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Pest resistance molecules, α-amylase/trypsin inhibitors from wheat, activate innate immune cells through engagement of TLR4 to elicit inflammatory responses in the intestine.

A combined extraction‐HPLC procedure was developed on a microscale to determine the amounts of the different gluten protein types (ω5‐, ω1,2‐, α‐ and γ‐gliadins; high molecular weight [HMW] and low molecular weight [LMW] glutenin subunits) in wheat flour. After preextraction of albumins and globulins from flour (100 mg) with a salt solution (2 × 1.0 mL), extraction of gliadins was achieved with 60% aqueous ethanol (3 × 0.5 mL). Subsequently, the glutenin subunits were extracted under nitrogen and at 60°C with 50% aqueous 1‐propanol containing Tris‐HCl (0.05 mol/L, pH 7.5), urea (2 mol/L) and dithioerythritol (1%). The separation and quantitative determination of gliadins and glutenin subunits was then performed by reversed‐phase HPLC on C8 silica gel at 50°C using a gradient of increasing acetonitrile concentration in the presence of 0.1% trifluoroacetic acid. The flow rate was 1.0 mL/min, and the detection wavelength was 210 nm. Temperature and flow rate were modified for the quantitation of single underivatized HMW subunits. To determine the absolute amounts of protein types, different protein standards (gliadin, LMW and HMW subunits, bovine serum albumin) with known protein contents were compared to HPLC absorbance areas. The calibration curves were almost identical and linear over a broad range (20–220 μg). This extraction‐HPLC procedure allows an accurate, reproducible, sensitive, and relatively fast quantitative determination of all gluten protein types in wheat flour, and can be applied to quality evaluation of cereals as raw materials or in processed products.

Spring wheat (Triticum aestivum L. cv. TRISO) was grown for three consecutive seasons in a free‐air carbon dioxide (CO2) enrichment (FACE) field experiment in order to examine the effects on crop yield and grain quality. CO2 enrichment promoted aboveground biomass (+11.8%) and grain yield (+10.4%). However, adverse effects were predominantly observed on wholegrain quality characteristics. Although the thousand‐grain weight remained unchanged, size distribution was significantly shifted towards smaller grains, which may directly relate to lower market value. Total grain protein concentration decreased significantly by 7.4% under elevated CO2, and protein and amino acid composition were altered. Corresponding to the decline in grain protein concentration, CO2 enrichment resulted in an overall decrease in amino acid concentrations, with greater reductions in non‐essential than essential amino acids. Minerals such as potassium, molybdenum and lead increased, while manganese, iron, cadmium and silicon decreased, suggesting that adjustments of agricultural practices may be required to retain current grain quality standards. The concentration of fructose and fructan, as well as amounts per area of total and individual non‐structural carbohydrates, except for starch, significantly increased in the grain. The same holds true for the amount of lipids. With regard to mixing and rheological properties of the flour, a significant increase in gluten resistance under elevated CO2 was observed. CO2 enrichment obviously affected grain quality characteristics that are important for consumer nutrition and health, and for industrial processing and marketing, which have to date received little attention.

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