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Evaluation of polyphenolic compounds in membrane concentrated pistachio hull extract
- Seifzadeh, Negin, Ali Sahari, Mohammad, Barzegar, Mohsen, Ahmadi Gavlighi, Hassan, Calani, Luca, Del Rio, Daniele, Galaverna, Gianni
- Food chemistry 2019 v.277 pp. 398-406
- 2,2-diphenyl-1-picrylhydrazyl, antioxidant activity, artificial membranes, cellulose, fouling, gallic acid, hulls, mixing, pistachios, polyphenols, pyrogallol
- Pistachio hull is a substantial source of natural polyphenols, but a substantial volume is being wasted annually. Aqueous pistachio green hull extract (PGHE) was subjected to two-stage membrane process in order to separate a polyphenol rich fraction. The membrane conditions of each stage were investigated. Total phenolic content and antioxidant activity were determined by Folin–Ciocalteu and DPPH· assay; also membrane fouling was monitored. The use of the 1 kDa cellulose membrane accompanied by 4 bar pressure and 250 rpm stirring speed was observed to be successful in the separation of a fraction with the highest amount of phenolic compound and antioxidant activity, in the retentate part. UHPLC/MSn characterization of PGHE polyphenols enabled us to identify 34 compounds, including the most abundant galloylshikimic acids, gallic acid, theogallin, galloyl-O-hexoside, quercetin-O-hexoside and pyrogallol.