Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review
Stabilizing vitamin D3 using the molten globule state of α-lactalbumin. / Pedersen, Jannik Nedergaard; Sørensen, Henrik V; Otzen, Daniel E.
In: Journal of Dairy Science, Vol. 101, No. 3, 03.2018, p. 1817–1826.Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review
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TY - JOUR
T1 - Stabilizing vitamin D3 using the molten globule state of α-lactalbumin
AU - Pedersen, Jannik Nedergaard
AU - Sørensen, Henrik V
AU - Otzen, Daniel E
N1 - Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
PY - 2018/3
Y1 - 2018/3
N2 - α-Lactalbumin (α-LA) is the second most abundant bovine whey protein. It has been intensively studied because of its readiness to populate the molten globular (MG) state, a partially folded state with native levels of secondary structure but loss of tertiary structure. The MG state of α-LA exposes a significant number of hydrophobic patches that could be used to bind and stabilize small hydrophobic molecules such as vitamin D3 (vitD). Accordingly, we tested the ability of α-LA to stabilize vitD in a pH interval from 7.4 to 2; over this pH interval, α-LA transitions from the folded state to the MG state. The MG state stabilized vitD better than the folded state and was superior to the major bovine whey protein β-lactoglobulin (β-LG), which is known to stabilize vitD. At pH 7.4, β-LG and α-LA stabilized vitD to the same extent. Tryptophan fluorescence quenching measurements indicated that α-LA has one binding site at pH 7.4 but acquires an additional binding site when the pH is lowered to pH 2 to 4. Stability measurements of the vitD in the α-LA-vitD complex at different temperatures suggest that UHT processing would lead to little loss of vitD. This study demonstrates the potential of α-LA as a component in vitD fortification, particularly for low pH applications.
AB - α-Lactalbumin (α-LA) is the second most abundant bovine whey protein. It has been intensively studied because of its readiness to populate the molten globular (MG) state, a partially folded state with native levels of secondary structure but loss of tertiary structure. The MG state of α-LA exposes a significant number of hydrophobic patches that could be used to bind and stabilize small hydrophobic molecules such as vitamin D3 (vitD). Accordingly, we tested the ability of α-LA to stabilize vitD in a pH interval from 7.4 to 2; over this pH interval, α-LA transitions from the folded state to the MG state. The MG state stabilized vitD better than the folded state and was superior to the major bovine whey protein β-lactoglobulin (β-LG), which is known to stabilize vitD. At pH 7.4, β-LG and α-LA stabilized vitD to the same extent. Tryptophan fluorescence quenching measurements indicated that α-LA has one binding site at pH 7.4 but acquires an additional binding site when the pH is lowered to pH 2 to 4. Stability measurements of the vitD in the α-LA-vitD complex at different temperatures suggest that UHT processing would lead to little loss of vitD. This study demonstrates the potential of α-LA as a component in vitD fortification, particularly for low pH applications.
KW - Journal Article
U2 - 10.3168/jds.2017-13818
DO - 10.3168/jds.2017-13818
M3 - Journal article
C2 - 29331461
VL - 101
SP - 1817
EP - 1826
JO - Journal of Dairy Science
JF - Journal of Dairy Science
SN - 0022-0302
IS - 3
ER -