Clarification of the Algerian grape juice and their effects on the juice quality

Abstract

The aim of this study was to find a good clarification method to eliminate the substances in Algerian grape juice and study the effects of the clarification agents on juice quality. The clarified grape juice was subjected to different treatments, namely bentonite, gelatin, combination of gelatin and bentonite, then stored for 4 weeks. The effects of fining treatment by determining the critical micillary concentration of each agent used accelerated stability test on turbidity, tannin contents (ethanol index, condensed tannins, total polyphenol and anthocyanins) and microbiological quality of clarified grape juice were evaluated during storage. Fining treatment and storage had a significant (p < 0.05) effect on turbidity, tannins, total polyphenol, condensed tannins and anthocyanins. However, a better percentage elimination was noted for freshly squeezed grape juice with a combination of gelatin and bentonite corresponding to a turbidity of 6.5 NTU. The clarifiers separately gave lower removal rates than average, up to 83% of tannins present in the freshly squeezed juice has been eliminated using the bentonite. The results obtained are very satisfactory since we were able to obtain a clear juice of good microbial quality while ensuring the preservation of the organoleptic and nutritional qualities during the treatment and the storage of the juice.   Bull. Chem. Soc. Ethiop. 2020, 34(1), 1-11. DOI: https://dx.doi.org/10.4314/bcse.v34i1.1