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关键词： caffeine   cyclodextrins   mechanochemical synthesis   analytical methods   toxicity   zebrafish  

摘要： Mechanochemical and in-solution synthesis of caffeine complexes with alpha-, beta-, and gamma-cyclodextrins was optimized. It was found that short-duration, low-energy cogrinding, and evaporation (instead of freeze-drying) are effective methods for the formation and isolation of these complexes. The products obtained, their pure components, and their mixtures were examined by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), FT-IR and Raman spectroscopy. Moreover, molecular modeling provided an improved understanding of the association process between the guest and host molecules in these complexes. The complexes were found to exhibit high toxicity in zebrafish (Danio rerio) embryos, in contrast to pure caffeine and cyclodextrins at the same molar concentrations. HPLC measurements of the caffeine levels in zebrafish embryos showed that the observed cytotoxicity is not caused by an increased caffeine concentration in the body of the organism, as the concentrations are similar regardless of the administered caffeine form. Therefore, the observed high toxicity could be the result of the synergistic effect of caffeine and cyclodextrins.

关键词： carotenoids   guava epicarp   nitrite reduction   frankfurters   fat oxidation  

摘要： Research background. The industrial transformation of tropical fruits, and in particular guava, generates a large quantity of by-products that are generally disposed of as organic waste. In these by-products a large quantity of bioactive substances is concentrated, such as carotenoids, which can be used for the partial substitution of nitrites in meat sausages without affecting their physicochemical, colour and conservation characteristics. Although there are some studies in this regard, there is still a lack of research, especially on guava residues, to verify this hypothesis. Therefore, the aim of this study is to investigate the influence of the components of the guava epicarp extract on the physicochemical, textural, colour and sensory properties of frankfurters. Experimental approach. There treatments were investigated (25, 50 and 75 % nitrite replacement with guava epicarp flour extract), along with a control treatment without the extract. The physicochemical properties, colour coordinates, and texture parameters were analysed, and a sensory evaluation was also carried out. The treatment that gave the best results was subjected to stability analysis over 30 days. Results and conclusions. The addition of 25 % guava epicarp flour extract gave the best results, since it did not affect the colouration of the sausages or their physicochemical and textural properties. Likewise, during the stability analysis over time, the parameters related to fat oxidation were not affected, and final products had a residual nitrite load of (23.6 +/- 0.2) mg/kg, lower than the maximum allowed (150 mg/kg). Novelty and scientific contribution. The partial substitution of the nitrites in frankfurters with the carotenoids from the guava epicarp flour added in a mass fraction up to 25 % can be a viable alternative to produce sausages with lower content of nitrites, without affecting their colouration or shelf life. This is important for the meat industry, which favours the development o

关键词： miso   grass pea   chemical composition   colour   texture   linear viscoelastic behaviour  

摘要： BACKGROUND Western consumers interest in Eastern fermented foods has been growing, due to their nutritional and healthy properties. In this study, new sweet misos and salty misos were produced using grass pea (Lathyrus sativusL.) - traditional Portuguese legume from local producers - to promote its consumption and preservation. The evolution of the new misos was evaluated in comparison to traditional miso (made from soybean), through analysis of the chemical composition, colour, texture and linear viscoelastic behaviour. RESULTS Throughout the fermentation process, the ascorbic acid and phenolic compounds content - with important nutritional value - increased in all misos, mainly in misos produced using grass pea, besides, grass pea sweet miso presented the fastest evolution and darkest colour. The texture parameters (firmness and adhesiveness) of misos decreased over time: grass pea sweet miso showed the highest firmness reduction (51.63 N to 6.52 N) and soybean sweet miso the highest adhesiveness reduction (27.76 N to 3.11 N). Viscoelastic moduli also decreased, reflecting a reduction in the degree of internal structuring for all misos. However, grass pea misos presented more structured internal systems with faster maturation kinetics than soybean misos, for which stabilization started earlier. CONCLUSION Two innovative misos were developed from grass pea. After 4 months, the texture parameters and viscoelastic moduli for grass pea misos, were similar to the control misos made from soybean, showing that grass pea can be used as a raw material to produce a sustainable miso with potentially healthy properties. (c) 2020 Society of Chemical Industry

关键词： Deep sea (-)   Seawater attack (-)   SEM EDS (B)   MAS NMR (-)   Mortar (E)  

