Extraction of barley β-glucans and partial characterization of residual starch/ Extracao de β-glucanas de cevada e caracterizacao parcial do amido residual

The objective of the study was to evaluate the parameters of the extraction of barley's β-glucans and partially characterize the residual starch after extraction. A method was developed for the extraction of barley β-glucans without damaging the residual starch, assessing the variables pH and extraction temperature. The percentage of β-glucans in the extracted fraction varied from 44,21 to 53,38%, being influenced by temperature and the extracted starch varied from 65,98% a 77,54%, being influenced by pH. The residual starch from barley's β-glucan extraction had a swelling power and solubility of 8.54 ± 0.29% and 6.04 ± 0.07%, respectively. The RVA's amylograph for this starch showed a maximum viscosity of 164.67 ± 1.30 RVU and breakdown viscosity of 45.79 ± 2.06 RVU. The infrared spectrum of the residual starch was typical of native barley starch and similar to isolated starch from corn, wheat and cassava. According to the scanning electron micrographs fraction of starch, it was possible to see a mixture of large lenticular granules with an average diameter of 19.15 µm and small spherically shaped ones, with 4.78 µm. The characteristics showed by the residual starch from barley's β-glucan extraction, suggest a possible application in the food industry.