Proteins Extracted from Defatted Wheat Germ: Nutritional and Structural Properties

The main by‐product of the wheat germ oil extraction process is a defatted wheat germ meal, which has a relatively high protein content, making it an attractive and promising source of vegetable proteins. Four protein fractions (albumin, globulin, prolamine, and glutelin) and protein isolate from defatted wheat germ flour (DWGF) were fractionated and then characterized by amino acid analysis, SDS‐PAGE, and differential scanning calorimetry (DSC). Albumin was the major fraction (34.5%) extracted, followed by globulin (15.6%), glutelin (10.6%), and prolamine (4.6%). Protein isolate was mainly composed of albumin and globulin. These protein fractions and protein isolate showed an excellent balance of all essential amino acids, with a relatively high level of glutamic acid, arginine, leucine, and glycine, whereas cystine was lacking. All the estimated nutritional quality parameters based on amino acids composition showed that defatted wheat germ proteins had good nutritional quality. Nonreduced and reduced SDS‐PAGE analyses showed that S‐S bonds ere deficient in the structure of wheat germ proteins. The albumin fraction consisted of 19 major polypeptide bands with M_r 14,000–84,000. The globulin fraction showed four distinct polypeptides or polypeptide group bands with M_r 55,000, 37,000–43,000, 24,000, and 12,000–20,000, which may be the components of the 8S‐type and 11S‐like proteins. The prolamine fraction showed a predominant doublet‐like band at M_r 17,000–16,000, while the glutelin fraction showed five major polypeptide bands with M_r 39,000, 20,000, 18,000, 17,000, and 14,000. Protein isolate and DWGF showed very similar SDS‐PAGE patterns. Except for prolamine and glutelin fractions without detectable calorimetric response, the globulin fraction possessed the highest thermal stability (T_d = 83.80°C, ΔH =1.36 J/g ), followed by protein isolate (T_d = 80.05°C, ΔH = 0.76 J/g), while the albumin fraction was lowest (T_d = 69.72°C, ΔH = 0.53 J/g). The findings on defatted wheat germ proteins are important for their potential application as functional food ingredients.     

Effects of Micronization on Protein and Rheological Properties of Spring Wheat

This research investigated the effects of micronization, at different moisture levels, on the chemical and rheological properties of wheat. A set of tests designed to analyze protein fraction characteristics and rheological behaviors were conducted on samples from four wheat cultivars (AC Karma, AC Barrie, Glenlea, and Kanata). After being subjected to infrared radiation at three moisture levels (as‐is, 16%, and 22%), the seeds were milled to produce straight‐grade flour. The protein fractionation test revealed significant decreases (P ≤ 0.01) in both monomeric proteins (from 54% of total protein in the control to 37% in the tempered micronized sample) and soluble glutenins (9.4–2.5%). There was a strong negative correlation (r = ‐0.98) between the percentages of monomeric proteins and insoluble glutenins. Total extractable proteins of micronized samples tempered to 22% moisture decreased 43.5% when compared with nonmicronized control samples using size‐exclusion HPLC (SE‐HPLC). Micronization had a significant effect on gluten properties, as seen from a decrease in water absorption (P ≤ 0.01) and dough development time (P ≤ 0.01). Results showed that micronization at 100 ± 5°C had detrimental effects on wheat flour gluten functionality, including a decrease in protein solubility and impairment of rheological properties. These phenomena could be due to the formation of both hydrophobic and disulfide bonds in wheat during micronization.     

