Occurrence of spp. in Maize Grain Harvested in Portugal and Accumulation of Related Mycotoxins during Storage.

Maize is an important worldwide commodity susceptible to fungal contamination in the field, at harvest, and during storage. This work aimed to determine the occurrence of spp. in maize grains produced in the Tagus Valley region of Portugal and the levels of related mycotoxins in the 2018 harvest and during their storage for six months in barrels, mimicking silos conditions.

Spectral features and stability of oligomeric pyranoanthocyanin-flavanol pigments isolated from red wines.

The spectral characteristics and stability of three red wine pigments (pyranoMv-catechin, pyranoMv-epicatechin, and pyranoMv-dimer B3) toward pH variation and bisulfite bleaching, as well as their color stability and degradation during storage, have been studied. Unlike the absorbance spectra of most wine pigments, the intensity of which is more increased in more acidic conditions, oligomeric pyranoMv-flavanols have maximum absorbance at wine pH around 3.6, up to 30-50% higher than that in pH 1.

Quantum Semiempirical Energy Based (SEEB) Descriptors Performance with Benzamidine Inhibitors of Trypsin.

MLR is a classical approach to regression problems in QSARs. In this study, the behaviour of SEEB descriptors was analysed with a MLR model. For this purpose a SEEB/MLR 3D-QSAR model was developed to evaluate the efficiency of benzamide trypsin inhibitors.

Unusual color change of vinylpyranoanthocyanin-phenolic pigments.

Anthocyanins are responsible for an interesting variety of colors in flowers, red fruits, and plant-derived foodstuffs. Experimental evidence is presented supporting an unusual color change from red to blue during storage. It has been investigated as a function of temperature at constant pH (pH <2).

Exact and effective pair-wise potential for protein-ligand interactions obtained from a semiempirical energy partition.

In this work, the partition method introduced by Carvalho and Melo was used to study the complex between Cucurbita maxima trypsin inhibitor (CMTI-I) and glycerol at the AM1 level. An effective potential, combining non-bonding and polarization plus charge transfer (PLCT) terms, was introduced to evaluate the magnitude of the interaction between each amino acid and the ligand. In this case study, the nonbonding-PLCT non-compensation characterizes the stabilization energy of the association process in study.

Isolation and structural characterization of new acylated anthocyanin-vinyl-flavanol pigments occurring in aging red wines.

Three newly formed pigments were detected and isolated from a 2-year-old Port wine through TSK Toyopearl HW-40(S) gel column chromatography and characterized by UV-visible spectrophotometry, NMR, and mass spectrometry (ESI/MS). (1)H NMR and (13)C NMR data for these pigments obtained using 1D and 2D NMR techniques (COSY, NOESY, gHSQC, and gHMBC) are reported for the first time. The structure of the pigments was found to correspond to the vinyl cycloadducts of malvidin 3-coumaroylglucoside bearing either a procyanidin dimer or a flavanol monomer ((+)-catechin or (-)-epicatechin).