Development of Ginkgo (Ginkgo biloba) Nut Starch Films Containing Cinnamon (Cinnamomum zeylanicum) Leaf Essential Oil.

There have been many studies on the development biodegradable films using starch isolated from various food sources as a substitute for synthetic plastic packaging films. In this study, starch was extracted from ginkgo (Ginkgo biloba) nuts, which were mainly discarded and considered an environment hazard. The prepared starch (GBS) was then used for the preparation of antioxidant films by incorporating various amounts of cinnamon (Cinnamomum zeylanicum) essential oil (CZEO), which provides antioxidant activity. The prepared GBS films with CZEO were characterized by measuring physical, optical, and thermal properties, along with antioxidant activity (ABTS, DPPH, and FRAP) measurements. With the increasing amount of CZEO, the flexibility and antioxidant activities of the GBS films increased proportionally, whereas the tensile strength of the films decreased. The added CZEO also increased the water vapor permeability of the GBS films, and the microstructure of the GBS films was homogeneous overall. Therefore, the obtained results indicate that the developed GBS films containing CZEO are applicable as antioxidant food packaging.

Effect of java citronella essential oil addition on the physicochemical properties of Gelidium corneum-chitosan composite films.

A new composite film was developed by combining Gelidium corneum (GC) with chitosan to enhance the physicochemical characteristics of GC film. In addition, to confer new functional property on the GC-chitosan composite film, various amounts (0.5%, 1.0%, and 1.5%) of java citronella essential oil (JCEO) were incorporated into the film. As the concentration of JCEO increased, the extensibility of the GC-chitosan film improved. In addition, the film became more opaque due to decreased light transmission. Especially, ultraviolet light was completely blocked in the composite films containing JCEO. Radical scavenging activities of the films also increased with increasing JCEO content, indicating that the films have antioxidant activity. Therefore, GC-chitosan composite film containing JCEO is applicable in food packaging to preserve food quality by retarding lipid oxidation.

Combined Treatment of High Hydrostatic Pressure and Cationic Surfactant Washing to Inactivate Listeria monocytogenes on Fresh-Cut Broccoli.

This study was conducted to examine the inactivation effect of the combined treatment of high hydrostatic pressure (HHP; 400 MPa for 1, 3, and 5 min) and cationic surfactant washing (0.05% benzethonium chloride, BEC) against Listeria monocytogenes inoculated on fresh-cut broccoli (FCB). Washing with BEC at concentrations exceeding 0.05% resulted in 2.3 logreduction of L. monocytogenes counts on FCB, whereas HHP treatment had approximately 5.5- 5.6 log-reductions regardless of the treatment time. Scanning electron microscopy corroborated microbial enumeration, revealing that the combined treatment was more effective in removing L. monocytogenes from FCB than individual treatment with HHP or BEC. Color and total glucosinolate content were maintained after the combined treatment, although the hardness of the FCB slightly decreased. The results clearly suggest that the combined treatment of HHP and BEC washing has potential value as a new sanitization method to improve the microbial safety of FCB.

Antibacterial activity of the noni fruit extract against Listeria monocytogenes and its applicability as a natural sanitizer for the washing of fresh-cut produce.

This study was conducted to investigate the antibacterial activity of the noni fruit extract (NFE) against Listeria monocytogenes (ATCC, 19111 and 19115) and assess its applicability for the washing of fresh-cut produce. Based on the results of the disc diffusion test, L. monocytogenes (ATCC, 19111 and 19115) was susceptible to the activity of NFE than other pathogens studied. Additionally, results of the time-kill assay indicated that NFE at a concentration of 0.5-0.7% effectively killed L. monocytogenes within 7 h. Furthermore, analysis of the intracellular components such as nucleic acids and proteins released from the bacterial cells and their SEM imaging revealed that NFE could increase the membrane permeability of cells resulting in their death. Compared to their unwashed samples, washing of romaine lettuce, spinach, and kale with 0.5% NFE gave a reduction of 1.47, 2.28, and 3.38 log CFU/g, respectively against L. monocytogenes (ATCC, 19111 and 19115), which is significantly different to that of NaOCl. A significant correlation was observed between the antibacterial effect induced due to NFE washing with the surface roughness of the fresh-cut produce than its surface hydrophobicity. Moreover, washing with NFE was not found to affect the color of the samples. These results indicated that NFE demonstrates good antibacterial activity against L. monocytogenes and can be used as a natural sanitizer to ensure the microbiological safety of fresh-cut produce.

Development of an antioxidative packaging film based on khorasan wheat starch containing moringa leaf extract.

