Development of Rapid, Simple and Low-Cost Methods for Quantification of Reducing Sugars in Cow Milk and Derivatives Using Smartphone Digital Images

The quantification of reducing sugars in cow milk and derivatives is necessary for quality control and to ensure food safety for consumers. Here, two rapid and simple methods were developed for the quantification of reducing sugars in samples of milk and derivatives, based on colorimetric assays followed by acquisition of digital images using a smartphone camera and PhotoMetrix® software. The data were processed by univariate analysis with multiple channels, obtaining satisfactory r values (> 0.90) for analytical curves of mixtures of reducing sugars. The methods were validated within a linear range of 10–100 mg mL⁻¹ and were applied in the analysis of eight samples of cow milk or it is derivatives with recovery values ranged from 93.64 to 105.21%, and the results were statistically comparable to those obtained using the reference Lane-Eynon titration method (AOAC 923.09). The new methods present themselves as promising alternatives for the quality control of reducing sugars in the dairy industry. They bring significant benefits, such as affordability, portability, and alignment with green chemistry principles. The sample data acquisition and processing time is only 2 min, enabling the execution of multiple analyses within a brief timeframe. This renders them particularly suitable for applications in routine analysis targeted at food quality control.