The influence of chitosan and titanium dioxide nanoparticles incorporated with polylactic acid on prolonging rye bread shelf life

Rye bread has a higher nutritional value, rich in fiber, vitamins and minerals. It is a valuable source of B vitamins, elements such as zinc, phosphorus, magnesium and calcium. Rye bread can increase the viscosity of the intestinal contents and reduce blood cholesterol. In this study, films based on polylactic acid (PLA), chitosan (CS), and titanium dioxide nanoparticles (TiO 2 NPs) were fabricated for extending the storage period of rye bread. Fourier transform infrared spectroscopy (FTIR) confirmed the successful synthesis of films. As compared with PLA coating, coated rye bread with PLA-CS 3%-TiO 2 5% showed higher values in TS (1.66 MPa), thickness (0.140 mm) water absorption capacity (WAC) (5.30%), and opacity (434.45) parameters, as well as lower values in water vapor permeability (WVP) (0.322 × 10 –7 g m −1 s −1 Pa −1 ), water solubility (2.83%), and oxygen permeability (OP) (1.85 × 10 −7 g −1 m −1 s −1 Pa −1 ) parameters. The highest L * , a * , and b * values were related to the film containing PLA-CS 3%-TiO 2 5%. The minimum and maximum values of hardness and water activity (a w ) were obtained 0.383 and 0.756, respectively, which are assigned to the PLA-CS 3%-TiO 2 5% film. Nanocomposite containing 3% CS and 5% TiO 2 revealed the most reducing effect versus mold and a significant difference was observed between different treatments during the storage time ( p ≤ 0.05). Overall, using PLA-CS-TiO 2 as a coating possesses an excellent potential in shelf life extension of rye bread with satisfactory quality. Hence, it can be a promising coating to preserve the quality of bread.