ENZYMATIC RELEASE OF ANTIOXIDANTS FOR HUMAN LOW-DENSITY-LIPOPROTEIN FROM GRAPE POMACE

Enzyme-assisted release of phenolic antioxidants from grape pomace fro m wine production was examined. The enzymes used were Grindamyl pectin ase from Aspergillus niger and Celluclast from Trichoderma reesei. Tot al phenols released ranged from 820 to 6055 mg/L gallic acid equivalen ts (GAE) and varied in response to enzyme type, time of enzyme treatme nt, particle size of the pomace, and type of extraction solvent employ ed. The yield of total phenols was correlated to the degree of plant c ell wall breakdown of grape pomace (r > 0.6, P < 0.01). Grindamyl pect inase catalyzed degradation of grape pomace polysaccharides (P < 0.001 ), whereas Celluclast did not. Reduction of the particle size of grape pomace to 125-250 mu m increased the enzymatic polysaccharide hydroly sis and the recovery of phenols. The grape pomace extracts significant ly retarded human low-density lipoprotein oxidation in vitro. When eva luated at 3.0 mu M GAE, phenolic extracts of Grindamyl pectinase treat ed pomace of small particle size (125-250 mu m) appeared to release mo re active antioxidant phenols than the other types of enzyme treatment s tested (P < 0.05).