Biodegradable active coating from chitosan/astaxanthin crosslinked with genipin to improve water resistance, moisture and oxygen barrier and mechanical properties of Kraft paper.

An active chitosan-based coating with an addition of a natural antioxidant and a natural crosslinker has been applied to improve the performance of Kraft paper. Coatings, including chitosan (CS), CS crosslinked with 1.5 % genipin (CS-1.5G), CS containing 1 % astaxanthin (CSA) and CSA crosslinked with 1 % genipin (CSA-1G) were coated on Kraft paper. Uncoated and coated papers were then evaluated for water content (WC), water vapor permeability (WVP), contact angle, oxygen permeability (OP), tensile strength (TS), bursting strength and elongation at break (EAB). Results indicated that the coating improved the properties of Kraft paper. When compared with CS-coated paper, WC and WVP of CSA-1G-coated paper decreased significantly by 40 % and 24 %, respectively. The lowest OP was also observed in CSA-1G-coated paper. CSA- and CSA-1G-coated paper had contact angle values >100°, indicating hydrophobic nature of coated paper surface. All coatings largely improved TS of the paper (by 182-224 %) whereas CS-1.5G and CSA-1G significantly improved the bursting strength of the paper. The developed genipin-crosslinked chitosan-based coating enriched with astaxanthin can improve the functional properties of Kraft paper and thus will facilitate the usage of the paper for food packaging applications.

Study of Optimal Conditions to Grow Thai Ganoderma, Fruiting Test, Proximate and Their Alpha Glucosidase Inhibitory Activity.

Ganoderma (Ganodermataceae) has a worldwide distribution and has been widely used in traditional medicines. In this study, we report wild strains of Ganoderma that include two G. sichuanense and one G. orbiforme from northern Thailand. Optimal conditions for mycelium growth were ensured. The most favourable medium was potato sucrose agar for G. sichuanense and oatmeal agar for G. orbiforme and at 25 °C and 30 °C and pH 4-8. All types of cereal grains can be used to promote the growth of the mycelia of Ganoderma species. Fruiting tests were performed. All strains of Ganoderma produce fruiting bodies successfully in bag culture at 28 ± 1 °C with 75-85% relative humidity. Only G. orbiforme produced fruiting bodies in field cultivation at the laboratory scale. In the first flush yields, the G. sichuanense strain MFLUCC 22-0064 gave better production (the B.E was 152.35 ± 6.98 g). This study is the first to document the bag and field cultivation of wild Thai G. orbiforme. Ganoderma species are revealed to contain high amounts of fiber (47.90-52.45% d.b.), protein (12.80-14.67% d.b.), fat (4.90-5.70% d.b.), and carbohydrates (3.16-4.02% d.b.). Additionally, G. sichuanense and G. orbiforme were preliminarily screened for biological activity for inhibition of alpha-glucosidase enzyme activity. The IC50 values of G. orbiforme (MFLUCC 22-0066) was 105.97 ± 1.36 µg/mL and G. sichuanense (MFLUCC 22-0064) was 126.94 ± 0.87 µg/mL. Both strains had better inhibition than acarbose (168.18 ± 0.89 µM). These results on wild strains of Ganoderma will be useful for further studies on the applications of Ganoderma. Later the species can be introduced to domestic markets for cultivation and medicinal use.

Effect of Chemical and Steam Explosion Pulping on the Physical and Mechanical Properties of Sugarcane Straw Pulp Trays.

Sugarcane straw fiber (SSF) samples were prepared by chemical pulping (CP) and steam explosion (STE). CP (5, 10, 15% NaOH + 0.2% w/w anthraquinone at 121 °C for 1 h) and STE pressure (1.77, 1.96, and 2.16 MPa at 220 °C for 4 min) SSF trays were molded with a hydraulic hot-press machine at 120 °C, 7 min, and 1.72 MPa. The yield (%) of SSF from STE (54-60% dry basis (db.)) was higher than CP (32-48% db.). STE trays had greater tensile strength than CP. However, STE's elongation and compression strength was lower than CP tray samples. The trays made from SSF using STE had less swelling in thickness, longer water wetting time, and a higher water contact angle than those made from CP. The micrographs displayed a smaller size of SSF obtained in STE than the CP. The appearance and area of peaks in ATR-FTIR spectra and XRD diffractograms, respectively, revealed that the STE trays had a larger residual lignin content from the lignin study and a lower crystallinity index than the CP trays. Moreover, the lightness values of the STE trays were lower than those of the CP trays due to lignin retention. The study results indicate that CP is the preferred method for producing SSF packaging material with high flexibility and fiber purity. However, when considering the specific SF of 4.28, the STE treatment showed superior physical and mechanical properties compared to CP. This suggests that STE could be an excellent alternative green pulping technique for producing durable biobased trays. Overall, the findings highlight the potential of STE as a viable option for obtaining trays with desirable characteristics, providing a sustainable and efficient approach to tray production.

