THERMAL, PASTING AND RHEOLOGICAL PROPERTIES OF PROCESSED BUCKWHEAT (FAGOPYRUM ESCULENTUM) FLOUR

  Objective: The aim of the study was to analyze the effect of various processing treatments on thermal, pasting, and rheological properties of buckwheat flour.Methods: Buckwheat seeds were processed through different processing treatments including cooking, germination, and fermentation, and their flours were produced. The processed flours were analyzed for their thermal properties using differential scanning calorimeter, pasting properties using rapid visco-analyzer, and rheological properties using rotational rheometer.Results: Fermented buckwheat flour showed significantly (p≤0.05) higher onset temperature (To=66.6°C), peak temperature (Tp=71.15°C), conclusion temperature (Tc=78.03°C), and enthalpy of gelatinization (1.89 J/g). The peak viscosity ranged from 39 to 1299 cp, lowest for cooked buckwheat flour and highest for fermented buckwheat flour. The native buckwheat flour showed the highest value, whereas cooked buckwheat flour showed the lowest value for storage modulus (G') and loss modulus (Gâ€). The value of tan ∂ was lower than 1 for native and processed buckwheat dough.Conclusion: The changes observed in physicochemical properties of buckwheat flour after processing treatments provided a crucial basis for its potential applications on an industrial scale. Furthermore, buckwheat seeds are gluten-free; therefore, their flour or products can be used for persons suffering from celiac diseases

Aminotroponiminatogermaacid Halides with a Ge(E)X Moiety (E = S, Se; X = F, Cl)

Fluorination of aminotroponiminate (ATI) ligand-stabilized germylene monochloride [(t-Bu)(2)ATI]GeCl (1) with CsF gave the aminotroponiminatogermylene monofluoride [(t-Bu)(2)ATI]GeF (2). Oxidative addition reaction of compound 2 with elemental sulfur and selenium led to isolation of the corresponding germathioacid fluoride [(t-Bu)(2)ATI]Ge(S)F (3) and germaselenoacid fluoride [(t-Bu)(2)ATI]Ge(Se)F (4), respectively. Similarly, reaction of aminotroponiminatogermylene monochloride [(i-Bu)(2)ATI]GeCl (9) with elemental sulfur and selenium gave the aminotroponiminatogermathioacid chloride [(i-Bu)(2)ATI]Ge(S)Cl (11) and aminotroponiminatogermaselenoacicl chloride [(i-Bu)(2)ATI]Ge(Se)Cl (12), respectively. Compound 9 has been prepared through a multistep synthetic route starting from 2-(tosyloxy)tropone S. All compounds (2-4 and 6-12) were characterized through the multinuclear NMR spectroscopy, and single-crystal X-ray diffraction studies were performed on compounds 2, 4, and 8-12. The germaselenoacid halide complexes 4 and 12 showed doublet (-142.37 ppm) and singlet (-213.13 ppm) resonances in their Se-77 NMR spectra, respectively. Germylene monohalide complexes 2 and 9 have a germanium center in distorted trigonal pyramidal geometry, whereas a distorted tetrahedral geometry is seen around the germanium center in germaacid halide complexes 4, 11, and 12. The length of the Ge=E bond in germathioacid chloride (11) and germaselenoacid halide (4 and 12) complexes is 2.065(1) and 2.194(av) angstrom, respectively. Theoretical studies (based on the DFT methods) on complexes 4, 11, and 12 reveal the nature of the Ge=E multiple bond in these germaacid halide complexes with computed Wiberg bond indices (WBI) being 1.480, 1.508, and 1.541, respectively

Use of Thio and Seleno Germanones as Ligands: Silver(I) Halide Complexes with Ge=E -> Ag-I (E = S, Se) Moieties and Chalcogen-Dependent Argentophilic Interaction

The potential of thio and seleno germanones [LPhGe=E] (L = aminotroponiminate (ATI) ligand, E = S 3, Se 4) to function as ligands has been demonstrated through the isolation of their silver(I) iodide complexes [{(t-Bu)(2)ATIGe(E)-Ph)(2)(Ag2I2)] (E = S 5, Se 6) with a planar and discrete Ag2I2 core. Compounds 5 and 6 possess the hitherto unknown Ge=E -> Ag-I moieties and the crystallographic data reveals the presence of a strong argentophilic interaction (2.950(1) angstrom) in complex 6, but is inconclusive in complex 5 (3.470(1) angstrom). Using theoretical studies, proof for the presence and absence of argentophilic interactions in complexes 6 and 5 was obtained, respectively. Further, it is disclosed that the donor ability of the chalcogen atoms in the Ge=E -> Ag-I moieties dictate the Ag center dot center dot center dot Ag interaction in these complexes

