β-Lactoglobulin nanofibrils: Effect of temperature on fibril formation kinetics, fibril morphology and the rheological properties of fibril dispersions
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Date
2012-05
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Elsevier Ltd
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Abstract
Almost all published studies of heat-induced b-lactoglobulin self-assembly into amyloid-like fibrils at
low pH and low ionic strength have involved heating at 80 C, and the effect of heating temperature on
self-assembly has received little attention. Here we heated b-lactoglobulin at pH 2 and 75 C, 80 C, 90 C,
100 C, 110 C or 120 C and investigated the kinetics of self-assembly (using Thioflavin T fluorescence),
the morphology of fibrils, and the rheological properties of fibril dispersions.
Self-assembly occurred at all temperatures tested. Thioflavin T fluorescence increased sigmoidally at
all temperatures, however it decreased sharply with >3.3 h heating at 110 C and with >5 h heating at
120 C. The sharp decreases were attributed partly to local gelation, but destruction of fibrils may have
occurred at 120 C. Thioflavin T fluorescence results indicated that maximal rates of fibril formation
increased with increasing temperature, especially above 100 C, but fibril yield (maximum Thioflavin
T fluorescence) was not affected by temperature.
At 100 C and 110 C, fibrils were slightly shorter than at 80 C, but otherwise they looked very similar.
Fibrils made by heating at 120 C for 1 h were also similar, but heating at 120 C for 8 h gave
predominantly short fibrils, apparently the products of larger fibrils fragmenting. Heating at 100 C gave
consistently higher viscosity than at 80 C, and heating for >2 h at 120 C decreased viscosity, which may
have been linked with fibril fragmentation seen in micrographs.
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Author manuscript
NOTICE: this is the author’s version of a work that was accepted for publication in Food Hydrocolloids. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Food Hydrocolloids, 27(1),(2012) DOI: 10.1016/j.foodhyd.2011.07.001
NOTICE: this is the author’s version of a work that was accepted for publication in Food Hydrocolloids. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Food Hydrocolloids, 27(1),(2012) DOI: 10.1016/j.foodhyd.2011.07.001
Keywords
β-Lactoglobulin, Whey proteins, Milk, Heat, Self-assembly, Proteins, Amyloid, Fibrils, Denaturation, Acid, Beta-lactoglobulin
Citation
Loveday, S. M., Wang, X. L., Rao, M. A., Anema, S. G., & Singh, H. β-Lactoglobulin nanofibrils: Effect of temperature on fibril formation kinetics, fibril morphology and the rheological properties of fibril dispersions. Food Hydrocolloids, 27(1), 242-249