1,721,010 research outputs found
Structural aspects of legume proteins and nutraceutical properties
No full textLegume proteins have been recognized to have a nutritional role far beyond that providing essential amino acids.
Besides small peptides, also partially digested proteins of different length and even intact proteins may play
important physiological and health-promoting effects, notably protection of cardiovascular health, reduction of
inflammation and cancer risk, weight control, and increased insulin sensitivity. Chance of modulating these
effects through control of protein structure is the challenge of future research. In particular, a deep understanding
of how protein structure impacts the release of bioactive sequences, as well as of structural modification
occurring during technological processing and gastrointestinal digestion will drive novel strategies aimed at
the improvement of nutraceutical potential of protein-rich plant foods. Major current knowledge about
relationship between protein structural features and bioactivity of specific seed components, will be presented
here. Structural elements relevant for biochemical, immunological and pharmaceutical activity ofwhole proteins
and peptides fromlegumes, in comparison with those from other plant foods, will be pointed out and discussed
Quantification of secondary structure elements of food proteins by diffuse reflectance FT-IR spectroscopy (DRIFTS): relationship to in vivo utilization
No full textRelationship between digestibility and secondary structure of raw and thermally treated legume proteins: a Fourier transform infrared (FT-IR) spectroscopic study
No full textThe secondary structure of proteins in legumes, cereals, milk products and chicken meat was studied by diffuse reflectance infrared spectroscopy in the region of the amide I band. Major secondary structure components ( beta-sheets, random coil, alpha-helix, turns), together with the low- and high-frequency side contributions, were resolved and related to the in vitro digestibility behaviour of the different foods. A strong inverse correlation between the relative spectral weights of the beta-sheet structures and in vitro protein digestibility values was measured. Structural modifications in legume proteins induced by autoclaving were monitored by the changes in the amide I spectra. The results indicate that the beta-sheet structures of raw legume proteins and the intermolecular beta-sheet aggregates, arising upon heating, are primary factors in adversely affecting the digestibility
FAR-INFRARED SPECTRA OF N2-AR ALLOYS
No full textThe far-infrared spectra of (N2)1-xArx solid mixtures have been studied at 18 K and p=0 for 0<x<0.25. At x=0, in addition to the phonon peaks Tu(1) and Tu(2), the combination bands recently observed at high pressure have been detected. In the alloy, the width of Tu(1) increases with x while its central frequency slowly decreases. In the phase (x=0.25) a translational mode still exists, which can be derived from the Tu(1) mode of the phase. Tu(2) is nearly insensitive to the concentration of impurities, but it disappears at the - transition. A concentration x=0.05 of Kr atoms is found to enhance the intensity of absorption in solid N2 by a factor of 5. © 1989 The American Physical Society
Chemico-physical and nutritional properties of traditional legumes (lentil, Lens culinaris L., and grass pea, Lathyrus sativus L.) from organic agriculture: an explorative study
No full textLegume crops represent a low input cultivation system, especially suitable to grow in organic farming conditions. We report here on chemico-physical, technological and nutritional evaluation of traditional lentils (Lens culinaris L.) and grass peas (Lathyrus sativus L.), consisting in local ecotypes at high risk of extinction. Lentils and grass peas were grown either under certified organic agriculture in the National Park of Alta Murgia in the Apulia region (Altamura) or under traditional practices in internal hill areas of the National Park of Cilento (Castelcivita) and in the High Sele Valley (Colliano), in the Campania region. Results indicate that lentils and grass pea from organic and traditional farming are characterized by peculiar properties, suggesting a high nutritional quality. In particular, it was possible to point out differences among ecotypes (i) in major building elements (α-helix, β-sheet) responsible for protein functionality and (ii) in the composition of phenolic (p-coumaric, ferulic, caffeic, vanillic) acid fractions with high bioavailability
Polaronic optical absorption in semiconducting and superconducting oxides
No full textThe infrared and Raman spectra of High-Tc superconductors (HCTS) in the normal phase exhibit vibrational modes (IRAV) which are superimposed to a Drude background from high-mobility carriers. In the far infrared the IRAV appear as well-resolved peaks, shifted in energy with respect to the normal modes of the lattice. In the midinfrared they are grouped into a broad polaron band peaked at about 0.1 eV. At corresponding energies, in the semiconducting phase one observes bands that are unambiguously identified as polaronic. Moreover, the IRAV show remarkable correspondences with the peaks in the Eliashberg function as determined in the same systems by tunneling measurements. These results point towards the existence of two types of carriers in HCTS, one at least being polaronic in nature
Application of Fourier transform infrared spectroscopy to legume seed flour analysis
No full textThe secondary structure of legume (Phaseolus vulgaris L. and Lens culinaris L.) proteins was investigated by studying the amide I infrared absorption band in whole seed flours, before and after dry heating and autoclaving thermal treatments. The analysis procedure, set up on 7S and different model proteins, shows that the content of β-sheet structures in lentil is higher than in common bean (47% vs. 32%). The dry heating does not appreciably affect secondary structures in lentil, while it causes a reduction of β-sheets (to 13%), an increase of aggregates, and the appearance of random coil structures in common bean. The autoclaving treatment produces high amounts of aggregates in both legumes. However, in lentil, random coil structures are lower than in common bean and some β-sheet structures are still detectable. These results indicate that multimeric heat-induced complexes of legume proteins have a high stability because of the high content in β-sheet structures, in particular in lentil, which may adversely affect protein utilization. © 2007 Elsevier Ltd. All rights reserved
- …