Digermylene Oxide Complexes: Facile Synthesis and Reactivity

A simple heating of aminotroponiminate (ATI) ligand stabilized germylene monochlorides [(R)(2)ATIGeCl] (R = t-Bu 1, i-Bu 2) with an excess of potassium hydroxide in toluene resulted in the first ATI ligand stabilized digermylene oxides [{(R)(2)ATIGe}(2)O] (R = t-Bu 3, i-Bu 4), respectively. Reaction of compound 3 with elemental sulfur and selenium gave the first germaacid anhydride complexes [{(t-Bu)(2)ATIGe(E)}(2)O] (E = S 5, Se 6) with (S)Ge-O-Ge(S) and (Se)Ge-O-Ge(Se) moieties, respectively. The digermylene oxide complexes 3 and 4 and germaacid anhydride complexes 5 and 6 were characterized by multinuclear NMR spectroscopy and single-crystal X-ray diffraction analysis. In its Se-77 NMR spectrum, compound 6 showed a resonance at -78.9 ppm. The Ge-O-Ge bond angles in compounds 5 and 6 are 178.66(2)degrees and 179.81(2)degrees, respectively. To understand further the bonding features, DFT calculations followed by MO, AIM, and NBO analysis were carried out on compounds 3, 5, and 6. The computed Wiberg bond indices of Ge-O bonds are slightly less than 0.5 in all the aforementioned compounds, and the same for the Ge=E bonds in compounds 5 and 6 are close to 1.4

Are Ligand-Stabilized Carboxylic Acid Derivatives with Ge=Te Bonds Isolable?

The stability of ligand-stabilized carboxylic acid derivatives (such as esters, amides, anhydrides, and acid halides) with terminal Ge=Te bonds is highly questionable as there is no report on such compounds. Nevertheless, we are able to isolate germatelluroester [LGe(Te)Ot-Bu] (4), germatelluroamide [LGe(Te)N(SiMe3)(2)] (5), and germatelluroacid anhydride [LGe(Te)OGe(Te)L] (6) complexes (L = aminotroponiminate (ATI)) as stable species. Consequently, the synthetic details, structural characterization, and UV-vis spectroscopic and theoretical studies on them are reported for the first time

Reactivity of LGe-NR2 and LGe(E)-NR2 over LGe-Cl and LGe(E)-Cl toward Me3SiX (L = Aminotroponiminate; NR2 = N(SiMe3)(2)/NC4H4; E = S/Se; X = Br/CN)

The halogen exchange reaction of either germylene monochloride [LGeCl] (1) or germachalcogenoacid chlorides [LGe(E)Cl] (L = (i-Bu)(2)ATI; ATI = aminotroponiminate; E = S (V)/Se (VI)) with Me3SiX (X = Br/CN) did not occur. Therefore, the reactions of germanium compounds containing Ge-N bonds with Me3SiBr/CN were tried. Germylene amide [LGeN(SiMe3)(2)] (2) reacted with Me3SiBr to afford the aminotroponiminatogermylene monobromide [LGeBr] (3). Similarly, the chalcogen derivatives of compound 2, viz., germachalcogenoamides [LGe-(E)N(SiMe3)(2)] (E = S 4 and Se 5) reacted with Me3SiBr and resulted in germachalcogenoacid bromides [LGe(E)Br] (E = S 6 and Se 7), respectively. N-Germylene pyrrole [LGeNC4H4] (2a) and N-germachalcogenoacylpyrroles [LGe(E)NC4H4] (E = S 4a, Se 5a) also reacted with Me3SiBr and afforded compounds 3, and 6-7 in excellent yields, respectively. Interestingly, the reaction of compound 2a with Me3SiCN afforded germanium(II) cyanide [LGeCN] (8). The difference in the reactivity of compounds (1, V, and VI) with Ge-Cl bonds against the compounds (2, 4, and 5) with Ge-N bonds was analyzed theoretically