Uptake of Microelements by Crops Grown on Heavy Metal–Amended Soil

Abstract

A small‐plot field experiment on microelement pollution (Aluminum (Al), Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Mercury (Hg), Lead (Pb), Zinc (Zn)) was initiated in 1994 at Tass‐puszta Model Farm of Gyöngyös College, Hungary. The experimental plants were winter wheat (Triticum aestivum L. emend. Fiori et Pool.) in 1995, maize (Zea mays L.) in 1996, and sunflower (Helianthus annuus L.) in 1997. Plant samples were taken each year during the vegetation period at phenophases characterized by intensive nutrient uptake. The Al content of crops was not influenced by Al load of the soil. Arsenic accumulation was not considerable in the grain with the highest As load. Cadmium accumulation was significant both in vegetative and reproductive parts of crops with increasing Cd loads of the soil. The Cd content was about 10–40 times higher in treated sunflower seeds than in the control; as a result the seeds were not suitable for consumption. Cadmium can accumulate in the reproductive tissue, so it is a real risk in the food chain. In the first year, Cr(VI) had a toxic effect on wheat, but it was not mobile in the soil–plant system. Vegetative parts of winter wheat accumulated significant amounts of Hg, but maize and sunflower seeds did not accumulate Hg. Lead, Cu, and Zn showed only moderate enrichment in crops following increasing loads in the soil.     

Comparative Studies on Composition and Distribution of Phenolic Acids in Cereal Grain Botanical Fractions

The phenolic acid composition and concentration of four manually separated fractions (pericarp, aleurone layer, germ, and endosperm fractions) as well as whole grains of yellow corn, wheat, barley, and oats were analyzed by HPLC‐MS/MS following microwave‐assisted alkaline aqueous extraction. Phenolic acid compositions in whole grains and their fractions were similar, with minor differences among the grain fractions. Significant differences (P < 0.05), however, were observed in phenolic acid concentrations among cereal types, within cereal varieties, and among grain fractions, with yellow corn exhibiting the highest values. The concentrations of p‐coumaric and syringic acid in the pericarp were 10‐ to 15‐fold and 6‐ to 10‐fold higher, respectively, in yellow corn than in wheat, barley, and oats. In the aleurone layer, sinapic and vanillic acids in yellow corn were about 8‐ and 30‐fold more than in wheat. The germ fraction of wheat had 1.8 times more syringic acid than yellow corn germ. Grain fractions, excluding endosperm, had enhanced levels of phenolic acids compared with whole grain. Sinapic acid was more concentrated in the pericarp and germ of wheat, whereas isoferulic acid was concentrated in the germ of purple barley. Syringic and vanillic acids were concentrated in the pericarp and sinapic acid in the aleurone layer of yellow corn. These findings are important in understanding the composition and distribution of phenolic acids, and they act as a guide in identification of grain fractions for use as food ingredients. In addition, yellow corn fractions (aleurone and pericarp) may be potential alternative phenolic‐rich functional food ingredients in grain‐based food products.     

Effects of Physicochemical Characteristics and Lipid Distribution in Algerian Durum Wheat Semolinas on the Technological Quality of Couscous

Semolinas milled from 18 Algerian durum wheat cultivars cropped over a two‐year period (1999‐2000) were used for making couscous. This study was designed to determine the impact of lipid components of durum wheat semolina on the quality of the couscous end product. Lipids were extracted from semolina by various techniques and classified as free or bound lipids, polar or apolar lipids, and glycolipids or phospholipids. An analysis of the overall results clearly revealed that the cooking quality of couscous made from different durum wheat semolinas was partially dependent on the semolina free lipid content and composition. We have shown that this is mainly a varietal characteristic (53.4%). The surface state of the couscous, i.e., caking index (r = ‐0.48) and cooking loss (r = ‐0.54), thus depends on the apolar lipid content. Polar lipids, and especially glycolipids, affect couscous texture in terms of firmness (r = 0.57 and r = 0.63, respectively). Polar bound lipids also contribute to couscous swelling (r = 0.53) and caking index (r = 0.70). Moreover, we obtained no correlation between cooked couscous quality and the semolina total lipid content (r < 0.3). We also showed that couscous characteristics were not significantly related to the semolina protein and dry gluten contents or gluten index (r < 0.3).     

