Investigating the Effect of Natural Coating of Chitosan Nanoparticles and Nanohydroxyapatite on the Physiological Characteristics and Shelf Life of Button Mushroom (Agaricus bisporus)

IntroductionExcessive human exposure to chemicals in agricultural practices contribute to the production of unhealthy and environmentally destructive products. For this reason, natural coatings are used to prevent adverse changes in the quality of various products. Natural coatings can be a barrier on the outer surface of food to prevent the loss of aromatic compounds, and moisture content and provide the possibility of selective natural exchange of some gases and increase shelf life post harvest. Considering the economic importance of button mushrooms and the need to provide optimal solutions to increase shelf life post harvest, the present study was conducted to investigate the effect of natural coatings based on chitosan nanoparticles and nanohydroxyapatite on increasing the shelf life of button mushrooms.Materials and MethodsFor this purpose, the effect of these coatings was evaluated in a factorial experiment in the form of a completely randomized design with three repetitions to prevent adverse changes in button mushroom quality. Button mushrooms were covered with different concentrations of chitosan nanoparticles (zero, 1% and 2%) and nanohydroxyapatite (0, 40, 80 mg) for 28 days. The mushrooms that were prepared for coating were divided into 9 groups. One sample without coating and 8 samples were coated with different percentages of chitosan nanoparticles and nanohydroxyapatite and coded. All mushroom sampless were immersed in each of the coating solutions for five minutes. The mushrooms were then taken out of the solutions and placed on the mesh basket (at room temperature) for 15 to 30 minutes so that the additional amount of coating material drips. Then the mushrooms were weighed individually and six numbers were transferred in three replicates in single-use plastic containers with perforated lids. Then they were transferred to the refrigerator. The control sample was immersed in distilled water for 5 minutes instead. The data was measured on days 0, 7, 14, 21 and 28. After coating, the characteristics of total phenol, flavonoid, antioxidant capacity, total protein, ascorbic acid content, and electrolyte leakage of mushrooms were recorded and analyzed during 28 days of storage.Results and DiscussionBased on the results, the highest amount of total phenol, flavonoid, antioxidant capacity, ascorbic acid content, total protein, and the lowest amount of electrolyte leakage were obtained in 1% nano chitosan coating containing 40 mg of nanohydroxyapatite during 28 days of storage. In the control treatment (without coating), the lowest amount of total phenol, flavonoid, antioxidant capacity, ascorbic acid content, total protein, and the highest amount of electrolyte leakage were obtained during 28 days of storage.ConclusionDue to the high perishability of button mushroom, its maintenance is very important. Coating is considered as one of the methods of keeping quality of button mushrooms. The purpose of this study was to evaluate the effect of natural coating based on chitosan nanoparticles and nanohydroxyapatite on the total phenolic, flavonoid, antioxidant capacity, ascorbic acid content, electrolyte leakage, and total protein of mushrooms on zero, 7, 14, 21, and 28 day, in order to maintain quality and increase the shelf life of button mushroom. For this purpose, the coating of chitosan nanoparticles (zero, 1%, 2%), nanohydroxyapatite (zero, 40, 80 mg), and the combination of chitosan nanoparticles with nanohydroxyapatite in the mentioned concentrations were used. Finally, according to the findings of this study, it can be stated that coating with 1% nano chitosan containing 40 mg of nanohydroxyapatite can increase the shelf life of button mushroom up to 14 days post harvest, with increased marketability.