Edward Souza

Identification and Characterization of a Low Phytic Acid Wheat

crease the absorption of essential micronutrients such as Ca (Kies, 1985), Fe (Brune et al., 1992), and Zn Phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate, or Ins P6) (Sandström et al., 1987). Phytate forms chelates with is the most abundant storage form of P in seeds, yet indigestible by humans and nonruminant livestock. A wheat (Triticum aestivum L.) these divalent minerals, which reduces bioavailability mutant is described herein with greatly reduced seed phytic acid P to humans (Jacobsen and Slotfeldt-Ellingsen, 1983). In but little change in seed total P, similar to lpa1-type mutants described developing countries, flatbreads may be prepared from in other grain species. One nonlethal mutant from 562 ethyl-methanewhole-wheat flour or high (≈95%) extraction flour. The sulfonate (EMS) mutagenized M2 lines was identified with a high phytate in wheat grain is found predominantly in the inorganic phosphate (HIP) phenotype and designated Js-12-LPA. aleurone layer, which remains attached to the pericarp Js-12-LPA homozygotes produced seed in which phytic acid P repreduring milling and therefore is concentrated in the bran sented 48.2% of seed total P, in contrast to 74.7% of seed total P in fraction. Although phytate decreases in proportion to nonmutant or wild-type control, Js-12-WT. The inorganic portion of fermentation time, in chapati bread, the phytate concenseed P was increased from 9.1% in Js-12-WT to 50.1% in Js-12-LPA, tration was only 18 to 24% lower than the concentration with little effect on total seed P. Weight distributions among milling fractions were similar for the Js-12-LPA and Js-12-WT genotypes. in the whole-wheat flour from which it was prepared The low phytic acid trait altered the distribution of total P within (Anjum et al., 2002). The phytate concentration in chathe kernel, increasing the P content of the central endosperm and pati breads was sixto nine-fold higher than in breads decreasing the P content of the bran. The low phytic acid trait deprepared from straight-grade flour. However, mineral creased the phytic acid concentration in the bran by 43% and increased concentrations generally were significantly higher in the inorganic P concentration in the bran nearly four-fold. Inheritance whole-grain flour than in straight-grade flour, which data of F2 and F4:6 families was inconsistent with a single-gene mutation might offset the effect of phytate on human nutrition. and suggests the involvement of two or more genes. This low phytic Human bioavailability studies will be necessary to conacid wheat mutant is a genetic resource for studying the biology of firm this hypothesis. seed phytic acid metabolism and wheat quality improvement. Nonlethal recessive mutations that decrease seed phytic acid concentration have been isolated in maize (Zea mays L.; Raboy and Gerbasi, 1996; Raboy et al., 2000), M is ubiquibarley (Hordeum vulgare L.; Larson et al., 1998; Rastous in eukaryotic cells, where it is typically the mussen and Hatzack, 1998), rice (Oryza sativa L.; Larmost abundant inositol phosphate (Ins P) (Sasakawa et son et al., 2000), and soybean [Glycine max (L.) Merr.; al., 1995). First observed as an abundant P-containing Hitz et al., 2002; Wilcox et al., 2000]. These low phytic compound in seeds, Ins P6 in plant species is thus reacid (lpa) mutants affect the partitioning of P into phytic ferred to as “phytic acid” in agronomic literature (Cosacid, inorganic phosphorus (Pi), and Ins P’s with five or grove, 1980). Applied interest in seed phytic acid is fewer P esters (Raboy, 2002). The lpa mutations are the result of its role in human and livestock nutritional divided into two groups, designated lpa1 and lpa2. Phyquality, as well as P management in integrated agricultic acid P reductions in lpa1 mutants are counterbaltural production systems. According to Shears (2001) anced by molar-equivalent increases in Pi. In contrast, and Raboy (1997), Ins P6 is a major pool in both P and phytic acid P reductions in lpa2 mutants are counterbalIns P metabolism. Phytic acid P typically represents anced by increases in both Pi and non-Ins P6 Ins P’s from 65 to 85% of seed total P and 90% of free Ins (Ins P’s of lower phosphorylation). The isolation and polyphosphates (Raboy, 1997). Trace levels ( 10% of characterization of seed P and Ins P phenotype of a total Ins P) of Ins tris-, tetrakis-, and pentakisphosphates heritable wheat lpa1-like mutant is described here. (Ins P’s with three, four, or five phosphomonoesters, respectively), as well as pyrophosphate-containing Ins P’s more highly phosphorylated than Ins P6, also are observed MATERIALS AND METHODS in mature, wild-type seeds (Dorsch et al., 2003). Mutant Isolation In humans, diets high in phytate can significantly deSeed of the breeding line A95631S-Js-12 was mutagenized with 2% EMS. A95631S-Js-12 has the pedigree ‘Kanto 79’/ M. Guttieri, D. Bowen, and E. Souza, Univ. of Idaho, Aberdeen 2*IDO488. IDO488 is a soft white spring wheat breeding line Research and Extension Center, P.O. Box 870, Aberdeen, ID 83210; with the pedigree PI 294994/4*‘Centennial’. M1 plants were J. Dorsch, BASF Corp., Research Triangle Park, NC 27709; V. Raboy, grown in the greenhouse. Approximately 50% of the M1 seeds USDA-ARS Small Grains and Potato Research Unit, P.O. Box 607, either did not germinate or senesced without setting seed. An Aberdeen, ID 83210; J. Dorsch is a former postdoctoral fellow of the USDA-ARS. Research supported by the Idaho Agric. Exp. Stn. M2 row was planted in the field from each of 562 M1 greenProject IDA1222, Manuscript no. 3725. Received 1 May 2003. *Corresponding author (esouza@uidaho.edu). Abbreviations: AACC, American Association of Cereal Chemistry; EMS, ethyl-methanesulfonate; HIP, high inorganic phosphate; Ins P, Published in Crop Sci. 44:418–424 (2004). uf8e9 Crop Science Society of America inositol phosphate; Ins P6, myo-inositol-1,2,3,4,5,6-hexakisphosphate; lpa, low phytic acid; Pi, inorganic phosphorus. 677 S. Segoe Rd., Madison, WI 53711 USA