Chemical fractionation of phosphorus in calcareous soils of Hamedan,western Iran under different land use

We investigated the effects of land uses on P distribution and availability in selected calcareous soils under different management practices. KCl‐P (labile P), NaOH‐P (Fe‐Al‐bound P), HCl‐P (Ca‐bound P), and residual P (Res‐P) fractions at 0–30 cm depth were determined for soils planted to garlic, orchard, pasture, potato, leafy vegetables, and wheat. Trends in P distribution between chemical fractions were similar between land uses. Ca‐bound P was the most abundant P fraction in the soils, constituting between 61% and 78% of the total P, whereas P associated with labile was less abundant (< 2%). Soils under leafy vegetables and wheat along with pasture presented the highest and lowest values in all fractions of P, respectively. Labile P generally was highest for leafy vegetables and potato. Labile P and Fe‐Al‐bound P comprised < 1.4% and 8% of total P, respectively. Residual P ranged from ≈ 14% (potato and garlic) to 31% (pasture). Long‐term fertilization increased P allocation to inorganic fractions, as Ca‐bound P contained 78% of total P for potato and garlic and 74% for leafy vegetables but 61% for pasture. A strong positive correlation between labile P and Fe‐Al‐bound P (r = 0.534, p < 0.01), labile P and Ca‐bound P (r = 0.574, p < 0.01), Ca‐bound P and Fe‐Al‐bound P (r = 0.504, p < 0.01), Olsen‐P and CaCl₂‐P (r = 0.821, p < 0.01) was found. Principal‐component analysis showed that the first four components accounted for most of the variation, 32.5%, 16.9%, 12.9%, and 7.9% of total variation, respectively.     

Impact of Cultivar and Environment on Size Characteristics of Wheat Proteins Using Asymmetrical Flow Field‐Flow Fractionation and Multi‐Angle Laser Light Scattering

The use of multi‐angle laser light scattering (MALLS) in conjunction with asymmetrical flow field‐flow fractionation (A‐FFFF) was investigated for the determination of the molecular weight distribution (MWD) of wheat proteins. The wheat flour proteins were dissolved by sonication in 0.1M sodium phosphate (pH 6.9) containing 2% SDS. The results presented make it evident that efficient separation and size characterization of monomeric (M < 10⁵ g/mol) and polymeric protein (10⁵ ≤ M < 10⁸ g/mol) wheat proteins can be achieved with A‐FFFF/MALLS/UV in a single run. Therefore, this method appears to be able to detect significant modifications of MWD of wheat protein, whatever the factor inducing these alterations (i.e., genetic or environmental) and whatever the nature of these alterations (i.e., monomeric‐to‐polymeric ratio or MWD of polymeric protein). In the present study, we have indeed demonstrated that the MWD of wheat proteins can be altered from one cultivar to another in three main ways: by changing the relative amounts of monomeric and polymeric proteins, by changing the MWD of polymeric protein, and then by changing both the monomeric‐to‐polymeric ratio and the MWD of polymeric protein.     

Comparison of Different Methods for Phenotyping Preharvest Sprouting in White‐Grained Wheat

The objective of this study was to identify a suitable method for phenotyping preharvest sprouting (PHS) resistance in white bread wheat. Forty doubled‐haploid (DH) lines derived from a cross between two white‐grained spring wheats (Triticum aestivum L.) cultivar Argent (nondormant) and wheat breeding line W98616 (dormant) were evaluated for germination frequency, Falling Number (FN), and α‐amylase activity in dry and water‐imbibed seeds and spikes. The α‐amylase activity in dry seeds or spikes did not differ significantly between parent lines or lines of the DH population. Wetting of seeds or spikes for two days caused a five‐ to sevenfold increase in α‐amylase activity but only in Argent and the nondormant subgroup (49–100% germination) of the DH lines. A positive association (r = 0.60***) was detected between germination frequency and α‐amylase activity in imbibed seeds and spikes. Germination frequency could not be correlated to FN or α‐amylase activity in dry‐harvested seeds. FN showed a strong correlation (r = –0.83***) to α‐amylase activity in the dry‐harvested seeds but could not be correlated to α‐amylase activity in the imbibed seeds. The germination test was the most reliable method for measuring PHS resistance because seed dormancy provides potential resistance to PHS, whereas high α‐amylase activity may occur in grains without causing PHS.     

