The apparent amylose content of F. thunbergii flour was deter-mined using the method proposed by Sun et al. (2014) withsome modifications. The flour (20 mg, dw basis) was dissolvedin dimethyl sulfoxide (8 mL) in 10-mL screw-cap reaction vials.The contents of the vials were vigorously agitated for 20 minand then heated in a water bath (with intermittent shaking) at85◦C for 15 min. The vials were then cooled to ambient tem-perature, and the contents diluted to 25 mL with water in avolumetric flask. The diluted solution (10 mL) was mixed with0.5 mL of I2/KI solution (0.2 g I2and 2 g KI dissolved in 100 mLof water), and the mixture was adjusted to a final volume of50 mL in a volumetric flask with diluted water. The absorbancewas measured at 625 nm.
The apparent soluble amylose content of F. thunbergii flourwas determined using the method described by Sun et al.(2014). About 100 mg of the flour was accurately weighed andtaken in a 100-mL conical flask. The flour was wetted with1 mL of distilled alcohol, and then about 50 mL of distilledwater was added. The flask was then covered with a bulb stop-per, heated for 20 min in a boiling water bath with occasionalshaking, and then cooled to ambient temperature. Then dis-tilled water was added to the contents in a volumetric flask toobtain a final volume of 100 mL. The mixture was then filteredthrough a Whatman No. 4 filter paper, and the first portionwas removed. About 20 mL of the extract was then transferredinto a graduated 50-mL glass-stoppered cylinder, and 7 mLof petroleum ether (boiling range, 60–80◦C) was added. Thecylinder was shaken intermittently for 10 min and allowed tostand for 10–15 min. The ether layer was then suctioned offusing a water suction device. The extraction using petroleumether was repeated. Then, 5 mL of the extracted solution waspipetted into a 100-mL volumetric flask, and about 10 mL ofthe diluted solution was mixed with 0.5 mL of I2/KI solution(0.2 g I2and 2 g KI dissolved in 100 mL of water). The mixturewas then adjusted to a final volume of 50 mL in a volumet-ric flask with diluted water. The iodine blank was preparedby adding 0.5 mL of iodine solution to 50 mL of distilled water.The solutions were read at 625 nm against the blank. Resultsare expressed as a percentage on dw.The insoluble amylose content was calculated by subtrac-ting the apparent amylose content from the content of solubleamylose.
The apparent amylose content of F. thunbergii flour was deter-mined using the method proposed by Sun et al. (2014) withsome modifications. The flour (20 mg, dw basis) was dissolvedin dimethyl sulfoxide (8 mL) in 10-mL screw-cap reaction vials.The contents of the vials were vigorously agitated for 20 minand then heated in a water bath (with intermittent shaking) at85◦C for 15 min. The vials were then cooled to ambient tem-perature, and the contents diluted to 25 mL with water in avolumetric flask. The diluted solution (10 mL) was mixed with0.5 mL of I2/KI solution (0.2 g I2and 2 g KI dissolved in 100 mLof water), and the mixture was adjusted to a final volume of50 mL in a volumetric flask with diluted water. The absorbancewas measured at 625 nm.The apparent soluble amylose content of F. thunbergii flourwas determined using the method described by Sun et al.(2014). About 100 mg of the flour was accurately weighed andtaken in a 100-mL conical flask. The flour was wetted with1 mL of distilled alcohol, and then about 50 mL of distilledwater was added. The flask was then covered with a bulb stop-per, heated for 20 min in a boiling water bath with occasionalshaking, and then cooled to ambient temperature. Then dis-tilled water was added to the contents in a volumetric flask toobtain a final volume of 100 mL. The mixture was then filteredthrough a Whatman No. 4 filter paper, and the first portionwas removed. About 20 mL of the extract was then transferredinto a graduated 50-mL glass-stoppered cylinder, and 7 mLof petroleum ether (boiling range, 60–80◦C) was added. Thecylinder was shaken intermittently for 10 min and allowed tostand for 10–15 min. The ether layer was then suctioned offusing a water suction device. The extraction using petroleumether was repeated. Then, 5 mL of the extracted solution waspipetted into a 100-mL volumetric flask, and about 10 mL ofthe diluted solution was mixed with 0.5 mL of I2/KI solution(0.2 g I2and 2 g KI dissolved in 100 mL of water). The mixturewas then adjusted to a final volume of 50 mL in a volumet-ric flask with diluted water. The iodine blank was preparedby adding 0.5 mL of iodine solution to 50 mL of distilled water.The solutions were read at 625 nm against the blank. Resultsare expressed as a percentage on dw.The insoluble amylose content was calculated by subtrac-ting the apparent amylose content from the content of solubleamylose.
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