Waxy Wheat Research Articles

Grain Yield, Starch Content and Activities of Key Enzymes of Waxy and Non-waxy Wheat (Triticum aestivum L.)

Waxy wheat has unique end-use properties; however, its production is limited due mainly to its low grain yield compared with non-waxy wheat. In order to increase its grain yield, it is critical to understand the eco-physiological differences in grain filling between the waxy and non-waxy wheat. In this study, two waxy wheat and two non-waxy wheat cultivars were used to investigate the differences in starch-associated enzymes processes, sucrose and starch dynamics, yield components, and the final grain yield. The results indicated that the mean total grain starch and amylose content, the average 1000-kernel weight and grain yield of the waxy wheat were lower than those of the non-waxy wheat at maturity. The amylose content was significantly and positively correlated with the activity of GBSS (r = 0.80, p < 0.01). Significant positive correlation also exists among activities of AGPase, SSS, GBSS, and SBE, except for GBSS-SBE. In summary, our study has revealed that the reduced conversion of sucrose to starch in the late grain filling stage is the main cause for the low kernel weight and total starch accumulation of the waxy wheat. The reduced conversion also appears to be a factor contributing to the lower grain yield of the waxy wheat.

Near infrared hyperspectral imaging of blends of conventional and waxy hard wheats

Recent development of hard winter waxy (amylose-free) wheat adapted to the North American climate has prompted the quest to find a rapid method that will determine mixture levels of conventional wheat in lots of identity preserved waxy wheat. Previous work documented the use of conventional near infrared (NIR) reflectance spectroscopy to determine the mixture level of conventional wheat in waxy wheat, with an examined range, through binary sample mixture preparation, of 0–100% (weight conventional / weight total). The current study examines the ability of NIR hyperspectral imaging of intact kernels to determine mixture levels. Twenty-nine mixtures (0, 1, 2, 3, 4, 5, 10, 15, …, 95, 96, 97, 98, 99, 100%) were formed from known genotypes of waxy and conventional wheat. Two-class partial least squares discriminant analysis (PLSDA) and statistical pattern recognition classifier models were developed for identifying each kernel in the images as conventional or waxy. Along with these approaches, conventional PLS1 regression modelling was performed on means of kernel spectra within each mixture test sample. Results indicated close agreement between all three approaches, with standard errors of prediction for the better preprocess transformations (PLSDA models) or better classifiers (pattern recognition models) of approximately 9 percentage units. Although such error rates were slightly greater than ones previously published using non-imaging NIR analysis of bulk whole kernel wheat and wheat meal, the HSI technique offers an advantage of its potential use in sorting operations.

Effects of Fertilizer Application Rate and Planting Density on Photosynthetic Characteristics, Yield and Yield Components in Waxy Wheat

Waxy wheat (Triticum aestivum L.) is grown throughout the world for its specific quality. Fertilization and planting density are two crucial factors that affect waxy wheat yield and photosynthetic capacity. The objectives of the research were to determine the effects of fertilization and planting density on photosynthetic characteristics, yield, and yield components of waxy wheat, including Yield, SSR, TGW, GNPP, GWPP, PH, HI, Pn, Gs, Ci, E and WUE using the method of field experiment, in which there were three levels (150, 300, and 450 kg ha–1) of fertilizer application rate and three levels (1.35, 1.8, and 2.25 × 106 plants ha–1) of planting density. The results suggested that photosynthetic characteristics, yield, and yield components had close relationship with fertilization levels and planting density. Under the same plant density, with the increase of fertilization, Yield, SSR, TGW, GNPP, GWPP, HI, Pn, Gs, E and WUE increased and then decreased, PH increased, but Ci decreased. Under the same fertilization, with the increase of plant density, Yield, SSR, TGW, GNPP, GWPP, HI increased and then decreased, PH, Pn, Gs and E increased, PH and WUE declined. The results also showed that F2 (300 kg ha–1) and D2 (1.8 × 106 plants ha–1) was a better match in this experiment, which could obtain a higher grain yield 4961.61 kg ha–1. Consequently, this combination of fertilizer application rate and plant densities are useful to get high yield of waxy wheat.