摘要： Achieving breakthroughs in marine technologies requires the development of infrastructures submerged in deepsea environments, whose physicochemical effects on cement-based materials considerably differ from those of shallow seas. However, very few studies focused on the cement-based materials subjected to deep-sea conditions. This work investigates the changes in the compressive strength and phase composition of the cement mortar kept on the seafloor with a depth of 1680 m for 608 d. The mortar specimens salvaged from the seafloor exhibited severe visible damages, including softened mashy structures and significantly decreased compressive strengths. The obtained X-ray diffraction, scanning electron microscopy, and nuclear magnetic resonance data revealed that the dissolution of portlandite, decalcification of calcium (alumino) silicate hydrate, and formation of brucite, magnesium (alumino) silicate hydrate, a hydrotalcite-like phase, thaumasite, and ettringite likely contributed to the disintegration of mortar, which could be further accelerated by the low temperature of the deep-sea environment.

关键词： Crops  

摘要： Bambara groundnut, malted sorghum, pearl millet, and banana were processed into flours and mixed in the ratio of 50:20:20:10, respectively. Using response surface methodology, screw speed (300-350 rpm), barrel temperature (180 degrees C-220 degrees C), and feed moisture (12%-16%) were varied and their effects on the chemical, physicochemical, sensory, and microbial characteristics of Bambara groundnut-based ready-to-eat breakfast cereal were investigated. The flour blend showed a significant increase in protein (20.00%) as compared to using cereal grains alone. Improved expansion ratio (7.27), protein solubility (0.36%), and in vitro starch digestibility (157.35 mu g/g) were achieved. Also, overall acceptability of 8.40 for the sweetened sample as well as microbial stable product were established. Bambara groundnut as a base ingredient for food extrusion can be used to produce a more nutritious, less expensive, and an overall acceptable breakfast cereal. Practical applications Breakfast cereals are very handy, especially for urban-based individuals due to tight working schedule resulting to insufficient time for cooking detailed foods. Therefore, the need to remodel the existing starch-based ready-to-eat breakfast cereals to more nutritious protein-based products using affordable local crops is paramount. The use of extrusion cooking would enhance palatability, production yield to meet the daily increasing population, and reduce high postharvest losses due to underutilization of these crops. In summary, the outcome of this study would provide information for the possibility of scaling up production of protein-based ready-to-eat breakfast cereals using available cheap crops and increasing the prevalence of healthy convenience food products in the market.

关键词： Surface analysis  

摘要： Two new organic-inorganic hybrid materials, based on 1,3-CycloHexaneBis-(Methyl Amine), abbreviated CHBMA, namely (H(2)CHBMA)ZnCl4 center dot 2H(2)O (CP1) and (H(2)CHBMA)CdI4 center dot 2H(2)O (CP2), have been synthesized under mild conditions in acidic media and characterized by single-crystal X-ray diffraction, spectroscopic techniques (C-13 NMR, FTIR, RAMAN) and thermal analysis. The crystal structures of the two compounds were solved by single-crystal X-ray diffraction methods. Both compounds show a 3-dimensional supramolecular structure directed by various interactions between tetrahalidometallate anions (ZnCl42-, CdI42-), water molecule and organic cations (H(2)CHBMA)(2+). For both compounds, the cyclohexane ring of the template cation is in a chair conformation with the methylammonium substituent in the equatorial positions and the two terminal ammonium groups in a cis conformation but with two different orientations (upward for CP1 and downward for CP2) which influences the supramolecular architecture of the two structures. Hirshfeld surface analysis and the associated two-dimensional finger print plots were used to explore and quantify the intermolecular interactions in the crystals.

关键词： goat milk   frozen-thawed   nutritive composition   physicochemical characteristic  

摘要： Frozen milk can help producers overcome the seasonality of goat milk production, low goat production and short lactation periods, and avoid discarding milk during some special periods. We investigated effects of combination between freezing (cryogenic refrigerator of -16 to -20 degrees C or ultra-cryogenic refrigerator of -76 to -80 degrees C) and thawing (homeothermy of 20 to 25 degrees C or refrigeration of 2 to 4 degrees C) on nutritive compositions and physicochemical characteristics of raw goat milk during storage period (80 d). Compared with fresh goat milk, the frozen-thawed milk decreased contents of fat, protein, and lactose, as well as surface tension and stability coefficient, whereas increased effective diameter and polydispersity index. The average values of color values (L*, a*, and b*) in 4 group samples changed from 83.01 to 82.25, -1.40 to -1.54, 3.51 to 3.81, respectively, and the Delta E of most samples did not exceed 2. In contrast to the other 3 frozen-thawed treatments, goat milk treated with ultra-cryogenic freezing-homeothermic thawing (UFHT) possessed higher fat (5.20 g/100 g), smaller effective particle diameter (0.32 mu m), and the lowest polydispersity index value (0.26). The color and confocal laser scanning microscopy images of UFHT were similar to those of fresh goat milk, illustrating UFHT was the optimal approach to maintain the natural quality of goat milk. Our finding provides a theoretical basis for producers to freeze surplus milk.

