Chitosan and Cystatin/Lysozyme Preparation as Protective Edible Films Components

This work characterizes biological, physical, and chemical properties of films formed from an aqueous solution of hydroxypropyl methylcellulose (HPMC), with different concentrations of chitosan (CH) and bioactive cystatin/lysozyme preparation (C/L). The properties of biocomposites were examined by Dynamic Mechanical Analysis (DMA), Fourier’s transfer infrared spectroscopy (FTIR), water vapour permeability (WVP), and tensile testing. Antimicrobial activity against Micrococcus flavus, Bacillus cereus, Escherichia coli, Pseudomonas fluorescens, and Candida famata was conducted. Films glass transition and storage modulus were dependent on the C/L and CH concentration. Modulus values decreased during the temperature scan and with higher reagents levels. An increase of CH and C/L concentrations in the films resulted in a decrease in tensile strength from 2.62 to 1.08 MPa. It suggests the hydrolyzing influence of C/L, also observed in smaller peak size of α relaxation. C/L addition caused shifting Tg to higher temperature. DMA and FTIR analysis proved that HPMC and CH are compatible polymers. Water resistance was improved with rising CH concentration from 1.08????−09to7.71????−10g/m∗s∗ PA . The highest inhibition zone in M. flavus and C. famata was recorded at the highest concentration of CH and C/L

Polysaccharide-Based Edible Coatings Containing Cellulase for Improved Preservation of Meat Quality during Storage

The objectives of this study were to optimize the composition of edible food coatings and to extend the shelf-life of pork meat. Initially, nine meat samples were coated with solutions containing chitosan and hydroxypropyl methylcellulose at various cellulase concentrations: 0%, 0.05%, and 0.1%, stored for 0, 7, and 14 days. Uncoated meat served as the controls. The samples were tested for pH, water activity (aw), total number of microorganisms (TNM), psychrotrophs (P), number of yeast and molds (NYM), colour, and thiobarbituric acid-reactive substances (TBARS). The pH and aw values varied from 5.42 to 5.54 and 0.919 to 0.926, respectively. The reductions in the TNM, P, and NYM after 14 days of storage were approximately 2.71 log cycles, 1.46 log cycles, and 0.78 log cycles, respectively. The enzyme addition improved the stability of the red colour. Significant reduction in TBARS was noted with the inclusion of cellulase in the coating material. Overall, this study provides a promising alternative method for the preservation of pork meat in industry

Antimicrobial and Antioxidant Activity of Chitosan/Hydroxypropyl Methylcellulose Film-Forming Hydrosols Hydrolyzed by Cellulase

The aim of this study was to evaluate the impact of cellulase (C) on the biological activity of chitosan/hydroxypropyl methylcellulose (CH/HPMC) film-forming hydrosols. The hydrolytic activity of cellulase in two concentrations (0.05% and 0.1%) was verified by determination of the progress of polysaccharide hydrolysis, based on viscosity measurement and reducing sugar-ends assay. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging effect, the ferric reducing antioxidant power (FRAP), and microbial reduction of Pseudomonas fluorescens, Yersinia enterocolitica, Bacillus cereus, and Staphylococcus aureus were studied. During the first 3 h of reaction, relative reducing sugar concentration increased progressively, and viscosity decreased rapidly. With increasing amount of enzyme from 0.05% to 0.1%, the reducing sugar concentration increased, and the viscosity decreased significantly. The scavenging effect of film-forming solutions was improved from 7.6% at time 0 and without enzyme to 52.1% for 0.1% cellulase after 20 h of reaction. A significant effect of cellulase addition and reaction time on antioxidant power of the tested film-forming solutions was also reported. Film-forming hydrosols with cellulase exhibited a bacteriostatic effect on all tested bacteria, causing a total reduction

Physicochemical Properties of Biopolymer Hydrogels Treated by Direct Electric Current

The objective of this study was to evaluate the changes within the physicochemical properties of gelatine (2%; 4%; 8%), carrageenan (1.5%; 2%; 2.5%) and sodium alginate (0.75%; 1%; 1.25%) hydrogels with different sodium chloride concentrations that were triggered by applying direct current (DC) of 400 mA for a duration of five minutes. There were three types of gels prepared for the purpose of the study: C, control; H, gels on the basis of hydrosols that were treated with DC; and G, gels treated with DC. In the course of the study, the authors carried out the following analyses: Texture Profile Analysis (TPA), Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Swelling Ratio (SR). Furthermore, the color and pH of hydrogels were measured. The FTIR spectra showed that the structures of gelatine, carrageenan and sodium alginate do not significantly change upon applying DC. The results of TPA, SR, color and pH measurement indicate that hydrogels’ properties are significantly dependent on the type of polymer, its concentration and the type of the gel. By changing those parameters, the characteristics of such gels can be additionally tuned, which extends their applicability, e.g., in the food industry. Moreover, the analysis revealed that SR of H gel gelatine after 72 h of storage was 1.84-times higher than SR of the control sample, which indicated that this gel may be considered as a possible component for wound dressing materials

