Association between SNP Markers and 11 Vitamin Contents in Grains of a Worldwide Bread Wheat Core Collection.

The metabolomic profiling analyses of 11 vitamins' statuses of wheat grain in a subsample of 167 accessions from the INRAE worldwide bread wheat core collection planted in two contrasting environments in France (Le Moulon and Clermont-Ferrand) have been evaluated using a high-throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) procedure. This has allowed us to perform a genome-wide association study (GWAS) for these nutritional traits of interest combining the phenotypic data with the genotypic data derived from the TaBW280K SNP chip. Considering both thresholds (P < 0.0003 and R2 ≥ 8%), the GWAS identified between 1 and 22 marker-trait associations (MTAs) for the individual vitamins at the individual locations, and 12 SNP markers were stable and associated with vitamin contents across two environments. Desirable alleles and superior genotypes identified in the current analysis provide novel genetic data that can be used for future research on the genetics of vitamins and their application in wheat breeding.

Development of a LC-MS/MS method for the simultaneous screening of seven water-soluble vitamins in processing semi-coarse wheat flour products.

Wheat is the second largest crop cultivated around the world and constitutes a major part of the daily diet in Europe. It is therefore important to determine the content of micronutrient in wheat and wheat-based food products to define the contribution of wheat-based foods to the nutrition of the consumers. The aim of the present work was to develop a simple and rapid method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of seven water-soluble vitamins in various wheat-based food materials. The vitamins present in the test material were separated in less than 15 min by using a reverse-phase C18 column, and analyzed by positive ion electrospray selected reaction monitoring MS/MS. The MS response for all the vitamins was linear over the working range (0.05 to 9 µg/mL) with correlation coefficients ranging between 0.991 and 1. Limits of quantification in the different food materials ranged from 0.09 to 3.5 µg/g. Intra-day and inter-day precision were found satisfactory. The developed method was applied for the simultaneous analysis of the water-soluble vitamin natural content of different semi-coarse wheat flours and in their corresponding baking products.

Reliable and inexpensive colorimetric method for determining protein-bound tryptophan in maize kernels.

Biofortification programs in maize have led to the development of quality protein maize (QPM) with increased contents of the essential amino acids lysine and tryptophan, and increased nutritional value for protein deficient populations where maize is a staple food. Because multiple genetic systems control and modify the protein quality of QPM, tryptophan or lysine monitoring is required to maximize genetic gain in breeding programs. The objective of this work was to develop an accurate, reliable, and inexpensive method for tryptophan analysis in whole-grain maize flour to support QPM research efforts around the world. Tryptophan reacts with glyoxylic acid in the presence of sulfuric acid and ferric chloride, producing a colored compound that absorbs at 560 nm. A series of experiments varying the reagent concentrations, hydrolysis time, and length of the colorimetric reaction resulted in an optimized protocol which uses 0.1 M glyoxylic acid in 7 N sulfuric acid and 1.8 mM ferric chloride, and 30 min reaction time. This method produced stable and reproducible results for tryptophan concentration in whole-grain maize flour and was validated by comparison with data obtained using an acetic acid-based colorimetric procedure (r(2) = 0.80) and high pressure liquid chromatography (HPLC) (r(2) = 0.71). We describe adaptations that permit high throughput application of this tryptophan analysis method using a microplate platform.