Search

Grain hardness, amylose content, and glutenin subunit composition are critical determinants for end-use properties of wheat. To improve the end-use properties of domestic wheats, we studied these traits between the Australian and North American wheat classes exported to Japan in 2009 and 2011 by analyzing the corresponding alleles. Most hard classes had Pina-D1b or Pinb-D1b. A partial waxy allele (Wx-B1b) was found in all Australian Standard White (ASW) seeds in 2009 and two-thirds of ASW seeds in 2011. All or most American hard wheat seeds had Glu-D1d. Most U.S. Western White (WW) seeds had a null allele (Glu-A1c) or alleles that lacked one of the two Glu-B1 subunits. Most hard red winter (HRW) seeds had Glu-B3b or Glu-B3g. Quality characteristics of these classes seemed to be consistent with these results. In addition, we also found new Glu-1 and Glu-3 alleles in HRW and WW. These results suggested that although there are variations in its allelic composition from year to year, each class has u...

After screening of 177 disomic addition lines (DALs) of wheat (Triticum aestivum) containing a pair of chromosomes from different alien species, we found that the chromosome 1E addition line of Agropyron elongatum, that is known to be a potential genetic resource for drought and salinity tolerance, showed potential for improvement of bread-making quality of wheat. This was indicated by increased SDS sedimentation, specific sedimentation, mixograph peak time and SE-HPLC analysis of polymeric proteins. This addition line spontaneously gave rise to a substitution line for chromosome 1D in subsequent generations that showed weak dough strength. Analysis of the x-type HMW-glutenin subunit sequence of Ag. elongatum from DAL1E indicated that it closely resembled the x-type sequence of the A and B genomes of wheat, and the y-type was intermediate between x- and y-type HMW-glutenin subunit genes. From these observations, it was inferred that 1E-encoded seed storage proteins have considerable potential for improvement of wheat end-product quality if transferred to specific chromosomes such as 1A of Chinese Spring (CS) wheat, which has a negative overall effect on bread-making quality.

Using various rice flours prepared by different milling methods, the relationship between rice flour properties and specific loaf volumes of one-loaf bread made from rice flour with wheat vital gluten were studied. Damaged starch content of rice flour varied from 1.0% to 22.1%. A significant negative correlation was verified between damaged starch content and specific loaf volume of one-loaf bread. Rice flour with low damaged starch content mainly consisted of compound starch granules, aggregated polyhedral single starch granules and smooth surface cells surrounded by the cell wall. The structures of starch granules and cells were maintained in rice flour with low damaged starch content. Rice flour with high damaged starch content consisted of only fine irregular particles without the apparent rice starch structure, or contained fractured large and small cells with rough surface. Although there was not significant correlation between specific loaf volume and median particle size, rice flours which were successful at making bread with high specific loaf volume commonly showed a peak centered around 60 µm with a smaller amount of larger size particles in the particle distribution profile. Thus, the flour particle size distribution appears to affect the specific loaf volume of one-loaf bread. Both the damaged starch content and the profile of particle size distribution were important for high specific loaf volume of one-loaf bread. Less damage to starch and cell structures while lowering the particle size during milling process is critical in obtaining better flour for rice one-loaf bread making.

This study involved screening of wild species of wheat in search of functionally useful seed storage proteins for improvement of breadmaking quality of wheat (Triticum aestivum). After screening of 177 disomic addition lines (DALs) of wheat belonging to different wild species, Aegilops searsii DALs were selected and studied in detail. These DALs of Ae. searsii were from chromosome 1Ss to 7Ss in the background of cultivated wheat cv. Chinese Spring (CS). By analyzing these addition lines, genetic loci of actively expressed genes for the high molecular weight glutenin subunits (HMW-GS) and gliadin were found on the chromosome 1Ss for the first time and have been designated as Glu-Ss1 and Gli-Ss1, respectively. Disomic addition line of chromosome 1Ss (DAL1Ss) showed improved dough strength in different generations compared with CS. SDS sedimentation value and specific sedimentation of DAL1Ss were higher than CS. Mixograph peak height and band width were higher, with no difference in mixing peak time...

We studied the effects of hardness allele Pinb-D1b on the flour quality characters for Japanese white salty noodles. With 110 doubled haploid lines derived from ‘Chugoku 140’ (hard, Pinb-D1b )בChikugoizumi’ (soft, Pinb-D1a ), Pinb-D1b hard lines were found to have larger L* and a* of 60% flour colour, and smaller RVA breakdown than those of Pinb-D1a soft lines in addition to the higher flour yield, and larger average flour particle size. The Pinb-D1b allele is thus regarded to effectively improve milling efficiency and flour brightness. The inferior flour viscosity of Pinb-D1b lines is compensated for by introducing waxy allele(s) to increase viscosity by lowering amylose content.

The production of angiotensin I converting enzyme (ACE) inhibitory peptides by autolysis reactions from wheat milling byproducts was investigated. Milled whole grain, bran, shorts, and red dog acquired ACE inhibitory activity though water soaking treatment. Among the milled fractions, the preparation of shorts exhibited the strongest inhibitory activity (IC50 = 0.08 mg protein/mL) followed by that of bran, red dog, and whole grain in decreasing order. The production of ACE inhibitory peptides was almost completely inhibited by pepstatin A, indicating the contribution of aspartic proteases. The optimal pH for acquiring ACE inhibitory activity of the byproduct fraction (mixtures of bran and shorts) was 3.2. The level of inhibitory activity rose with increasing temperature up to 40 degrees C. The inhibitory activity reached a maximal level after a 12 h reaction time and maintained the same level up to 24 h at 40 degrees C, pH 3.2. From the hydrolysate of the byproduct fraction, six peptides were isolated by several steps of chromatography, and their amino acid sequences were Leu-Gln-Pro, Ile-Gln-Pro, Leu-Arg-Pro, Val-Tyr, Ile-Tyr, and Thr-Phe. Thus, wheat milling byproducts have the possibility to become an effective source for ACE inhibitory peptides.