Limits...
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.


Changes in the total protein content of soymilk with different amounts of calcium chloride.SSF: soymilk supernatant fraction; SPF: soymilk pellet fraction. Vertical bars represent standard deviations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4542527&req=5

f1: Changes in the total protein content of soymilk with different amounts of calcium chloride.SSF: soymilk supernatant fraction; SPF: soymilk pellet fraction. Vertical bars represent standard deviations.

Mentions: Soymilk samples were incubated with varying concentrations of calcium chloride (0, 2.5, 5, 7.5 or 10 mM) for 1 h. The amount of total protein in the SSF and SPF was determined. As shown in Fig. 1, the total protein contents in the SSF and SPF, without calcium chloride treatments, were 9.57 ± 0.05 and 0.10 ± 0.04 mg/mL, respectively. This indicates that protein coagulation did not occur in the soymilk samples in the absence of calcium chloride. Following the 2.5 mM calcium chloride treatment, the total protein in the SSF decreased from 9.57 ± 0.05 to 7.92 ± 0.23 mg/mL. The total protein in the SSF decreased to 0.70 ± 0.03 mg/mL after the addition of 5 mM calcium chloride. Approximately 92.6% of the soymilk proteins were coagulated by the addition of 5 mM calcium chloride, and the total protein in the SPF significantly increased from 0.10 ± 0.04 mg/mL (without calcium chloride) to 8.63 ± 0.05 mg/mL (P < 0.05). The concentration of calcium in soymilk is very low (<0.02 mM) and that adding 25 mM calcium chloride to soymilk can precipitate soymilk proteins13. Ono14 reported that the coagulation of soymilk occurs due to the combination of calcium ions and soymilk proteins. The protein molecules bound by calcium ions have been described as being located on the side-chain carboxyl groups of aspartic and glutamic acid residues and the side-chain imidazole group of histidine residues. Ju and Kilara15 reported that Ca2+-induced protein aggregation is thought to arise from three effects: 1) electrostatic shielding, 2) ion-specific hydrophobic interaction, and 3) crosslinking of adjacent anionic molecules through the formation of protein-Ca2+-protein bridges. The binding of Ca2+ to soy proteins is an endothermic process (ΔH > 0) based on binding titration curves of soy protein dispersions with calcium chloride16.


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

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

Changes in the total protein content of soymilk with different amounts of calcium chloride.SSF: soymilk supernatant fraction; SPF: soymilk pellet fraction. Vertical bars represent standard deviations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542527&req=5

f1: Changes in the total protein content of soymilk with different amounts of calcium chloride.SSF: soymilk supernatant fraction; SPF: soymilk pellet fraction. Vertical bars represent standard deviations.
Mentions: Soymilk samples were incubated with varying concentrations of calcium chloride (0, 2.5, 5, 7.5 or 10 mM) for 1 h. The amount of total protein in the SSF and SPF was determined. As shown in Fig. 1, the total protein contents in the SSF and SPF, without calcium chloride treatments, were 9.57 ± 0.05 and 0.10 ± 0.04 mg/mL, respectively. This indicates that protein coagulation did not occur in the soymilk samples in the absence of calcium chloride. Following the 2.5 mM calcium chloride treatment, the total protein in the SSF decreased from 9.57 ± 0.05 to 7.92 ± 0.23 mg/mL. The total protein in the SSF decreased to 0.70 ± 0.03 mg/mL after the addition of 5 mM calcium chloride. Approximately 92.6% of the soymilk proteins were coagulated by the addition of 5 mM calcium chloride, and the total protein in the SPF significantly increased from 0.10 ± 0.04 mg/mL (without calcium chloride) to 8.63 ± 0.05 mg/mL (P < 0.05). The concentration of calcium in soymilk is very low (<0.02 mM) and that adding 25 mM calcium chloride to soymilk can precipitate soymilk proteins13. Ono14 reported that the coagulation of soymilk occurs due to the combination of calcium ions and soymilk proteins. The protein molecules bound by calcium ions have been described as being located on the side-chain carboxyl groups of aspartic and glutamic acid residues and the side-chain imidazole group of histidine residues. Ju and Kilara15 reported that Ca2+-induced protein aggregation is thought to arise from three effects: 1) electrostatic shielding, 2) ion-specific hydrophobic interaction, and 3) crosslinking of adjacent anionic molecules through the formation of protein-Ca2+-protein bridges. The binding of Ca2+ to soy proteins is an endothermic process (ΔH > 0) based on binding titration curves of soy protein dispersions with calcium chloride16.

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.