Fabrication of edible and biodegradable cutlery from morning glory (Ipomoea aquatic) stem fiber-reinforced onto soy protein isolate.

This study aimed to investigate the preparation of soy protein isolated (SPI) cutlery incorporated with 5-20% (w/w) crude morning glory stem fiber (MGSF). SPI cutlery samples without and with MGSF were subjected to hydraulic hot press molding at 160 °C for 5 min pressing time. SPI with 5% MGSF showed decreased lightness values compared to the control SPI (without MGSF) (p < 0.05). Flexural modulus attained in SPI with 5% MGSF was higher and subsequently showed decreases in impact strength and compression load compared to the control SPI (p < 0.05). SPI with 5% MGSF sample showed slightly lower water absorption followed by decreases in degree of swelling and solubility with that of the control SPI (p < 0.05). Micrographs revealed a 5% MGSF formed uniform matrix with SPI in comparison to the control and other treatments that showed cracks with the increased fiber addition. Additionally, stiffness decreased with the addition of 5% MGSF to SPI thereby increasing deflection in comparison to the control SPI and other treatments. Thus, SPI cutlery added with 5% MGSF potentially retained the physical and mechanical properties of edible and biodegradable cutlery for food applications.

Extraction and Characterization of Cellulose from Agricultural By-Products of Chiang Rai Province, Thailand.

Cellulose is an abundant component of the plant biomass in agricultural waste valorization that may be exploited to mitigate the excessive use of synthetic non-biodegradable materials. This work aimed to investigate the cellulose utilized by alkaline extraction with a prior bleaching process from rice straw, corncob, Phulae pineapple leaves, and Phulae pineapple peels. The bleaching and alkaline extraction process was performed using 1.4% acidified sodium chlorite (NaClO2) and 5% potassium hydroxide (KOH) in all the samples. All the samples, without and with the alkaline process, were characterized for their physico-chemical, microstructure, thermal properties and compared to commercial cellulose (COM-C). The extraction yield was the highest in alkaline-extracted cellulose from the corncob (AE-CCC) sample (p < 0.05), compared to the other alkaline-treated samples. The undesired components, including mineral, lignin, and hemicellulose, were lowest in the AE-CCC sample (p < 0.05), compared to raw and alkaline-treated samples. The microstructure displayed the flaky AE-CCC structure that showed a similar visibility in terms of morphology with that of the alkaline-treated pineapple peel cellulose (AE-PPC) and COM-C samples compared to other alkaline-treated samples with a fibrous structure. Fourier Transform Infrared (FTIR) and X-ray Diffraction (XRD) of AE-CCC samples showed the lowest amorphous regions, possibly due to the elimination of hemicellulose and lignin during bleaching and alkaline treatment. The highest crystallinity index obtained in the AE-CCC sample showed a close resemblance with the COM-C sample. Additionally, the AE-CCC sample showed the highest thermal stability, as evidenced by its higher Tonset (334.64 °C), and Tmax (364.67 °C) compared to the COM-C and alkaline-treated samples. Therefore, agricultural wastes after harvesting in the Chiang Rai province of Thailand may be subjected to an alkaline process with a prior bleaching process to yield a higher cellulose content that is free of impurities. Thus, the extracted cellulose could be used as an efficient, eco-friendly, and biodegradable material for packaging applications.

Mechanical and Physicochemical Properties of Composite Biopolymer Films Based on Carboxymethyl Cellulose from Young Palmyra Palm Fruit Husk and Rice Flour.

