Prospecção química em produtos da cana-de-açúcar da Região Sul do Brasil

Abstract

This work was sub divided into three chapters. In the first chapter, aimed to evaluate the physico chemical parameters in products from sugarcane (different types of sugars, brown sugar candy and molasses) from Southern of Brazil. In these samples, parameters such as pH, color, soluble solids and the content of moisture, ash, total and reducing sugars, and the majority sugars present in the samples were evaluated. According to the results it was observed variations in the physico chemical parameters according to the type and degree of sample processing. The second chapter refers to the proposal of an alternative method for multielemental determination (Ba, Ca, Cu, Fe K, Mg, Mn and Na) in sugar cane products, where acid decomposition with reflux system was used as sample preparation, and it was followed by the determination by the technique of Microwave Induced Plasma Optical Emission Spectrometry (MIP OES). For this, a complete study of optimization of variables involving the sample mass, time, decomposition temperature and the addition of hydrogen peroxide was carried out. In all stages of optimization, the remaining acidity and the percentage of total dissolved solids were evaluated, and at final step it was evaluated the residual carbon content. The detection limits of the method varied from 0.02 to 0.26 mg kg-1 for the investigated analytes. The accuracy of the method was evaluated using the analyte addition technique, obtaining recoveries in the range of 80 to 119%, being considered satisfactory. The concentrations of the analytes in the different samples varied according to the type and degree of processing of the samples. In the third chapter, the bioactive compounds (phenolic compounds, flavonoids and carotenoids) and antioxidant activities by radical scavenging using DPPH and ABTS in these products were evaluated. The phenolic compounds varied in the range of 3.01 to 279.56 mg EAG 100 g-1, flavonoids from 0.63 to 28.33 mg EQ 100 g-1, and carotenoids from 0.18 to 4.37 μg g-1 expressed in β-carotene. The antioxidant activities by DPPH and ABTS x varied between 9.99 to 275.33 and 14.03 to1263.46, respectively, both expressed in μM trolox g-1. Higher contents of bioactive compounds and antioxidant properties were observed in the samples of brown sugar, brown sugar candy and molasses, confirming the loss of bioactive compounds and antioxidant properties in the most purified sugars (refined and crystal sugars). Based on the results of the present study, it can be iferred that the substitution of refined sugars with unrefined sugars can be an alternative in the diet with beneficial effects on health due to the presence of a higher content of essential minerals and bioactive compounds in addition to the greater antioxidant activity.