关键词： Red currant   Pectin   Intrinsic viscosity   Osmotic pressure   Dynamic light scattering   Diffusion coefficient  

摘要： In this study red currant was used as a source of pectin. The aim of this study was to investigate the physicochemical properties of obtained polysaccharide, with an emphasis on behaviour in aqueous solutions. Pectin was obtained using water extraction, then the basic characteristics of the obtained polysaccharide was performed (FT-IR-ATR, molar mass distribution, sugar composition, DE). An applied extraction method resulted in a water-soluble pectin fraction with M-omega = 1020 ***(-)(1) and DE = 57.1%. To study the behaviour of pectins in aqueous solutions various methods were used: membrane osmometry, viscosity measurements, rheology, NMR and DLS. The obtained results allowed to describe pectin chains properties in both dilute and semi-dilute regimes, including c* value determination. Osmotic tests indicated low water affinity and strong intermolecular interactions for red currant pectin. Viscosity measurements revealed strong polyelectrolyte behaviour, initially the reduced viscosity of the solutions decreased, until the overlap concentration (c* = 0.78 ***(-1) ) was reached and then increased sharply. Comprehensive interpretation of the results obtained by means of used methods allowed to conclude that red currant pectin takes the form of tightly wound coils in dilute solutions, with increasing concentration chains tending to expand and intermolecular interactions are being enhanced, which result in the formation of complex structures.

关键词： Pretreatment   Vigna subterranea   Germinated flour   Microstructure  

摘要： The physicochemical, functional, thermal properties and in vitro digestibility of flours from germinated Bambara groundnut (BGN) were monitored over 72 h. In a time dependent manner, germination led to significant (p <= 0.05) increases in protein (26.1-28.79 g/100 g), dietary fiber components, digestible starch, in vitro protein digestibility (73.67-88.9%), calcium, magnesium, potassium, total phenolic content, and majority of the amino acids. Germination significantly decreased phytic acid, tannin and trypsin inhibitory activity. Protein solubility, oil and water absorption capacity, foaming capacity, emulsion stability and activity of BGN flour increased significantly with germination. Germination also modified the thermal and pasting properties of the flour. However, scanning electron microscopy did not reveal significant changes in starch granular structure. There were significant decreases in relative crystallinity (57.94-20.92%) as observed from the X-ray diffractograms. This study has demonstrated that germination significantly improved the nutritional, total phenolic content, functional and processing properties of BGN flour. This could encourage its utilization in food product development, particularly as a functional food ingredient.

关键词： Edible mushrooms   Cordyceps militaris   Albumin   Globulin   Glutelin   Sequential extraction  

摘要： The physicochemical and functional as well as structural properties of major protein fractions (albumin, globulin, glutelin) sequentially extracted in water, salt, alkaline solution respectively from Cordyceps militaris Minfu20 fruit body were investigated. The glutelin (43.11%, w/w) was the predominant protein component of C. militaris fruit body followed by albumin (36.47%) and globulin (17.94%). The three proteins extracted from different solvents showed different characteristics, which were related to the alternation of amino acid composition, surface hy-drophobicity, and structural feature. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the albumin and globulin mainly consisted of polypeptides with size < 20 kDa. The glutelin showed serious staining on the lane which may have a relatively bigger molecular weight. Intrinsic fluorescence intensity (FI) suggested glutelin contained more unfolding conformations (highest FI) which were probably resulted in a better foaming capacity of 151% and emulsion formation with the smallest size oil droplets (10.410 ?m). The protein fractions showed great nutritional quality since they satisfied all recommended essential amino acid allowances for adults of Food & Agriculture Organization (FAO)/World Health Organization (WHO). Therefore, Cordyceps militaris Minfu20 fruit body proteins have potential alternative renewable edible fungi (mushroom) protein and could be used effectively as a food ingredient to improve food nutrition and product diversification compared with plant proteins.