THE INFLUENCE OF THE WAXY WHEAT FLOUR ON THE CAKE`S STALING

Nowadays the use of waxy wheat in bread and pastry technologies, is gaining interest in view of extending the shelf-life of flour products, avoiding the use of additives. The obtained results shows the expediency of using waxy wheat flour, starch of which does not contain amylose, for the stabilization of the cake`s quality during its storage. The influence of the mass fraction of non-amylose wheat flour on the physico-chemical and sensory characteristics of finished products were studied. Quality parameters like moisture content, rheological characteristics of the crumb, microbial and sensory analysis of developed products were evaluated during 7 days of storage period. It is found that replacement of bakery wheat flour with traditional starch content for the waxy wheat flour has the positive influence on the cake`s staling process. These samples were characterized with lower decrease of moisture loss, less reduction of the amount of bound water in cake`s crumb and higher organoleptic quality at the end of the shelf-life without adding of synthetic improvers.

THE INFLUENCE OF THE WAXY WHEAT FLOUR ON THE CAKE`S STALING

Nowadays the use of waxy wheat in bread and pastry technologies, is gaining interest in view of extending the shelf-life of flour products, avoiding the use of additives. The obtained results shows the expediency of using waxy wheat flour, starch of which does not contain amylose, for the stabilization of the cake`s quality during its storage. The influence of the mass fraction of non-amylose wheat flour on the physico-chemical and sensory characteristics of finished products were studied. Quality parameters like moisture content, rheological characteristics of the crumb, microbial and sensory analysis of developed products were evaluated during 7 days of storage period. It is found that replacement of bakery wheat flour with traditional starch content for the waxy wheat flour has the positive influence on the cake`s staling process. These samples were characterized with lower decrease of moisture loss, less reduction of the amount of bound water in cake`s crumb and higher organoleptic quality at the end of the shelf-life without adding of synthetic improvers.

Rheological properties and baking performance of new waxy lines: Strengths and weaknesses

In Western countries, the use of waxy wheat in bread-making is gaining interest in view of extending the shelf-life of bread, avoiding the use of additives. Considering the high impact of the environment on wheat properties, selection of waxy lines able to adapt to a particular environment is highly recommended. In this frame, the behavior of three new Italian waxy lines (IW) were compared with that of two waxy lines breeded in United States (USW). Compared to USW, two out of three IW lines exhibited better mixing properties in terms of higher tolerance to mechanical stress (stability and softness index). IW dough showed similar water absorption, stickiness values and visco-elasticity (G′ and G″) compared to USW samples. On the other hand, the waxy wheat lines adapted to the Italian environmental conditions showed a more developed loaf volume with respect to USW lines. The difficulties in dough handling that is typical of waxy wheat when used alone could be partially solved using waxy wheat in combination with non-waxy flours.

Release of 19 Waxy Winter Wheat Germplasm, with Observations on Their Grain Yield Stability

“Waxy” wheats (Triticum aestivum L.) produce endosperm starch devoid, or nearly so, of amylose. Waxy starch consists only of amylopectin, imparts unique cooking properties, and serves as an efficient substrate for the production of modified food starches. To expand the genetic variation of waxy wheats useful to Great Plains breeding programs, the USDA‐ARS, in cooperation with the University of Nebraska, developed and released 19 waxy winter wheats (Reg. No. GP‐1003, PI 677864 to Reg. No. GO‐1021, PI 677882) . Three of the waxy germplasm lines have soft endosperm texture; the remaining 16 lines have hard‐textured grain. The grain yields of six of the waxy winter wheat germplasm lines were not significantly different from the highest yielding nonwaxy cultivar (‘Freeman’). All but four waxy germplasm lines had grain yields statistically equal to that of the waxy winter wheat cultivar Mattern. Grain yield stability (or response to changing environments) of the waxy germplasm lines demonstrated similar trends to those of the nonwaxy controls. Grain yield observations and responses to changing production potentials argue against any yield drag associated with waxy starch and indicate potential for the development of additional and competitive cultivars.