Wheat Rusts and the Costs of Genetic Diversity in the Punjab of Pakistan

The theory of impure public goods is used to demonstrate why farmers may not grow wheat cultivars with the socially desirable level of rust resistance. First, they may grow cultivars that are high yielding though susceptible to rust. Second, many farmers may grow cultivars with a similar genetic basis of resistance. Expected rust losses can be reduced by (a) more diversified genetic background in released wheat cultivars; (b) greater spatial diversity in planted cultivars; or (c) use of a temporally changing list of cultivars known to be rust resistant. Yield trade-offs associated with these policies illustrate potential costs of increasing genetic diversity. Copyright 1997, Oxford University Press.

Functional properties of waxy wheat flours: genotypic and environmental effects

A set of waxy (amylose-free) experimental spring wheats (Triticum aestivum L.) of diverse parentage were grown, along with two nonwaxy and two partial waxy check cultivars, at diverse North American cultural environments. Grain yield and functional attributes of derived flours were determined. Average grain yield of the waxy lines did not differ significantly from the average yield of the check cultivars, but significant differences were observed amongst the waxy lines. Grain hardness varied significantly amongst the waxy lines, and both hard and soft textured waxy lines were identified. Analysis of flour quality traits showed few differences between waxy lines and check cultivars for traits primarily related to protein concentration or protein quality, but many significant differences between properties primarily dependent upon starch structure, or related to milling behavior. Protein-related quality attributes of waxy wheats demonstrated environmental and genotypic variances similar to those typical of non-waxy wheats. Starch-related quality attributes of waxy wheats showed remarkable stability across environments, but some significant genetic variation was observed. End-users interested in employing waxy wheats should be able to select desired waxy lines, and feel confident that the starch-related functional properties will be environmentally stable. Published by Elsevier Science Ltd.

Composition and reactivity of A- and B-type starch granules of normal, partial waxy, and waxy wheat

ABSTRACT Wheat has great potential to make inroads into starch markets with the advent of partial waxy and waxy starches of diverse composition and properties. The majority of isolated starch utilized in food applications is chemically modified to improve starch properties according to the intended use. Therefore, it is critical to understand factors that affect wheat starch reactivity. This work investigated the relative reactivities of normal, partial waxy, and waxy wheat starches and their respective A- and B-type starch granule fractions. Native starch isolated from four closely related soft wheat lines (normal, partial waxy, and full waxy) was modified through 1) substitution (propylene oxide analog) and 2) cross-linking (phosphorus oxychloride) reactions to generate both types of modified starch products for each wheat line. Characterization of the unmodified starch fractions confirmed compositional differences among the cultivars and their respective granule types. In cross-linking reactions, B-typ...

Assessing Environmental Influences on Solvent Retention Capacities of Two Soft White Spring Wheat Cultivars

ABSTRACT The solvent retention capacity test (SRC) (AACC Approved Method 56-11) of flour is used to evaluate multiple aspects of wheat (Triticum aestivum L.) quality including pentosan content, starch damage, gluten strength, and general water retention based on the ability of flour to retain a range of solvents. The objectives of this study were to evaluate the effects of grain production environment in general and crop irrigation and fertility management in particular on SRC of soft wheat flour, and to evaluate the ability of SRC to predict end-use quality across diverse environments. Two soft white spring wheat cultivars ‘Pomerelle’ and ‘Centennial’ were produced in a range of irrigated and rain-fed production environments. SRC profiles and milling and baking quality parameters were measured. In a two-year study at Aberdeen, ID, with two late-season irrigation management regimes and two crop nitrogen fertility treatments, only wheat genotype significantly affected flour SRC. In two-year studies at Teto...

