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To investigate the effect of the interaction between protocatechuic acid (PCA) and gelatin on the functional properties and stability of gelatin-PCA complexes. Gelatin-PCA complexes were prepared by non-covalent and covalent binding. Afterward, the interaction between PCA and gelatin was analyzed using UV-Vis spectroscopy, fluorescence spectroscopy, and Fourier transform infrared spectroscopy. Meanwhile, an analysis was also performed on the antioxidant activity, antibacterial activity, and stability of the complexes. The findings showed a higher PCA binding rate for the covalent complexes than the non-covalent complexes. Additionally, the interaction between PCA and gelatin resulted in the fluorescence quenching of gelatin, with a higher level of fluorescence quenching observed for the covalent binding. Moreover, in addition to excellent DPPH and ABTS+ radical scavenging abilities. Compared with GPCA-2, the noncovalent complex GPCA-1 showed more significant (P<0.05) scavenging abilities against DPPH and ABTS+ free radicals, with clearance rates of 49.71%±2.9% and 38.39%±0.57%, respectively. Gelatin-PCA complexes also exhibited antibacterial activity against Escherichia coli, Listeria monocytogenes, and Salmonella. Moreover, the antibacterial effect of GPCA-1 was more significant (P<0.05), with inhibition zone diameters of 11.31±0.91, 12.57±0.93 and 8.83±0.35 mm for E. coli, L. monocytogenes and Salmonella, respectively. Despite reducing the antioxidant and antibacterial activities of PCA to some extent, the interaction between PCA and gelatin significantly (P<0.05) improved the photostability and thermal stability of PCA. Specifically, the retention rates of PCA in gelatin-PCA covalent complexes after 80 min of UV and heat treatment were 92.58%±0.62% and 90.30%±0.97%, respectively. In conclusion, these findings provide a theoretical basis for the development and utilization of functional gelatin-PCA complex products. [ABSTRACT FROM AUTHOR]

Ink as an important part of documents is a key material evidence in the field of forensic science. Its in-depth study and accurate identification are of great significance for the detection and trial of cases. Different inks may have different volatile components, so these volatile components play an important role in the identification of ink and the judgment of the writing age. According to the different application fields and components, the types and components of ink are sorted out, and various instrument methods for the identification of volatile components are introduced, mainly including UV-Vis spectroscopy, Raman spectroscopy, infrared spectroscopy, fluorescence spectroscopy, gas chromatography，gas-liquid combination method, mass spectrometry，etc. These methods have their own advantages and disadvantages, and are suitable for different inks. In addition, the development of ink volatile component testing methods is prospected, and the existing defects in the current methods are pointed out, in order to provide reference for forensic science document testing workers. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Interaction between epigallocatechin gallate (EGCG) and millet bran protein under conditions that simulate human physiological conditions was investigated by Endogenous fluorescence spectroscopy synchronous fluorescence spectroscopy, Three-dimensional fluorescence spectroscopy and ultraviolet-visible spectroscopy. The results indicated that EGCG can greatly quench the endogenous fluorescence of millet bran protein in the mixed of static mode and dynamic mode. Synchronous fluorescence spectroscopy, ultraviolet-visible spectroscopy and three-dimensional fluorescence spectroscopy indicated that EGCG changed the protein peptide backbone and microenvironment of aromatic amino acid residues of millet bran protein. The synchronous fluorescence results showed that they mainly affected the microenvironment around tryptophan residues and reduced the hydrophobicity of the surrounding microenvironment. The binding constants (KA) and site numbers (n) between EGCG and millet bran protein obtained at different temperatures were 8.691 6×104 L/moL, 1.084 8 (290 K); 1.317 0×106 L/moL, 1.300 9 (298 K); 7.868 6×106 L/moL, 1.489 3 (310 K), respectively. According to the thermodynamic parameters, EGCG and millet bran protein were combined by hydrophobic interaction to form a complex. The binding distance (r) between EGCG and millet bran protein was calculated to be about 2.341 8 nm based on the theory of Föster’s non-radiation energy transfer. The theoretical model of the binding ratio between EGCG and millet bran protein at different temperatures was established, and the binding ratio between EGCG and millet bran protein decreased as concentration of EGCG increased, while the temperature had effect on the binding ratio.