Improvement of the Mechanical and Barrier Properties of Potato Starch-based Films using ZnO Nanoparticles & its Application in Iranian Sour Cherry Packaging

Because of high perishable properties of sour cherry, there is no possibility to export the fruit freshly. Packaging would be one of the efficient factors playing an important role for increasing the shelf-life of the food products. On the other hand, application of natural and eco-friendly materials such as starch in packaging industry seems unfavorable aroused from poor mechanical and barrier properties. To overcome these defects, addition of nanofillers is advised. In this regard, ZnO nanoparticles are a right choice for reinforcement of biopolymers due to their safety, appropriate price and high availability. The objective of this paper is to design a new kind of packaging based on potato starch films reinforced with loading various amounts of ZnO nanoparticles (0, 0.5, 1, 2, 3, 4 wt%) and evaluation its performance on quality parameters of Iranian sour cherry. The resulting films were characterized with FE-SEM(Field Emissionscanning electron microscopy), water vapor permeability(WVP) and mechanical tests. Upon the ZnO nanoparticles content increased, both the tensile strength yield (TS) and Young’s modulus (YM) increased from 3.7 to 4.8 MPa and from 63 to 92 MPa, while elongation at the break point (E(%)) and WVP decreased from 26% to 22% and from 5.7×10-7 to 5.3×10-7 g.Pa-1.h-1.m-1, respectively. The starch bio-film containing 2% ZnO nanoparticles was selected as the best reinforced packaging film for maintaining sour cherry quality parameters. The results showed the better quality of fruits packaged in starch films containing 2% ZnO nanoparticles in comparison with either the samples packaged in nonreinforced starch films, or even in polyethylene (PE) films due to a higher total soluble solids, titrable acidity and firmness. The SPSS software was used for statistical analysis.