Measurement of the degree of deacetylation in chitosan films by FTIR, 1H NMR and UV spectrophotometry.

The chitosan films were prepared from shrimp, squid, and crab to corroborate that regardless of the source of the chitosan, it was possible to measure the degree of deacetylation. In this work, the degree of deacetylation of chitosan was evaluated via UV, FTIR and 1H NMR spectrophotometry methodologies. Values in a range of 74 to 99% degree of deacetylation (DD) were obtained and varied depending on the method used and the source of chitosan. The spectrophotometric method is one of the most commonly used for this determination; however, it has the limitation that D-glucosamine and N-acetylglucosamine share similar wavelengths. All three methods were simple and provided rapid analysis; however, NMR, in particular, was expensive due to its equipment specifications. For this reason, its important to select the simplest method than can be routinely used.•The simplest used technique to determine the degree of deacetylation is infrared spectroscopy.•The degree of acetylation of chitosan is related to its physicochemical properties; its determination is an important parameter due to its association with chitosan applications in different industrial areas.•The 1H NMR method is very precise and requires expensive equipment and trained personal. Thus, it cannot be used routinely to determine the degree of deacetylation.

Efficacy of chitosan in the treatment of chronic skin lesions in a horse: A case report.

Consultation was requested for a 7-year-old Gypsy Vanner male horse with a 2-year history of foreskin injury. Upon revision, an ulcer, 153 cm2 in size, with yellowish granules was observed; a RESVECH 2.0 evaluation revealed a score of 32/35 points. Medical history confirmed multiple failed deworming, anti-inflammatory, and antibiotic treatments with different topical therapies and recurrence in summer. Laboratory results confirmed elevated total proteins (8.8 g/dL) and globulins (5.5 g/dL), negative bacterial and fungal cultures, as well as negative coproparasitoscopic findings, and finally, identification of stable fly larvae (Stomoxys calcitrans) in the feces. Microscopy showed disorganized collagen, thickened tissue, polymorphonuclear cells, and acanthosis without neoplastic tissue or parasite remains. Debridement was performed and systemic treatment with ivermectin, penicillin, and non-steroidal anti-inflammatory drugs (NSAIDs) continued. In addition, 2% chitosan gel and films were applied to the entire surface of the lesion for 72 hours on 30 occasions; vector control with nets and insecticides was performed. On day 94, there was a 6 cm2 surface with involvement of the dermal and epidermal layers, moist epithelial tissue, and diffuse edges, with a RESVECH 2.0 evaluation of 6/35 points. Microscopy showed an intact basement membrane, presence of hair follicles, sweat glands, aligned collagen, and angiogenesis. It was concluded that chronic skin lesions in horses represent a diagnostic challenge, and topical chitosan is an adequate treatment due to its biocompatibility and efficacy, in addition to the functional and cosmetic results in dermal regeneration.

Evaluation of the status quo of polyphenols analysis: Part II-Analysis methods and food processing effects.

Nowadays due to the concern with the environmental impact of analytical techniques and in order to reduce the ecological footprint there is a tendency to use more efficient and faster procedures that use a smaller amount of organic solvents. Polyphenols have been widely studied in plant-based matrices due to their wide and potent biological properties; however there are no standardized procedures both for sample preparation and analysis of these compounds. The second of a two-part review will carry out a critical review of the extraction procedures and analytical methods applied to polyphenols and their selection criteria over a wide range of factors in relation to commerce-associated, environmental, and economic factors. It is foreseen that in the future the analysis of polyphenols in plant-based matrices includes the use of techniques that allow the simultaneous determination of different subclasses of polyphenols using fast, sophisticated, and automated techniques that allow the minimal consumption of solvents.

Characterization data of chitosan-based films: Antimicrobial activity, thermal analysis, elementary composition, tensile strength and degree crystallinity.

This set of raw and analyzed data are complement to the research article that is titled "Mechanical, structural and physical aspects of chitosan-based films as antimicrobial dressings" (Escárcega-Galaz et al., 2018) [1]. The mechanical, structural and biological properties of the chitosan-based films determine their potential application in biomedicine. The films were prepared from pure chitosan and in combination with honey or glycerol. Afterwards, the characterization data related to thermal analysis, elementary composition, tensile strength and degree crystallinity was collected. The data of the antimicrobial activity of the films correspond to Klebsiella pneumoniae and Pseudomonas aeruginosa, both isolated from cutaneous ulcers. This set of data indicate that the chitosan-based films possess biological and physicochemical characteristics for their application as antimicrobial dressings for their action when are used by direct contact during the treatment of cutaneous ulcers.

