Encapsulation of Mulberry leaf extract in chitosan nanoparticle to develop eco-friendly edible coating for fresh strawberry reservation

Abstract

In this research, Morus alba Mulberry leaf extract was encapsulated in chitosan nanoparticles by ionic gelation method to develop coating for fresh strawberries. We aimed to study encapsulation of mulberry leaf extract in chitosan nanoparticle for coating on the fresh strawberry. The obtained nanoparticles exhibited a regular distribution and spherical shape with the average size range of 87.23 to 139.5 nm as observed by using a laser light scattering equipment and SEM technique. The results of FTIR studies were clearly indicated that the nanochitosan gets effectively bonds with the molecules of secondary metabolites in Morus alba Mulberry leaf extract. The FTIR spectra showed the present of peak at 1163.38 cm-1 which represented the interaction between NH3+ of chitosan and PO43- of tripolyphosphate crosslinker and the peaks at 3402, 1078, 1023 and 699 cm-1 which indicated the presence of C-N, C-OH, -C-O-C- and N-H bonds of protein molecules of secondary metabolites in Morus alba Mulberry leaf extract. The XRD pattern showed the change in crystallinity of chitosan to the amorphous polymer region of chitosan nanoparticles. The effect of mulberry leaf extract loaded chitosan nanoparticle coating on the shelf life of strawberry showed slower deterioration compared to uncoated strawberry at 12 days while the uncoated strawberry started to decay at day 4. According to the result, the 40 mg/mL mulberry leaf extract loaded chitosan nanoparticle inhibited the growth of Bacillus subtillis with the mean inhibition zone diameter of 7.87±0.20 mm. The hGF cell line viability after treating with 1–10,000 g/mL sample concentration ranged from 98.26±10.25% to 88.37±7.54%cell viability. Therefore, it showed that the effectiveness against B. subtillis was significantly higher due to encapsulation process which could serve as a promising strategy to replace other coated materials for higher post-harvest quality.