Enhancing functional properties of fruit juices with highly active xylanase from Aspergillus tubingensis FAT35.

Background: The growing consumer demand for functional fruit juices has emphasized the need for targeted enzyme applications in juice processing. Among these, xylanase has emerged as a critical enzyme for improving the extraction and quality of juices from xylan-rich fruits. However, despite its potential, xylanase remains insufficiently characterized for functional juice production, and further evaluation is necessary.

Results: In the present study, a screening assay identified Aspergillus tubingensis FAT35 as the most efficient xylanase-producing isolate among a set of fungal strains. Solid-state fermentation using agro-industrial residues was optimized, resulting in high-yield enzyme production: 550 U mL^-1, which corresponds to 2333 U g^-1. The enzyme exhibited high xylanase activity with negligible pectinase and cellulase side activities. Application of the xylanase to orange and pineapple juices significantly improved juice yield (17% and 3%), sugar content (22% and 39%) and clarity (2% and 22%). Furthermore, treated juices showed enhanced antioxidant and antimicrobial activities. These functional improvements were attributed to the formation of the prebiotic oligosaccharide xylotetraose (X4), indicating added health value.

Conclusion: The optimized xylanase from A. tubingensis FAT35 demonstrates strong potential for use in the fruit juice industry. Its ability to enhance both technological parameters and bioactive properties of juices highlights its role in the development of functional beverages and underscores the importance of further testing and application of xylanases in food biotechnology. © 2025 Society of Chemical Industry.