Abstract

Pure whey protein isolate (WPI)-based cast films are very brittle due to its strong formation of protein cross-linking of disulphide bonding, hydrogen bonding as well as hydrophobic and electrostatic interactions. However, this strong cross-linking is the reason for its final barrier performance. To overcome film brittleness of whey protein layers, plasticisers like glycerol are used. It reduces intermolecular interactions, increases the mobility of polymer chains and thus film flexibility can be achieved. The objective of this study was to investigate the influence of hydrolysed whey protein isolate (WPI) in whey protein isolate-based cast films on their techno-functional properties. Due to the fact, that the addition of glycerol is necessary but at the same time increases the free volume in the film leading to higher oxygen and water vapour permeability, the glycerol concentration was kept constant. Cast films with different ratios of hydrolysed and not hydrolysed WPI were produced. They were characterised in order to determine the influence of the lower molecular weight caused by the addition of hydrolysed WPI on the techno-functional properties. This study showed that increasing hydrolysed WPI concentrations significantly change the mechanical properties while maintaining the oxygen and water vapour permeability. The tensile and elastic film properties decreased significantly by reducing the average molecular weight whereas the yellowish coloration and the surface tension considerably increased. This study provided new data which put researchers and material developers in a position to tailor the characteristics of whey protein based films according to their intended application and further processing.

Highlights

  • The primary function of a food packaging is the protection of the food product against external influences especially against oxygen and/or water vapour [1,2,3,4]

  • This function is often provided by petroleum-based polymers like EVOH which acts as an oxygen barrier material in multilayer structures for achieving high barrier properties

  • There was no significant difference in WVTR values of whey protein isolate (WPI)-based films if molecular weight (MW) reduction takes place (Figure 1)

Read more

Summary

Introduction

The primary function of a food packaging is the protection of the food product against external influences especially against oxygen and/or water vapour [1,2,3,4] This function is often provided by petroleum-based polymers like EVOH (ethylene-vinyl-alcohol) which acts as an oxygen barrier material in multilayer structures for achieving high barrier properties. A possible alternative to achieve suitable mechanical as well as high oxygen and water vapour barrier properties is coating of polymer films with whey protein, which is a by-product of cheese manufacturing [6,7,8,9]. The use of whey proteins as barrier material in multilayer structures could increase the attractive value of whey and new branches of production in the cheese manufacturing and polymer processing industry could be established and in addition could contribute to sustainability [11]

Objectives
Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call