Morphology, Mechanical, and Water Barrier Properties of Carboxymethyl Rice Starch Films: Sodium Hydroxide Effect.

Carboxymethyl rice starch films were prepared from carboxymethyl rice starch (CMSr) treated with sodium hydroxide (NaOH) at 10-50% w/v. The objective of this research was to determine the effect of NaOH concentrations on morphology, mechanical properties, and water barrier properties of the CMSr films. The degree of substitution (DS) and morphology of native rice starch and CMSr powders were examined. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were used to investigate the chemical structure, crystallinity, and thermal properties of the CMSr films. As the NaOH concentrations increased, the DS of CMSr powders increased, which affected the morphology of CMSr powders; a polyhedral shape of the native rice starch was deformed. In addition, the increase in NaOH concentrations of the synthesis of CMSr resulted in an increase in water solubility, elongation at break, and water vapor permeability (WVP) of CMSr films. On the other hand, the water contact angle, melting temperature, and the tensile strength of the CMSr films decreased with increasing NaOH concentrations. However, the tensile strength of the CMSr films was relatively low. Therefore, such a property needs to be improved and the application of the developed films should be investigated in the future work.

Effect of Pectin/Nanochitosan-Based Coatings and Storage Temperature on Shelf-Life Extension of "Elephant" Mango (Mangifera indica L.) Fruit.

The aim of extending shelf-life and maintaining quality is one of the major issues regarding mango fruit preservation. The quality of mango fruits is greatly affected by postharvest factors, especially temperature and fruit treatment. In this study, the effect of coating and storage temperature on the characteristics of mango fruits was investigated. The mango fruits were immersed in different concentrations (1.5%, 2.0%, and 2.5%) of pectin/nanochitosan dispersion (with ratios of pectin:nanochitosan 50:50), and (0.75%, 1% and 1.25%) of nanochitosan dispersion and stored at 17, 25, and 32 °C for 24 days. Changes in fruit, including weight loss, firmness, color, chemical composition (such as the total soluble solids concentration (TSS)), total sugar, reducing sugar, titratable acidity (TA), and vitamin C were periodically recorded. The results indicated that the pectin/nanochitosan coating significantly prevented reductions in the fruit weight, firmness, TSS, TA, and vitamin C content. Additionally, pectin/nanochitosan at a low temperature (17 °C) had a greater positive effect on fruit shelf-life and weight maintenance than 25 and 32 °C. The coated mango fruits maintained good quality for 24 days at 17 °C, while coated fruits stored at 25 °C and 32 °C, as well as uncoated ones stored at 17 °C, were destroyed after two weeks. At the maximum storage time evaluated, the coating formulations containing pectin and nanochitosan exhibited microbial counts below the storage life limit of 106 CFU/g of fruit. In general, the results showed that the pectin/nanochitosan coating (2%) with a storage temperature of 17 °C is the most effective strategy for improving quality and extending the shelf-life of mango fruits.

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.

Characterization of Chitosan Film Incorporated with Curcumin Extract.

Curcumin is a phenolic compound derived from turmeric roots (Curcuma longa L.). This research studied the effects of curcumin extract on the properties of chitosan films. The film characteristics measured included mechanical properties, visual aspects, color parameters, light transmission, moisture content, water solubility, water vapor permeability, infrared spectroscopy, and antioxidant activity. The results suggest that adding curcumin to chitosan-based films increases yellowness and light barriers. Infrared spectroscopy analysis showed interactions between the phenolic compounds of the extract and the chitosan, which may have improved the mechanical properties and reduced the moisture content, water solubility, and water vapor permeability of the films. The antioxidant activity of the films increased with increasing concentrations of the curcumin extract. This study shows the potential benefits of incorporating curcumin extract into chitosan films used as active packaging.

Effect of Monochloroacetic Acid on Properties of Carboxymethyl Bacterial Cellulose Powder and Film from Nata de Coco.

