Effect of moisture-controlled packaging treatment with acid-modified expanded vermiculite-calcium chloride on the quality of fresh mushrooms (Agaricus bisporus) during low-temperature storage.

BACKGROUND: Fresh mushrooms (Agaricus bisporus) are highly perishable and easily lose quality during storage. The packaging system can retard the deterioration of fresh mushrooms. However, water vapor transmission rates of commodity plastic films are lower than the transpiration rate of mushrooms, resulting in increased moisture condensation in the package and perishability of mushrooms due to microbial growth. A possible solution for controlling the humidity level in the package is to use a hygroscopic material. Acid leaching can improve the chemical and physical properties of expanded vermiculite (EV). The aim of this study was to develop a novel hygroscopic agent from acidified expanded vermiculite (AEV) and calcium chloride (CaCl2 ) that has a high moisture absorption capacity and maintains a powdered form in the packaging system for fresh mushrooms. RESULTS: Our findings revealed that leaching EV with hydrochloric acid increased porosity and hydrophilicity. The combination of AEV:CaCl2 at 6:4 (w/w, AEV/CS40) showed the highest moisture adsorption capacity at 1.724 ± 0.03 g water per gram of material. Then, 1.55 g of AEV/CS40 was applied to the mushroom packaging and stored at 4 °C. The results indicated that AEV/CS40 could delay mushroom deterioration in terms of color change, firmness, pH, total soluble solids, and microbial growth. CONCLUSION: The study findings indicate that the alternative solid hygroscopic material obtained by combining AEV with CaCl2 has potential for use as a hygroscopic material for preserving the quality of white button mushrooms. © 2021 Society of Chemical Industry.

Antimicrobial and antioxidant properties of polyvinyl alcohol bio composite films containing seaweed extracted cellulose nano-crystal and basil leaves extract.

Polyvinyl alcohol (PVA) films containing seaweed extracted cellulose nanocrystal (CNC) (5% w/v) and 5, 10, and 20% (w/v) basil leaves extract (BE) were prepared using the solvent casting method, and their physical properties, and antimicrobial and antioxidant activity were analyzed. The addition of 5% (w/v) CNC to PVA improved the tensile strength and water vapor permeability. Addition of BE to film the antioxidant activity and antimicrobial properties of the films were enhanced. Further, increasing the amount of BE slightly affected the color of the bio-nanocomposites. The thermal stability of films was improved with addition of CNC. Due to functional groups and linkage properties of the CNC surface and macromolecular chains of the PVA were responsible for improvement of the interfacial interactions between the CNC and PVA. The dispersion of CNC in PVA were affected with increase in the amount of BE in PVA. This study showed the benefits of the incorporation of CNC and BE into PVA films and the potential for their use as active packaging material for food.

Plum coatings of lemongrass oil-incorporating carnauba wax-based nanoemulsion.

Nanoemulsions containing lemongrass oil (LO) were developed for coating plums and the effects of the nanoemulsion coatings on the microbial safety and physicochemical storage qualities of plums during storage at 4 and 25 °C were investigated. The emulsions used for coating were produced by mixing a carnauba wax-based solution (18%, w/w) with LO at various concentrations (0.5% to 4.0%, w/w) using dynamic high pressure processing at 172 MPa. The coatings were evaluated for their ability to inhibit the growth of Salmonella Typhimurium and Escherichia coli O157:H7 and their ability to preserve various physicochemical qualities of plums. Uniform and continuous coatings on plums, formed with stable emulsions, initially inhibited S. Typhimurium and E. coli O157:H7 by 0.2 to 2.8 and 0.8 to 2.7 log CFU/g, respectively, depending on the concentration of LO and the sequence of coating. The coatings did not significantly alter the flavor, fracturability, or glossiness of the plums. The antimicrobial effects of the coatings against S. Typhimurium and E. coli O157:H7 were demonstrated during storage at 4 and 25 °C. The coatings reduced weight loss and ethylene production by approximately 2 to 3 and 1.4 to 4.0 fold, respectively, and also retarded the changes in lightness and the concentration of phenolic compounds in plums during storage. The firmness of coated plums was generally higher than uncoated plums when stored at 4 °C and plum respiration rates were reduced during storage. Coatings containing nanoemulsions of LO have the potential to inhibit Salmonella and E. coli O157:H7 contamination of plums and may extend plum shelf life.