Abstract
Amylose and amylopectin in corn and potato starches were fractionated by centrifugation at 124,000g for 3-72 h at 40°C in a gradient media, Nycodenz, based on their sedimentation rate differences. The fractions were collected from a centrifuge tube, and then analyzed by the phenol-sulfuric acid method and iodine-binding test. Amylopectin, a large and highly branched starch molecule, migrated faster than amylose and quickly reached its isopycnic point with a buoyant density of about 1.25 g/mL, exhibiting a sharp and stable carbohydrate peak. Amylose, which is a relatively small and linear molecule, however, migrated slowly in a broad density range and continued moving to higher density regions, eventually overlapping with amylopectin peak as the centrifugation continued. This could indicate that the buoyant density of amylose is similar to that of amylopectin. Under centrifugal conditions of 3 h and 124,000g, amylose and amylopectin molecules were clearly separated, and the presence of intermediate starch molecules (11.5 and 7.7% for corn and potato starch, respectively) was also observed between amylose and amylopectin fractions. The amylose content of corn and potato starches was 22.6 and 21.1%, respectively, based on the total carbohydrate analysis after the ultracentrifugation for 3 h. In alkaline gradients (pH 11 or 12.5), the sedimentation rate of starch molecules and the buoyant density of amylopectin were reduced, possibly due to the structural changes induced by alkali.
| Original language | English |
|---|---|
| Pages (from-to) | 611-617 |
| Number of pages | 7 |
| Journal | Carbohydrate Research |
| Volume | 338 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 2003 Mar 28 |
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Keywords
- Density-gradient
- Nycodenz
- Starch
- Ultracentrifugation
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Organic Chemistry
Cite this
Molecular fractionation of starch by density-gradient ultracentrifugation. / Yoon, Jae Wook; Lim, Seung Taik.
In: Carbohydrate Research, Vol. 338, No. 7, 28.03.2003, p. 611-617.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Molecular fractionation of starch by density-gradient ultracentrifugation
AU - Yoon, Jae Wook
AU - Lim, Seung Taik
PY - 2003/3/28
Y1 - 2003/3/28
N2 - Amylose and amylopectin in corn and potato starches were fractionated by centrifugation at 124,000g for 3-72 h at 40°C in a gradient media, Nycodenz, based on their sedimentation rate differences. The fractions were collected from a centrifuge tube, and then analyzed by the phenol-sulfuric acid method and iodine-binding test. Amylopectin, a large and highly branched starch molecule, migrated faster than amylose and quickly reached its isopycnic point with a buoyant density of about 1.25 g/mL, exhibiting a sharp and stable carbohydrate peak. Amylose, which is a relatively small and linear molecule, however, migrated slowly in a broad density range and continued moving to higher density regions, eventually overlapping with amylopectin peak as the centrifugation continued. This could indicate that the buoyant density of amylose is similar to that of amylopectin. Under centrifugal conditions of 3 h and 124,000g, amylose and amylopectin molecules were clearly separated, and the presence of intermediate starch molecules (11.5 and 7.7% for corn and potato starch, respectively) was also observed between amylose and amylopectin fractions. The amylose content of corn and potato starches was 22.6 and 21.1%, respectively, based on the total carbohydrate analysis after the ultracentrifugation for 3 h. In alkaline gradients (pH 11 or 12.5), the sedimentation rate of starch molecules and the buoyant density of amylopectin were reduced, possibly due to the structural changes induced by alkali.
AB - Amylose and amylopectin in corn and potato starches were fractionated by centrifugation at 124,000g for 3-72 h at 40°C in a gradient media, Nycodenz, based on their sedimentation rate differences. The fractions were collected from a centrifuge tube, and then analyzed by the phenol-sulfuric acid method and iodine-binding test. Amylopectin, a large and highly branched starch molecule, migrated faster than amylose and quickly reached its isopycnic point with a buoyant density of about 1.25 g/mL, exhibiting a sharp and stable carbohydrate peak. Amylose, which is a relatively small and linear molecule, however, migrated slowly in a broad density range and continued moving to higher density regions, eventually overlapping with amylopectin peak as the centrifugation continued. This could indicate that the buoyant density of amylose is similar to that of amylopectin. Under centrifugal conditions of 3 h and 124,000g, amylose and amylopectin molecules were clearly separated, and the presence of intermediate starch molecules (11.5 and 7.7% for corn and potato starch, respectively) was also observed between amylose and amylopectin fractions. The amylose content of corn and potato starches was 22.6 and 21.1%, respectively, based on the total carbohydrate analysis after the ultracentrifugation for 3 h. In alkaline gradients (pH 11 or 12.5), the sedimentation rate of starch molecules and the buoyant density of amylopectin were reduced, possibly due to the structural changes induced by alkali.
KW - Density-gradient
KW - Nycodenz
KW - Starch
KW - Ultracentrifugation
UR - http://www.scopus.com/inward/record.url?scp=0037470738&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037470738&partnerID=8YFLogxK
U2 - 10.1016/S0008-6215(02)00539-6
DO - 10.1016/S0008-6215(02)00539-6
M3 - Article
C2 - 12644374
AN - SCOPUS:0037470738
VL - 338
SP - 611
EP - 617
JO - Carbohydrate Research
JF - Carbohydrate Research
SN - 0008-6215
IS - 7
ER -