Effect of Ascorbic Acid, CaCl2, and Hydrogen Peroxide on Mushrooms (Agaricus bisporus) Shelf Life

Mushrooms are characterized by a very short shelf life and browning, weight-loss and microbial infections are known as the most deteriorating postharvest modifications in the mushrooms, leading to notable economic losses. In this study, the effects of some postharvest treatments including calcium chloride (0.30 and 0.45%), ascorbic acid (1, 2 and 3 mM) and hydrogen peroxide (1%) on increasing mushroom shelf life were evaluated. Mushrooms were dipped in the solution treatments for 2 min, then dried at room temperature and packed in polyethylene container by cellophane cover and were stored at 4°C. Some qualitative and quantitative parameters were measured on 8th and 16th days of storage. Results showed that, 0.45% CaCl2, as well as 2 and 3 mM ascorbic acid and 1% peroxide hydrogen effectively maintained mushrooms marketability and kept the cap closed. CaCl2 treatment was effective in extending the postharvest life of mushrooms due to reducing weight loss, maintaining firmness, reducing electrolyte leakage and lowering bacterial populations. Ascorbic acid was an effective treatment in reducing the weight loss, electrolyte leakage, bacterial populations and, thereby, maintaining the firmness. Hydrogen peroxide treatment improved the postharvest quality of mushrooms only through reducing bacterial populations

A DXDR large deflection analysis of uniformly loaded square, circular and elliptical orthotropic plates using non-uniform rectangular finite-differences

A finite-difference analysis of the large deflection response of uniformly loaded square, circular and elliptical clamped and simply-supported orthotropic plates is presented. Several types of non-uniform (graded) mesh are investigated and a mesh suited to the curved boundary of the orthotropic circular and elliptical plate is identified. The DXDR method-a variant of the DR (dynamic relaxation) method-is used to solve the finite-difference forms of the governing orthotropic plate equations. The DXDR method and irregular rectilinear mesh are combined along with the Cartesian coordinates to treat all types of boundaries and to analyze the large deformation of non-isotropic circular/elliptical plates. The results obtained from plate analyses demonstrate the potential of the non-uniform meshes employed and it is shown that they are in good agreement with other results for square, circular and elliptical isotropic and orthotropic clamped and simply-supported plates in both fixed and movable cases subjected to transverse pressure loading