Arthur D. Bettge

Determination and evaluation of the sequence and textural effects of the puroindoline a and puroindoline b genes in a population of synthetic hexaploid wheat.

Aegilops tauschii (2n=2 x=14, DD) is a rich source of genetic variability for hexaploid wheat (Triticum aestivum, 2n=6 x=42, AABBDD) improvement. This variability can be accessed through utilizing synthetic hexaploid wheat lines, which contain genomes from Ae. tauschii and T. turgidum (2n=4 x=28, AABB). Numerous desirable characteristics can and have been introgressed into common hexaploid wheat with this germplasm. In this work, the genetic variability in the two puroindoline genes (a and b) contained on the D genome, and the relationship that sequence polymorphisms in these genes have on endosperm texture among a population of 75 CIMMYT synthetic hexaploid accessions is described. Kernel texture was evaluated using the single kernel characterization system (SKCS). Kernel texture differed significantly (P≤0.0001) among the synthetic hexaploid accessions (range 2.6–40.9) and the parent types, durum or Ae. tauschii. The interaction term between parent types was also a significant effect (P≤0.0001). In addition to the ‘wild-type’ protein sequences of the puroindoline genes (those present in ‘Chinese Spring’ and all other soft wheats), three other translated sequences were identified in puroindoline a and two others in puroindoline b. These protein sequences were associated with significantly (P≤0.0001) softer endosperm textures than the wild-type protein sequences. As the softer alleles are expressed in a hexaploid background, they are immediately available to wheat breeding programs.

Distribution of Total, Water-Unextractable, and Water-Extractable Arabinoxylans in Wheat Flour Mill Streams

ABSTRCT Arabinoxylans are a minor but important constituent in wheat that affects bread quality, foam stability, batter viscosity, and sugar snap cookie diameter. Therefore, it is important to determine the distribution of arabinoxylans in flour mill streams to better formulate flour blends. Thirty-one genetically pure grain lots representing six wheat classifications common to the western U.S. were milled on a Miag Multomat pilot mill, and 10 flour mill streams were collected from each. A two-way ANOVA indicated that mill streams were a greater source of variation compared to grain lots for total arabinoxylans (TAX), water-unextractable arabinoxylans (WUAX), and water-extractable arabinoxylans (WEAX). TAX and WUAX were highly correlated with ash at r = 0.94 and r = 0.94, respectively; while the correlation for WEAX and ash decreased in magnitude at r = 0.60. However, the 5th middlings mill streams exhibited disparity between TAX and ash content as well as between WUAX and ash content. This may indicate t...

Endogenous and Enhanced Oxidative Cross-Linking in Wheat Flour Mill Streams

ABSTRACT A better understanding of the variation in oxidative cross-linking potential among flour mill streams can improve flour quality through the formulating of superior flour blends, and hence end-product attributes. The purpose of this research was to study the variation of oxidative cross-linking among 10 Miag Multomat pilot mill streams from 31 hard, soft and club wheat cultivars using Bostwick viscosity measurements. Flour slurries were made with either water alone (to measure the endogenous oxidative cross-linking viscosity) or with added hydrogen peroxide-peroxidase (to measure the enhanced oxidative cross-linking viscosity). Hard cultivars tended to produce more viscous flour slurries for both water and peroxide-peroxidase viscosity measurements in most mill streams. Mill streams with high oxidative cross-linking potential were those with the largest differences between water and peroxide-peroxidase viscosity including 1st Break, 1st and 2nd Middlings, and 1st Midds Redust. Conversely, mill str...

Evaluation of maternal parent and puroindoline allele on kernel texture in a reciprocal cross between two hard spring wheat cultivars

