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Coagulation of β-conglycinin, glycinin and isoflavones induced by calcium chloride in soymilk.

Hsiao YH, Yu CJ, Li WT, Hsieh JF - Sci Rep (2015)

Bottom Line: Isoflavones, including daidzein and genistein, were also coagulated into the SPF after the addition of 5 mM calcium chloride.The amounts of daidzein and genistein in the SSF decreased to 39.4 ± 1.6 and 11.8 ± 7.0%, respectively.HPLC analysis suggested that daidzein and genistein were bound with 7S and 11S proteins and then were coprecipitated into the SPF by 5 mM calcium chloride.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Food Science, Fu Jen Catholic University, Taipei 242, Taiwan [2] Ph.D. Program in Nutrition &Food Science, Fu Jen Catholic University, Taipei 242, Taiwan.

ABSTRACT
The coagulation of β-conglycinin (7S), glycinin (11S) and isoflavones induced by calcium chloride was investigated. Approximately 92.6% of the soymilk proteins were coagulated into the soymilk pellet fraction (SPF) after the addition of 5 mM calcium chloride. SDS-PAGE and two-dimensional electrophoresis analysis indicated that most of the 7S (α', α and β), 11S acidic (A1a, A1b, A2, A3 and A4) and 11S basic (B1a) proteins in the SSF were coagulated into the SPF after treatment with 5 mM calcium chloride. Isoflavones, including daidzein and genistein, were also coagulated into the SPF after the addition of 5 mM calcium chloride. The amounts of daidzein and genistein in the SSF decreased to 39.4 ± 1.6 and 11.8 ± 7.0%, respectively. HPLC analysis suggested that daidzein and genistein were bound with 7S and 11S proteins and then were coprecipitated into the SPF by 5 mM calcium chloride.

No MeSH data available.


HPLC chromatograms of isoflavones extracted from the (A) soymilk, (B) 7S and (C) 11S proteins. Mobile phase: a gradient elution with H2O/acetonitrile (92:8, v/v,→50:50, v/v). Flow rate: 2 mL/min. Detection: UV 262 nm. Arrow: isoflavones. 1: daidzin. 2: glycitin. 3: genistin. 4: daidzein. 5: genistein.
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f5: HPLC chromatograms of isoflavones extracted from the (A) soymilk, (B) 7S and (C) 11S proteins. Mobile phase: a gradient elution with H2O/acetonitrile (92:8, v/v,→50:50, v/v). Flow rate: 2 mL/min. Detection: UV 262 nm. Arrow: isoflavones. 1: daidzin. 2: glycitin. 3: genistin. 4: daidzein. 5: genistein.

Mentions: The isoflavones extracted from soymilk and 7S and 11S proteins were analyzed by HPLC (Fig. 5). Isoflavones from soymilk were subjected to the HPLC (Fig. 5a). Five isoflavones (arrows, compounds 1–5) were isolated, which were collected at the elution times of 4–5, 5–6, 7–8, 11–12 and 14–15 min, respectively. The total yields of compounds 1–5 were 1.4, 1.0, 1.2, 1.1 and 1.3 mg, respectively. These purified isoflavones were analyzed using high-resolution ESI-TOF mass spectrometry, FT-IR and UV and were identified as daidzin, glycitin, genistin, daidzein and genistein, respectively. The quantification of these isoflavones by HPLC was performed, and commercial daidzin, glycitin, genistin, daidzein and genistein (LC Laboratories, Woburn, MA, USA) were used as the standards. The amount of each isoflavone in the soymilk (daidzin, glycitin, genistin, daidzein and genistein) were 20.2 ± 0.8, 3.3 ± 0.2, 6.9 ± 0.5, 15.7 ± 0.7 and 13.5 ± 0.1 μg/mL, respectively (Fig. 5A). The contents of daidzin, glycitin, genistin, daidzein and genistein in 95 °C heated soymilk were 0.50, 0.14, 0.59, 0.31 and 0.26 μmol/g dry basis, respectively8. The isoflavone content in soymilk could be affected by the ratio of water and soybean22. Among these isoflavones, daidzin, daidzein and genistein were isolated from 7S and 11S proteins, and the amount of each isoflavone in the 7S proteins were 1.4 ± 0.1, 2.5 ± 0.2 and 1.9 ± 0.1 μg/mg dry basis, respectively (Fig. 5B). The amount of each isoflavone in the 11S proteins (daidzin, daidzein and genistein) were 1.1 ± 0.1, 1.5 ± 0.1 and 1.5 ± 0.1 μg/mg dry basis (Fig. 5C). The contents of daidzin, daidzein and genistein in the 7S proteins were 0.25, 0.43 and 0.54 μmol/g dry basis, respectively23. Furthermore, the contents of daidzin, daidzein and genistein in the 11S proteins were 0.62, 0.39 and 0.41 μmol/g dry basis, respectively. The difference in the content of isoflavones between 7S and 11S might be due to structural differences in the proteins, causing a different affinity between proteins and isoflavones24.


