methylcellulose and 1-1-diphenyl-2-picrylhydrazyl

A novel pH-sensitive colorimetric film was prepared based on immobilizing red barberry anthocyanins (RBAs) within composite chitin nanofiber (CNF) and methylcellulose (MC) matrices. The incorporation of CNFs and RBAs improved their mechanical properties, moisture resistance, and UV-vis screening properties. Moreover, the RBAs could be used as colorimetric indicators to detect food spoilage because they are sensitive to changes in pH and ammonia gas production. The RBA-halochromic indicator changed from reddish/crimson → pink → yellow with increasing pH, and from pink → yellow with increasing ammonia vapor concentration. Furthermore, the smart films possessed good antioxidant and antimicrobial activity owing to the presence of the RBAs and CNFs. Finally, the validity of the indicator to monitor the freshness/spoilage of a model food (fish) was demonstrated. Overall, this study shows that active/smart films can be assembled from food grade ingredients that can protect and monitor the freshness of products, like meat and fish.

Topics: Ammonia; Anthocyanins; Anti-Infective Agents; Antioxidants; Berberis; Biodegradation, Environmental; Biphenyl Compounds; Chitin; Color; Escherichia coli; Fish Products; Food Packaging; Fruit; Humans; Hydrogen-Ion Concentration; Membranes, Artificial; Methylcellulose; Nanofibers; Picrates; Plant Extracts; Smart Materials; Staphylococcus aureus; Tensile Strength

The current work aims to prepare biologically active and pH responsive smart films based on Chitosan (CS)/Methylcellulose (MC) matrix integrated with Phyllanthus reticulatus (PR) ripen fruit anthocyanin. The prepared smart films (CMPR) were fabricated through a cost-effective solvent casting technique. The existences of secondary interactions were confirmed by the FT-IR analysis. The smooth SEM images revealed the miscibility and compatibility of the CS/MC matrix with PR anthocyanin. The incorporation of PR anthocyanin significantly blocked the UV light transmission of the CS/MC films while slight decrease in the transparency was observed. The water solubility, moisture retention capacity, and water vapor transmission rate were significantly enhanced with an increase in the PR anthocyanin content. Additionally, the prepared CMPR smart films showed pink color in acidic pH while yellowish in basic pH solution and further exhibited strong antioxidant activity as well as antibacterial activity against the common foodborne pathogens such as S. aureus, P. aeruginosa, and E. coli. The CMPR smart film also displayed potential result for monitoring the fish fillet freshness at room temperature. The results proclaim that the prepared CMPR smart films could be utilized for quality assurance as well as shelf life extension of the marine food products.

Topics: Animals; Anthocyanins; Anti-Bacterial Agents; Antioxidants; Bacteria; Biphenyl Compounds; Chitosan; Color; Fishes; Food Microbiology; Food Packaging; Food Quality; Hydrogen-Ion Concentration; Methylcellulose; Phyllanthus; Picrates; Seafood; Stimuli Responsive Polymers

The aim a present study was developed methylcellulose (MC) active edible films with extracts of green apple skin, as model systems of edible coating. Active edible films were developed by incorporation of ethanolic extract of freeze-dried apple skin (EEFD) and aqueous extract of apple skin (AES) at 10, 20 and 25% (v/v) concentrations. Analysis of thermal, mechanical and functional properties was carried out. Results showed that incorporation of green apple skin extracts into MC films contribute to total phenolic content and antioxidant properties. Addition of green apple skin extracts generated shifts toward lower glass transition temperature values regarding MC films without extracts. A lower tensile strength and increased elongation at break in MC-AES films were observed. Mechanical properties of MC-EEFD films were less affected by the increase in extract concentration due to absence of the plasticizing effect of sugars present in AES. The methylcellulose films are important for actives edibles coatings with applications in the food industry.

Topics: Antioxidants; Ascorbic Acid; Biphenyl Compounds; Coated Materials, Biocompatible; Ethanol; Food Packaging; Freeze Drying; Fruit; Humans; Malus; Methylcellulose; Phase Transition; Picrates; Plant Extracts; Polyphenols; Solvents; Tensile Strength