Impact of heat treatment on size, structure, and bioactivity of elemental selenium nanoparticles

Abstract

Background

Elemental selenium nanoparticles have emerged as a novel selenium source with the advantage of reduced risk of selenium toxicity. The present work investigated whether heat treatment affects the size, structure, and bioactivity of selenium nanoparticles.

Methods and results

After a one-hour incubation of solution containing 80 nm selenium particles in a 90°C water bath, the nanoparticles aggregated into larger 110 nm particles and nanorods (290 nm × 70 nm), leading to significantly reduced bioavailability and phase II enzyme induction in selenium-deficient mice. When a solution containing 40 nm selenium nanoparticles was treated under the same conditions, the nanoparticles aggregated into larger 72 nm particles but did not transform into nanorods, demonstrating that the thermostability of selenium nanoparticles is size-dependent, smaller selenium nanoparticles being more resistant than larger selenium nanoparticles to transformation into nanorods during heat treatment.

Conclusion

The present results suggest that temperature and duration of the heat process, as well as the original nanoparticle size, should be carefully selected when a solution containing selenium nanoparticles is added to functional foods.

Keywords:

• nanoparticle
• selenium
• bioactivity
• heat treatment

Acknowledgments

This work was supported by the National Natural Science Foundation of China (grant 31170648 to JZ), the National Basic Research Program of China (973 Program, grant 2009CB930204), and by a grant from Anhui Agricultural University to JZ.

Disclosure

The authors have no financial conflict of interest in this work.

Supplementary material

Figure S1. Impact of heat treatment on size and structure of 31 nm selenium nanoparticles. (A) Unheated precursor selenium nanoparticles. (B) Precursor selenium nanoparticle solution after heating at 60°C for 40 minutes. (C) Size before and after heat treatment.

Note: Data are presented as the mean ± standard deviation (n = 70).