Coagulation of β-conglycinin, glycinin and isoflavones induced by calcium chloride in soymilk.

Hsiao YH, Yu CJ, Li WT, Hsieh JF - Sci Rep (2015)

HPLC chromatograms of isoflavones extracted from the (A) soymilk, (B) 7S and (C) 11S proteins. Mobile phase: a gradient elution with H2O/acetonitrile (92:8, v/v,→50:50, v/v). Flow rate: 2 mL/min. Detection: UV 262 nm. Arrow: isoflavones. 1: daidzin. 2: glycitin. 3: genistin. 4: daidzein. 5: genistein.
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f5: HPLC chromatograms of isoflavones extracted from the (A) soymilk, (B) 7S and (C) 11S proteins. Mobile phase: a gradient elution with H2O/acetonitrile (92:8, v/v,→50:50, v/v). Flow rate: 2 mL/min. Detection: UV 262 nm. Arrow: isoflavones. 1: daidzin. 2: glycitin. 3: genistin. 4: daidzein. 5: genistein.
Mentions: The isoflavones extracted from soymilk and 7S and 11S proteins were analyzed by HPLC (Fig. 5). Isoflavones from soymilk were subjected to the HPLC (Fig. 5a). Five isoflavones (arrows, compounds 1–5) were isolated, which were collected at the elution times of 4–5, 5–6, 7–8, 11–12 and 14–15 min, respectively. The total yields of compounds 1–5 were 1.4, 1.0, 1.2, 1.1 and 1.3 mg, respectively. These purified isoflavones were analyzed using high-resolution ESI-TOF mass spectrometry, FT-IR and UV and were identified as daidzin, glycitin, genistin, daidzein and genistein, respectively. The quantification of these isoflavones by HPLC was performed, and commercial daidzin, glycitin, genistin, daidzein and genistein (LC Laboratories, Woburn, MA, USA) were used as the standards. The amount of each isoflavone in the soymilk (daidzin, glycitin, genistin, daidzein and genistein) were 20.2 ± 0.8, 3.3 ± 0.2, 6.9 ± 0.5, 15.7 ± 0.7 and 13.5 ± 0.1 μg/mL, respectively (Fig. 5A). The contents of daidzin, glycitin, genistin, daidzein and genistein in 95 °C heated soymilk were 0.50, 0.14, 0.59, 0.31 and 0.26 μmol/g dry basis, respectively8. The isoflavone content in soymilk could be affected by the ratio of water and soybean22. Among these isoflavones, daidzin, daidzein and genistein were isolated from 7S and 11S proteins, and the amount of each isoflavone in the 7S proteins were 1.4 ± 0.1, 2.5 ± 0.2 and 1.9 ± 0.1 μg/mg dry basis, respectively (Fig. 5B). The amount of each isoflavone in the 11S proteins (daidzin, daidzein and genistein) were 1.1 ± 0.1, 1.5 ± 0.1 and 1.5 ± 0.1 μg/mg dry basis (Fig. 5C). The contents of daidzin, daidzein and genistein in the 7S proteins were 0.25, 0.43 and 0.54 μmol/g dry basis, respectively23. Furthermore, the contents of daidzin, daidzein and genistein in the 11S proteins were 0.62, 0.39 and 0.41 μmol/g dry basis, respectively. The difference in the content of isoflavones between 7S and 11S might be due to structural differences in the proteins, causing a different affinity between proteins and isoflavones24.

Bottom Line: Isoflavones, including daidzein and genistein, were also coagulated into the SPF after the addition of 5 mM calcium chloride.The amounts of daidzein and genistein in the SSF decreased to 39.4 ± 1.6 and 11.8 ± 7.0%, respectively.HPLC analysis suggested that daidzein and genistein were bound with 7S and 11S proteins and then were coprecipitated into the SPF by 5 mM calcium chloride.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Food Science, Fu Jen Catholic University, Taipei 242, Taiwan [2] Ph.D. Program in Nutrition &Food Science, Fu Jen Catholic University, Taipei 242, Taiwan.

ABSTRACT
The coagulation of β-conglycinin (7S), glycinin (11S) and isoflavones induced by calcium chloride was investigated. Approximately 92.6% of the soymilk proteins were coagulated into the soymilk pellet fraction (SPF) after the addition of 5 mM calcium chloride. SDS-PAGE and two-dimensional electrophoresis analysis indicated that most of the 7S (α', α and β), 11S acidic (A1a, A1b, A2, A3 and A4) and 11S basic (B1a) proteins in the SSF were coagulated into the SPF after treatment with 5 mM calcium chloride. Isoflavones, including daidzein and genistein, were also coagulated into the SPF after the addition of 5 mM calcium chloride. The amounts of daidzein and genistein in the SSF decreased to 39.4 ± 1.6 and 11.8 ± 7.0%, respectively. HPLC analysis suggested that daidzein and genistein were bound with 7S and 11S proteins and then were coprecipitated into the SPF by 5 mM calcium chloride.

No MeSH data available.