Abstract High density polyethylene (HDPE) and nano-ZnO were used to prepare nano-ZnO/HDPE composite film with a nano-ZnO content of 0.5wt%. The morphology, mechanical, barrier and antibacterial properties, as well as the preservation to cheese of the films were studied. The results showed that the ZnO nanoparticles had a good dispersion in HDPE matrix so that the improvement of the mechanical, barrier and antibacterial performances of the film was achieved after the addition of nano-ZnO to HDPE. In comparison to cheese packaged in HDPE bags, it was found that the sensory score of the cheese in nano-ZnO/HDPE bags increased from 66.6 to 73.7 and the pH of cheese was closer to the standard sample at storage time of 7d. Furthermore, nano-ZnO/HDPE inhibited effectively the increase of the total bacterial count (TBC) on cheese contrast of HDPE. That indicates the prepared nano-ZnO/HDPE is potential in cheese packaging to extend the shelf life.

Abstract The modified atmosphere packages (MAP) was used to preserve the fresh noodles and the effect of atmosphere ratio (N2: CO2 = 0:100, 20:80, 30:70, 40:60 or 50:50) on noodle quality was investigated with normal packages as control. The results showed that the MAP could significantly extend the shelf life of fresh noodles up to at least 7 d, compared with the control. On the 7th day of storage, the elasticity and hardness gradually decreased with the increase of N2: CO2 ratio (P > 0.05) even if the MAP group were poor than the control (P > 0.05). In terms of water content, on the 7th day of storage, the decrease of 0:100 group and 20:80 group was less than that of control group (P < 0.05), and the effect of water retention was better. On the 7th day of storage, pH in the MAP group decreased less than that in the control group (P < 0.05). During the same storage period, the inhibition effect of the 0:100 group was significantly higher than that of the control group (P < 0.05), while the L* values decreased less in the 0:100 and 30:70 groups than in the control group (P < 0.05).

Abstract High-barrier and antibacterial materials have potential applications in the field of preservative packaging for fresh meat products. In this paper, UV irradiation and silane coupling agent (KH550) were used to modify the surface of SiOx coating on polyester (PET)/SiOx film to prepare the PET/SiOx/chitosan and PET/SiOx/chitosan-nano-ZnO composite film, respectively. The contact angle test revealed that KH550 improved the surface hydrophilicity of SiOx significantly compared to UV irradiation, and thus PET/SiOx/chitosan and PET/SiOx/chitosan-nano ZnO composite films were successfully prepared and their physical and chemical properties were characterized. SEM images showed that the surface of the composite film was a smooth and layered structure. The mechanical performance testing of the films has revealed that mechanical performance of the PET was improved by SiOx deposition while the coating (KH550, chitosan, and chitosan-nano ZnO) does not affect the mechanical performance of PET/SiOx. The oxygen resistance of PET/SiOx films treated with KH550 was enhanced with the addition of chitosan and chitosan-nano ZnO coating, but the moisture resistance was slightly decreased. Furthermore, PET/SiOx/chitosan and PET/SiOx/chitosan-nano ZnO composite films showed excellent growth inhibition against Staphylococcus aureus and Escherichia coli. The PET/SiOx/chitosan-nano-ZnO films had exhibited the strongest inhibition of bacteria.

Abstract Biodegradable and antimicrobial films via combing ε-polylysine (ε-PL) and polyvinyl alcohol (PVA) is a promising material for food packaging. We prepared the ε-PL/ PVA films with the ε-PL content of 0%, 1%, 3%, 5% and 7% (wt., relative to PVA) by casting method and their physical and chemical properties were characterized. SEM indicated the surface of ε-PL/PVA films was smooth with well compatibility between ε-PL and PVA at the ε-PL addition content of 1%. The tensile strength and barrier properties for water vapor and oxygen of the ε-PL/PVA films initially elevated and then decreased when ε-PL content exceeded 1%. The ε-PL doped endows antibacterial activity of PVA and the antibacterial property of ε-PL/PVA films was increasing with increase of ε-PL content. Compared with the control, the ε-PL/PVA packaging films could inhibit effectively the pericarp browning and pulp breakdown for longan, consequently the rate of commercially acceptable fruit packaged by ε-PL/PVA films was improved dramatically. However, the effect of ε-PL/PVA on weight loss rate for longan was worse than the control.