Valorization of grape pomace and orange peels: Improved production of hydrolytic enzymes for the clarification of orange juice

• Published in: Food and bioproducts processing Vol. 91; no. 4; pp. 580 - 586
• Main Authors: Díaz, Ana Belén, Alvarado, Octavio, de Ory, Ignacio, Caro, Ildefonso, Blandino, Ana
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2013
• Subjects: Aeration; Agro-industrial residues; air flow; Aspergillus awamori; bioreactors; business enterprises; Citrus; cloud cover; Contaminants; enzymatic treatment; Enzymes; grape pomace; Grapes; Hydrolytic enzymes; Juice clarification; Juices; orange juice; Orange peel; orange peels; Reactors; Solid state fermentation; Turbidity; Vitaceae; xylanases; Aeration; Agro-industrial residues; Hydrolytic enzymes; Juice clarification; Solid state fermentation
• ISSN: 0960-3085; 1744-3571
• DOI: 10.1016/j.fbp.2013.01.007

► Two agro-industrial residues have been valorized for the production of enzymes. ► Aeration improved the production of exo-polygalacturonase, xylanase and CMC-ase. ► Trays reactor is better than column reactor for obtaining high enzymes productivities. ► Enzyme extracts obtained can be successfully applied for orange juice clarification. The production in solid state fermentation (SSF) of several hydrolytic enzymes by Aspergillus awamori on a mixture of grape pomace and orange peels has been studied in two configurations of bioreactor: packed bed and tray-type. When the effect of aeration in both reactors was compared, using the trays-type with an air flow rate of 3mL/gds·min, average activities of 42.64 and 2.16IU/gds were measured for xylanase and CMCase, respectively; however in the case of the column reactor the aeration must be doubled to obtain similar activity values. These differences were more significant in the case of exo-PG. The extracts obtained in this reactor were applied to orange juice and the cloudiness was markedly reduced, even improving the efficiency of a commercial enzyme preparation. Thus, while the turbidity of the fresh juice was 4625 NTU, treatment with the extracts reduced the value to 24.25 NTU. In a similar way the clarity increased to 95% after treatment with enzyme extracts. According to the results obtained, the proposed process for grape pomace and orange peels reutilization constitutes a viable alternative for many companies to revalorize their residues and to reduce their contaminant capacity.