The present work aimed at optimizing a two-step enzymatic plus solvent-based process for the recovery of bioactive compounds from white grape (Vitis vinifera L., mix of Trebbiano and Verdicchio cultivars) pomace, the winemaking primary by-product. Phenolic compounds solubilised by water enzyme-assisted and ethanol-based extractions of wet (WP) and dried (DP) pomace were characterised for composition and tested for antioxidant, anti-tyrosinase and anti-inflammatory bioactivities. Ethanol treatment led to higher phenol yields than water extraction, while DP samples showed the highest capacity of releasing polyphenols, most probably as a positive consequence of the pomace drying process. Different compositions and bioactivities were observed between water and ethanol extracts and among different treatments and for the first time the anti-tyrosinase activity of V. vinifera pomace extracts, was here reported. Enzymatic treatments did not significantly improve the total amount of solubilised compounds; Celluclast in DP led to the recovery of extracts enriched in specific compounds, when compared to control. The best extracts (enzymatic plus ethanol treatment total levels) were obtained from DP showing significantly higher amounts of polyphenols, flavonoids, flavanols and tannins and exerted higher antioxidant and anti-tyrosinase activities than WP total extracts. Conversely, anti-inflammatory capacity was only detected in water (with and without enzyme) extracts, with WP samples showing on average a higher activity than DP. The present findings demonstrate that white grape pomace constitute a sustainable source for the extraction of phytochemicals that might be exploited as functional ingredients in the food, nutraceutical, pharmaceutical or cosmetic industries.

中文翻译：

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白葡萄果渣提取物，通过连续酶促加乙醇提取获得，具有抗氧化、抗酪氨酸酶和抗炎活性

目前的工作旨在优化用于从白葡萄（Vitis vinifera L.，Trebbiano 和 Verdicchio 品种的混合物）果渣（酿酒的主要副产品）中回收生物活性化合物的两步酶法和溶剂法工艺。对湿（WP）和干（DP）果渣的水酶辅助和乙醇提取物溶解的酚类化合物进行了成分表征，并测试了抗氧化、抗酪氨酸酶和抗炎生物活性。乙醇处理导致苯酚产量高于水提取，而 DP 样品显示出最高的多酚释放能力，这很可能是果渣干燥过程的积极结果。在水和乙醇提取物之间以及不同处理之间观察到不同的组成和生物活性，并且首次报道了葡萄果渣提取物的抗酪氨酸酶活性。酶处理没有显着提高溶解化合物的总量；与对照相比，DP 中的 Celluclast 可回收富含特定化合物的提取物。从 DP 获得的最佳提取物（酶促加乙醇处理的总水平）显示出比 WP 总提取物更高的多酚、黄酮类化合物、黄烷醇和单宁含量，并具有更高的抗氧化和抗酪氨酸酶活性。相反，仅在水（含和不含酶）提取物中检测到抗炎能力，WP 样品平均显示出比 DP 更高的活性。