Quality of Spaghetti Made from Full and Partial Waxy Durum Wheat

The waxy character is achieved in durum wheat (Triticum turgidum L. var. durum) when the granule‐bound starch synthase activity is eliminated. The result is a crop that produces kernels with no amylose in the starch. The presence of two Waxy loci in tetraploid wheat permits the production of two partial waxy wheat genotypes. Advanced full and partial waxy durum wheat genotypes were used to study the effect of waxy null alleles on pasta quality. Semolina from full and partial waxy durum wheats was processed into spaghetti with a semicommercial‐scale extruder, and pasta quality was evaluated. Cooked waxy pasta was softer and exhibited more cooking loss than pasta made from traditional durum cultivars. These features were attributed to lower setback of waxy starch as measured with the Rapid Visco Analyser. High cooking loss may be due to the lack of amylose‐protein interaction, preventing the formation of a strong protein network and permitting exudates to escape. Waxy pasta cooked faster but was less resistant to overcooking than normal pasta. Partial waxy pasta properties were similar to results obtained from wild‐type pasta. This indicates that the presence of a single pair of functional waxy genes in durum wheat was sufficient to generate durum grain with normal properties for pasta production. Waxy durum wheat is not suitable for pasta production because of its softening effect. However, this property may offer an advantage in other applications.     

Comparison of Quality‐Related Alleles Among Australian and North American Wheat Classes Exported to Japan

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 unique quality‐related alleles corresponding to its end use. We proposed two matrices for classification of starch properties on the basis of Pin and Wx allelic combinations and for classification of gluten strength on the basis of glutenin allelic combinations.     

Acid soil tolerances of wheat lines selected for high grain protein content

Literature suggests that nitrogen (N) metabolism is involved in differential acid soil (Al) tolerances among wheat (Triticwn aestivum L. en Thell) genotypes. Atlas 66 wheat is characterized by acid soil and aluminum (Al) tolerance, nitrate (NO₃ ^‐) preference, pH increase of the rhizosphere, high nitrate reductase activity, and high protein in the grain. Atlas 66 has been used as a high protein gene donor in the development of new high protein wheat lines at Lincoln, NE. The objective of our study was to determine the acid soil tolerances of such lines and to relate such tolerances to their abilities to accumulate grain protein when grown on near‐neutral, non‐toxic soils. Twenty‐five experimental lines, nine cultivars not previously classified as Al‐tolerant or ‐sensitive and three cultivars previously classified according to acid soil tolerance, were grown for 28 days in greenhouse pots of acid, Al‐toxic Tatum subsoil. Relative shoot dry weight (pH 4.35/pH 5.41%) varied from 83.2% for Atlas 66 to 19.3% for Siouxland. Atlas 66 was significantly more tolerant to the acid soil than all other entries except Edwall. Yecorro Roja and Cardinal were intermediate in tolerance. None of the high protein lines approached Atlas 66 in tolerance, but two lines (N87U106 and N87U123) were comparable to Cardinal (relative shoot yield = 54%) which is used on acid soils in Ohio. At pH 4.35, the most acid soil tolerant entries contained significantly lower Al and significantly higher potassium (K) concentrations in their shoots than did sensitive entries. Shoots of acid soil sensitive entries, Scout 66, Siouxland, Plainsman V, and Anza contained deficient or near deficient concentrations of K when grown at pH 4.35. Acid soil tolerance was not closely related to calcium (Ca), magnesium (Mg), phosphorus (P), manganese (Mn), or iron (Fe) concentrations at pH 4.35. Liming the soil to pH 5.41 tended to equalize Al and K concentrations in shoots of tolerant and sensitive entries. Results indicated that acid soil tolerance and grain protein concentrations were not strongly linked in the wheat populations studied. Hence, the probability of increasing acid soil tolerance by crossing Atlas 66 with Nebraskan wheat germplasm is low. However, the moderate level of acid soil tolerance in N87U106 and N87U123 (comparable to that of Cardinal) may be useful in further studies.     

