Fabrication and characterization of jujube extract-loaded electrospun polyvinyl alcohol nanofiber for strawberry preservation.

Recently, using of natural ingredients gains much attention in the field of food science and active packaging. In this study, first, jujube extract was investigated for its antimicrobial and antioxidant properties, and then, the effect of electrospun PVA/JE (jujube extract loaded into Poly vinyl alcohol) nanofiber as active packaging was evaluated to increase the shelf-life of strawberry. PVA/ZE nanofiber film was prepared using electrospinning method, and their morphology was confirmed by scanning electron microscopy (SEM). Fruit preservation abilities of the nanofiber film were tested on strawberries. The strawberries were then kept at 4℃ for 15 days and characterized in terms of their properties (weight loss, TSS, firmness, and sensory analysis). Results indicated that flavonoid content of jujube extract ranged from 4.80 ± 0.01 to 13.54 ± 0.08 mg CEQ/100 g, and the DPPH free radical-scavenging activity was from 210 ± 2.66 to 1498 ± 2.65 (GAE/g DW). The jujube extract also presented potent antibacterial activity against the investigated bacteria and fungi. The scanning electron microscopy (SEM) images of nanofibers had a linear morphology and bead-free structure; however, PVA/JE (jujube extract encapsulated into PVA nanofiber) had strip and flat organization. Strawberries in control group showed signs of decay and a decrease in visual appearance on the 6th. However, fruits in PVA/JE group had acceptable overall appearance for marketing, as no obvious sign of decay was observed on 12th day of storage. Active packaging containing herbal extracts and essential oils preserves the organoleptic and physicochemical properties of the fruits.