Produção do edulcorante d-tagatose a partir do hidrolisado ácido de kappa-carragenana

Abstract

Tagatose is a natural, functional, rare sweetener, with sweetness equivalent to sucrose, and noncaloric. The production of D-tagatose can be chemical or enzymatical, both using galactose as feedstock. The present work aimed to chemically hydrolyze κ-carrageenan extracted from Hypnea musciformis to produce D-galactose and then convert it into D-tagatose using Larabinose isomerase. Initially, the effects of temperature and sulfuric acid concentration on the generation of reducing sugar and galactose through the acid hydrolysis of κ-carrageenan extracted from the macroalga were evaluated. Then galactose was subjected to enzymatic bioconversion to tagatose. As results, the temperature and concentration of acid in the linear mode had significant and positive effects for the generation of reducing sugar and galactose, as well as their interactions. The maximum content of reducing sugars was 7.0 g.L-1 in the hydrolysates, while the galactose and glucose were 1.4 and 0.2 g.L-1, respectively. Surprisingly, the results further suggested a concentration of 1.7 g.L-1 tagatose in the hydrolysates. Regarding the enzymatic assay, a conversion of D-galactose into D-tagatose was not observed by the enzyme, due to the presence of tagatose in the hydrolyzate. Therefore, it was possible to conclude that κ-carrageenan extracted from H. musciformis was shown to be a source of galactose for chemical and enzymatic production of tagatose. However, further studies are needed to elucidate the mechanism of chemical and enzymatic production of tagatose from marine macroalgae galactans.