Investigating of some physical properties of whey protein isolate – polydextrose based nanobiocomposite film containing cellulose nanofiber and Lactobacillus plantarum and its effect on beef shelf-life

There is a growing interest in bioactive packaging systems due to their potential for the extended shelf life of food products. In this way, to produce probiotic nanocomposite whey protein isolate-polydextrose film containing cellulose nanofiber and Lactobacillus plantarum probiotic bacteria and evaluation of its antimicrobial effect on beef shelf life during storage time, different concentrations of polydextrose (0, 10 and 20 wt / wt% whey protein isolate) and cellulose nanofiber (0, 2.5 and 5 wt / wt% whey protein isolate) were used for film preparation. Effect of variables on physical properties of the film (thickness, moisture absorption, water contact angle, and color properties) and effect of optimal film antimicrobial properties on enhancing the beef shelf-life during 8-day storage time in refrigerated conditions was examined. The results showed compatibility between the protein matrix of whey protein isolate, cellulose nanofiber and polydextrose. The use of polydextrose and cellulose nanofiber had a significant effect on increasing the film thickness, water contact angle, color changes and decreased the moisture absorption of the film. The results of covering the meat samples with the optimum film indicated a significant decrease in the growth of aerobic mesophilic bacteria, psychrotrophic and coliform bacteria during storage time. Finally, the results showed that the application of cellulose nanofiber and polydextrose in the film produced from whey protein isolate could improve the shelf-life of  beef compared to the uncovered meat sample by creating a bioactive food packaging.