The vine leaves are composed of a wide range of phenolic compounds. The Mediterranean coast has benefited from by-products of grape. The grape leave oils are rich in palmitic, oleic, and linoleic acid. Brined vine leaves have a significant place in human nutrition.