Carboxymethyl cellulose from young Palmyra palm fruit husk (CMCy) film has low water barrier properties, which can limit its application. Thus, the combination of CMCy with other polysaccharides, such as rice flour (RF), may solve this problem. The aim of this study is to prepare the CMCy/RF composite films in different proportions (CMCy100, CMCy75/RF25, CMCy50/RF50, CMCy25/RF75, and RF100) and investigate their mechanical and physicochemical properties. The film strength (33.36−12.99 MPa) and flexibility (9.81−3.95%) of the CMCy/RF composite films decreased significantly (p < 0.05) with an increase in the RF proportion. Blending the RF with CMCy could improve the water vapor permeability (9.25−6.18 × 10−8 g m m−2 s−1 Pa−1) and film solubility (82.70−21.64%) of the CMCy/RF composite films. Furthermore, an increased lightness with a coincidental decreased yellowness of the CMCy/RF composite films was pronounced when the RF proportion increased (p < 0.05). However, the addition of RF in different proportions did not influence the film thickness and transparency. Based on SEM micrographs, all film samples had a relatively coarser surface. FTIR spectra showed that some interactions between CMCy and RF blended films had occurred. According to these findings, the CMCy50/RF50 composite film was found to be the best formulation because it has good mechanical and physicochemical properties.

Preparation and Characterization of Bioactive Chitosan Film Loaded with Cashew (Anacardium occidentale) Leaf Extract.

Chitosan is a biopolymer known for its rapid biodegradability and film-forming properties. This research aimed to synthesize and characterize chitosan films loaded with cashew leaf extract (CLE) obtained from immature and mature cashew leaves via aqueous and 70% ethanolic extraction methods. Freeze-dried CLE samples were dissolved in 50% dimethyl sulfoxide for in vitro analysis and chitosan film preparation. The total phenolic content of mature cashew leaves extracted in ethanol (MECLE) showed higher free radicle scavenging activity by a 2,2-diphenyl-1-picrylhydrazyl assay than the other extracts (p < 0.05). MECLE displayed a lower minimal inhibitory concentration, minimum fungal concentration, and higher zone of inhibition against Aspergillus niger compared to the other treatments (p < 0.05). Film-forming solutions were prepared using 2% chitosan, 2% chitosan with 5% mature cashew leaves extracted in deionized water (MACLE) (w/v), and 2% chitosan with 5% MECLE (w/v), respectively, to cast films. Of these, 2% chitosan (CH) with 5% MECLE (CH-MECLE-5) displayed the highest thickness and water vapor transmission rate, water vapor permeability, and oxygen transmission rate when compared to other film samples (p < 0.05). The CH-MECLE-5 film showed the highest inhibition zone of A. niger compared to the control and treated films (p < 0.05). The lightness (L*) of the CH-MECLE-5 film decreased with increment in b* values, which represented the yellow color of the film. In addition, two-photon microscopy revealed a uniform distribution via the auto-fluorescent 3D structure of MECLE in the CH-MECLE-5 film. Therefore, chitosan combined with 5% MECLE may be a potential bioactive and eco-friendly packaging film.

Effects of storage temperature on the quality of eggs coated by cassava starch blended with carboxymethyl cellulose and paraffin wax.

A blend of cassava starch (CS), carboxymethyl cellulose (CMC), and paraffin was prepared as a coating material to maintain the quality of eggs during 4 wk of storage at different temperatures. The efficacy of the CS/CMC/paraffin (6/1/0.5% w/v) coating was investigated in terms of the Haugh unit (HU), weight loss, pH, and microbial load at the end of storage. The best egg storage temperature was 4°C, which maintained an HU of grade AA in coated and uncoated eggs for 4 wk. Lower weight loss (2.14%) was observed in coated eggs at 4°C storage than at 30°C storage (3.26%). The pH in the albumen of coated and uncoated eggs at 4°C increased from 6.84 to 6.88 and 7.01 to 7.03, respectively, after 4 wk of storage. No microbes were detected in the coated and uncoated eggs at 4°C. The maximum microbial count was 728 ± 35 cfu/mL in uncoated eggs at 30°C storage. Egg coating prevented microbial contamination of eggs stored at 30°C for 4 wk. The freshness of the eggs did not affect the nutrient content. The egg-coating material effectively maintained egg quality, prevented microbial contamination of eggs, and increased the shelf life of eggs at storage temperatures of 25 and 30°C.

Effect of Egg-Coating Material Properties by Blending Cassava Starch with Methyl Celluloses and Waxes on Egg Quality.