The aim of this study was to develop and characterize the properties of khorasan wheat starch (KWS) films containing moringa leaf extract (MLE) as an antioxidative packaging material. KWS was isolated from khorasan wheat and used as a film base material. Different amounts (0, 0.4, 0.7, and 1.0%, w/v) of MLE were added to the KWS film-forming solution and the film properties were examined. Tensile strength of the KWS films decreased and elongation at break increased with increasing MLE content. In addition, the KWS films containing MLE possessed good antioxidative activities and ultraviolet light blocking ability. In particular, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging abilities of the KWS films with 1.0% MLE were 59.45% and 37.89%, respectively. Moreover, KWS films containing 1.0% MLE were biodegradable within 30 days. These findings indicate that the developed KWS films containing MLE can be applied as a biodegradable packaging material with antioxidative activity.

Surfactant type affects the washing effect of cinnamon leaf essential oil emulsion on kale leaves.

With increasing foodborne illness associated with fresh-cut produce, a chemical sanitizer to substitute chlorine is needed in the food industry. This study examined the washing effect of cinnamon leaf essential oil (CL-EO) emulsions on fresh-cut produce according to the ionic properties of surfactants. Washing effect of CL-EO emulsion (CLC) with cetylpyridinium chloride was the highest among all treatments on kale leaves. After CLC treatment, 1.83 and 1.54 log reductions against Listeria monocytogenes and Escherichia coli O157:H7 were achieved, respectively, compared to washing with distilled water, and had about 0.6 log-reductions higher than NaOCl treatment. CL-EO droplets in CLC had a positive ζ-potential (+55 mV) compared to other emulsions. These results indicate that ionic properties of surfactants are very important in the washing effect of CL-EO emulsion. Additionally, CLC treatment did not affect the quality of kale leaves during storage. Therefore, CLC can be an effective chemical sanitizer for washing kale leaves.

Characterization of Ecklonia cava Alginate Films Containing Cinnamon Essential Oils.

In this study, Ecklonia cava alginate (ECA) was used as a base material for biodegradable films. Calcium chloride (CaCl2) was used as a cross-linking agent, and various concentrations (0%, 0.4%, 0.7%, and 1.0%) of cinnamon leaf oil (CLO) or cinnamon bark oil (CBO) were incorporated to prepare active films. The ECA film containing 3% CaCl2 had a tensile strength (TS) of 17.82 MPa and an elongation at break (E) of 10.36%, which were higher than those of the film without CaCl2. As the content of essential oils (EOs) increased, TS decreased and E increased. Addition of CLO or CBO also provided antioxidant and antimicrobial activities to the ECA films. The antioxidant activity of the ECA film with CBO was higher than that of the film containing CLO. In particular, the scavenging activities of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals in the ECA film containing 1% CBO were 50.45% and 99.37%, respectively. In contrast, the antimicrobial activities against Escherichia coli O157:H7, Salmonella Typhimurium, Staphylococcus aureus, and Listeria monocytogenes were superior in the ECA films with CLO. These results suggest that ECA films containing CLO or CBO can be applied as new active packaging materials.

Antibacterial activities of a cinnamon essential oil with cetylpyridinium chloride emulsion against Escherichia coli O157:H7 and Salmonella Typhimurium in basil leaves.

This study examined the antibacterial activities of two different cinnamon essential oil emulsions against Escherichia coli O157:H7 and Salmonella Typhimurium on basil leaves. Cinnamon oil (0.25%) treatments containing CPC (0.05%) exhibited greater effects on the pathogenic bacteria than cinnamon oil treatment without this emulsifier (p < 0.05). Treatment with cinnamon bark and leaf oil emulsions (CBE and CLE, respectively) reduced the populations of E. coli O157:H7 by 4.10 and 5.10 log CFU/g, and S. Typhimurium by 2.71 and 2.82 log CFU/g, respectively. Scanning electron micrographs showed morphological changes in the two pathogenic bacteria following emulsion treatment. In addition, there was no difference in the color or ascorbic acid content of the basil leaves by the emulsion treatment. These results suggest that CBE or CLE treatment can be an effective way to ensure the microbial safety of minimally processed vegetables and a good alternative to chlorination treatment in the fresh produce industry.

Combined effect of a positively charged cinnamon leaf oil emulsion and organic acid on the inactivation of Listeria monocytogenes inoculated on fresh-cut Treviso leaves.