Reoxidation Behavior of Wheat and Rye Glutelin Subunits

The ability of HMW and LMW subunits of wheat glutelin to form a polymeric gluten network by intermolecular disulfide bonds is responsible for the unique rheological properties and baking quality of wheat dough. Because the mechanism of gluten formation is not fully understood, the reoxidation behavior of HMW and LMW subunits of wheat glutelin and HMW subunits of rye glutelin was studied. The subunits were isolated from wheat flour cv. Rektor (REK) and from rye flour cv. Danko (DAN) with a selective extraction and precipitation method. For reoxidation, different oxidants (KBrO₃ and KIO₃), protein concentrations (0.5, 1.0, and 2.0%), solvent compositions, pH values (2.0 and 8.0), and reaction times (0–360 min) were compared. The characterization of reoxidized products was achieved by the determination of the thiol content with the Ellman's reagent, and of the M_r distribution by gel‐permeation chromatography. The results demonstrated that both HMW and LMW subunits could be slowly reoxidized with KBrO₃ to polymers with M_r up to several millions. Yield and M_r distribution of polymers were dependent both on the protein concentration and on the molar ratio of oxidants to thiol groups. The HMW subunits of wheat glutelin (HMW‐REK) yielded slightly higher quantities of polymeric proteins than did the HMW subunits of rye (HMW‐DAN). Reoxidation with KIO₃ proceeded much faster than with KBrO₃ and led to lower proportions of polymerized proteins for HMW‐REK and HMW‐DAN. Obviously, more intra‐ and fewer intermolecular disulfide bonds were formed by reoxidation with KIO₃ compared with KBrO₃. In contrast, LMW‐REK was reoxidized with KIO₃ to higher amounts of polymeric aggregates, which indicated that LMW subunits formed intermolecular disulfide bonds with both KIO₃ and KBrO₃. Independent of the protein type and the oxidant used for reoxidation, more inter‐ and fewer intramolecular disulfide bonds were formed when the protein concentration was increased. Single subunits 5, 7, and 10 were isolated from HMW‐REK by preparative acid‐PAGE and were reoxidized with KBrO₃ for 360 min. The M_r distribution indicated that x‐type subunit 5 had a greater tendency to form polymers than x‐type subunit 7. The y‐type subunit 10 was characterized by a lower proportion of polymers after reoxidation than x‐type subunits 5 and 7.     

Effect of zinc‐biofortified seeds on grain yield of wheat,rice, and common bean grown in six countries

Seeds enriched with zinc (Zn) are ususally associated with better germination, more vigorous seedlings and higher yields. However, agronomic benefits of high‐Zn seeds were not studied under diverse agro‐climatic field conditions. This study investigated effects of low‐Zn and high‐Zn seeds (biofortified by foliar Zn fertilization of maternal plants under field conditions) of wheat (Tritcum aestivum L.), rice (Oryza sativa L.), and common bean (Phaseolus vulgaris L.) on seedling density, grain yield and grain Zn concentration in 31 field locations over two years in six countries. Experimental treatments were: (1) low‐Zn seeds and no soil Zn fertilization (control treatment), (2) low‐Zn seeds + soil Zn fertilization, and (3) Zn‐biofortified seeds and no soil Zn fertilization. The wheat experiments were established in China, India, Pakistan, and Zambia, the rice experiments in China, India and Thailand, and the common bean experiment in Brazil. When compared to the control treatment, soil Zn fertilization increased wheat grain yield in all six locations in India, two locations in Pakistan and one location in China. Zinc‐biofortified seeds also increased wheat grain yield in all four locations in Pakistan and four locations in India compared to the control treatment. Across all countries over 2 years, Zn‐biofortified wheat seeds increased plant population by 26.8% and grain yield by 5.37%. In rice, soil Zn fertilization increased paddy yield in all four locations in India and one location in Thailand. Across all countries, paddy yield increase was 8.2% by soil Zn fertilization and 5.3% by Zn‐biofortified seeds when compared to the control treatment. In common bean, soil Zn application as well as Zn‐biofortified seed increased grain yield in one location in Brazil. Effects of soil Zn fertilization and high‐Zn seed on grain Zn density were generally low. This study, at 31 field locations in six countries over two years, revealed that the seeds biofortfied with Zn enhanced crop productivity at many locations with different soil and environmental conditions. As high‐Zn grains are a by‐product of Zn biofortification, use of Zn‐enriched grains as seed in the next cropping season can contribute to enhance crop productivity in a cost‐effective manner.     