An egg-coating material was developed to extend the shelf-life and freshness of eggs by blending cassava starch (CS) with gelling agents and waxes. The effects of the properties of this egg coating on egg quality were investigated. Hydroxypropyl methylcellulose (HPMC), carboxymethyl cellulose (CMC), beeswax, and paraffin wax were used. CS blended with low-molecular-weight paraffin (Paraffin(L)) and CMC coating material displayed a tensile strength of 4 MPa, 34% elongation at break, 0.0039 g day-1 m-2 water vapor permeability, and a water contact angle of 89° at 3 min. Eggs coated with CS/CMC/Paraffin(L) solutions had a Haugh unit value of 72 (AA grade) and exhibited a weight loss of 2.4% in 4 weeks. CMC improved the compatibility of CS and Paraffin(L). This improvement and the hydrophobicity of Paraffin(L) provided suitable mechanical and water-resistance properties to the coating material that helped to maintain the quality of the coated AA-grade eggs with low weight loss for 4 weeks.

Effect of Active Packaging Material Fortified with Clove Essential Oil on Fungal Growth and Post-Harvest Quality Changes in Table Grape during Cold Storage.

Fungal growth in table grapes (Vitis vinifera cv. beauty seedless) is triggered by Botrytis cinerea, Penicillium sp., Aspergillus sp., and Rhizopus stolonifera during post-harvest storage. Due to the safety aspects, this research aimed to develop antifungal packaging embedded with essential oils (EOs) to alleviate the fungal decay of table grapes (TG). The various levels of EOs (0.5-5%, v/v) from clove, cinnamon, thyme, peppermint, lemon, bergamot, ginger, spearmint, and lemongrass were tested against Aspergillus sp. The results attained in radial growth, disk diffusion method, minimal inhibitory concentration, and minimal fungicidal concentration revealed that 1% clove essential oil (CEO) showed higher efficacy against Aspergillus sp. compared to the untreated control and other treatments. CEO at the 1% level exhibited a pleasant odor intensity in TG than the other EOs. The active polyvinyl alcohol (7% PVA) film with 1% CEO resulted in lower weight loss, disease severity, and TG berry drop than the control and other treated samples. Additionally, the acceptance score in the TG sample wrapped with a PVA film containing 1% CEO was augmented. Therefore, the PVA film with 1% CEO retarded the fungal growth and prolonged the shelf life of TG during storage of 21 days at 13 °C and 75% relative humidity (RH).

High Substitution Synthesis of Carboxymethyl Chitosan for Properties Improvement of Carboxymethyl Chitosan Films Depending on Particle Sizes.

This study investigated the effect of chitosan particle sizes on the properties of carboxymethyl chitosan (CMCh) powders and films. Chitosan powders with different particle sizes (75, 125, 250, 450 and 850 µm) were used to synthesize the CMCh powders. The yield, degree of substitution (DS), and water solubility of the CMCh powders were then determined. The CMCh films prepared with CMCh based on chitosan with different particle sizes were fabricated by a solution casting technique. The water solubility, mechanical properties, and water vapor transmission rate (WVTR) of the CMCh films were measured. As the chitosan particle size decreased, the yield, DS, and water solubility of the synthesized CMCh powders increased. The increase in water solubility was due to an increase in the polarity of the CMCh powder, from a higher conversion of chitosan into CMCh. In addition, the higher conversion of chitosan was also related to a higher surface area in the substitution reaction provided by chitosan powder with a smaller particle size. As the particle size of chitosan decreased, the tensile strength, elongation at break, and WVTR of the CMCh films increased. This study demonstrated that a greater improvement in water solubility of the CMCh powders and films can be achieved by using chitosan powder with a smaller size.

Antioxidant Films from Cassava Starch/Gelatin Biocomposite Fortified with Quercetin and TBHQ and Their Applications in Food Models.

Edible and active packaging are attractive for use in food packaging applications due to their functionality and sustainability. This research developed new antioxidant active food packaging materials from cassava starch/gelatin (7:3 w/w) composite films with varied antioxidant types (quercetin and tertiary butylhydroquinone (TBHQ)) and concentrations (0-200 mg/200 mL film-forming solution) and evaluated their properties. Antioxidant addition altered the mechanical and barrier properties of the films. At 34% relative humidity (RH), increasing the concentration of quercetin increased the tensile strength and decreased the elongation at break of the composite films. Increasing quercetin and TBHQ contents increased the film water solubility and water vapor transmission rate. Intermolecular interactions between the antioxidants and films, as found in Fourier transform infrared (FT-IR) spectra and XRD micrographs, were related to the changed film functionalities. In food application studies, the cassava starch/gelatin films containing quercetin and TBHQ retarded the oxidation of lard (more than 35 days) and delayed the redness discoloration of pork. Cassava starch/gelatin composite films integrated with quercetin and TBHQ can be utilized as active packaging that delays oxidation in foods.