Development of a kompetitive allele‐specific PCR marker for selection of the mutated Wx‐D1d allele in wheat breeding

AbstractWaxy (Wx) protein is a key enzyme for synthesis of amylose in endosperm. Amylose content in wheat grain influences the quality of end‐use products. Seven alleles have been described at the Wx‐D1 locus, but only two of them (Wx‐D1b, Wx‐D1e) were genotyped with codominant markers. The waxy wheat line K107Wx1 developed by treating ‘Kanto 107’ seeds with ethyl methanesulphonate carries the Wx‐D1d allele. However, no molecular basis supports this nomenclature. In the present study, DNA sequence analysis confirmed that a single nucleotide polymorphism in the sixth exon of Wx‐D1 changed tryptophan at position 301 into a termination codon. Based on this sequence variation, a PCR‐based KASP marker was developed to detect this point mutation using 68 BC8F1 plants and 297 BC8F2 lines derived from the cross ‘Ningmai 14’*9/K107Wx1. Combined with codominant markers for the Wx‐A1 and Wx‐B1 alleles, waxy and non‐waxy near‐isogenic lines were distinguished. The KASP marker was efficient in identifying the mutant allele and can be used to transfer waxiness to elite lines.

Interplay between starch and proteins in waxy wheat

Most of the unique properties of waxy wheat have been associated with the lack of amylose, that in turn may affect the mutual interactions between starch and proteins. To address this particular aspect, we carried out molecular, rheological, and calorimetric studies on flours from two waxy wheat lines that were compared with a non-waxy one. Dough thermal properties and water binding capacity were investigated by Differential Scanning Calorimetry (DSC) and by thermogravimetric analysis, respectively. Protein solvation, aggregation, and thiol accessibility were also investigated, together with dough mixing properties and stickiness. Proteins in waxy wheat samples needed more water to complete solvation, likely because of the water-retaining capacity of waxy wheat starch. In waxy wheat dough, water was tightly bound to starch, and DSC studies indicated an increase in gelatinization temperature. Moreover, the low water mobility in waxy wheat resulted in low and retarded gluten hydration and in high stickiness. In samples with the highest stickiness, protein aggregates were stabilized mainly by hydrophobic interactions. Differences between waxy wheat lines may be attributed to a different structural organization of components within each class of biopolymers.

Effect of high hydrostatic pressure and retrogradation treatments on structural and physicochemical properties of waxy wheat starch

In this study, the effects of high hydrostatic pressure and retrogradation (HHPR) treatments on in vitro digestibility, structural and physicochemical properties of waxy wheat starch were investigated. The waxy wheat starch slurries (10%, w/v) were treated with high hydrostatic pressures of 300, 400, 500, 600MPa at 20°C for 30min, respectively, and then retrograded at 4°C for 4d. The results indicated that the content of slowly digestible starch (SDS) in HHPR-treated starch samples increased with increasing pressure level, and it reached the maximum (31.12%) at 600MPa. HHPR treatment decreased the gelatinization temperatures, the gelatinization enthalpy, the relative crystallinity and the peak viscosity of the starch samples. Moreover, HHPR treatment destroyed the surface and interior structures of starch granules. These results suggest that the in vitro digestibility, physicochemical, and structural properties of waxy wheat starch are effectively modified by HHPR.

Waxy Wheat Flour as a Freeze-Thaw Stable Ingredient Through Rheological Studies

A large variety of foods including soups, sauces, and other items that may experience freezing use specialty ingredients to prevent negative effects of freezing. While multiple modified starches derived from maize are available to do this, unmodified flours that may be able to carry a “natural” label are not used widely. To begin to analyze whether other alternative solutions are possible in unutilized flours, waxy wheat flour was subjected to freeze-thaw characterization through rheology to provide insight to textural changes that may occur. In order to determine freeze-thaw-induced changes, gelatinized solutions of waxy and regular wheat flours were subjected to shear rate sweeps, oscillatory rheological tests, and large amplitude oscillatory shear testing before and after freeze-thaw cycles. Minimal changes in rheological behaviors were observed in waxy wheat samples compared to regular wheat samples. Waxy wheat flour was also analyzed through differential scanning calorimetry both before and after being subjected to ten freeze-thaw cycles. Syneresis effects were also determined after each freeze-thaw cycle. Waxy wheat exhibited <5% water loss while regular wheat showed 25–40% water loss. Differential scanning calorimetry after freeze-thaw cycles were found to exhibit negligible retrogradation enthalpy values in waxy wheat samples as compared to 1.3–1.8 J/g in regular wheat samples. Results suggested that waxy wheat can serve as a novel and natural food ingredient for freeze-thaw stabilization in foods such as soups, dressings, and frozen meals.

