Effects of High-Molecular-Weight Glutenin Subunits on the Texture of Yellow Alkaline Noodles Using Near-Isogenic Lines

Abstract

The effects of high-molecular-weight glutenin (HMWG) subunits on the physical properties of yellow alkaline noodles (YAN) were investigated by using 10 near-isogenic lines (NILs) that only differed in HMWG composition and the recurrent parent Harunoakebono (HA). Although there were some differences among NILs, including HA, regarding protein content, other characteristics of the flours, such as the ash content and the starch traits, were not notably different. Differences in HMWG composition had a significant effect on the micro SDS-sedimentation volume (MSDSS), breaking force (BF, an index of hardness) and breaking deformation (BD, an index of extensibility) of raw noodles and the BF and BF/BD (an index of elasticity) of boiled noodles. In particular, the BF of raw and boiled noodles were significantly and positively correlated with MSDSS, which is an index of flour protein strength (the quality of flour protein). There were no significant differences in the physical properties of YAN between HMWG subunits 1 and 2 at the Glu-A1 allele. In a comparison of all subunits at the Glu-B1 allele, subunits 17+18 and 20 had significantly higher and lower BF than subunits 7+9 (HA) in raw noodles, respectively, and the BD of subunits 6+8 and 20 was also significantly lower than that of other subunits. No large differences were observed in the physical properties of subunits at the Glu-B1 allele in boiled noodles, with a few exceptions. At the Glu-D1 allele, subunits 2+12, 4+12, and 2.2+12 basically had smaller BF and BF/BD in raw and boiled noodles than subunits 5+10 (HA). The physical properties of NILs with subunits 17+18 and 2.2+12 were similar to those of HA with subunits 7+9 and 5+10. Conversely, those of NIL with subunits 20 and 2.2+12 were extremely small compared to those of HA. The results obtained in this study indicate that the dough strength (the quality of flour protein), as evaluated by MSDSS, has a significant effect on the physical properties of YAN, and that a desirable texture of boiled YAN with a large BF and BF/BD, especially BF, was obtained from flour with HMWG subunits with positive effects on dough strength. Regarding HMWG composition, subunits 2+12, 4+12, and 2.2+12 had the most negative effect on texture, particularly BF, of YAN, followed by subunits 20 and 7+8. In contrast, subunits 5+10 and 17+18, especially the former, had positive effects. NILs with both subunits 5+10 and 17+18 had the best YAN texture (the largest BF and moderate BF/BD values for boiled noodles) among all NILs.