Mechanical, structural and physical aspects of chitosan-based films as antimicrobial dressings.

Chitosan is a biodegradable, non-toxic, and antimicrobial polymer. Chitosan films can be used as a dressing because they promote the healing of cutaneous ulcers. In this study, the mechanical, physical, and microbiological properties films of pure chitosan and films formulated with a glycerol-honey mixture were characterized. The films were smooth, homogenous, transparent, and porous, with no fractures or cracks. Additionally, it was found that all were resistant to breaking, that the tearing force was directly related to the chitosan concentration, and that the addition of honey and glycerol improved the elongation percentage. When evaluating the antimicrobial activity of the films against Pseudomonas aeruginosa and Klebsiella pneumoniae, the films were found to have an effect only by direct contact. In the films formulated with honey, the area of contact increased to 44%. The excellent color, structural, antimicrobial, and surface morphological properties of the newly developed films make them a promising alternative for use as a dressing for the healing of skin ulcers.

Antioxidant and chelating capacity of Maillard reaction products in amino acid-sugar model systems: applications for food processing.

BACKGROUND: Maillard reaction products (MRP) have gained increasing interest owing to their both positive and negative effects on human health. Aqueous amino acid-sugar model systems were studied in order to evaluate the antioxidant and chelating activity of MRP under conditions similar to those of food processing. Amino acids (cysteine, glycine, isoleucine and lysine) combined with different sugars (fructose or glucose) were heated to 100 and 130 °C for 30, 60 and 90 min. Antioxidant capacity was evaluated via ABTS and DPPH free radical scavenging assays, in addition to Fe2+ and Cu2+ ion chelating capacity. RESULTS: In the ABTS assay, the cysteine-fructose model system presented the highest antioxidant activity at 7.05 µmol mL-1 (130 °C, 60 min), expressed in Trolox equivalents. In the DPPH assay, the cysteine-glucose system presented the highest antioxidant activity at 3.79 µmol mL-1 (100 °C, 90 min). The maximum rate of chelation of Fe2+ and Cu2+ was 96.31 and 59.44% respectively in the lysine-fructose and cysteine-glucose systems (100 °C, 30 min). CONCLUSION: The model systems presented antioxidant and chelating activity under the analyzed temperatures and heating times, which are similar to the processing conditions of some foods. © 2017 Society of Chemical Industry.

An HPLC Procedure for the Quantification of Aloin in Latex and Gel from Aloe barbadensis Leaves.

Aloin is an anthraquinone-C-glycoside present in Aloe vera. This compound is extremely variable among different species and highly depends on the growing conditions of the plants. The quantification of aloin in different extraction preparations has been a frequent problem due to the high instability of the compound. The aim of the present study is to develop and validated an analytical method for aloin detection in fresh and dry samples of Aloe barbadensis gel and latex using high performance liquid chromatography coupled to a diode array detector (HPLC-DAD). Phosphate buffered saline (pH 3) was selected as the extraction solvent. The aloin was separated using a Zorbax Eclipse AAA column (4.6 × 150 mm) at 35°C, and water and acetonitrile were used as the mobile phase at a flow rate of 0.9 mL/min. The linearity was satisfactory with a correlation coefficient greater than 0.999. Under these conditions, the method precision (relative standard deviation) was 3.71% for FL, 4.41% for dry latex, 0.81% for fresh gel and 4.42% for dry gel samples. Aloe latex was determined to have a greater amount of aloin than aloe gel. The method validation was satisfactory and exhibited adequate linearity, repeatability and accuracy.

Modeling of breakthrough curves for aqueous iron (III) adsorption on chitosan-sodium tripolyphosphate.

A fixed bed column packed with chitosan-sodium tripolyphosphate (CTPP) beads was used to remove aqueous Fe (III) ions. The adsorption of Fe (III) ions on CTPP beads was found to be dependent on operating conditions, such as the flow rate, adsorbent bed length, and feed concentration. The experimental data were assessed with Thomas, Adams-Bohart and Yoon-Nelson models to predict the breakthrough curves using linear regression. The breakthrough curves were better fitted with the Thomas and Yoon-Nelson models when the flow rate was varied and the feed concentration and the bed height of the column were fixed. Therefore, chemical adsorption may be the limiting step that controls the continuous adsorption process. The Adams-Bohart model presented a good fit to the experimental data, showing that external mass transfer was controlling the adsorption process in the initial part of the breakthrough curves. The parameters obtained from the continuous adsorption assays may be used as a basis for designing columns packed with CTPP beads for the removal of Fe (III) ions.

