Synergistic Effects of Hydroxypropyl Methylcellulose–Silver Nanoparticle Coating and Modified Atmosphere Packaging on the Postharvest Quality of Fresh White Mulberries ( Morus alba L .)

ABSTRACT

This study investigated the effects of edible coatings based on hydroxypropyl methylcellulose (HPMC) incorporated with silver nanoparticles (AgNPs), combined with different modified atmosphere packaging (MAP) systems, on the quality of fresh white mulberries ( Morus alba L.). The fruits were stored for 21 days at 4°C and 10°C. Fresh mulberries had high moisture content (92.40% ± 1.21%), total soluble solids (12.90 ± 0.45 °Brix), pH (5.45 ± 0.17), and firmness (3.07 ± 0.92 N). The results showed that active MAP combined with HPMC–AgNP coating effectively reduced respiration rate and helped maintain gas balance by increasing O ₂ retention and reducing CO ₂ accumulation. Coated fruits showed 3–5 times lower weight loss compared to controls. The increase in pH was reduced by about 60%, while the rise in total soluble solids was slowed by approximately 1.6 times. Firmness was better preserved, reaching up to 4.0 N after 21 days in MAP‐B treatment. Color stability was also improved, with reduced changes in L* , a* , and b* values. The browning index remained below the perceptible threshold (≤ 0.32), and coated samples showed about 25% less browning than controls. Microbial counts were significantly reduced in coated fruits (0.91–1.31 Log CFU g ^{− 1} ), confirming the antimicrobial activity of AgNPs. Sensory evaluation indicated that fruits treated with HPMC–AgNP coating and stored under active MAP at 4°C achieved the highest overall acceptability (4.50/5.00), closely resembling fresh fruit quality. Overall, the combination of HPMC–AgNP edible coating and MAP effectively extended the shelf life of white mulberries while maintaining physicochemical, microbial, and sensory quality.