Physical and Antioxidant Properties of Cassava Starch-Carboxymethyl Cellulose Incorporated with Quercetin and TBHQ as Active Food Packaging.

Antioxidant integration has been advocated for in polymer films, to exert their antioxidative effects in active packaging. In this study, the new antioxidant food packaging made from cassava starch-carboxymethyl cellulose (CMC), which is biodegradable, edible and inexpensive, was developed. Their properties were determined and applied in food models for application. Antioxidants (quercetin and tertiary butylhydroquinone (TBHQ)) were added at various concentrations into cassava starch-carboxymethyl cellulose (CMC) (7:3 w/w) films containing glycerol (30 g/100 g starch-CMC) as a plasticizer. The effects of quercetin and TBHQ concentrations on the mechanical properties, solubility, antioxidative activity, and applications of the films were investigated. Addition of antioxidant improved tensile strength, but reduced elongation at break of the cassava starch-CMC film. Cassava starch-CMC films containing quercetin showed higher tensile strength, but lower elongation at break, compared to films with TBHQ. Increases in quercetin and TBHQ content decreased water solubility in the films. Both the total phenolic content and antioxidative activity (DPPH scavenging assay) still remained in films during storage time (30 days). In application, cassava starch-CMC film containing quercetin and TBHQ can retard the oxidation of lard (35-70 days) and delay the discoloration of pork.

Impact of the homogenization process on the structure and antioxidant properties of chitosan-lignin composite films.

This work investigated the impact of two homogenization treatments, High Shear (HS) and High Pressure (HP), on the structure and antioxidant activity of chitosan-lignin bio-composite films. Laser light scattering analysis revealed that smaller lignin particles were obtained after HP processing, around 0.6µm, compared to HS treatment, between 2.5 and 5µm. Moreover, these particles were more homogeneously distributed in the chitosan film matrix after HP process, while some aggregates remained after HS treatment, as highlighted by two-photon microscopy. The surface hydrophobicity of the composite films, as measured by water contact angle, increased after the two homogenization treatments. Finally, the antioxidant activity of the composite films was determined using the DPPH· assay. No significant difference in the radical scavenging activity was noticeable, neither after HS nor HP processing. However, a migration of lignin residues from the film to the extraction medium was noticed, particularly for HP process.

Effect of carboxymethyl cellulose concentration on physical properties of biodegradable cassava starch-based films.

BACKGROUND: Cassava starch, the economically important agricultural commodity in Thailand, can readily be cast into films. However, the cassava starch film is brittle and weak, leading to inadequate mechanical properties. The properties of starch film can be improved by adding plasticizers and blending with the other biopolymers. RESULTS: Cassava starch (5%w/v) based films plasticized with glycerol (30 g/100 g starch) were characterized with respect to the effect of carboxymethyl cellulose (CMC) concentrations (0, 10, 20, 30 and 40%w/w total solid) and relative humidity (34 and 54%RH) on the mechanical properties of the films. Additionally, intermolecular interactions were determined by Fourier transform infrared spectroscopy (FT-IR), melting temperature by differential scanning calorimetry (DSC), and morphology by scanning electron microscopy (SEM). Water solubility of the films was also determined. Increasing concentration of CMC increased tensile strength, reduced elongation at break, and decreased water solubility of the blended films. FT-IR spectra indicated intermolecular interactions between cassava starch and CMC in blended films by shifting of carboxyl (C = O) and OH groups. DSC thermograms and SEM micrographs confirmed homogeneity of cassava starch-CMC films. CONCLUSION: The addition of CMC to the cassava starch films increased tensile strength and reduced elongation at break of the blended films. This was ascribed to the good interaction between cassava starch and CMC. Cassava starch-CMC composite films have the potential to replace conventional packaging, and the films developed in this work are suggested to be suitable for low moisture food and pharmaceutical products.