Simple Method for Sucrose Determination Based on Self-Assembled Nano-Levan Synthesized by Levansucrase

A simple and specific method for sucrose quantification was developed using nanolevan formation catalyzed by levansucrase from <i>Erwinia tasmaniensis</i> (<i>Et</i>Lsc). When <i>Et</i>Lsc reacted with sucrose, it quickly produced nanolevan, which generated turbidity that could be measured using spectrophotometry. This method showed a strong linear correlation between optical density and sucrose concentration within the range of 0.2-3.0% w/v. Optimal conditions for the reaction were determined to be pH 6.0-8.0 and enzyme concentration of 20 U/mL. The method demonstrated high specificity toward sucrose without interference from other common sugars. Additionally, a smartphone-based detection approach was developed and validated, providing a portable alternative for on-site analysis. When applied to real fruit juice samples, the results were less than 9% different from those of HPLC analysis. This approach offers a cost-effective, rapid, and user-friendly alternative for sucrose determination in food and beverage samples.