Comparative Study on Gluten Protein Composition of Ancient (Einkorn, Emmer and Spelt) and Modern Wheat Species (Durum and Common Wheat).

Geisslitz Geisslitz,Scherf Scherf,Koehler Koehler,Longin Longin

doi:10.3390/foods8090409

Abstract

The spectrophotometric Bradford assay was adapted for the analysis of gluten protein contents (gliadins and glutenins) of spelt, durum wheat, emmer and einkorn. The assay was applied to a set of 300 samples, including 15 cultivars each of common wheat, spelt, durum wheat, emmer and einkorn cultivated at four locations in Germany in the same year. The total protein content was equally influenced by location and wheat species, however, gliadin, glutenin and gluten contents were influenced more strongly by wheat species than location. Einkorn, emmer and spelt had higher protein and gluten contents than common wheat at all four locations. However, common wheat had higher glutenin contents than einkorn, emmer and spelt resulting in increasing ratios of gliadins to glutenins from common wheat (< 3.8) to spelt, emmer and einkorn (up to 12.1). With the knowledge that glutenin contents are suitable predictors for high baking volume, cultivars of einkorn, emmer and spelt with good predicted baking performance were identified. Finally, spelt, emmer and einkorn were found to have a higher nitrogen partial factor productivity than common and durum wheat making them promising crops for a more sustainable agriculture.

Highlights

The “ancient” wheats einkorn (Triticum monococcum L., diploid), emmer (T. dicoccum L., tetraploid) and spelt (T. aestivum ssp. spelta, hexaploid) have been cultivated in very low amounts compared to the “modern” wheat species common wheat (T. aestivum L., hexaploid) and durum wheat (T. durumL., tetraploid) in the 20th century
It was unknown if the GLIA and GLUT fractions from common wheat were suitable as calibrants for the other wheat species, because the composition of gluten protein types varies considerably [11,18]
Contents of GLIA and GLUT fractions in eight cultivars of each wheat species, which were already characterized in detail for gluten protein composition and for baking quality [11], were quantitated both with the photometric Bradford assay and by reversed-phase high-performance liquid chromatography (RP-HPLC)

Summary

Introduction

The “ancient” wheats einkorn (Triticum monococcum L., diploid), emmer (T. dicoccum L., tetraploid) and spelt (T. aestivum ssp. spelta, hexaploid) have been cultivated in very low amounts compared to the “modern” wheat species common wheat (T. aestivum L., hexaploid) and durum wheat (T. durumL., tetraploid) in the 20th century. Spelta, hexaploid) have been cultivated in very low amounts compared to the “modern” wheat species common wheat (T. aestivum L., hexaploid) and durum wheat The reasons for the low cultivation of ancient wheats are 30–60%. Lower grain yields, the presence of husks and poor baking properties compared to common wheat [1]. Common wheat is most suitable for bread making, because the flour forms a viscoelastic dough with a high gas holding capacity when it is mixed with water. Flours of ancient wheats yield softer dough with low elasticity and high extensibility because of their poor gluten quality [1,9,10,11]. It is generally accepted that gluten proteins are one of the most important factors determining the baking quality of wheat flours.

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