This study was performed to examine the inhibitory effect of combined treatments with a positively charged cinnamon leaf oil (P-CL) emulsion and various organic acids against Listeria monocytogenes inoculated on fresh-cut Treviso leaves. Combined treatments with a P-CL emulsion and an organic acid exhibited a higher inhibitory effect than treatment with each alone or NaOCl. The highest inhibitory effect was achieved by combined treatment with the P-CL emulsion and lactic acid (LA), which showed a 2.85-log reduction compared to distilled water washing. In addition, the inhibitory effect of the combined treatment was maintained during 6 days of subsequent storage, and showed a 3.24-3.39-log reduction compared to unwashed samples. Treviso leaves treated with the P-CL emulsion and LA also maintained their sensorial properties, including appearance, odor, hardness, freshness, and overall acceptability, during subsequent storage. Therefore, combined treatment with a P-CL emulsion and LA can be used to effectively ensure the microbial safety and organoleptic quality of fresh-cut Treviso leaves.

Sea Squirt Shell Protein and Polylactic Acid Laminated Films Containing Cinnamon Bark Essential Oil.

Sea squirt (Halocynthia roretzi) shell protein (SSP) was used as a biodegradable film material and laminated with polylactic acid (PLA) to improve its physical and water barrier properties. Cinnamon bark oil (CBO) was incorporated into the SSP film as a bioactive material. After laminating with PLA, the tensile strength and elongation at break of the SSP film increased from 4.07 to 9.09 MPa and from 8.68 to 138.84%, respectively. In addition, water vapor permeability and water solubility decreased from 5.62 to 0.91 × 10-9 g m/m2 s Pa and from 42.17% to 23.93%, respectively. DSC results of the SSP films indicate that melting point temperature increased 140.05 to 163.52 °C by laminating PLA. The addition of 0.5%, 0.7%, and 1.0% CBO conferred the antimicrobial activity against four pathogenic bacteria to the SSP/PLA-laminated films. The SSP/PLA-laminated films containing CBO also had antioxidant activities. Therefore, the SSP/PLA-laminated films containing CBO are applicable as biodegradable packaging films. PRACTICAL APPLICATION: Sea squirt shell has been discarded after the consumption of sea squirt, and sea squirt shell protein can be a base material for biodegradable films. In this study, sea squirt shell protein and polylactic acid laminated films containing cinnamon bark essential oil were developed. The developed films are promising environmentally-friendly alternatives for active packaging material.

Improving the Microbial Safety of Fresh-Cut Endive with a Combined Treatment of Cinnamon Leaf Oil Emulsion Containing Cationic Surfactants and Ultrasound.

Endive is widely consumed in a fresh-cut form owing to its rich nutritional content. However, fresh-cut vegetables are susceptible to contamination by pathogenic bacteria. This study investigated the antibacterial activities of the combined treatment of cinnamon leaf oil emulsion containing cetylpyridinium chloride or benzalkonium chloride (CLC and CLB, respectively) as a cationic surfactant and ultrasound (US) against Listeria monocytogenes and Escherichia coli O157:H7 on endive. The combined treatment of CLC or CLB with US reduced the population of L. monocytogenes by 1.58 and 1.47 log colony forming units (CFU)/g, respectively, and that of E. coli O157:H7 by 1.60 and 1.46 log CFU/g, respectively, as compared with water washing treatment. The reduction levels of both pathogens were higher than those observed with 0.2 mg/ml sodium hypochlorite. In addition, the combined treatment showed no effect on the quality of the fresh-cut endive (FCE). In particular, the degree of browning in FCE was less for the treatment group than for the control and water washing treatment groups. Thus, cationic surfactant-based cinnamon leaf oil emulsions combined with US may be an effective washing treatment for the microbial safety of FCE.

Development of Burdock Root Inulin/Chitosan Blend Films Containing Oregano and Thyme Essential Oils.

In this study, inulin (INU) extracted from burdock root was utilized as a new film base material and combined with chitosan (CHI) to prepare composite films. Oregano and thyme essential oils (OT) were incorporated into the INU-CHI film to confer the films with bioactivities. The physical and optical properties as well as antioxidant and antimicrobial activities of the films were evaluated. INU film alone showed poor physical properties. In contrast, the compatibility of INU and CHI demonstrated by the changes in attenuated total reflectance-Fourier transformation infrared spectrum of the INU-CHI film increased tensile strength and elongation at break of the INU film by 8.2- and 3.9-fold, respectively. In addition, water vapor permeability, water solubility, and moisture content of the films decreased proportionally with increasing OT concentration in the INU-CHI film. Incorporation of OT also increased the opacity of a and b values and decreased the L value of the INU-CHI films. All INU-CHI films containing OT exhibited antioxidant and antimicrobial properties. Particularly, the INU-CHI film with 2.0% OT exhibited the highest 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), 2,2-diphenyl-1-picrylhydrazyl radical scavenging, and antimicrobial activities against four pathogens. Thus, the INU-CHI film containing OT developed in this study might be utilized as an active packaging material in the food industry.