Nata de coco has been used as a raw material for food preparation. In this study, the production of carboxymethyl cellulose (CMC) film from nata de coco and the effect of monochloroacetic acid on carboxymethyl bacterial cellulose (CMCn) and its film were investigated. Bacterial cellulose from nata de coco was modified into CMC form via carboxymethylation using various concentrations of monochloroacetic acid (MCA) at 6, 12, 18, and 24 g per 15 g of cellulose. The results showed that different concentrations of MCA affected the degree of substitution (DS), chemical structure, viscosity, color, crystallinity, and morphology of CMCn. The optimum treatment for carboxymethylation was found using 24 g of MCA per 15 g of cellulose, which provided the highest DS at 0.83. The morphology of CMCn was related to DS value; a higher DS value showed denser and smoother surface than nata de coco cellulose. The various MCA concentrations increased the mechanical properties (tensile strength and percentage of elongation at break) and water vapor permeability of CMCn, which were related to the DS value.

Carboxymethyl Bacterial Cellulose from Nata de Coco: Effects of NaOH.

Bacterial cellulose from nata de coco was prepared from the fermentation of coconut juice with Acetobacter xylinum for 10 days at room temperature under sterile conditions. Carboxymethyl cellulose (CMC) was transformed from the bacterial cellulose from the nata de coco by carboxymethylation using different concentrations of sodium hydroxide (NaOH) and monochloroacetic acid (MCA) in an isopropyl (IPA) medium. The effects of various NaOH concentrations on the degree of substitution (DS), chemical structure, viscosity, color, crystallinity, morphology and the thermal properties of carboxymethyl bacterial cellulose powder from nata de coco (CMCn) were evaluated. In the carboxymethylation process, the optimal condition resulted from NaOH amount of 30 g/100 mL, as this provided the highest DS value (0.92). The crystallinity of CMCn declined after synthesis but seemed to be the same in each condition. The mechanical properties (tensile strength and percentage of elongation at break), water vapor permeability (WVP) and morphology of CMCn films obtained from CMCn synthesis using different NaOH concentrations were investigated. The tensile strength of CMCn film synthesized with a NaOH concentration of 30 g/100 mL increased, however it declined when the amount of NaOH concentration was too high. This result correlated with the DS value. The highest percent elongation at break was obtained from CMCn films synthesized with 50 g/100 mL NaOH, whereas the elongation at break decreased when NaOH concentration increased to 60 g/100 mL.

The Effect of Ebola Virus Disease on Maternal and Child Health Services and Child Mortality in Sierra Leone, 2014-2015: Implications for COVID-19.

During Sierra Leone's 2014-2015 Ebola virus disease (EVD) epidemic, early reports warned of health system collapse and potential effects on other-cause mortality. These same warnings are reverberating during the COVID-19 pandemic. Consideration of the impacts of EVD on maternal and child health services from facility data can be instructive during COVID-19. We surveyed all peripheral healthcare units (PHUs) in Sierra Leone in October 2014 and March 2015 to assess closures, staffing, amenities, medicines, supplies, and service utilization during May 2014-January 2015 and October 2013-January 2014. We report PHU characteristics and service utilization changes for equivalent 4-month periods during the epidemic and the prior year. We present utilization changes by district and service type, and model excess child mortality. PHU closures (-8%) and staff attrition (-3%) were limited, but many facilities lacked amenities, medicines, and supplies. Utilization of preventive and scheduled services fell more than individualized, clinical care interventions, aside from malaria treatment which declined significantly. Ebola virus disease intensity in districts was weakly associated with utilization, aside from two districts that were severely affected. Modeling suggests utilization declines resulted in 6,782 excess under-five deaths (an increase of 21%) between 2014 and 2015. Ebola virus disease negatively affected service provision, but utilization declined relatively more, particularly for preventive and scheduled interventions. Although these findings are specific to Sierra Leone's EVD epidemic, they illustrate the magnitude of possible effects in other settings due to COVID-19-induced service disruptions, where collateral impacts on child mortality from other preventable causes may far outweigh COVID-19 mortality.

