RESUMO
The aim of extending shelf-life and maintaining quality is one of the major issues regarding mango fruit preservation. The quality of mango fruits is greatly affected by postharvest factors, especially temperature and fruit treatment. In this study, the effect of coating and storage temperature on the characteristics of mango fruits was investigated. The mango fruits were immersed in different concentrations (1.5%, 2.0%, and 2.5%) of pectin/nanochitosan dispersion (with ratios of pectin:nanochitosan 50:50), and (0.75%, 1% and 1.25%) of nanochitosan dispersion and stored at 17, 25, and 32 °C for 24 days. Changes in fruit, including weight loss, firmness, color, chemical composition (such as the total soluble solids concentration (TSS)), total sugar, reducing sugar, titratable acidity (TA), and vitamin C were periodically recorded. The results indicated that the pectin/nanochitosan coating significantly prevented reductions in the fruit weight, firmness, TSS, TA, and vitamin C content. Additionally, pectin/nanochitosan at a low temperature (17 °C) had a greater positive effect on fruit shelf-life and weight maintenance than 25 and 32 °C. The coated mango fruits maintained good quality for 24 days at 17 °C, while coated fruits stored at 25 °C and 32 °C, as well as uncoated ones stored at 17 °C, were destroyed after two weeks. At the maximum storage time evaluated, the coating formulations containing pectin and nanochitosan exhibited microbial counts below the storage life limit of 106 CFU/g of fruit. In general, the results showed that the pectin/nanochitosan coating (2%) with a storage temperature of 17 °C is the most effective strategy for improving quality and extending the shelf-life of mango fruits.
RESUMO
This study was aimed at creating new films and determine some functional packaging properties of pectin:nanochitosan films with ratios of pectin:nanochitosan (P:NSC) of 100:0; 75:25; 50:50; 25:75 and 0:100 (%w/w). The effects of the proportions of pectin:nanochitosan incorporation on the thickness, mechanical properties, water vapor permeability, water-solubility, and oxygen permeability were investigated. The microstructural studies were done using scanning electron microscopy (SEM). The interactions between pectin and nanochitosan were elucidated by Attenuated total reflectance-Fourier transform infrared (ATR-FTIR). The results showed that the blending of pectin with nanochitosan at proportions of 50:50 increased the tensile strength to 8.96 MPa, reduced the water solubility to 37.5%, water vapor permeability to 0.2052 g·mm/m2·day·kPa, and the oxygen permeability to 47.67 cc·mm/m2·day. The results of the contact angle test indicated that P:NCS films were hydrophobic, especially, pectin:nanochitosan films inhibited the growth of Colletotrichum gloeosporioides, Saccharomyces cerevisiae, Aspergillus niger, and Escherichia coli. So, P:NCS films with a proportion of 50:50 can be used as active films to extend the shelf life of food.