Microencapsulation of sulforaphane from broccoli seed extracts by gelatin/gum arabic and gelatin/pectin complexes.

Sulforaphane is a phytochemical that has received attention in recent years due to its chemopreventive properties. However, the uses and applications of this compound are very limited, because is an unstable molecule that is degraded mainly by changes in temperature and pH. In this research, the use of food grade polymers for microencapsulation of sulforaphane was studied by a complex coacervation method using the interaction of oppositely charged polymers as gelatin/gum arabic and gelatin/pectin. The polymers used were previously characterized in moisture content, ash and nitrogen. The encapsulation yield was over 80%. The gelatin/pectin complex had highest encapsulation efficiency with 17.91%. The presence of sulforaphane in the complexes was confirmed by FTIR and UV/visible spectroscopy. The materials used in this work could be a new and attractive option for the protection of sulforaphane.

Effect of the refining process on Moringa oleifera seed oil quality.

We evaluated the physicochemical properties and oxidative stability of the oil extracted from the seeds of Moringa oleifera during its refining process. Refining is accomplished in three stages: neutralization, degumming, and bleaching. Four samples were analyzed, corresponding to each step of the processed and crude oil. Increases in the density, viscosity, saponification value and oxidation of the oil were detected during the refining, while the peroxide value and carotenoid content diminished. Moreover, the refractive index and iodine content were stable throughout the refining. Nine fatty acids were detected in all four samples, and there were no significant differences in their composition. Oleic acid was found in the largest amount, followed by palmitic acid and behenic acid. The crude, neutralized, and degummed oils showed high primary oxidation stability, while the bleached oil had a low incidence of secondary oxidation.

Effect of solvents and methods of stirring in extraction of lycopene, oleoresin and fatty acids from over-ripe tomato.

Lycopene and oleoresin extraction from powder of tomato over-ripe by three agitation methods and four solvents have been evaluated. Also, tomato powder and the oleoresins were characterized biochemically. On average, the moisture content of powder was found to be 4.30, ash 8.90, proteins 11.23 and lipids 4.35 g 100 g(-1). The best oleoresin extraction yield was achieved by combining sonication and acetone at 1.43 g 100 g(-1). The greatest amount of lycopene (65.57 ± 0.33 mg 100 g(-1)) was also obtained using the same treatment. The presence of trans-lycopene was positively confirmed by HPLC and FTIR. In oleoresins, linoleic acid (C18:2n6) was the predominant with 50% of total fatty acids, whereas stearic acid (C18:0) is presented in a smaller proportion (5%). A simple and suitable method for extraction of lycopene from over-ripe tomato was optimized. In industrial applications, tomato by-products are a viable source of analytes, such as lycopene and unsaturated fatty acids.

Ultra-high pressure LC determination of glucosamine in shrimp by-products and migration tests of chitosan films.

Chitosan, a multiple applications molecule, was isolated from shrimp by-products by fermentation. The amount of chitosan in the solid fraction of the fermented extract was measured after its conversion in the respective glucosamine units. The procedure includes an acid hydrolysis (110 °C, 4 h with HCl 8 M) and a derivatization with 9-fluorenylmethyl chloroformate (Fmoc-Cl). Ultra-high-pressure liquid chromatography method was developed and optimized. Excellent peaks resolution was achieved in just 10 min. The method was evaluated in what concerns to validation parameters such as linearity, repeatability, quantification limit, and recovery. Migration tests of films prepared with chitosan were carried out in two simulants: ultrapure water and ethanol 95% (v/v).

Adsorption of allura red dye by cross-linked chitosan from shrimp waste.

The present study was designed to evaluate the chitosan, which has been obtained by deacetylation of chitin, as a biosorbent. The chitin was isolated from fermented shrimp waste by an important local industrial food biopolymer. The aim of this work was the characterization of chitosan and preparation of cross-linked chitosan- tripolyphosphate (chitosan-TPP) beads for the removal of allura red food dye from aqueous solutions. Conditions of batch adsorption such as pH, time and adsorbent dose were examined. The effectiveness of cross-linked chitosan beads for dye removal was found to be higher for pH 2 (98%, percentage of dye removal) and tends to decrease at pHs of 3 to 11 (up to 49%). The values of percentage removal show that the adsorption capacity increases with time of contact and dosage of chitosan-TPP, but red dye adsorption is mainly influenced by pH level. The cross-linked chitosan-TPP beads can significantly adsorb allura red monoazo dye from aqueous solutions even at acidic pHs unlike raw chitosan beads that tend to dissolve in acidic solutions. Consequently, this modified chitosan has characteristics that allow minimization of environmental pollution and widening the valorization of shrimp waste.

