Chitosan, nisin, silicon dioxide nanoparticles coating films effects on blueberry (Vaccinium myrtillus) quality

Chitosan coating plus silicon dioxide nanoparticles and nisin were applied on fresh blueberry samples in order to find out safety packaging assay during the post-harvest process. Studies were performed in-vitro for fruit quality as physicochemical parameters and oxidation, while microbiological analyses as molds/yeast and mesophilics populations were examined in-vivo. The selected silicon dioxide nanoparticles 1% and nisin 1%, were added into a chitosan solution, which resulted in four groups of coated blueberries. After storage at ambient temperature, fruits were examined for two, four, six, and eight days. It was noticed that the hardness, chewiness, and cohesiveness of all blueberry samples were increased during the storage. Chitosan-nano-silicon dioxide (CHN-Nano) and (CHN-N-Nano) with the addition of nisin helped to control shrinking (38.52%) and decay rates (8.61%). Moreover, (CHN-N-Nano) reported the lowest L* values (10.54) for the color index, and inhibited the microbial populations (3.60 and 2.73 log CFU/g) for molds/yeast and mesophilics, respectively. (CHN-Nano) reported the lowest value for ph (2.61) and the highest for anthocyanin content (75.19 cyanidin-3-glucoside mg/100 g). The chitosan coating substantially maintained Vitamin C (7.34 mg/100 g) and polyphenoloxidase (PPO) (558.03 U min^{− 1}·g^{− 1}). The results suggest that nano-material with chitosan film coatings that contained nisin were effective for fresh blueberry preservation under ambient temperature.