Fia Giovanna, Bucalossi Ginevra, Zanoni Bruno
DAGRI-Department of Agricultural, Food, Environmental, and Forestry Sciences and Technologies, University of Florence, Via Donizetti, 6-50144 Firenze, Italy.
Foods. 2021 Jun 28;10(7):1499. doi: 10.3390/foods10071499.
Unripe grapes (UGs) are a waste product of vine cultivation rich in natural antioxidants. These antioxidants could be used in winemaking as alternatives to SO. Three extracts were obtained by maceration from Viognier, Merlot and Sangiovese UGs. The composition and antioxidant activity of the UG extracts were studied in model solutions at different pH levels. The capacity of the UG extracts to protect wine colour was evaluated in accelerated oxidation tests and small-scale trials on both red and white wines during ageing in comparison with sulphur dioxide, ascorbic acid and commercial tannins. The Viognier and Merlot extracts were rich in phenolic acids while the Sangiovese extract was rich in flavonoids. The antioxidant activity of the extracts and commercial tannins was influenced by the pH. In the oxidation tests, the extracts and commercial products showed different wine colour protection capacities in function of the type of wine. During ageing, the white wine with the added Viognier UG extract showed the lowest level of colour oxidation. The colour of the red wine with the UG extract evolved similarly to wine with SO and commercial tannins. The obtained results indicated that natural and healthy UG extracts could be an interesting substitute for SO during wine ageing.
未成熟葡萄（UGs）是葡萄种植的一种富含天然抗氧化剂的废弃物。这些抗氧化剂可作为二氧化硫的替代品用于酿酒。通过浸渍法从维欧尼、梅洛和桑娇维塞未成熟葡萄中获得了三种提取物。在不同pH值的模型溶液中研究了未成熟葡萄提取物的成分和抗氧化活性。与二氧化硫、抗坏血酸和商业单宁相比，在加速氧化试验以及红葡萄酒和白葡萄酒陈酿过程中的小规模试验中，评估了未成熟葡萄提取物保护葡萄酒色泽的能力。维欧尼和梅洛提取物富含酚酸，而桑娇维塞提取物富含黄酮类化合物。提取物和商业单宁的抗氧化活性受pH值影响。在氧化试验中，提取物和商业产品根据葡萄酒类型表现出不同的葡萄酒色泽保护能力。在陈酿过程中，添加维欧尼未成熟葡萄提取物的白葡萄酒色泽氧化程度最低。添加未成熟葡萄提取物的红葡萄酒色泽变化与添加二氧化硫和商业单宁的葡萄酒相似。所得结果表明，天然且健康的未成熟葡萄提取物在葡萄酒陈酿过程中可能是二氧化硫的一种有趣替代品。
