Optimization of a process for enzyme-assisted pigment extraction from grape (Vitis vinifera L.) pomace.

Publikations-Art

Zeitschriftenbeitrag (peer-reviewed)

Autoren

MAIER, T., GÖPPERT, A., KAMMERER, D.R., SCHIEBER, A., CARLE, R.,

Erscheinungsjahr

2008

Veröffentlicht in

European Food Research and Technology

Band/Volume

227/

Serie/Bezeichnung

DOI: 10.1007/s00217-007-0720-y

Seite (von - bis)

267-275

A process for enzyme-assisted extraction of polyphenols from grape pomace was developed on laboratory and pilot-plant scale. After resuspending grape pomace in water, the skins were ground and the resulting mash was pasteurized to inactivate the deteriorative enzymes responsible for polyphenol degradation, and then pre-extracted with hot water. Subsequently, cell wall polysaccharides were hydrolyzed. The extract was separated from the solid residue by pressing, and finally spray dried. Before scaling-up, enzymatic hydrolysis was optimized on laboratory scale using a D-optimal design and analyzed by response surface methodology. A mixture of pectinolytic and cellulolytic enzyme preparations (ratio 2:1) yielded the highest amounts of phenolic compounds after 2 h of treatment, applying a dosage of 4500 mg/kg (based on dry matter) at T= 40 °C and pH 4.0. Aqueous pre-extraction of the pomace followed by enzymatic treatment resulted in significantly improved extraction yields reaching 91.9%, 92.4% and 63.6% for phenolic acids, non-anthocyanin flavonoids and anthocyanins, respectively. As the yields obtained were comparable to those from sulfite-assisted extraction, this process can be considered a suitable alternative to the application of sulfite.