•Curcumin–β-CD complex using co-precipitation enhanced its solubility 31-fold.•Curcumin–β-CD complex exhibited higher sunlight, pH, storage and heating stability.•XRD and the spectroscopic techniques ...produced important evidences of complexation.•The use of the complex in vanilla ice creams resulted in potential savings.
Curcumin was complexed with β-CD using co-precipitation, freeze-drying and solvent evaporation methods. Co-precipitation enabled complex formation, as indicated by the FT-IR and FT-Raman techniques via the shifts in the peaks that were assigned to the aromatic rings of curcumin. In addition, photoacoustic spectroscopy and X-ray diffraction, with the disappearance of the band related to aromatic rings, by Gaussian fitting, and modifications in the spectral lines, respectively, also suggested complex formation. The possible complexation had an efficiency of 74% and increased the solubility of the pure colourant 31-fold. Curcumin–β-CD complex exhibited a sunlight stability 18% higher than the pure colourant. This material was stable to pH variations and storage at −15 and 4°C. With an isothermal heating at 100 and 150°C for 2h, the material exhibited a colour retention of approximately 99%. The application of curcumin–β-CD complex in vanilla ice creams intensified the colour of the products and produced a great sensorial acceptance.
Abstract
The objective of this work was to adapt the FT Raman spectroscopy analysis in the differentiation of haploid and diploid kernels in maize, developing a new efficient, agile, precise, and ...nondestructive methodology. The main difference observed in FT Raman readings was a peak in the region between 1600 and 1700 cm
−1
in possibly haploid kernels. It was possible to correlate the characteristics of the kernels with the presence of the
R1‐nj gene
and the readings obtained in the Raman spectrometry technique. Most of the kernels previously classified as haploid showed positive values for principal component analysis (PCAs), indicating a correlation in the identification of haploids by the techniques adopted. The identification of haploids by
R‐Navajo
was superior to FT Raman. However, FT Raman spectroscopy is an agile analysis technique that enables the development of non‐invasive and non‐destructive analytical methods in maize kernels, in addition to providing relevant information about the chemical structures present in the composition of the samples.
Palmarosa essential oil (PEO) is an alternative to synthetic fungicides to control the contamination by food-deteriorating fungi, such as Aspergillus nomius. Nonetheless, the low long-term stability ...and volatility hamper its utilization. Thus, this study aimed to develop nanostructured lipid carriers (NLCs) containing PEO to improve its stability and consequently prolong the activity against A. nomius. A mixture design was applied to find the best preparation conditions for antifungal activity. The characterization analyses included size measurements, zeta potential (ζ-potential), entrapment efficiency (EE), and antifungal activity (by inhibition of mycelial growth (IMG) and/or in situ test (pre-contaminated Brazil nuts) tests). The nanocarriers presented particle sizes smaller than 300 nm, homogeneous size distribution, ζ-potential of −25.19 to −41.81 mV, and EE between 73.6 and 100%. The formulations F5 and F10 showed the highest IMG value (98.75%). Based on the regression model, three optimized formulations (OFs) were tested for antifungal activity (IMG and in situ test), which showed 100% of inhibition and prevented the deterioration of Brazil nuts by A. nomius. The preliminary stability test showed the maintenance of antifungal activity and physicochemical characteristics for 90 days. These results suggest a promising system as a biofungicide against A. nomius.
Pure and Co-doped ZnO nanoparticles were synthesized with different cobalt levels (1–10 mol%) via adapted sol–gel method using water as solvent and characterized by X-ray diffraction, transmission ...electron microscopy, Raman spectroscopy and photoacoustic absorption spectroscopy. The results showed that all the samples have hexagonal wurtzite structure, with no evidence of any secondary phases until 10 mol% of the dopant. The average crystallite size of the samples was in the range of 25–50 nm, do not showing significant differences with the increase of the dopant level. However, the band gap energy of the nanoparticles decreases from 2.98 eV (pure ZnO) to 1.95 eV (10 mol% of Co). The photocatalytic activity of the samples was evaluated on the removal of methylene blue under visible light irradiation, which revealed an efficiency reduction by Co-doping ZnO. The antibacterial property was carried out indicating activity of the prepared samples against gram-positive bacteria.
To investigate the chemical interactions between a high-viscosity glass ionomer cement (GIC) (KetacTM Molar Easymix, 3M ESPE, Seefeld, Bavaria, Germany) and human dentin. It was also analyzed the ...dynamics of GIC setting mechanism based on the time intervals required for the GIC and the GIC mixed with dentin to achieve stability.
Each constituent of GIC - powder (P) and liquid (L) - and powdered dentin (D), as well as the associations P+L, D+L, and P+L+D in the concentrations of 29%, 50%, 65%, 78%, 82%, and 92% of GIC were analyzed with Fourier transform infrared (FTIR) and Raman spectroscopy.
New optical absorption bands and/or Raman bands, which were not present in P, L, or D, were observed in the associations. The concentrations of 29% and 50% of GIC showed higher interaction, revealing that the amount of dentin influences the formation of new optical absorption or scattering bands. FTIR bands showed that the setting time to achieve bond stability was longer for the high-viscosity GIC (38±7 min) than for the sample with 29% of GIC (28±4 min).
The analysis revealed the formation of new compounds or molecular rearrangements resulting from the chemical interactions between GIC and dentin. Moreover, this study provides an effective method to evaluate the dynamics of the setting mechanism of GICs.