Determination of volatile compounds in heat-treated straight-grade flours from normal and waxy wheats

Volatile compounds formed during heat-treatment of wheat flour influence the application of treated flour. In this study, normal and waxy hard wheat flours before and after dry-heat treatment were subjected to headspace analysis by solid-phase microextraction of volatiles followed gas chromatography–mass spectrometry (GC/MS). The untreated waxy wheat flour contained higher levels of odor-active compounds than normal wheat flour including aldehydes, alcohols, furans, and ketones. Lipid oxidation appears to play major role in producing such odor compounds. Heat treatments, depending on the severity, alter the profile of volatile compounds. Low temperature (100–110 °C) treatments effectively eliminated cereal odor (aldehyde) and did not introduce additional odors, providing a possible way to produce low-odor flours. Heat treatments at 120 °C and higher temperatures elevated the content of pyrazines, furans, and sulfur-containing compounds which together gave a roasty aroma to the flours. Considering organoleptic properties, treatments of flours at 140 °C was superior to 160 °C. The waxy wheat flour was more prone to produce odor-active compounds than normal wheat flour during the same heat treatment.

Study of the mechanism of improvement due to waxy wheat flour addition on the quality of frozen dough bread

Waxy wheat flour (WWF) was substituted for 10% regular wheat flour (RWF) in frozen doughs and the physicochemical properties of starch and protein isolated from the frozen doughs stored for different time intervals (0, 1, 2, 4 and 8 weeks) were determined to establish the underlying reasons leading to the effects observed in WWF addition on frozen dough quality. Using Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimeter (DSC) and X-ray Diffraction (XRD) among others, the gluten content, water molecular state, glutenin macropolymer content, damaged starch content, starch swelling power, gelatinization properties, starch crystallinity and bread specific volume were measured. Compared to RWF dough at the same frozen storage condition, 10% WWF addition decreased dry gluten and glutenin macropolymer contents and T23 proton density of frozen dough, but increased the wet gluten content, T21 and T22 proton density. 10% WWF addition also decreased damaged starch content, but increased starch swelling power, gelatinization temperature and enthalpy, crystallinity of starch and bread specific volume of frozen dough. Results in the present study showed that the improvement observed due to WWF addition in frozen dough bread quality might be attributed to its inhibition of redistribution of water molecules bound to proteins, increase in damaged starch content and decrease in starch swelling power.

Genetic dissection of the sensory and textural properties of Chinese white noodles using a specific RIL population

To dissect the genetic control of the sensory and textural quality traits of Chinese white noodles, a population of recombinant inbred lines (RILs), derived from the cross of waxy wheat Nuomai 1 (NM1) and Gaocheng 8901 (Gc8901), was used. The RILs were tested in three different environments to determine the role of environmental effects on quantitative trait loci (QTL) analysis. A total of 45 QTLs with additive effects for 17 noodle sensory and textural properties under three environments were mapped on 15 chromosomes. These QTLs showed 4.23–42.68% of the phenotypic variance explained (PVE). Nineteen major QTLs were distributed on chromosomes 1B, 1D, 2A, 3B, 3D, 4A, and 6A, explaining more than 10% of the phenotypic variance (PV). Clusters were detected on chromosomes 2B (3 QTLs), 3B (11 QTLs) and 4A (5 QTLs). The cluster detected on chromosome 4A was close to the Wx-B1 marker. Five co-located QTLs with additive effects were identified on chromosomes 2B, 3D, 4A, 6A, and 7B. The two major QTLs, Qadh.sdau-3B.1 and Qspr.sdau-3B.1, in cluster wPt666008–wPt5870 on chromosome 3B were detected in three different environments, which perhaps can be directly applied to improve the textural properties of noodles. These findings could offer evidence for the selection or development of new wheat varieties with noodle quality using molecular marker-assisted selection (MAS).

