Optimization of konjac glucomannan/carrageenan/nano-SiO2 coatings for extending the shelf-life of Agaricus bisporus.

ABSTRACT

Nano-SiO2 was inserted into konjac glucomannan (KGM)/carrageenan (KC) coatings to improve the properties of the coating. The optimization of the concentrations of the nano-SiO2, KGM, and KC of the coatings was investigated using a response surface method. The coatings were characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and ultraviolet-visible (UV-vis) spectroscopy. The effect of the nano-SiO2/KGM/KC coatings on the postharvest quality of the white mushrooms stored at 4 ±â€¯1 °C was determined. The results showed that the nano-SiO2/KGM/KC coatings exhibited the optimal properties at a nano-SiO2 concentration of 0.3%, a KC concentration of 0.6%, and a KGM concentration of 0.48%. The water vapor transmission rate, transparency, tensile strength, oxygen transmission rate, and carbon dioxide transmission rate were 62.31 g/(m2·d), 83.41%, 323.16 N, 0.015 g/(m2·d), 0.18 g/(m2·d) respectively. The nano-SiO2 decreased the gas permeability of the coatings. It demonstrated that the incorporation of the nano-SiO2 delayed the effect of the UV light on the food quality because it increased the absorbance of the UV light (300 nm) by the KGM/KC three fold. The application of the nano-SiO2/KGM/KC coatings represents a feasible and effective technique for extending the storage time of white mushrooms.