Technical study of removing tannins from Rosa roxburghii juice using ginger protein

Abstract

With the aim of effectively removing tannin from Rosa roxburghii juice, reducing astringency, and enhancing its taste, chemical precipitation was applied, and ginger protein was used as the tannin remover. Besides, tannin removal rate and vitamin C (VC) retention rate were adopted as the key analytical parameters. In addition, single-factor experiment and orthogonal test were used to determine the optimal tannin removal process for ginger protein. The results were as follows: (1) The optimal conditions for removing tannin from R. roxburghii juice with ginger protein were a liquid-solid ratio of 30∶1.2 (mL∶g), R. roxburghii juice pH of 3.0, a stirring temperature of 5 ℃, and a stirring time of 30 min. (2) According to orthogonal test analysis, the degree of influence of various factors on removing tannin from R. roxburghii juice was liquid-solid ratio > stirring temperature > R. roxburghii juice pH > stirring time. (3) Under the optimal process conditions, the tannin removal rate and VC retention rate were (47.451±0.608)% and（75.904±1.244）% respectively. (4) Under the optimal process conditions, juice transmittance rate increased from (8.44±0.662)% to (92.47±0.397)%, the astringency of R. roxburghii juice was significantly reduced, and its flavor was improved. In summary, this study provides a novel approach and a new technological route for solving common key technical problems faced by the deep processing industry of R. roxburghii juice and also provides a certain technical reference for exploiting ginger resources comprehensively.

Keywords

• rosa roxburghii juice
• ginger protein
• tannin
• chemical precipitation
• vitamin c (vc)