Quantificação de quercetina presentes em extratos de alface obtidos em diferentes condições

Abstract

In contemporary society, there is a constant evolution, which drives the continuous transformation of living standards, so there has been a growing interest in healthy eating among Brazilians. In this context, the existence of nutraceuticals stands out, which are foods that offer significant health benefits, such as reducing the risk of various diseases and promoting physical and mental well-being. Lettuce – Lactuca sativa – of the Alface Itapuã Super species, a vegetable widely consumed in Brazil, becomes the object of evaluation of its nutraceutical quality. The objective of this research was to quantify the concentration of phenolic compounds in lettuce extract, with specific focus on quercetin. For this, lettuce extracts were prepared using a solution of distilled water and ethanol, at concentrations of 100:0, 75:25, 50:50 and 0:100. The samples were maintained under constant agitation at 200 rpm for 4, 6, 24, 48, 72 and 96 hours in a Shaker incubator, at a controlled temperature of 40 °C and 60 °C. Then, absorbance spectrophotometric analysis at 440 nm was performed to determine the concentration of quercetin-like phenolic compounds in all samples. From the results obtained, it was possible to quantify the quercetin present in the lettuce extract, and to evaluate the time and temperatures, which provided the best results during the extraction and analysis process. The experiment carried out in triplicate obtained the quercetin concentration within the same range, with a standard deviation of 0.0590. Comparing the results within the same period of time with the variation in the concentration of the water-ethanol solution, the most satisfactory was with the concentration of water:ethanol 0:100, in the extraction time of 48 hours, at 60 °C. The quercetin amount values, which did not result as expected, can be explained due to the fact that the samples are heterogeneous and in natura.