ABSTRACT
Lupines and faba beans are protein-rich legumes, which can be utilized as a plant-based substitute for animal proteins in human nutrition in general and in the beverage industry in particular. However, their application is hampered by low protein solubility in the acidic pH range and by antinutrients such as flatulence-causing "raffinose family oligosaccharides" (RFOs). Germination is known in the brewing industry for increasing enzymatic activities and mobilizing storage compounds. Therefore, germinations of lupines and faba beans were performed at different temperatures, and their impact on protein solubility, the concentration of free amino acids, and degradation of RFOs, alkaloids, and phytic acid was evaluated. In general, changes were comparable for both legumes but less pronounced in faba beans. Germination depleted the RFOs entirely in both legumes. The protein size distribution was found to be shifted toward smaller fractions, the concentrations of free amino acids multiplied, and protein solubility increased. No substantial reductions in the binding capacity of phytic acid toward iron ions were observed, but a release of free phosphate in lupines was detected. The results prove that germination is an applicable process for refining lupines and faba beans for use not only in refreshing beverages or milk alternatives but also in other food applications.
Subject(s)
Fabaceae , Lupinus , Vicia faba , Animals , Humans , Fabaceae/chemistry , Vicia faba/chemistry , Lupinus/chemistry , Germination , Phytic Acid/metabolism , Solubility , Vegetables/metabolism , Oligosaccharides/metabolism , Raffinose/metabolism , Amino Acids/metabolism , Beverages , Seeds/chemistryABSTRACT
Lupines and faba beans are promising ingredients for the beverage industry. They contain high amounts of protein and can be grown in different climate zones and agricultural areas. Therefore, these legumes appear as ideal raw material for vegan, functional, and sustainable beverages. Nevertheless, the sensory characteristic of legumes is generally not accepted in beverages. Therefore, the market contribution of legume-based beverages is currently only marginal. This review highlights known major flavor aspects of lupines and faba beans and the possibilities to improve these by germination, heat treatment, enzymatic treatment, and subsequent lactic acid fermentation. First, the main aroma and taste compounds are described. Thereby, the "beany" aroma is identified as the most relevant off-flavor. Second, the nutrients and antinutrients of these legumes regarding to their use as food and as substrate for lactic acid fermentation are reviewed, and possibilities to modulate the substrate are summarized. Finally, the modification of the sensory profile by lactic acid fermentation is outlined. To conclude, it seems likely that the nutritional and flavor attributes in legume-based beverages can be improved by a combined process of substrate modulation and fermentation. In a first step, antinutrients should be decomposed and proteins solubilized while transforming the solid grains into a liquid substrate. Due to such substrate modulation, a broader variety of strains could be employed and the fermentation could be based exclusively on their impact on the flavor. By applying the concept of combining a substrate modulation with a subsequent fermentation, the use of legumes in beverages could be facilitated and new products like vegan, protein-rich, refreshing beverages could be marketed.
Subject(s)
Lupinus , Vicia faba , Beverages , Fermentation , Lactic Acid/analysis , Lactic Acid/metabolism , Vegetables , Vicia faba/metabolismABSTRACT
The modulation of biological signal transduction pathways by masking phosphorylated amino acid residues represents a viable route toward pharmacologic protein regulation. Binding of phosphorylated amino acid residues has been achieved with synthetic metal-chelate receptors. The affinity and selectivity of such receptors can be enhanced if combined with a second binding site. We demonstrate this principle with a series of synthetic ditopic metal-chelate receptors, which were synthesized and investigated for their binding affinity to phosphorylated short peptides under conditions of physiological pH. The compounds showing highest affinity were subsequently used to inhibit the interaction of the human STAT1 protein to a peptide derived from the interferon-gamma receptor, and between the checkpoint kinase Chk2 and its preferred binding motif. Two of the investigated ditopic synthetic receptors show a significant increase in inhibition activity. The results show that regulation of protein function by binding to phosphorylated amino acids is possible. The introduction of additional binding sites into the synthetic receptors increases their affinity, but the flexibility of the structures investigated so far prohibited stringent amino acid sequence selectivity in peptide binding.
