44D-4 |
Hydrolysis of sorghum straw using sulphuric acid at atmospheric pressure to obtain xylose |
S. J. TÉLLEZ LUIS1, J. A. Ramírez de León1, and M. Vázquez2. (1) Food Science, Universidad Autónoma de Tamaulipas, UAM Reynosa-Aztlán, Calle 16 y Lago de Chapala - Col Aztlán, Reynosa, 88740, Mexico, (2) Food Science, Universidad de Santiago de Compostela, Escuela Politecnica Superior - Campus de Lugo, Lugo, 27002, Spain Sorghum straw is an agricultural waste widely generated in Mexico. This lignocellulosic material has a high content in xylose. A hydrolysis process to achieve xylose solutions from sorghum straw could be very interesting because the xylose solutions can be used as fermentation media to obtain food additive using microorganisms. Xylose solutions from others bioresources has been used to obtain food sweeter (xylitol) and pigments (astaxanthin). The objective of this work was evaluated the hydrolysis of sorghum straw using sulphuric acid at atmospheric pressure (100şC) to obtain solutions with a maximum xylose concentration and minimum concentration of phenolic compounds (growth inhibitors). Xylose production can be considered a first step to produce biotechnological food additives. Sorghum straw was collected at a local farm. Moisture was determined gravimetrically, xylose was determined by HPLC with IR detector, and phenolic compounds were determined by UV-Vis spectrometry. The effect of several sulphuric acid concentrations (2, 4 or 6%) on xylose and phenolic compound concentrations were evaluated in the hydrolysis of sorghum straw during 5 hours. A xylose concentration of 17.57±0.58 g/l and 0.59±0.02 g/l of phenolic compounds expressed as furfural were obtained after 5 hour using 2% of sulphuric acid. The xylose concentration was increased quickly using 4% or 6% of sulphuric acid. 16.96±0.36 and 18.82±0.86 g/l were achieved after 1 hour using 4% or 6%, respectively. Phenolic compounds were 0.47±0.01 and 0.57±0.02 g/l, also respectively. The higher result of xylose concentration (19.74±1.06 g/l) was obtained using 6% of acid and 5 hours. In these conditions, 1.37±0.10 g/l of phenolic compounds were also obtained. The results showed that it is possible obtain xylose solutions from sorghum straw, an important waste in Mexico. The xylose solutions had a low concentration of phenolic compounds. Therefore, these solutions can be used as media for biotechnological production of food additives.
Session 44D, International
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