This study focused on evaluating a technique for the psyllium husk mucilage (PHM) purification with simultaneous microencapsulation of curcumin. PHM was extracted with water and purified with ...ethanol. For the mucilage purification and simultaneous microencapsulation, an ethanolic solution of curcumin was used. After dehydration, the samples were analysed by instrumental techniques and evaluated for thermal stability. The presence of curcumin in the solution did not impair the yield of precipitated polysaccharide. Interactions of the dye and carbohydrates were confirmed by displacement of peaks in FT-IR and FT-Raman spectroscopy. The onset temperature of degradation of microcapsules was superior to that of curcumin. Thermal stability in solution at 90°C also improved. After 300 minutes of heating, the microcapsules had a remnant curcumin content exceeding 70%, while, in standard sample, the remaining curcumin content was 4.46%. Thus, the developed technique was successful on purification of PHM and microencapsulation of curcumin.
•The cement’s mode of interaction with dentine had no effect on fibre post retention.•The cement’s depth of diffusion did not influence retention of fibre posts either.•However, chemical interaction ...between the cement and dentine was important.•Sandblasting and silane application on posts was preferable to application of universal adhesive.
To investigate the relationship between physicochemical interactions of resin luting cements with dentine and retention of fibre posts in root canals.
Retention of fibre posts (RelyX Fiber Post) was assessed by the pull-out method. The diffusion zone of the cements and their chemical interaction with dentine were estimated by micro-Raman spectroscopy. Resin luting cements employing etch-and-rinse (Rely X Ultimate and Variolink II), self-etch (Rely X Ultimate and Panavia F2.0), or self-adhesive (RelyX Unicem 2) modes were investigated. Data were analyzed by analysis of variance followed by Tukey HSD tests.
The retention of the fibre posts decreased in the following order: RelyX Ultimate, etch-and-rinse mode>RelyX Unicem 2≥RelyX Ultimate, self-etch mode≥Panavia F2.0≥Variolink II (p<0.05). One of the etch-and-rinse mode cements presented the deepest diffusion zone, while the other, along with the self-adhesive cement, produced the shallowest zone. Cements used in the self-etch mode showed intermediary diffusion into dentine (p<0.05). All resin luting cements showed some degree of chemical interaction with dentine, the highest recorded for RelyX Ultimate used in the etch-and-rinse mode and the lowest for Panavia F2.0 (p<0.05). The retention of fibre posts in the root canal could be attributed neither to the mode of interaction of the luting cements with dentine nor to their ability to diffuse into dentine.
Chemical interaction between the resin luting cement and the dentine paired with adequate post pretreatment contribute positively to the retention of fibre posts.
The use of discolored teeth is required to test whitening products, and it is difficult to obtain them, given their scarcity.
To present a technique for in vitro darkening of extracted teeth ...simulating pulpal necrosis discoloration.
Hemolysates I and II from human blood were subjected or not to laser irradiation (442 nm) for 1 h. The concentration of oxyhemoglobin (O
Hb) was analyzed by ultraviolet/visible spectroscopy, and the conversion of O
Hb to methemoglobin (MetHb) by transmission spectroscopy was assessed immediately and after 3 and 40 days. For darkening evaluation, bovine incisors were divided into two groups (n = 25), and their pulp chambers were filled with hemolysate solution II (HSII) and hemolysate II solution + laser (HSII+L). After storage in artificial saliva for 40 days at 37°C, color changes were measured by a colorimeter and ΔE was compared with the NBS parameters. Data were analyzed using a mixed linear model (α=5%).
HSII+L presented the lowest O
Hb and higher MetHb. The conversion of O
Hb to MetHb in HSII+L was 42% higher than in HSII. Both groups were effective in darkening the teeth, according to the NBS. Darkening stabilized from day 35. HSII promoted a marked color difference.
The proposed technique was effective in darkening the extracted teeth simulating necrosis discoloration for in vitro models.
OH−-free calcium aluminosilicate (CAS) glasses present interesting properties for optical and photonic device applications. Optical properties have direct relation with SiO2 content in the glass ...composition. However, there is an interval (10–25 wt%) of SiO2 content which was not capable forming glassy-phase in previous works. In this study, the glass-forming ability was investigated as a function of the SiO2 content within this specific interval. The proposal was to use glass frits as precursor material to overcome this difficulty. Glass frits were produced from CAS glasses with 7 and 34 wt% of SiO2. These compositions were chosen by having a well established production procedure. Using glass frits, samples with concentration of 10, 15, 20 and 25 wt% of SiO2 were produced. With the exception of 25 wt%, all the samples vitrified, X-ray diffraction measurements reveal the amorphous nature of the prepared glasses. Raman spectroscopy and differential thermal analysis show that the samples present formation of a single phase in each sample, and these phases are between the limit phases obtained in the 7 and 34 wt% samples. In addition, mechanical, thermal, optical and thermo-optical properties of the samples were accessed. The results show that glass frits method is an alternative solution for the glass production, and, the process does not affect the sample properties comparing with the standard procedure.
•Glass frits as precursor material to enable the process the production process of OH--free calcium CAS glasses.•X-ray diffraction indicates the characteristic CAS amorphous nature and no crystallization during the glass synthesis.•Raman and DTA confirm the behavior of unique glass phase formation within the standard glass limits phases.•Samples prepared by glass frits show physical properties in agreement with results reported in previous works.•Glass frits method is an alternative for glass production when the standard production procedure is not satisfactory.
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