Michela Alfieri

Development of a NIRS calibration for total antioxidant capacity in maize germplasm.

The feasibility of predicting total antioxidant capacity (TAC) in maize flours by NIRS was assessed in a set of 391 samples, comprising Italian and public inbred lines, F1 seeds, commercial hybrids and traditional varieties, using ABTS direct assay as reference value. A subset of 81 samples were also used to test the development of a calibration model for soluble phenolic content (SPC), whereas 101 samples were analysed by DPPH assay. The models obtained for TAC by ABTS in different genetic materials were characterized by a good stability of the regression coefficients and showed a RER>2, allowing to develop both global and specific predictive models for this trait. On the contrary, only specific models were developed for SPC, and no predictive models were obtained for TAC by DPPH assay. These results demonstrated that NIR spectroscopy could be applied efficiently to the screening of the genotypes currently selected for the food industry.

Gene sequences of vromindolines in Avena species

Vromindolines, a family of oat starch-bound proteins responsible for the extremely soft endosperm of this cereal, are characterized by a tryptophan-rich domain and ten conserved cysteine residues, as it was observed in the starch-bound proteins from other cereals, and proved to be specific of the genus Avena. Two-dimensional electrophoresis of vromindolines from different oat species, both cultivated and wild, revealed that they are present in all genomes and ploidy levels, with no major differences in their molecular weight and electrophoretic mobility. PCR amplification and sequencing of genes coding for VIN-2 and VIN-3 indicated that both proteins are strongly conserved across the species analysed. Some differences were found between diploid and polyploid accessions at specific amino acid positions along the protein. In particular the C-genome accessions (A. clauda, A. eriantha, A. ventricosa) differed from the A-genome diploids (A. canariensis, A. damascena, A. longiglumis, A. nuda, A. strigosa) for some peculiar sequences. Tetraploids (A. barbata, A. magna and A. insularis) showed two sequences each for both proteins; the variability observed in them was similar to that found in A. sativa. The characteristics of these genes could help to clarify the genetic relationship among the various species of the genus Avena. Moreover, the knowledge of the genetic control of these proteins represent an important tool for the modulation of oat endosperm texture.