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND There are differences in the production characteristics, chemical composition, coloration mechanism and formation conditions of green tourmaline from different producing areas. At present, the mineral species and coloration mechanism of Tanzanian green tourmaline have not been solved, which makes it difficult for its scientific identification and quality rating. OBJECTIVES To study the mineralogical characteristics and coloration mechanism of Tanzanian green tourmaline. METHODS The mineral component was analyzed by infrared spectroscopy and Raman spectroscopy. Microtexture was characterized by polarized light microscopy. Electron probe microanalyzer, and ultraviolet-visible (UV-Vis) spectroscopy were applied to analyze the chemical composition. RESULTS The main mineral component of tourmaline in Tanzania was MgO tourmaline, which was characterized by single crystal, small grain, no cleavage, and split development, and can be used as a gemstone. The main chemical component of green tourmaline was SiO2, Al2O3, MgO and B2O3, with average contents of 37.52%, 36.26%, 9.65% and 8.42%, respectively. In addition, it contained a small amount of FeO, Cr2O3 and TiO2. Combined with the absorption spectrum in the ultraviolet region of 440nm, 600nm and 680nm in UV-Vis spectroscopy, it was concluded that the tiny amounts of Cr3+ replacing Al3+ into the crystal lattice was the main cause of the green color. CONCLUSIONS The mineralogical characteristics and coloration mechanism of green tourmaline in Tanzania was confirmed, which provides a theoretical basis for the scientific identification, further quality evaluation and utilization.

Two novel stigmasterol derivatives as gelators are synthesized，and named as compounds 1 and 2， respectively. The structure and properties of gels are studied by scanning electron microscopy（SEM），Fourier transform infrared spectroscopy（FT-IR）and UV-Vis spectrophotometer. The results of the gelation properties of compounds 1 and 2 show that they could gelate in DMSO and methanol. Compound 1 also forms a stable gel in DMSO/water mixed solvents at a volume ratio of 9∶1，8∶2，and 7∶3，respectively. In addition，when compounds 1 and 2 are gelated at a mass concentration of 12 mg/mL in DMSO，the gel-sol phase transition temperatures（Tgel）of the two compounds are 51 and 46 ℃，respectively，indicating that the thermal stability of their gelation decreases significantly with the increase of steroidal structural units in the gelator. With the increase of steroid structural units in the gelators，the thermal stability of the gel formation decreases significantly. On this basis，the gel prepared by compound 1 is used as the carrier，and its encapsulation and release in rhodamine B and methylene blue，as well as the anticancer drug doxorubicin are studied by UV-Vis spectroscopy. The results show that the prepared gels could be used as a drug carrier，and the maximum release value reaches 84% in water at 240 min. Furthermore，this study may provide a useful idea for the preparation of stigmasterol derivative gels and its application as a drug carrier in drug delivery. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hebei University of Science & Technology is the property of Hebei University of Science & Technology, Journal of Hebei University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: There are differences in the production characteristics, chemical composition, coloration mechanism and formation conditions of green tourmaline from different producing areas. At present, the mineral species and coloration mechanism of Tanzanian green tourmaline have not been solved, which makes it difficult for its scientific identification and quality rating. OBJECTIVES: To study the mineralogical characteristics and coloration mechanism of Tanzanian green tourmaline. METHODS: The mineral component was analyzed by infrared spectroscopy and Raman spectroscopy. Microtexture was characterized by polarized light microscopy. Electron probe microanalyzer, and ultraviolet-visible (UV-Vis) spectroscopy were applied to analyze the chemical composition. RESULTS: The main mineral component of tourmaline in Tanzania was MgO tourmaline, which was characterized by single crystal, small grain, no cleavage, and split development, and can be used as a gemstone. The main chemical component of green tourmaline was SiO2, Al2O3, MgO and B2O3, with average contents of 37.52%, 36.26%, 9.65% and 8.42%, respectively. In addition, it contained a small amount of FeO, Cr2O3 and TiO2. Combined with the absorption spectrum in the ultraviolet region of 440 nm, 600 nm and 680 nm in UV-Vis spectroscopy, it was concluded that the tiny amounts of Cr3+ replacing Al3+ into the crystal lattice was the main cause of the green color. CONCLUSIONS: The mineralogical characteristics and coloration mechanism of green tourmaline in Tanzania was confirmed, which provides a theoretical basis for the scientific identification, further quality evaluation and utilization. [ABSTRACT FROM AUTHOR]