Impact of Variation in Amylose Content on Durum Wheat Svevo Technological and Starch Properties

Abstract: Reserve starch, the main component of durum wheat semolina, is constituted by two glucan homopolymers (amylose and amylopectin) that differ in their chemical structure. Amylose is mainly a linear structure formed of α-1,4 linked glucose units, with a lower polymerization degree, whereas amylopectin is a highly branched structure of α-1,4 chains linked by α-1,6 bonds. Variation of the amylose/amylopectin ratio has a profound effect on the starch properties which may impact wheat technological and nutritional characteristics and their possible use in the food and non-food sector. Therefore, some breeding programs were focused on the production of high (HA) and low amylose (LA) genotypes using transgenic and conventional strategies. A great interest was aroused by new genotypes enriched in amylose for their beneficial effects for human health in the prevention of non-communicable diseases. Differently the low-amylose genotypes find applications in different industrial sectors (i.e. frozen and baby foods; starch-based sweeteners and industrial alcohol) for their unique properties. In this work a set of genotypes, with a range of amylose from 14.9 to 57.8%, derived from the durum wheat cv. Svevo was characterized at biochemical and rheological level and used for the production of pasta. A negative correlation was observed between amylose content and semolina swelling power, starch peak viscosity and pasta stickiness. A worsening of the firmness was observed in the low amylose pasta compared to the control (cv. Svevo), whereas no difference was highlighted in the high amylose samples. The resistant starch was higher in the HA pasta compared to the control and LA pasta. Noteworthy, the extent of starch digestion was reduced in the high amylose pasta while the low amylose genotypes offered a higher starch digestion, suggesting other possible applications.