Characterization of Edible Coatings Consisting of Pea Starch, Whey Protein Isolate, and Carnauba Wax and their Effects on Oil Rancidity and Sensory Properties of Walnuts and Pine Nuts
Version of Record online: 6 FEB 2012
© 2012 Institute of Food Technologists®
Journal of Food Science
Volume 77, Issue 2, pages E52–E59, February 2012
How to Cite
Mehyar, G. F., Al-Ismail, K., Han, J. H. and Chee, G. W. (2012), Characterization of Edible Coatings Consisting of Pea Starch, Whey Protein Isolate, and Carnauba Wax and their Effects on Oil Rancidity and Sensory Properties of Walnuts and Pine Nuts. Journal of Food Science, 77: E52–E59. doi: 10.1111/j.1750-3841.2011.02559.x
- Issue online: 17 FEB 2012
- Version of Record online: 6 FEB 2012
- MS 20110958 Submitted 8/7/2011, Accepted 11/13/2011.
- antioxidant activity;
- edible coatings;
- lipid oxidation;
- packaging materials
Abstract: Edible coatings made of whey protein isolate (WPI), pea starch (PS), and their combinations with carnauba wax (CW) were prepared and characterized. WPI combined with CW formed stable emulsion while PS with CW formed unstable emulsion and both formulations produced non-homogeneous films. Addition of PS to WPI: CW combination at the ratio of 1: 1: 1, respectively, resulted in stable emulsion and homogenous films. The emulsion PS: WPI: CW (1: 1: 2) was stable and formed a continuous film but had less homogenous droplets size distribution when compared to 1: 1: 1 film. Combined films had a reduced tensile strength and elongation compared to single component films. WPI : CW (1: 1) films had higher elastic modulus than the WPI films, but the modulus reduced by the addition of PS. All the coating formulations were effective in preventing oxidative and hydrolytic rancidity of walnuts and pine nuts stored at 25 °C throughout the storage (12 d) but were less effective at 50 °C. Increasing the concentration of CW from 1: 1: 1 to 1: 1: 2 in PS: WPI: CW formulation did not contribute in further prevention of oil rancidity at 25 °C. Using of PS: WPI: CW (1: 1: 1) coating on both nuts significantly (P < 0.05) improved their smoothness and taste but the PS: WPI: CW (1: 1: 2) coatings imparted unacceptable yellowish color on walnuts.
Practical Application: Edible coating of walnuts and pine nuts by whey protein isolate, pea starch, and carnauba wax reduced the oxidative and hydrolytic rancidity of the nuts and improved sensory characteristics.