Characterization and structure of cold-extruded whey protein isolate: impact of ball milling
- 5 Downloads
The effect of ball milling on physicochemical, functional and rheological properties and structural characteristics of cold-extruded whey protein isolate (TWPI) was investigated as a function of grinding time. Ball milling decreased the free sulfhydryl content of all the samples. Furthermore, ball milling and cold extrusion could enhance surface hydrophobicity, emulsifying and rheological properties of WPI. The solubility of cold-extruded WPI was far higher than the traditional heat-extruded WPI. The viscoelastic modulus of TWPI, ground by ball milling for 10 h, dramatically increased compared to that of WPI at 85 °C. Scanning electron microscopy revealed that a ball-milling treatment of 2 h remarkably decreased the particle size of all the samples. FTIR demonstrated that ball-milling treatment decreased the ordered secondary structure (α-helix and β-sheet) of WPI. Therefore, a combination of cold extrusion and ball milling could remarkably enhance the emulsifying and rheological properties of WPI, an effective way for providing novel functional ingredients to the dairy industry.
KeywordsWhey protein isolate Cold extrusion Ball milling Second structure Functional properties
This study was supported by the project for the Academic Research Program of Northeast Agricultural University (no. 16XG21) and the Natural Science Foundation of Heilongjiang Province of China (no. C2017029).
Compliance with ethical standards
Conflict of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.
- Jiang J, Xiong YL, Chen J (2010) pH shifting alters solubility characteristics and thermal stability of soy protein isolate and its globulin fractions in different pH, salt concentration, and temperature conditions. J Agric Food Chem 58:8035–8042. https://doi.org/10.1021/jf101045b CrossRefGoogle Scholar
- Mcclements DJ, Monahan FJ, Kinsella JE (1993) Disulfide bond formation affects stability of whey protein isolate emulsions. J Food Sci 58:1036–1039. https://doi.org/10.1111/j.1365-2621.1993.tb06106.x CrossRefGoogle Scholar
- Mustapha NA, Ruttarattanamongkol K, Rizvi SSH (2012) The effects of supercritical fluid extrusion process on surface hydrophobicity of whey protein concentrate and its relation to storage and heat stability of concentrated emulsions. Food Res Int 48:470–477. https://doi.org/10.1016/j.foodres.2012.05.015 CrossRefGoogle Scholar
- Nir I, Feldman Y, Aserin A, Garti N (2010) Surface properties and emulsification behavior of denatured soy proteins. J Food Sci 59:606–610. https://doi.org/10.1111/j.1365-2621.1994.tb05573.x CrossRefGoogle Scholar
- Onwulata CI, Tunick MH, Qi PX (2011) Extrusion texturized dairy proteins: processing and application. Adv Food Nutr Res 62:173–200. https://doi.org/10.1016/b978-0-12-385989-1.00005-3 CrossRefGoogle Scholar
- Sun C, Wu T, Liu R, Liang B, Tian Z, Zhang E, Zhang M (2015b) Effects of superfine grinding and microparticulation on the surface hydrophobicity of whey protein concentrate and its relation toemulsions stability. Food Hydrocoll 51:512–518. https://doi.org/10.1016/j.foodhyd.2015.05.027 CrossRefGoogle Scholar
- Vakifahmetoglu C, Buldu M, Karakuscu A, Ponzoni A, Assefa D, Soraru GD (2015) High surface area carbonous components from emulsion derived SiOC and their gas sensing behavior. J Eur Ceram Soc 35:4447–4452. https://doi.org/10.1016/j.jeurceramsoc.2015.08.030 CrossRefGoogle Scholar
- Yu GQ, Warkentin T, Niu Z, Khan NA, Yu P (2015) Molecular basis of processing-induced changes in protein structure in relation to intestinal digestion in yellow and green type pea (Pisum sativum L.): a molecular spectroscopic analysis. Spectrochim Acta A Mol Biomol Spectrosc 151:980–988. https://doi.org/10.1016/j.saa.2015.06.050 CrossRefGoogle Scholar
- Zhou XM, Li YX (2011) Influence of the measurement on superfine powder by different laser particle analyzer. Adv Mater Res 308–310:2446–2449. https://doi.org/10.4028/www.scientific.net/amr.308-310.2446 CrossRefGoogle Scholar