Application of Wheat Meal Solvent Retention Capacity Tests Within Soft Wheat Breeding Populations

ABSTRACT The solvent retention capacity (SRC) test is a relatively new AACC Approved Method (56-11) for evaluating soft wheat flour quality. The test measures the ability of flour to retain a set of four solvents (water, 50% sucrose, 5% sodium carbonate, and 5% lactic acid) after centrifugation. The objective of this study was to evaluate the utility of wheat meal sodium carbonate and lactic acid SRC tests and SDS sedimentation volume within three populations of soft spring wheat inbred lines as tools for selecting for improved flour SRC profiles, flour extraction, and cookie and pastry quality. The populations were derived from the crosses Vanna/Penawawa, Kanto 107/IDO488, and M2/IDO470 and were grown in replicated, irrigated trials in 2000 and 2001 near Aberdeen, Idaho. Within each of the three populations, wheat meal sodium carbonate SRC effectively predicted straight-grade flour sodium carbonate (r = 0.69–0.81) and sucrose SRC (r = 0.74–0.84). Wheat meal sodium carbonate SRC also was negatively correl...

Relationship of Dough Extensibility to Dough Strength in a Spring Wheat Cross

ABSTRACT A negative relationship between dough strength and dough extensibility would pose a problem for breeding hard wheats, as both dough strength and dough extensibility are desirable. We derived 77 recombinant inbred lines (RIL) from a cross between hard red spring wheat cultivars McNeal and Thatcher. McNeal produces flour with stronger dough and lower extensibility than does Thatcher. RIL were evaluated for strength-related properties using mixograph analysis and extensibility parameters using the Kieffer attachment to the TA.XT2 texture analyzer. Additionally, the RIL were test baked. Measurements using the mixograph and the Kieffer attachment were highly heritable. Maximum dough extensibility (Extmax) was negatively correlated with resistance to extension (Rmax) (r = -0.74) and with mixograph tolerance (r = -0.45). Loaf volume was correlated with both Rmax (r = 0.42) and area under the extensigraph curve (r = 0.44) based on partial correlation analysis adjusted for protein differences. Extmax was ...

Nonstarch Polysaccharides in Wheat Flour Wire-Cut Cookie Making

Nonstarch polysaccharides in wheat flour have significant capacity to affect the processing quality of wheat flour dough and the finished quality of wheat flour products. Most research has focused on the effects of arabinoxylans (AX) in bread making. This study found that water-extractable AX and arabinogalactan peptides can predict variation in pastry wheat quality as captured by the wire-cut cookie model system. The sum of water-extractable AX plus arabinogalactan was highly predictive of cookie spread factor. The combination of cookie spread factor and the ratio of water-extractable arabinose to xylose predicted peak force of the three-point bend test of cookie texture.

Single Kernel Near-Infrared Analysis of Tetraploid (Durum) Wheat for Classification of the Waxy Condition

ABSTRACT Plant breeding programs are active worldwide in the development of waxy hexaploid (Triticum aestivum L.) and tetraploid (T. turgidum L. var. durum) wheats. Conventional breeding practices will produce waxy cultivars adapted to their intended geographical region that confer unique end use characteristics. Essential to waxy wheat development, a means to rapidly and, ideally, nondestructively identify the waxy condition is needed for point-of-sale use. The study described herein evaluated the effectiveness of near-infrared (NIR) reflectance single-kernel spectroscopy for classification of durum wheat into its four possible waxy alleles: wild type, waxy, and the two intermediate states in which a null allele occurs at either of the two homologous genes (Wx-1A and Wx-1B) that encodes for the production of the enzyme granule bound starch synthase (GBSS) that controls amylose synthesis. Two years of breeders samples (2003 and 2004), corresponding to 47 unique lines subdivided about equally into the fou...

Exploration of sugar functionality in sugar-snap and wire-cut cookie baking: implications for potential sucrose replacement or reduction.

ABSTRACT The sugar series—xylose, glucose, fructose, and sucrose—can be used diagnostically to explore the effects of sugar type on differential scanning calorimetry (DSC), Rapid Visco-Analyser (RVA), and cookie baking performance because of the differences in glass-forming abilities (related to plasticization) and solubility parameters (related to solvent preference) of different sugars. Sugar concentration (% S), total solvent (TS), and dough formulation defined a core experimental design for cookie baking with the four sugar types and two baking methods. Although wire-cut cookie baking (66% S and 64 TS) showed the same trends as sugar-snap cookie baking (73% S and 79 TS) for diameter, height, and moisture content, the wire-cut formulation enabled greater discrimination among the effects of different sugar types on dough and cookie responses. Use of two different crystal sizes of sucrose confirmed the dominant impact of both gluten development during dough mixing and starch pasting during cookie baking ...