Influence of Amylose Content on Cookie and Sponge Cake Quality and Solvent Retention Capacities in Wheat Flour

Reduced amylose wheat (Triticum æstivum L.) produces better quality noodles and bread less prone to going stale, while little is known about the relationships between amylose content and the quality of soft wheat baking products such as sugar snap cookies (SSC) and Japanese sponge cakes (JSC). Near‐isogenic lines developed from wheat cultivar Norin 61, differing in their level of granule‐bound starch synthase (Wx protein) activity, were used to produce wheat grains and ultimately flours of different amylose contents. These were tested with regard to their effect on soft wheat baking quality and solvent retention capacities (SRC). Amylose content was strongly correlated to cookie diameter (r = 0.969, P < 0.001) and cake volume (r = 0.976, P < 0.001), indicating that the soft wheat baking quality associated with SSC diameter and JSC volume were improved by an incremental increases in amylose content. Among the four kinds of SRC tests (water, sodium carbonate, sucrose and lactic acid), the water SRC test showed the highest correlation with amylose content, SSC diameter, and JSC volume. When the regression analysis was conducted between the nonwaxy and partial waxy isogenic lines that are available in commercial markets, only water SRC was significantly correlated to amylose content (r = –0.982, P < 0.001) among of four SRC tests. This suggests that, unlike udon noodle quality, high‐amylose content is indispensable in improving soft wheat baking quality, a process requiring less water retention capacity.     

Tolerance of durum wheat lines to an acid,aluminum‐toxic subsoil

Durum wheat, Triticum durum Desf., is reportedly more sensitive to aluminum (Al) toxicity in acid soils than hexaploid wheat, Triticum aestivum L. em. Thell. Aluminum‐tolerant genotypes would permit more widespread use of this species where it is desired, but not grown, because of acid soil constraints. Durum wheat germplasm has not been adequately screened for acid soil (Al) tolerance. Fifteen lines of durum wheat were grown for 28 days in greenhouse pots of acid, Al‐toxic Tatum subsoil at pH 4.5, and non‐toxic soil at pH 6.0. Aluminum‐tolerant Atlas 66 and sensitive Scout 66 hexaploid wheats were also included as standards. Based on relative shoot and root dry weight (wt. at pH 4.5/wt. at pH 6.0 X 100), durum entries differed significantly in tolerance to the acid soil. Relative shoot dry weight alone was an acceptable indicator of acid soil tolerance. Relative dry weights ranged from 55.1 to 15.5% for shoots and from 107 to 15.8% for roots. Durum lines PI 195726 (Ethiopia) and PI 193922 (Brazil) were significantly more tolerant than all other entries, even the Al‐tolerant, hexaploid Atlas 66 standard. Hence, these two lines have potential for direct use on acid soils or as breeding materials for use in developing greater Al tolerance in durum wheat. Unexpectedly, the range of acid soil tolerance available in durum wheat appears comparable to that in the hexaploid species. Hence, additional screening of durum wheat germplasm for acid soil (Al) tolerance appears warranted. Durum lines showing least tolerance to the acid soil included PI 322716 (Mexico), PI 264991 (Greece), PI 478306 (Washington State, USA), and PI 345040 (Yugoslavia). The Al‐sensitive Scout 66 standard was as sensitive as the most sensitive durum lines. Concentrations of Al and phosphorus were significantly higher in shoots of acid soil sensitive than in those of tolerant lines, and these values exceeded those reported to cause Al and phosphorus (P) toxicities in wheat and barley.     