Subject(s)
Metals/metabolism , Peptides , Checkpoint Kinase 2 , Chelating Agents/metabolism , Humans , Molecular Structure , Peptides/chemistry , Peptides/metabolism , Phosphorylation , Protein Binding , Protein Serine-Threonine Kinases/chemistry , Protein Serine-Threonine Kinases/metabolism , STAT1 Transcription Factor/chemistry , STAT1 Transcription Factor/metabolism , Signal Transduction/physiologyABSTRACT
Artificial ditopic receptors for the differentiation of phosphorylated peptides varying in i+3 amino acid side chains were synthesized, and their binding affinities and selectivities were determined. The synthetic receptors show the highest binding affinities to phosphorylated peptides under physiological conditions (HEPES, pH 7.5, 154 mM NaCl) reported thus far for artificial systems. The tight and selective binding was achieved by high cooperativity of the two binding moieties in the receptor molecules. All receptors interact with phosphorylated serine by bis(ZnII-cyclen) complex coordination and a second binding site recognizing a carboxylate or imidazole amino acid side chain functionality.
Subject(s)
Phosphopeptides/chemical synthesis , Molecular Structure , Phosphopeptides/chemistry , Phosphopeptides/metabolism , Protein Binding , TitrimetryABSTRACT
In the crystal structure of the title compound, [Cu(C(18)H(16)N(6))(C(36)H(28)OP(2))]PF(6)·0.5CH(2)Cl(2) or [Cu(DPEPhos)(Bn-bta)]PF(6)·0.5CH(2)Cl(2) {DPEPhos = bis-[(diphenyl-phosphan-yl)phen-yl] ether and Bn-bta = 1,1'-dibenzyl-1H,1'H-4,4'-bi-1,2,3triazol-e}, the Cu atom is coordinated by two N and two P atoms of the ligands in a strongly distorted tetra-hedral environment. There are two crystallographically independent complex cations present, which differ significantly in their geometrical parameters. The solvent molecule is disordered but satisfactory atomic positions could not be determined.
ABSTRACT
A simple flavin-based catalytic system is able to transform light into chemical output with amplified response utilizing a Cu(I)-catalyzed cycloaddition reaction.
Subject(s)
Flavins/chemistry , Photochemistry , Alkynes/chemistry , Azides/chemistry , Catalysis , Copper/chemistry , Molecular StructureABSTRACT
OBJECTIVE: The measurement and evaluation of ductus venosus (DV) blood flow velocity waveform in high-risk pregnancies has been studied intensively in recent years in order to find a more intermediate signal of fetal compromise. Our objective was to study the fetal outcome of pregnancies with intrauterine growth retardation (IUGR) and normal pulsatility of DV compared to an IUGR group with increased DV pulsatility. METHODS: The outcome of 42 fetuses before 32 weeks of gestational age without chromosomal or structural aberrations was analyzed. All fetuses showed IUGR <5th percentile based on placental insufficiency diagnosed by pathologic RI >90th percentile of both maternal uterine arteries. One group (30 fetuses; mean weight 730 g/SD 190 g; mean gestational age 197 days/SD 12 days) showed normal, the other (12 fetuses, mean weight 675 g/SD 179 g; mean gestational age 198 days/SD 12 days) reduced, but neither absent nor reverse DV flow during atrial contraction. All 42 fetuses were delivered by cesarean section because of severe variable or prolonged decelerations. We measured blood flow velocities of the DV in every fetus on an average 3.7 days (range 1-5 days) before cesarean section. Fetal outcome was determined by Apgar scores after 5 and 10 min, arterial pH and base excess; neonatal morbidity was recorded by intensive follow-up. RESULTS: There were no significant differences of pH, umbilical artery base excess, Apgar scores and severe neonatal complications between the two groups. CONCLUSIONS: Our own data show no correlation between increased pulsatility in the DV (without absent or reverse flow during atrial contraction) and fetal outcome before 32 gestational weeks, even in cases of severe growth restriction based on placental insufficiency. Therefore in these cases reduced DV flow during atrial contraction should cautiously be interpreted regarding obstetrical decisions.