Increasing the versatility of durum wheat through modifications of protein and starch composition and grain hardness

Authors: LAFIANDRA, D - University Of Tuscia; SESTILI, FRANCESCO - University Of Tuscia; SISSONS, MIKE - Nsw Department Of Primary Industries; Kiszonas, Alecia; Morris, Craig

Submitted to: Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2022
Publication Date: 5/24/2022
Citation: Lafiandra, D., Sestili, F., Sissons, M., Kiszonas, A., Morris, C.F. 2022. Increasing the versatility of durum wheat through modifications of protein and starch composition and grain hardness. Foods. 11(11). Article 1532. https://doi.org/10.3390/foods11111532.
DOI: https://doi.org/10.3390/foods11111532

Interpretive Summary: Durum wheat is widely grown in the Mediterranean area representing a major staple crop used for the preparation of different end products whose history and utilization have accompanied the journey of man for thousands of years. Though commonly known for its use in pasta, durum wheat, also thanks to its glassy texture, is used for the preparation of different types of bread, biscuits, pastries, and other different kinds of foods, whose processing can include whole or crushed kernels. About 25% of the durum wheat produced in the world is used for breadmaking and up to 70%–90% in some Middle East countries. Durum wheat has a limited use compared to bread wheat, with pasta being the major end product, and this can be associated with its high hardness and lack of D genome. The use of classical and innovative biotechnological tools has made it possible to modify the pro-cessing and nutritional characteristics of durum wheat. In particular modification of ker-nel texture and introduction of D-genome HMW-GS have been both achieved via ph1-mediated homoeologous recombination and the transfer of genetic material from bread wheat to durum wheat, whereas mutagenesis via TILLING has proved very effective in modifying starch composition.

Technical Abstract: While durum wheat (Triticum durum L. ssp. durum Desf.) has traditionally been used to make a range of food products its use has been restricted due to the absence of the D-genome glutenin proteins, relatively low variability in starch composition, and its very hard grain texture. In or-der to improve the technological and nutritional value of durum wheat, the manipulation of starch and protein composition has been the target of different works. In addition, kernel hard-ness has also been modified with the isolation of durum wheat with soft texture, resulting in the opportunity to expand the utilization of durum wheat for the realization of a wider number of end products. Starch is composed of amylopectin and amylose in a 3:1 ratio and their manipula-tion has been explored in order to realize starch with modified composition. In particular, si-lencing of the genes involved in amylose and amylopectin synthesis have made it possible to isolate durum wheat lines with amylose content varying from 2-3% up to 75%. This has created opportunities for new products with different properties and enhanced nutritional value. Durum made bread has generally inferior quality to bread made from common wheat. Attempts to in-troduce Glu-D1 subunits 1Dx5+1Dy10 and 1Dx2+1Dy12 produced stronger dough but the former produced excessively strong, inelastic doughs and loaf volume was either inferior or not affect-ed. Whereas, the 1Dx2 + 1Dy12 sometimes improved bread Loaf Volume (LV) depending on the glutenin subunit background of the genotype receiving these genes. Further breeding and selec-tion is needed to improve the dough extensibility to allow higher LV and better texture. The versatility of durum wheat has been greatly expanded with the creation of soft-textured durum, via non-GMO introgression means. This soft durum mills like soft hexaploid wheat and has baking properties similar to soft hexaploid wheat. The pasta quality is not diminished by the soft textured kernels. The Glu-D1 locus containing the subunits 1Dx2 + 1Dy12 has also been in-trogressed to create higher quality soft durum bread.