ABSTRACT
The seaweeds are bio-resource rich in sulfated and neutral polysaccharides. The tropical seaweed species used in this study (Solieria filiformis), after dried, shows 65.8% (w/w) carbohydrate, 9.6% (w/w) protein, 1.7% (w/w) lipid, 7.0% (w/w) moisture and 15.9% (w/w) ash. The dried seaweed was easily hydrolyzed under mild conditions (0.5 M sulfuric acid, 20 min.), generating fermentable monosaccharides with a maximum hydrolysis efficiency of 63.21%. Galactose and glucose present in the hydrolyzed were simultaneously fermented by Saccharomyces cerevisiae when the yeast was acclimated to galactose and cultivated in broth containing only galactose. The kinetic parameters of the fermentation of the seaweed hydrolyzed were Y(P/S) = 0.48 ± 0.02 g.g−1, PP = 0.27 ± 0.04 g.L−1.h−1, η = 94.1%, representing a 41% increase in bioethanol productivity. Therefore, S. filiformis was a promising renewable resource of polysaccharides easily hydrolyzed, generating a broth rich in fermentable monosaccharides for ethanol production.
As algas marinhas são recursos naturais ricos em polissacarídeos sulfatados e neutros. A espécie de macroalga tropical utilizada neste estudo (Solieria filiformis) apresentou teores de carboidratos de 65,8% (m/m), proteínas de 9,6% (m/m), lipídios de 1,7% (m/m), umidade de 7,0% (m/m) e 15,9 % (m/m) de cinzas. A macroalga seca foi facilmente hidrolisada em condições brandas, na presença de ácido sulfúrico 0,5 M, por 20 min, produzindo monossacarídeos fermentáveis com uma eficiência de hidrólise máxima de 63,21%. A galactose e a glicose presentes no hidrolisado foram fermentadas simultaneamente por Saccharomyces cerevisiae, após aclimatação da levedura cultivada em meio contendo apenas galactose como fonte de carbono. Os parâmetros cinéticos da fermentação do hidrolisado algáceo pela levedura aclimatada a galactose foram Y(P/S) = 0,48 ± 0,02 g.g-1, PP = 0,27 ± 0,04 g.L- 1.h-1, η = 94,1%. Portanto, a macroalga S. filiformis se mostrou um recurso renovável promissor como fonte de polissacarídeos facilmente hidrolisados, gerando um meio nutritivo rico em glucose e galactose para a produção de etanol.
Subject(s)
Carrageenan , Cellulose , Fermentation , Galactose , Seaweed , Sulfuric AcidsABSTRACT
El objetivo del presente trabajo es evaluar la mezcla más adecuada de los estabilizantes goma guar, goma xantan y carragenina iota en la bebida láctea tipo kumis. Se lleva a cabo un estudio preliminar que define la mezcla óptima de estos estabilizantes, utilizando el nivel máximo de 0,5%, aprobado por el Ministerio de la Protección Social de la República de Colombia, la variable respuesta medida es viscosidad. Definida la mejor mezcla, es utilizada en tres concentraciones (T1: 0,08%; T2: 0,1% y T3: 0,12%), y comparada con un control (T4: sin adición de estabilizante) en el producto lácteo tipo kumis. La mezcla óptima encontrada fue de 93% goma xantan y 7% goma guar, y los parámetros empleados para su evaluación son fisicoquímicos reométricos y sensoriales. Los resultados fisicoquímicos corresponden a los estándares aceptados para esta bebida. En lo referente a las pruebas de viscosidad y deformación, el tratamiento que muestra los mejores resultados es la concentración 0,12%; que corresponde al tratamiento T3. El análisis sensorial indica que T3 es el tratamiento más aceptado, junto con el control. Según los resultados, el nivel óptimo de concentración de la mezcla de hidrocoloides es 0,12%; con diferencia significativa (p<0,05) frente a los otros tratamientos.
The aim of this study was to evaluate the most appropriate mix of stabilizers: guar gum, xanthan gum and iota carrageenan in dairy beverages kumis type. A preliminary study defining the optimal mix between these stabilizers was carried, using the maximum level of 0.5% approved by the Colombian Ministry of Health. Viscosity was used as response variable. Once the best mix was selected it was used in three concentrations (T1: 0.08%, T2: 0.1% and T3: 0.12%), and compared to a control (T4: no added stabilizer) in the milk product type kumis. The parameters used for the assessment of the optimal mix of 93% xanthan gum and 7% guar gum were physicochemical, viscosity and sensory. Physicochemical results fitted to the accepted standards for such milk drinks. In terms of viscosity and strain tests, the treatment showing the best results was T3. Sensory analysis indicated that T3 is the more accepted treatment with the control. Based on the results obtained, the optimum concentration level of the hydrocolloids mixture was 0.12% of the mixture with a p <0.05.