C‐Glycosylflavone and Lignan Diglucoside Contents of Commercial,Regular, and Whole‐Wheat Spaghetti

Consumption of whole‐wheat products, including whole‐wheat spaghetti, is associated with beneficial health effects. Flavonoids and lignans are antioxidant phytochemicals that have received much attention from researchers. Investigations were conducted on the content of flavonoid glycosides, lignan diglucoside, and secoisolariciresinol diglucoside (SDG) as contributors to the health‐promoting properties of whole‐wheat spaghetti. Flavonoid glycosides present in regular and whole‐wheat spaghetti samples were identified as 6‐C‐glucosyl‐8‐C‐arabinosyl apigenin and the sinapic acid ester of apigenin‐C‐diglycoside while, in a previous study, the sinapic acid ester of apigenin‐C‐diglycoside was found only in wheat germ tissues. The content of these compounds was significantly higher in whole‐wheat spaghetti (17.0 and 15.1 μg of apigenin equivalent/g) compared to the regular brands (9.5 and 5.8 μg apigenin equivalent/g). SDG content was also significantly higher in whole‐wheat spaghetti (41.8 μg/g) compared to the regular brands (12.9 μg/g). These findings lend further support to the notion that phenolic compounds, along with dietary fiber, are concentrated in the bran layers of the wheat kernel; hence, consumption of whole grain products is strongly recommended to obtain significant levels of health‐promoting phytochemicals.     

Preparation and Functional Properties of Gluten Hydrolysates with Wheat‐Bug (Eurygaster spp.) Protease

Suni‐bug (Eurygaster spp.) enzyme was partially purified from bug‐damaged wheat and used to prepare gluten hydrolysates at 3% and 5% degree of hydrolysis (DH). Functional properties of gluten and gluten hydrolysates were determined at 0.2% (w/v) protein concentration and pH 2–10. Gluten solubility after enzymatic hydrolysis increased significantly (P < 0.05) up to 89.1, 89.6, and 95.0% at pH 7, 8, and 10, respectively. Emulsion stability (ES) of gluten hydrolysates improved at neutral and alkaline pH (P < 0.05) and emulsifying capacity (EC) increased significantly (P < 0.05) except at pH 10. Foaming capacity (FC) values of gluten hydrolysates were significantly higher (P < 0.05) at pH 6, 7, 8; foam stability (FS) values of gluten hydrolysates were significantly higher (P < 0.05) at pH 6 and 7. Enzymatic modification of gluten by wheat‐bug enzyme resulted in hydrolysates with higher antioxidant activity compared to gluten. Significant correlations (P < 0.001) were found between solubility and EC, ES, FC, and FS values of gluten and its hydrolysates with 3% and 5% DH.     

Effect of Growing Environment of Soft Wheats on Amylose Content and Its Relationship with Cookie and Sponge Cake Quality and Solvent Retention Capacity

The effect of growing environments of soft wheat on amylose content and its relationship with baking quality and solvent retention capacities (SRC) was investigated. Near‐isogenic soft wheat lines of Norin 61 differing in granule‐bound starch synthase (Wx protein) activity and grown in three different regions of Japan: Hokkaido (spring‐sown) for 2006 and 2007, Kanto (autumn‐sown), and Kyushu (autumn‐sown) for 2007 were evaluated. Spring‐sown samples produced grains of greater protein content (10.9–12.4%) than autumn‐sown samples (7.3–9.1%). In contrast, spring‐sown samples of 2007 with higher maturing temperature had lower amylose content (25.5% for Norin 61) compare to the autumn‐sown and spring‐sown samples of 2006 (27.6–28.4% for Norin 61). Amylose content was strongly correlated to sugar snap cookie (SSCD) diameter (r = 0.957–0.961; n = 10, all samples; P ≤ 0.001, r = 0.701–0.976; n = 7 partial waxy and nonwaxy samples; and Japanese sponge cake (JSCV) volume r = 0.971–0.993; n = 10; P≤ 0.001, r = 0.764–0.922; n = 7 partial waxy and nonwaxy samples), regardless of seeding season and growing conditions. The strength of the JSVC‐amylose relationship (slope) was similar among the three regions, whereas the strength of the SSCD‐amylose relationship was slightly weaker for spring‐sown samples and slightly stronger for partial waxy and nonwaxy autumn‐sown samples. Among of the four solvents (water, solutions of sodium carbonate, sucrose, or lactic acid), water‐SRC showed the greatest correlation to amylose content (r = –0.969 to –0.996; n = 10; P ≤ 0.001, r = –0.629 to –0.983; n = 7 partial waxy and nonwaxy samples), indicated that amylose content can be accurately estimated from the water‐SRC within the samples from the same grown environment.     

