Cellulose nanofibre reinforced methylcellulose/nano zinc oxide edible coatings improved the shelf life of pomegranate aril sacs

This study aimed to examine the effect of methylcellulose-zinc oxide nanoparticle (MC-ZnONP) composite coatings reinforced with cellulose nanofibre (CNF) to improve the shelf life of pomegranate aril sacs extracted from whole fruit subjected to prolonged storage before processing. Pomegranate fruit were stored at 5°C for 2 months before processing into pomegranate aril sacs. The minimally processed aril sacs were sanitized and coated for 3 min by dipping in MC-ZnONP composite reinforced with CNF at 0, 0.5, 1, 3 and 5% and distilled water was used as control. Aril sacs were packed in punnets and stored at 4°C for 15 d. Quality assessments, including weight loss, respiration, firmness, and antioxidant capacity, were investigated at 3-day intervals. MC-ZnONP reinforced with CNF (0.5%) significantly (p<0.05) reduced the weight loss, respiration rate and loss of firmness while effectively preserving the antioxidant content, and thus increased the shelf life of the aril sacs to 15 d, compared to the control which was limited to 9 d shelf life due to increased microbial growth. The treatment MC-ZnONP+CNF (5%) displayed 7.84% weight loss and 0.72 mL CO2 kg^-1 h^-1 respiration rate and maintained firmness (10.56 N), antioxidant capacity (FRAP, 34 mM TE mL^-1) compared to control, which experienced a higher weight loss (9.48%) and respiration rate (1.86 mL CO2 kg^-1 h^-1) and decreased aril firmness (7.68 N). However, there were no significant differences in the antioxidant capacity (FRAP) between treated and control until 9 d. MC-ZnONP+CNF (5%) showed a promise in extending shelf life and maintaining quality attributes of aril sacs obtained from pomegranate fruit subjected to prolonged storage duration.