[Sulforaphane (1-isothiocyanato-4-(methylsulfinyl)-butane) content in cruciferous vegetables]. / Contenido de sulforafano (1-isotiocianato-4-(metilsulfinil)-butano) en vegetales crucíferos.

Sulforaphane (1-isothiocyanato-4-(methylsulfinyl)-butane) content in cruciferous vegetables. Sulforaphane is an isothiocyanate which has antimicrobial and anticarcinogenic properties, this compound is found in a wide variety of plants from genus Brassica oleracea, being the most important broccoli and cabbage. The objective of this research was to quantify sulforaphane in the edible parts of broccoli and cabbage leaves by high-performance liquid chromatography (HPLC). Sample preparation for the quantification of sulforaphane include the conversion of glucoraphanin to sulforaphane (45 +/- 2 degrees C for 2.5 h), extracted with dichloromethane, purification of the extract in columns of solid phase extraction and detection by HPLC- UV. Sulforaphane concentration in broccoli is in the range of 214 microg/g DW (stems) to 499 microg/g DW (inflorescences). The purple cabbage (101.99 microg/g DW) has values greater than the green cabbage (7.58 microg/g DW). The inflorescences of broccoli and red cabbage leaves are rich in sulforaphane.

Biochemical composition and physicochemical properties of broccoli flours.

The objective of this research was to study the biochemical composition and physicochemical properties of three different flours prepared from broccoli crop remains. Florets, leaves and stalks of broccoli were dried at 60 degrees C, and the flours obtained were analysed for proximate composition, amino acid profile, fatty acid composition, and physicochemical properties. The florets flour showed the highest protein content (22.41 g/100 g dry weight); ash was higher in leaves flour (14.67 g/100 g dry weight), and the lipid content was similar in the flours of leaves and stalks. The stalks flour had high crude fibre content and low protein content. All flours presented a high water absorption index. Tyrosine, aspartic acid, glutamic acid, proline and valine were found in larger concentration. The most abundant fatty acids in the lipids were linolenic acid (C18:3n3), palmitic acid (C16:0) and linoleic acid (C18:2n6). Broccoli flours prepared in this study are good source of nutrients and could be utilized as dietary supplements.

Contenido de sulforafano (1-isotiocianato-4-(metilsulfinil)-butano) en vegetales crucíferos: [revisión] / Sulforaphane (1-isothiocyanato-4-(methylsulfinyl)-butane) content in cruciferous vegetables: [review]

El sulforafano es un isotiocianato con propiedades antimicrobianas y anticarcinogénicas, se encuentra en una amplia variedad de vegetales del género Brassica oleracea, considerándose las más importantes el brócoli y repollo. El objetivo de esta investigación fue cuantificar sulforafano en las partes comestibles de brócoli y en hojas de repollo por cromatografía líquida de alta resolución (HPLC). La preparación de la muestra para la cuantificación del sulforafano incluye la conversión de glucorafanina a sulforafano (45 ± 2°C durante 2,5 h), extracción con diclorometano, purificación del extracto en columnas de extracción de fase sólida, y detección por HPLC-UV. En brócoli la concentración de sulforafano está en el rango de 214 µg/g bs (tallos) a 499 µg/g bs (inflorescencias). El repollo morado (101,99 µg/g bs) presentó valores mayores de sulforafano que el repollo verde (7,58 µg/g bs). Las inflorescencias de brócoli y las hojas de repollo morado son ricos en sulforafano.

Sulforaphane is an isothiocyanate which has antimicrobial and anticarcinogenic properties, this compound is found in a wide variety of plants from genus Brassica oleracea, being the most important broccoli and cabbage. The objective of this research was to quantify sulforaphane in the edible parts of broccoli and cabbage leaves by high-performance liquid chromatography (HPLC). Sample preparation for the quantification of sulforaphane include the conversion of glucoraphanin to sulforaphane (45 ± 2 °C for 2.5 h), extracted with dichloromethane, purification of the extract in columns of solid phase extraction and detection by HPLC- UV. Sulforaphane concentration in broccoli is in the range of 214 µg/g DW (stems) to 499 µg/g DW (inflorescences). The purple cabbage (101.99 µg/g DW) has values greater than the green cabbage (7.58 µg/g DW). The inflorescences of broccoli and red cabbage leaves are rich in sulforaphane.