Composição físico química e perfil elementar de açúcar mascavo brasileiro

Abstract

The brown sugar is a raw sugar that does not go through any type of refining, being its production performed in a craft way and for that reason without much quality control. This type of sugar because it is not industrialized is rich in minerals, vitamins, phenolic compounds, among other essential nutrients, and therefore its consumption brings several benefits. However, during the cultivation of sugarcane, as well as during the artisanal manufacture of brown sugar, there is the possibility of aggregation of contaminants, such as toxic metals. In view of these reported informations and by absence of researches on the subject it is necessary to carry out studies on the elemental profile and the physicochemical composition of this type of food. The quantification of metallic ions in foods is still considered an analytical challenge due to the great complexity of the matrix. In this work, analytical methods were developed for the determination of several elements using different techniques of atomic spectrometry and sample preparation methods. For Pb, Cd and Cr was developed a methodology using suspension sampling and GF AAS. For Ca, Mg, Fe, Mn and Zn was developed a methodology using ultrasonic assisted digestion and F AAS. For Li, Be, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Ba, U, Al, Ca, Mg and Fe a methodology using microwave assisted digestion and ICP-MS and F AAS. The three methods developed were validated. A bioaccessibility study of metallic ions was performed using the simulation of gastrointestinal digestion in vitro. Besides this, physicochemical parameters such as total phenolics, pH, acidity, sugars and ICUMSA color were determined in the brown sugar samples. From the analysis of the validation parameters was verified that the developed methods have linearity, precision and accuracy adequate for the determination of metallic ions in brown sugar. The Pb, Cd and Cr contents are in general below the allowed limits, however, in three samples were highlighted regarding the level of Pb and in one sample regarding the level of Cd because they are above the limit established in the legislation. From the analysis of the essential metals Ca, Mg, Fe, Mn and Zn, it was verified that the order of the abundance of these metallic ions in brown sugar was Ca > Mg > Fe > Mn > Zn. According to the total contents found, the majority of brown sugar samples can be considered as source of these metallic ions. The results of the average bioaccessibility percentage for the 34 samples analyzed were 64 ± 9, 92 ± 9, 44 ± 25, 85 ± 13 and 79 ± 14 for Ca, Mg, Fe, Cu and Mn, respectively. The low percentage of bioaccessibility of some elements in the samples is an indicative that there are compounds in brown sugar that bind to metallic ions and prevent their absorption during the gastrointestinal digestion process. The best conditions for extraction of the phenolic compounds were of extracting solvent composition of 4.9 mL of water and 1.1 mL of ethanol 70 % (v / v), sample mass of 0.1 g, extraction time of 32.5 minutes and without HCl addition. The great variability observed in the results of the physicochemical parameters (ICUMSA color, sucrose and reducing sugar contents, pH and acidity) indicated that there is no standardization in the production of brown sugar. The main contribution of this thesis is to increase the understanding of the scientific community as well as the population regarding the elemental profile and physicochemical composition of brown sugar, and emphasize that although the presence of some elements is beneficial to the consumer, there are also undesirable substances in brown sugar and therefore it is necessary to establish an specific legislation and patterns to ensure the quality control of this food.