Characteristic of Gelatine, Carrageenan and Sodium Alginate Hydrosols Treated by Direct Electric Current

The aim of the study was to investigate the effect of using direct electric current (DC) of 400 mA for five minutes on the physiochemical properties of gelatine (2%, 4%, and 8%), carrageenan (1.5%, 2%, and 2.5%) and sodium alginate (0.75%, 1%, and 1.25%) hydrosols with different sodium chloride concentration. The pH, oxidation-reduction potential (ORP), electrical conductivity (EC), available chlorine concentration (ACC) and rheological parameters were measured. Moreover, Fourier transform infrared spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) analysis were carried out. The results have shown that pH, ORP, EC and ACC values are changed upon applying DC and the magnitude of change depends on the concentration of the polymer and the addition of sodium chloride. After seven days of storage, the ACC of the samples exposed to DC decreased by 88%–96%. The FT-IR spectra demonstrated that the structure of gelatine, carrageenan and sodium alginate are not significantly affected by DC. Furthermore, the use of DC did not affect the flow and gelation temperature of the hydrosols. These results suggest that the use of DC did not cause undesirable changes in hydrosols layer and these innovative materials can be used, e.g., for food preservation

Study on Alginate–Chitosan Complex Formed with Different Polymers Ratio

Biomaterials based on polyelectrolyte complexation are an innovative concept of coatings and packaging production to be applied in a wide range of food products. The aim of this study was to obtain and characterize a sodium alginate–chitosan complex material with variable degree of polyion interactions by complexation of oppositely charged polysaccharides. In order to characterize polyelectrolyte complexes, theromogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), matrix-assisted laser desorption/ionization technique with time of flight analyzer (MALDI-TOF), and scanning electron microscopy (SEM) were performed. TGA analysis showed that thermal decomposition temperature depends on the polymer ratio (R) and thermal resistance of samples was improved by increasing chitosan dosage. Accordingly to DMTA results, polyelectrolyte complexation led to obtain more flexible and resistant to mechanical deformation materials. Comparative analysis of the FTIR spectra of single polyelectrolytes, chitosan and alginate, and their mixtures indicated the formation of the polyelectrolyte complex without addition of reinforcing substances. MALDI-TOF analysis confirms the creation of polyelectrolyte aggregates (~197 Da) in samples with R ≥ 0.8; and their chemical stability and safety were proven by NMR analysis. The higher R the greater the number of polyanion–polycation aggregates seen in SEM as film morphology roughness

Effect of Film-Forming Alginate/Chitosan Polyelectrolyte Complex on the Storage Quality of Pork

Meat is one of the most challenging food products in the context of maintaining quality and safety. The aim of this work was to improve the quality of raw/cooked meat by coating it with sodium alginate (A), chitosan (C), and sodium alginate-chitosan polyelectrolyte complex (PEC) hydrosols. Antioxidant properties of A, C, and PEC hydrosols were determined. Subsequently, total antioxidant capacity (TAC), sensory quality of raw/cooked pork coated with experimental hydrosols, and antimicrobial efficiency of those hydrosols on the surface microbiota were analysed. Application analyses of hydrosol were performed during 0, 7, and 14 days of refrigerated storage in MAP (modified atmosphere packaging). Ferric reducing antioxidant power (FRAP) and (2,2-diphenyll-picrylhydrazyl (DPPH) analysis confirmed the antioxidant properties of A, C, and PEC. Sample C (1.0%) was characterized by the highest DPPH value (174.67 μM Trolox/mL) of all variants. PEC samples consisted of A 0.3%/C 1.0% and A 0.6%/C 1.0% were characterized by the greatest FRAP value (~7.21 μM Fe2+/mL) of all variants. TAC losses caused by thermal treatment of meat were reduced by 45% by coating meat with experimental hydrosols. Application of PEC on the meat surface resulted in reducing the total number of micro-organisms, psychrotrophs, and lactic acid bacteria by about 61%, and yeast and molds by about 45% compared to control after a two-week storage