Determinação de açúcar em amostras alimentícias a partir de imagens digitais

Abstract

Sugar is the general term for carbohydrate compounds that occurs naturally or is intentionally added to many food products. Its main function is energy supply, but its high consumption can cause serious health problems (obesity, decayed teeth, and chronic diseases). Thus, analytical methods for quality control and to guarantee food safety compliance with legislation is required. In this context, this study aimed to develop procedures for the determination of reducing sugar in beverage samples (juice, coconut water, and sugar cane spirits). The reducing sugar content was determined by the wellknown DNS and Benedict colorimetric methods combined with digital image analysis. Linear responses were observed in the glucose concentration range between 0.10 and 0.30 g L−1, with a detection limit of 0.5 g L−1 for the DNS method and from 1.0 to 5.0 g L−1, with a detection limit of 1.0 g L−1 for the Benedict method. Recovery values between 97% and 104% were obtained in the addition and recovery experiments for both procedures. These analytical procedures were applied to different beverage samples (juice, coconut water, and sugar cane spirits) and the results were in close agreement with those obtained using a reference method, with a confidence level of 95%. Thus, the combination of colorimetric reaction with digital image analysis proved to be a viable strategy for reducing sugar quantification in beverage samples by fast, accurate, precise, and low-cost analytical methods.