Assessment of (poly)phenols in grape (Vitis vinifera L.) stems by using food/pharma industry compatible solvents and Response Surface Methodology.

A Box-Behnken design of Response Surface Methodology (RSM) was conducted to analyse the effect of time (10-30 min), temperature (25-95°C), and solvents concentration (5-90%) on the extraction of total phenolics, flavonoids, ortho-diphenols, and anthocyanins as well as to assess the ABTS(+) scavenging capacity, which were considered as response variables. Values coefficients of determination (R(2)), ranging from 0.903 to 0.996, fitted for describing efficient extraction of bioactive (poly)phenols and antioxidant activity. The recorded data allowed to establish the optimal extraction conditions at 23.0 min, 95.0°C, and 57.9% of food-quality ethanol/water for Vitis vinifera L. var. 'Viosinho' (white variety), and 23.4 min, 84.2°C, and 63.8% for var. 'Touriga Nacional' (red variety). The achievement of optimal extraction conditions of phenolics from grape stems using solvents compatible with further uses in food/pharma industries demonstrated that RSM constitutes a powerful tool for deriving optimal conditions for extraction of antioxidant phenolic compounds from grape stems.

[1]  Yongmei Wang,et al.  Microwave-Assisted Extraction of Polyphenols from Camellia oleifera Fruit Hull , 2011, Molecules.

[2]  Baoshan Sun,et al.  Transfer of Catechins and Proanthocyanidins From Solid Parts of the Grape Cluster Into Wine , 1999, American Journal of Enology and Viticulture.

[3]  Takuya Katsube,et al.  Effect of air-drying temperature on antioxidant capacity and stability of polyphenolic compounds in mulberry (Morus alba L.) leaves , 2009 .

[4]  M. Rosa,et al.  Effect of drying conditions on bioactive compounds and antioxidant activity of broccoli (Brassica oleracea L.) , 2006 .

[5]  Veronica Dewanto,et al.  Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity. , 2002, Journal of agricultural and food chemistry.

[6]  Veronica Dewanto,et al.  Processed sweet corn has higher antioxidant activity. , 2002, Journal of agricultural and food chemistry.

[7]  Giorgia Spigno,et al.  Antioxidants from grape stalks and marc: Influence of extraction procedure on yield, purity and antioxidant power of the extracts , 2007 .

[8]  F. Anwar,et al.  Evaluation of the antioxidant activity of rice bran extracts using different antioxidant assays , 2006 .

[9]  D. Kletsas,et al.  Grape stem extracts: Polyphenolic content and assessment of their in vitro antioxidant properties , 2012 .

[10]  Yogesh Mohan,et al.  Microwave Assisted Extraction-An Innovative and Promising Extraction Tool for Medicinal Plant Research , 2007 .

[11]  P. Alves,et al.  Portuguese winemaking residues as a potential source of natural anti-adenoviral agents , 2010, International journal of food sciences and nutrition.

[12]  F. Shahidi,et al.  Phenolics in food and nutraceuticals , 1995 .

[13]  Giorgia Spigno,et al.  Effects of extraction time, temperature and solvent on concentration and antioxidant activity of grape marc phenolics , 2007 .

[14]  V. L. Singleton,et al.  Colorimetry of Total Phenolics with Phosphomolybdic-Phosphotungstic Acid Reagents , 1965, American Journal of Enology and Viticulture.

[15]  Ioannis S. Arvanitoyannis,et al.  Potential uses and applications of treated wine waste: a review , 2006 .

[16]  George Boskou,et al.  Polyphenolic content and in vitro antioxidant characteristics of wine industry and other agri-food solid waste extracts , 2007 .

[17]  V. Karathanos,et al.  Deployment of response surface methodology to optimise recovery of grape (Vitis vinifera) stem polyphenols. , 2009, Talanta.

[18]  T. Mehmood,et al.  Effect of drying method and extraction solvent on the total phenolics and antioxidant activity of cauliflower ( Brassica oleracea L.) extracts , 2013 .

[19]  S. Simal,et al.  Proanthocyanidin composition and antioxidant potential of the stem winemaking byproducts from 10 different grape varieties (Vitis vinifera L.). , 2012, Journal of agricultural and food chemistry.

[20]  M. D. Pérez-Murcia,et al.  Agrochemical characterisation of the solid by-products and residues from the winery and distillery industry. , 2008, Waste management.

[21]  Cristóbal N. Aguilar,et al.  Bioactive phenolic compounds: production and extraction by solid-state fermentation. A review. , 2011, Biotechnology advances.