Synthesis, Characterization, and Application of Carboxymethyl Cellulose from Asparagus Stalk End.

Cellulose from Asparagus officinalis stalk end was extracted and synthesized to carboxymethyl cellulose (CMCas) using monochloroacetic acid (MCA) via carboxymethylation reaction with various sodium hydroxide (NaOH) concentrations starting from 20% to 60%. The cellulose and CMCas were characterized by the physical properties, Fourier Transform Infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), Scanning electron microscopy (SEM) and X-ray diffraction (XRD). In addition, mechanical properties of CMCas films were also investigated. The optimum condition for producing CMCas was found to be 30% of NaOH concentration for the carboxymethylation reaction, which provided the highest percent yield of CMCas at 44.04% with the highest degree of substitution (DS) at 0.98. The melting point of CMCas decreased with increasing NaOH concentrations. Crystallinity of CMCas was significantly deformed (p < 0.05) after synthesis at a high concentration. The L* value of the CMCas was significantly lower at a high NaOH concentration compared to the cellulose. The highest tensile strength (44.59 MPa) was found in CMCas film synthesized with 40% of NaOH concentration and the highest percent elongation at break (24.99%) was obtained in CMCas film treated with 30% of NaOH concentration. The applications of asparagus stalk end are as biomaterials in drug delivery system, tissue engineering, coating, and food packaging.

Physical Properties of Carboxymethyl Cellulose from Palm Bunch and Bagasse Agricultural Wastes: Effect of Delignification with Hydrogen Peroxide.

The aim of this work was to synthesize carboxymethyl cellulose (CMC) and produce CMC films from the cellulose of palm bunch and bagasse agricultural waste. The effect of various amounts of H2O2 (0-40% v/v) during delignification on the properties of cellulose, CMC, and CMC films was studied. As the H2O2 content increased, yield and the lignin content of the cellulose from palm bunch and bagasse decreased, whereas lightness (L*) and whiteness index (WI) increased. FTIR confirmed the substitution of a carboxymethyl group on the cellulose structure. A higher degree of substitution of CMC from both sources was found when 20%-30% H2O2 was employed. The trend in the L* and WI values of each CMC and CMC film was related to those values in their respective cellulose. Bleaching each cellulose with 20% H2O2 provided the cellulose with the highest viscosity and the CMC films with the greatest mechanical (higher tensile strength and elongation at break) and soluble attributes, but the lowest water vapor barrier. This evidence indicates that cellulose delignification with H2O2 has a strong effect on the appearance and physical properties of both CMCs.

Characteristics and Antimicrobial Properties of Active Edible Films Based on Pectin and Nanochitosan.

This study was aimed at creating new films and determine some functional packaging properties of pectin:nanochitosan films with ratios of pectin:nanochitosan (P:NSC) of 100:0; 75:25; 50:50; 25:75 and 0:100 (%w/w). The effects of the proportions of pectin:nanochitosan incorporation on the thickness, mechanical properties, water vapor permeability, water-solubility, and oxygen permeability were investigated. The microstructural studies were done using scanning electron microscopy (SEM). The interactions between pectin and nanochitosan were elucidated by Attenuated total reflectance-Fourier transform infrared (ATR-FTIR). The results showed that the blending of pectin with nanochitosan at proportions of 50:50 increased the tensile strength to 8.96 MPa, reduced the water solubility to 37.5%, water vapor permeability to 0.2052 g·mm/m2·day·kPa, and the oxygen permeability to 47.67 cc·mm/m2·day. The results of the contact angle test indicated that P:NCS films were hydrophobic, especially, pectin:nanochitosan films inhibited the growth of Colletotrichum gloeosporioides, Saccharomyces cerevisiae, Aspergillus niger, and Escherichia coli. So, P:NCS films with a proportion of 50:50 can be used as active films to extend the shelf life of food.