Thesis Title

Effect of Tannin Additions on the Formation of Polymeric Pigments in Norton Wine

Author

Jing Zhang

Date of Graduation

Fall 2006

Degree

Master of Science in Plant Science (Agriculture)

Department

College of Agriculture

Committee Chair

Karl Wilker

Keywords

anthocyanins, tannin, large polymeric pigment, small polymeric pigment, color

Subject Categories

Plant Sciences

Abstract

In red wines condensation reactions between anthocyanins and tannins form new polymeric pigments which stabilize red color and enhance quality. This research project compared the effect of tannins additions before and after fermentation of Norton wines. The addition of the tannins product Graptan PC increased the tannin content of Norton wine. Larger tannin increases were achieved when it was added after the alcoholic fermentation than at the start of the fermentation. Altering the tannin to anthocyanin ratio in the wines after the fermentation resulted in greater large polymeric pigment content, with little effect on small polymeric pigment. The later tannin addition also caused an increase in browning.

Copyright

© Jing Zhang

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Dissertation/Thesis

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