Application of Adzuki Bean Starch in Antioxidant Films Containing Cocoa Nibs Extract.

In this study, starch extracted from adzuki bean (ABS) was used as a biodegradable film source. In addition, to develop a new antioxidant film, various amounts of cocoa nibs extract (CNE, 0.3%, 0.7%, and 1%) were incorporated. With the addition of CNE, the elongation at break of the ABS films increased and the tensile strength decreased. The ABS films with CNE showed increased 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activities with increasing amounts of CNE. In particular, the ABTS and DPPH radical scavenging activities of the ABS films containing 1% CNE were 100% and 94.9%, respectively. Furthermore, decomposition of the films was observed after 28 days of biodegradation. Thus, ABS films containing CNE can be applied as a new active packaging material.

Edible Coating Using a Chitosan-Based Colloid Incorporating Grapefruit Seed Extract for Cherry Tomato Safety and Preservation.

Grapefruit seed extract (GSE)-containing chitosan-based coating was developed and applied to cherry tomatoes to protect them from Salmonella invasion and improve their storability. The coating colloids were produced by mixing a chitosan colloid (1% [w/w] chitosan) with GSE at various concentrations (0.5%, 0.7%, 1.0%, and 1.2% [w/w]) using high-shear mixing (10000 rpm, 2 min). Coatings with chitosan colloids containing GSE at 0.0%, 0.5%, 0.7%, and 1.0% (w/w) inactivated Salmonella on cherry tomatoes by 1.0 ± 0.3, 1.2 ± 0.3, 1.6 ± 0.1, and 2.0 ± 0.3 log CFU/cherry tomato, respectively. Coatings both with and without GSE (1.0%) effectively inhibited the growth of Salmonella and total mesophilic aerobes, reduced CO2 generation, and retarded titratable acidity decrease during storage at 10 and 25 °C. The advantage of incorporating GSE in the formulation was demonstrated by delayed microorganism growth and reduced weight loss at 25 °C. The chitosan-GSE coating did not affect lycopene concentration, color, and sensory properties (P > 0.05). Chitosan-GSE coating shows potential for improving the microbiological safety and storability of cherry tomatoes, with stronger efficacy at 25 °C than that of chitosan coating without GSE. PRACTICAL APPLICATION: A novel chitosan coating containing grape fruit seed extract (GSE) improved the microbiological safety against Salmonella and storability of cherry tomatoes without altering their flavor, demonstrating its strong potential as an effective postharvest technology. Chitosan coating containing GSE might be preferable over chitosan coating without GSE for application to tomatoes that are stored at room temperature in that it more effectively inhibits microbial growth and weight loss than the coating without GSE at 25 °C.

Characterization of an Olive Flounder Bone Gelatin-Zinc Oxide Nanocomposite Film and Evaluation of Its Potential Application in Spinach Packaging.

Olive flounder bone gelatin (OBG) was used for a film base material in this study. In addition, zinc oxide nanoparticles (ZnO) were incorporated into the OBG film to prepare a nanocomposite film and to impart antimicrobial activity to it. The tensile strength of the OBG film increased by 6.62 MPa, and water vapor permeability and water solubility decreased by 0.93 × 10-9 g/m s Pa and 13.79%, respectively, by the addition of ZnO to the OBG film. In particular, the OBG-ZnO film exhibited antimicrobial activity against Listeria monocytogenes. To investigate the applicability of the OBG-ZnO packaging film, fresh spinach was wrapped in this film and stored for a week. The results indicated that the OBG-ZnO film showed antimicrobial activity against L. monocytogenes inoculated on spinach without affecting the quality of spinach, such as vitamin C content and color. Thus, the OBG-ZnO nanocomposite film can be applied as an efficient antimicrobial food packaging material. PRACTICAL APPLICATION: As a base material of edible films, gelatin was extracted from olive flounder bone, which is fish processing by-product. Olive flounder bone gelatin (OBG) nanocomposite films were prepared with zinc oxide nanoparticles (ZnO). For an application to antimicrobial packaging, spinach was wrapped with the OBG-ZnO nanocomposite film.

Preparation and Characterization of an Olive Flounder (Paralichthys olivaceus) Skin Gelatin and Polylactic Acid Bilayer Film.