Antioxidant Capacity of Water‐Extractable Arabinoxylan from Commercial Barley,Wheat, and Wheat Fractions

The objective of this research was to analyze the antioxidant capacity directly of water‐extractable nonstarch polysaccharides (NSP) and feruloylated arabinoxylans (WEAX) following their characterization. NSP were isolated from barley, wheat, and wheat fractions (germ, bran, and aleurone). WEAX were extracted only from wheat fractions. Antioxidant capacity of NSP measured with the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS), and oxygen radical absorbance capacity (ORAC) assays was 24.0–99.0, 40.0–122.0, and 140.0–286.0μM Trolox equivalents (TE)/g, respectively. The antioxidant capacity of WEAX was 75.7–84.0, 58.0–105.0, and 110.0–235.0μM TE/g for those three assays. DPPH and ABTS were highly correlated to xylose content (R² = 0.85), degree of substitution (R² = −0.99), total phenolic acids (R² = >0.73), total phenolic content (TPC) (R² = >0.78), and ferulic acid content (R² = >0.86). ORAC was only influenced by TPC (R² = 0.63). By taking yield and antioxidant capacity into account, NSP would provide about 0.4–4.2, 0.6–5.1, and 2.8–12.0μM TE/g of flour of radical scavenging activity as measured by DPPH, ABTS, and ORAC, respectively, compared with WEAX (0.4–1.0, 0.3–1.3, and 0.6–2.8μM TE/g). Our results suggest that NSP or WEAX may play a role in protection against free radicals in a food matrix and likely in the gastrointestinal tract.     

Cation binding by acid-washed peat, interpreted with Humic Ion-Binding Model VI-FD

A sample of ombrotrophic peat from Moor House in northern England was extensively extracted with dilute nitric acid (pH 1) to free it of bound cations. Suspensions of the acid‐washed peat (5–30 g l^?1), prepared with different concentrations of background electrolyte (NaCl and KCl), were used to conduct batch acid–base titrations. A strong dependence of proton release on ionic strength (I) was observed, the apparent acid dissociation constant (pK_app) being found to decrease by approximately 1.0 for each tenfold increase in I. This behaviour could not be explained satisfactorily with Humic Ion‐Binding Model VI, a discrete‐site/electrostatic model of cation binding by humic substances, parameterized with data from laboratory studies on isolated samples. More success was obtained by abandoning the impermeable‐sphere electrostatic submodel used in Model VI, and instead assuming the peat to consist of aggregates with fixed internal volume, and with counterion accumulation described by the Donnan model, as proposed by Marinsky and colleagues. The fixed‐volume Donnan model (Model VI‐FD) could also approximately explain other reported results from acid–base titrations of peat, including the effects on the titrations of complexing cations (Al, Ca, Cu). Copper titrations of the Moor House sample were performed using an ion‐selective electrode, with peat suspensions in the acid pH range, at two ionic strengths, and in the presence of Al and Ca. The measured concentrations of Cu²⁺ were in the range 10^?13?10^?5 m . Model VI‐FD provided reasonable fits of the experimental data, after optimization of the intrinsic binding constant for Cu, the optimized value being close to the default value derived previously from data referring to isolated humic substances. The optimized constants for Al and Ca, derived from their competition effects, were also close to their default values. Additional experiments were performed in which the centrifugation‐depletion method was used to measure the binding of a cocktail of metals (Al, Ni, Cu, Zn, Cd, Eu, Pb) at a single pH. The model correctly predicted strong binding of Al, Cu, Eu and Pb, and weaker binding of Ni, Zn and Cd. For the strongly binding metals, the dissolved forms were calculated to be mainly due to complexes with dissolved humic matter, whereas the free ions (Ni²⁺, Zn²⁺, Cd²⁺) dominated for the weakly binding metals. Acid‐washed soil appears to provide a valuable intermediate between isolated humic substances and untreated soil for the investigation of cation binding by natural organic matter in the natural environment.