Abstract

Aim of this study is to determine the effect of oil on the extrusion cooking process. Editable oils are often desired in extruded snacks to improve their eating quality. But the incorporation of oil into the extrusion process causes considerable changes in the expansion of the extruded products until it inhibits expansion in higher concentrations. In order to specify the effects of oil on the extrusion cooking process, in this study maize semolina with different oil contents (0, 2, 4, 5 and 6%, respectively) were expanded in a co-rotating twin screw extruder. Oil was applied to the maize semolina prior to the extrusion process. Diameter of the extrudates and pressure in the extruder were measured for each oil contents in order to determine the effect of oil content on these parameters. With increasing oil content, the change of diameter constantly increased. Pressure increased slightly at low oil contents but dropped significantly at higher oil contents. In this setup extrusion was feasible up to 4% oil content without a loss of the diameter of the extrudates and up to 6% of oil with increasing variabilities in the diameter of the extrudates and in the process pressure.

Keywords:

Expansion, extrusion cooking, maize semolina, oil content, pressure, twin screw extruder,

References

1. Bhattacharya, M. and M.A. Hanna, 1987. Influence of process and product variables on extrusion energy and pressure requirements. J. Food Eng., 6(2): 153-163.
   CrossRef    
2. Bhattacharya, M. and M.A. Hanna, 1988. Effect of lipids on the properties of extruded products. J. Food Sci., 53(4): 1230-1231.
   CrossRef    
3. Chen, J. and A.J. Rosenthal, 2015. Modifying Food Texture. Volume 2, Sensory Analysis, Consumer Requirements and Preferences. Woodhead Publishing, Cambridge, UK.
   
4. Guy, R.C.E., 1994. Raw Materials for Extrusion Cooking Processes. In: Frame, N.D. (Ed.), The Technology of Extrusion Cooking. Blackie Academic and Professional, London, pp: 52-72.
   CrossRef    
5. Horvat, M., M. Azad Emin, B. Hochstein, N. Willenbacher and H.P. Schuchmann, 2013. Influence of medium-chain triglycerides on expansion and rheological properties of extruded corn starch. Carbohyd. Polym., 93(2): 492-498.
   CrossRef    PMid:23499088    
6. Ilo, S., R. Schoenlechner and E. Berghofe, 2000. Role of lipids in the extrusion cooking processes. Grasas Aceites, 51(1-2): 97-110.
   CrossRef    
7. Lin, S., F. Hsieh and H.E. Huff, 1997. Effects of lipids and processing conditions on degree of starch gelatinization of extruded dry pet food. LWT-Food Sci. Technol., 30(7): 754-761.
   
8. Moraru, C.I. and J.L. Kokini, 2003. Nucleation and expansion during extrusion and microwave heating of cereal foods. Compr. Rev. Food Sci. F., 2(4): 147-165.
   CrossRef    
9. Onwulata, C.I., S.J. Mulvaney and F. Hsieh, 1994. System analysis as the basis for control of density of extruded cornmeal. Food Control, 5(1): 39-48.
   CrossRef    
10. Singh, N. and A.C. Smith, 1999. Rheological behaviour of different cereals using capillary rheometry. J. Food Eng., 39(2): 203-209.
    CrossRef    
11. Wang, S., J. Casulli and J.M. Bouvier, 1993. Effect of dough ingredients on apparent viscosity and properties of extrudates in twin-screw extrusion-cooking. Int. J. Food Sci. Tech., 28(5): 465-479.
    CrossRef    
12. Willett, J.L., B.K. Jasberg and C.L. Swanson, 1994. Melt rheology of thermoplastic starch. ACS Sym. Ser., 575: 50-68.
    CrossRef    

Competing interests

The authors have no competing interests.

Open Access Policy

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Copyright

The authors have no competing interests.