Kernel texture is an important characteristic for both the milling and the end-use quality of wheat (Triticum aestivum L.). Gene sequence variation and mutations to the two puroindoline genes (Pina and Pinb), located at the Ha locus on chromosome 5DS, account for the majority of variation in wheat kernel texture. Other factors also influence kernel texture, including effects associated with different maternal parent backgrounds. To investigate the effect of two hard puroindoline alleles in different maternal backgrounds, a population of 228 recombinant inbred lines (RILs) derived from a reciprocal cross between two wheat cultivars ‘ID377s’ (Pina-D1b/Pinb-D1a) and ‘Klasic’ (Pina-D1a/Pinb-D1b) were examined in two succeeding generations (F7 & F8). Kernel texture was determined using the Single Kernel Characterization System (SKCS) and the RIL puroindoline haplotype was identified by the sequence-specific PCR amplification of each gene. Analysis of variance identified a significant (P ≤ 0.001) effect of the maternal parent and puroindoline mutation on kernel texture. RILs containing the Pina-D1b mutation were significantly harder than lines containing the Pinb-D1b mutation. RILs which had Klasic as the maternal parent were significantly harder than those which had ID377s as the maternal parent. When the maternal parent and puroindoline allele were analyzed in combination, RILs derived from Klasic as the maternal parent and the Pina-D1b allele were significantly harder (P ≤ 0.001) than those containing the same allele but ID377s as the maternal parent. The same occurred for RILs containing the Pinb-D1b allele, lines with Klasic as the maternal parent were harder than lines with ID377s as the maternal parent. These results corroborate the harder phenotype of the Pina-D1b allele and indicate a significant maternally-inherited contribution to kernel texture variation.

Repeatability Precision of the Falling Number Procedure Under Standard and Modified Methodologies

The falling number (FN) procedure is used worldwide to assess the integrity of the starch stored within wheat seed. As an indirect measurement of the activity level of α-amylase, FN relies on a dedicated viscometer that measures the amount of time needed for a metal stirring rod of precise geometry to descend a fixed distance through a column of water–flour or water–meal slurry that undergoes enzyme-activated starch hydrolysis under controlled mixing and heating conditions. For U.S. wheat, FN values of 300 s and above generally indicate soundness in the condition of the seed starches, whereas values less than 300 s often indicate that some seeds have broken dormancy, which deleteriously affects bread-, cake-, and noodle-making quality of products derived from their flour. Domestic and especially overseas sales contracts will often specify a minimum FN value for consignments, thus making it critical to ensure that the FN procedure be highly precise. The study described herein examined the level of repeatab...

Collaborative Analysis of Wheat Endosperm Compressive Material Properties

ABSTRACT The objective measurement of cereal endosperm texture, for wheat (Triticum spp. L.) in particular, is relevant to the milling, processing, and utilization of grain. The objective of this study was to evaluate the interlaboratory results of compression failure testing of wheat endosperm specimens of defined geometry. Parallelepipeds (bricks) and cylinders were prepared from individual soft and hard near-isogenic wheat kernels and compressed in two orientations (parallel and perpendicular to the long brush-to-germ axis). Compression curves were used to derive failure stress, failure strain, work density (area under the curve), and Youngs modulus. In all five laboratories, the ability to delineate hard from soft wheat endosperm material properties was quite high. Four laboratories compressed endosperm bricks in the same orientation, on edge; texture class (soft vs. hard) was consistently the greatest source of variation in analysis of variance models (F-values from 417 to 1401, Youngs modulus and ...

Measuring Oxidative Gelation of Aqueous Flour Suspensions Using the Rapid Visco Analyzer

ABSTRACT The Rapid Visco Analyzer (RVA) was investigated as a tool to measure oxidative gelation capacity (OGC) of aqueous wheat flour suspensions. One club wheat patent flour was used to determine optimal hydration time, and 33 straight-grade flours (representing 12 hard and 21 soft varieties) were used to observe varietal differences in OGC. A 33.3% w/w flour–water suspension was tested in the RVA at 30°C and 160 rpm for 1 min to establish the flour–water baseline viscosity, and then 65 μL of 3% H2O2 was added and the viscosity of the suspension measured at 160 rpm for a further 5 min. Flour from the club wheat showed that 20 min of prehydration was needed to observe full OGC potential. For the 33 straight-grade flours, final RVA water baseline viscosity was correlated with Bostwick Consistometer (BC) flow (r = −0.93, P ≤ 0.01), and RVA H2O2 peak viscosity was correlated with H2O2 BC flow (r = –0.81, P ≤ 0.01). The RVA was able to differentiate H2O2-reactive from nonreactive flours. The RVA can observe ...