Development of a quantitative approach using Raman spectroscopy for carotenoids determination in processed sweet potato

The orange-fleshed sweet potato is a vegetable-rich in carotenoids. The thermic treatment for sweet potato processing can decrease the content of these constituents in the foods, lowering their bioactive properties. Raman spectroscopy has been growing as a fast tool to food analysis, especially for detection of low concentrations of carotenoids and to the monitoring of its degradation profile over time. Therefore, in this work were evaluated two methods of drying, hot air and microwaving with rotary drum, combined with quantitative Raman spectroscopy. The results showed carotenoids degradation around 50% for both types of drying processes studied. PCA plot proved the potential of reproducibility of analyses for microwave drying samples. For samples heated with hot air, the best linear correlation achieved was R-2 = 0.90 and by microwave was R-2 = 0.88. Also, partial least squares (PLS) regression models were constructed obtaining a satisfactory coefficient of determination.