Olive flounder skin gelatin (OSG) was used as a film base material. A bilayer film of OSG and polylactic acid (PLA) was prepared using solvent casting method to enhance the film properties. Physical properties of the OSG-PLA film were increased compared with the nonaugmented OSG film. In particular, the PLA lamination decreased water vapor permeability from 2.17 to 0.92 × 10-9 g·m/m2 ·s·Pa, as well as of the water solubility from 16.62% to 9.27%, in the bilayer film relative to the OSG film. The oxygen permeability of the OSG-PLA bilayer film was held low by the OSG film, compensating for the high oxygen permeability of the PLA layer. Therefore, the OSG-PLA bilayer film with its enhanced physical properties and high water and oxygen barrier properties can be applied as a food packaging material.

Characterization of red ginseng residue protein films incorporated with hibiscus extract.

An edible film was prepared from red ginseng residue protein (RGRP) and incorporated with hibiscus extract (HE). RGRP was extracted from red ginseng residue, which is an inexpensive by-product of the red ginseng processing industry. Different concentrations of HE were added to an RGRP film-forming solution as a natural antioxidant. The prepared RGRP films without HE had a tensile strength of 16.9 MPa and an elongation at break of 25.1%. The antioxidant activity of the RGRP film increased with increasing concentration of HE. In addition, the RGRP film with 1% HE exhibited the lowest value of water vapor permeability (1.88×10-9 g·m/m2·s·Pa), which indicates that the film has high water barrier property. The results present the production of edible films from discarded red ginseng residue, and the antioxidant activity of RGRP films as a packaging material can prevent lipid oxidation and quality loss of food products.

Antimicrobial activity of gelatin films based on duck feet containing cinnamon leaf oil and their applications in packaging of cherry tomatoes.

Duck feet gelatin (DFG) films were prepared and applied to the packaging of cherry tomatoes. Cinnamon leaf oil (CLO) was incorporated into the DFG films at concentrations of 0.5, 1.0, and 1.5% to provide antimicrobial activity. The DFG films with 1.0% CLO incorporation exhibited the most desirable tensile strength (41.6 MPa) and elongation at break (18.5%). Regarding the antimicrobial activity, the DFG films containing CLO significantly inhibited the growth of foodborne pathogens. In addition, the DFG film with 1.0% CLO was employed in the coating and wrapping of cherry tomatoes inoculated with Salmonella typhimurium. The DFG film with 1.0% CLO incorporation reduced the population of the bacteria to below the detection limit. Moreover, the DFG film with CLO delayed the color change on cherry tomatoes. Overall, the DFG film with CLO enhanced the shelf life of cherry tomatoes and can be used as an antimicrobial packaging.

Combined Treatment with Low Concentrations of Aqueous and Gaseous Chlorine Dioxide Inactivates Escherichia coli O157:H7 and Salmonella Typhimurium Inoculated on Paprika.

Combined treatment with gaseous and aqueous chlorine dioxide (ClO2) was performed to improve the microbiological safety and quality of paprika. A single treatment of 50 ppmv ClO2 gas for 30 min decreased the populations of Escherichia coli O157:H7 and Salmonella Typhimurium by 2.33 and 2.91 log CFU/g, respectively. In addition, a single treatment of aqueous ClO2 (50 ppm) for 5 min decreased these populations by 1.86 and 1.37, respectively. The most dramatic effects were achieved by combined treatment of 50 ppm aqueous and gaseous ClO2 for 30 min, which decreased populations of E. coli O157:H7 and S. Typhimurium by 4.11 and 3.61 log CFU/g, respectively. With regard to the qualities of paprika, no adverse effects were elicited by the combined treatment. Thus, combined treatment with aqueous and gaseous ClO2 is a suitable approach that can be used to improve the microbial safety and quality of paprika.

Antimicrobial Activity of Flaxseed Meal Extract against Escherichia coli O157:H7 and Staphylococcus aureus Inoculated on Red Mustard.

This study examined the antimicrobial activity of flaxseed meal extract (FME) against Staphylococcus aureus and Escherichia coli O157:H7 inoculated on red mustard. With the treatment of 0.7% FME for 3 min, the reduction levels of S. aureus and E. coli O157:H7 populations were 1.23 and 1.83 log CFU/g, respectively. In addition, the combined treatment of 0.7% FME at 50°C for 3 min reduced the populations of the pathogenic bacteria by 2.28 and 2.41 log CFU/g, respectively. The color and the vitamin C content were not significantly different between treatments. Thus, FME can be used as a novel antimicrobial agent in freshcut vegetables.