Novel Biodegradable Starch Film for Food Packaging with Antimicrobial Chicory Root Extract and Phytic Acid as a Cross-Linking Agent

Abstract

The aim of the study was to obtain and evaluate the properties of biodegradable starch film with the addition of phytic acid (0.05%) as a cross-linking agent and chicory root extract (1–5%) as an antimicrobial agent. To prepare biodegradable film, extracts from chicory root obtained with water or methanol were used. The content of bioactive compounds (sesquiterpene lactones and total polyphenols) was evaluated in chicory extracts. The antibacterial activity of the extracts was tested against Gram-negative bacteria (Pseudomonas fluorescens, Escherichia coli) and Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus) using the microculture method. The extracts acted as bacteriostatic agents, decreasing the growth rate (µmax), and extending the lag phase (tlag). The most sensitive bacterium in terms of film bacteriostatic activity was P. fluorescens; all extracts, irrespective of the solvent used, decreased its µmax value. S. aureus was the least sensitive. The obtained films were tested for their properties as food packaging (color, thickness, permeability, mechanical strength). Phytic acid improved the tensile strength and barrier properties of the films. The antimicrobial activity of the films was studied by the disk diffusion method against Gram-negative (P. fluorescens, E. coli) and Gram-positive (B. subtilis, S. aureus) bacteria, as well as fungi (Candida albicans, Aspergillus niger). The growth-inhibiting activity of each obtained film was observed for all tested microorganisms, and the most beneficial effect was observed for films with the 5% level of added extracts obtained with water. The growth-inhibiting activity for fungi, in particular for the yeast C. albicans, was low.

Applications of Natural Antimicrobials in Food Packaging and Preservation

“…The GC-FID analysis of basil EO reported that the component most present by far was linalool (41.3%) followed by 1,8-cineole (9.6%), (Z)-isoeugenol (5.9%), 1-epi-cubenol (4.8%), α-transbergamotene (4.6%), and (Z)-anethol (3.2%). Jaśkiewicz et al [ 5 ] obtained and evaluated the properties of biodegradable starch film with the addition of phytic acid (0.05%) as a cross-linking agent and chicory root extract (1–5%) as an antimicrobial agent. Chicory was extracted by different methods obtaining water, water/methanol, and water/enzyme extracts that were analyzed (UHPLC-ESI-MS) to determine the main groups of compounds showing antimicrobial properties.…”

“…Somrani et al [ 1 ] applied them to fight biofilms formed in the food processing industries. Djenane et al [ 2 ], Amor et al [ 4 ] and Martelli et al [ 6 ] added the antimicrobials directly to the foods, while Motelica et al [ 3 ], Jaśkiewicz et al [ 5 ] and Lee et al [ 7 ] included them in the packaging material.…”

“…Agar diffusion was also used by Martelli et al [ 6 ] to test the in vitro efficacy of the antimicrobials extracted from their algae species against several foodborne pathogens ( Salmonella spp., L. monocytogenes, Escherichia coli, Staphylococcus aureus and Bacillus cereus ). On their side, Jaśkiewicz et al [ 5 ] used the microculture method, to check the antibacterial effect of chicory root extracts against Pseudomonas fluorescens, E. coli, S. aureus and Bacillus subtilis.…”

“…Lee et al [ 7 ] checked the antibacterial properties of their bioelastomer fabricated from aronia juice processing by-products against S. aureus and E. coli , by just placing pieces of the bioelastomer onto the agar plates. Jaśkiewicz et al [ 5 ] also used this method to test the biodegradable starch films they developed incorporating chicory root extracts as antimicrobial against P. fluorescens, E. coli, S. aureus, B. subtilis and two fungi, Candida albicans and Aspergillus niger. Motelica et al [ 3 ] checked the antimicrobial activity of their biodegradable chitosan films with ZnO and Ag nanoparticles loaded with citronella essential oil against C. albicans, S. aureus and E. coli by means of placing film strips onto the agar plates and measuring inhibition zones after incubation.…”

“…Lee et al [ 7 ] found no changes in the surface and chemical properties of their bioelastomer when aronia juice processing by-products were included, although tensile strength was not appropriate when the mixture contained 50% aronia powder. An increase in the thickness, tensile strength and opacity [ 4 , 5 ] and a decrease in water vapor permeability [ 3 , 5 ] has been observed when adding antimicrobials into the packaging films.…”