The Effect of Clarification Protocols on the Vinification of White Wines with Papain and Bromelain Immobilized on Glutaraldehyde Activated Chitosan

The aim of this study is the implementation of reliable, inexpensive, and practical clarification methods of white wines, without affecting their traditional organoleptic characteristics, through treatment of musts and/or white wines with immobilized papain and bromelain. In all vinifications which focused on the production of white wines with improved organoleptic characteristics, the yeast strain Saccharomyces cerevisiae Z622 was used. Both purified papain and bromelain were immobilized on high-molecular-weight chitosan microparticles using three different protocols. The immobilized proteases with the most effective protocol were applied to both unfermented musts and fermented wines. Control vinifications were also performed using bentonite as a clarifying agent. Quantitative analyses of the white wines were carried out at the end of the alcoholic fermentation and after six months of bottling and storage in the refrigerator. The organoleptic characteristics of the clarified white wines treated with the immobilized proteases were compared with those treated with bentonite, a blank untreated white wine sample, and a commercial sample of Debina white wine through sensory evaluation. The results showed that only the musts treated with immobilized papain before fermentation resulted in clarified white wines with stable and improved sensory characteristics, similar to those of the Debina white wine sample.