title: Valorization of solid wastes from chestnut industry processing: Extraction and optimization of polyphenols, tannins and ellagitannins and its potential for adhesives, cosmetic and pharmaceutical industry.
abstract: The aim of the current study was to evaluate the potential of chestnut peels to produce pomaces enhanced with tannins to be used in the formulations of wood adhesives, leather tanning or as natural antioxidants in food, cosmetic and pharmaceutical industry. An analytical procedure was planned as 2 factorial design to analyze the influence of solvent (water, Na2SO3 and NaOH at different concentrations of 1, 2, 4, and 8% in water) and extraction time (30, 60, and 120, 240, 480 and 960min) on extraction yield, pH, Stiasny index, and tannins. HPLC-diode array detector equipped with an ionization mass spectrophotometer was used to assess the polyphenol composition. Our results showed that both extraction properties and phytochemicals were significantly affected (P<0.001) by all independent factors. The main tannins identified were the hydrolyzable gallic acid, vescalagin castalagin and ellagic acid, and the condensed epigallocatechin, catechin and epicatechin. The solvent 1% Na2SO3 was more effective to extract the condensed tannins whilst hydrolyzable tannins were extracted efficiently by 1% NaOH. The multivariable analysis and the Pearson's correlation coefficients showed a direct association between Stiasny number and the average levels of condensed tannins.
authors.affiliation: Centre for the Research and Technology for Agro-Environment and Biological Sciences, CITAB, Universidade de Trás-os-Montes e Alto Douro, UTAD, Quinta de Prados, 5000-801 Vila Real, Portugal. Electronic address: alfredoa@utad.pt.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Aires
authors.affiliation: Agronomy Department, Universidade de Trás-os-Montes e Alto Douro, UTAD, Quinta de Prados, 5000-801 Vila Real, Portugal.
authors.forename: Rosa
authors.initials: R
authors.lastname: Carvalho
authors.affiliation: Animal and Veterinary Research Centre, CECAV, Universidade de Trás-os-Montes e Alto Douro, UTAD, Quinta de Prados, 5000-801 Vila Real, Portugal.
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Saavedra
mesh_terms: D000269:Adhesives; D000383:Agriculture; D000975:Antioxidants / Q000737:chemistry; D003358:Cosmetics; D029962:Fagaceae; D019649:Food Industry; D005735:Garbage; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D047348:Hydrolyzable Tannins / Q000737:chemistry*; D007220:Industrial Waste; D015999:Multivariate Analysis; D004364:Pharmaceutical Preparations / Q000737:chemistry; D010636:Phenols / Q000737:chemistry; D059808:Polyphenols / Q000737:chemistry*; D011174:Portugal; D012037:Refuse Disposal / Q000379:methods*; D062611:Solid Waste; D013634:Tannins / Q000737:chemistry*
chemical_list: D000269:Adhesives; D000975:Antioxidants; D003358:Cosmetics; D047348:Hydrolyzable Tannins; D007220:Industrial Waste; D004364:Pharmaceutical Preparations; D010636:Phenols; D059808:Polyphenols; D062611:Solid Waste; D013634:Tannins
keywords: Adhesives; Antioxidants; Chestnut-waste; Co-products; Condensed-tannins; Hydrolyzable-tannins; Polyphenols; Tanning