Effects of Post-Flowering Shading Intensities on Starch Components and Physicochemical Properties in Waxy and Non- waxy Wheats

Effects of Post-Flowering Shading Intensities on Starch Components and Physicochemical Properties in <i>Waxy</i> and Non- <i>waxy</i> Wheats

Classification of 31 Korean Wheat (Triticum aestivum L.) Cultivars Based on the Chemical Compositions.

Whole grain wheat flour (WGWF) is the entire grain (bran, endosperm, and germ) milled to make flour. The WGWF of 31 Korean wheat (Triticum aestivum L.) cultivars were analyzed for the chemical compositions, and classified into groups by hierarchical cluster analysis (HCL). The average composition values showed a substantial variation among wheat varieties due to different wheat varieties. Wheat cv. Shinmichal1 (waxy wheat) had the highest ash, lipid, and total dietary fiber contents of 1.76, 3.14, and 15.49 g/100 g, respectively. Using HCL efficiently classified wheat cultivars into 7 clusters. Namhae, Sukang, Gobun, and Joeun contained higher protein values (12.88%) and dietary fiber (13.74 %). Regarding multi-trait crop breeding, the variation in chemical compositions found between the clusters might be attributed to wheat genotypes, which was an important factor in accumulating those chemicals in wheat grains. Thus, once wheat cultivars with agronomic characteristics were identified, those properties might be included in the breeding process to develop a new variety of wheat with the trait.

Technological characteristics of yeast-containing cakes production using waxy wheat flour

This article shows the feasibility of using waxy wheat flour, the starch of which doesn`t contain amylose, in order to stabilize the quality of yeast-containing cakes. The influence of the waxy wheat flour mass fraction and the stage of its adding on the physical, chemical and organoleptic characteristics of the products are studied. According to the technological properties of a new type of wheat flour, two methods of its adding are proposed ‒ adding the maximum amount of waxy wheat flour at dough kneading stage or using the mixture of waxy and bakery wheat flours for kneading sourdough and dough. It is shown that the replacement of 60 % bakery wheat flour with waxy wheat flour in the recipe of yeast-containing cakes at the dough kneading stage contributes to the production of products with higher quality and organoleptic characteristics compared to both the control and cakes based on a mixture of different types of wheat flour. These samples are characterized by increased by 1.7 – 11.3 % specific volume, porosity – 2.6 – 5.5 % and the total deformation of the crumb – 6.5 – 41.4 %.

Quality characteristics of northern-style Chinese steamed bread prepared from soft red winter wheat flours with waxy wheat flour substitution

Quality characteristics of northern-style Chinese steamed bread (CSB) prepared from two soft red winter (SRW) wheat flours blended with 0–30% waxy wheat flour (WWF) were analyzed to estimate the influence of starch amylose content. The increased proportion of WWF in blends raised mixograph absorption with insignificant changes in protein content and dough strength-related parameters. WWF incorporation generally increased specific volume and crumb softness of CSB. The analysis of covariance revealed that CSB quality attributes were little affected by protein content and dough strength-related parameters, indicating that starch amylose content was largely responsible for the changes in CSB quality. Flour blends with 5–10% WWF, of which starch amylose content was 22.4–24.7%, produced CSB with superior crumb structure compared to other blends, but insignificant changes in surface smoothness, stress relaxation and total score compared to the respective control wheat flours. Flour blends with 15% WWF to produce a starch amylose content of 21.4–22.7% exhibited reduced staling of CSB with total scores comparable to the respective control wheat flours. CSB prepared from blends with more than 10% WWF exhibited a higher soluble starch content, indicative of reduced starch retrogradation, than that prepared from wheat flours without WWF during storage for 3 days.

Observations on the Quality Characteristics of Waxy (Amylose‐Free) Winter Wheats

Previous investigations have suggested waxy (amylose‐free) wheats (Triticum aestivum L.) possess weak gluten properties and may not be suitable for commercial gluten extraction. This limitation could prevent the use of waxy wheat as a source of unique starch, because gluten is a by‐product of the wheat starch purification process. Fifty waxy wheat lines were used to determine the extent to which gluten protein and other grain quality related traits might vary and, consequently, allow the development of waxy wheat with acceptable gluten properties. Among the waxy lines, significant variation was observed for all measured quality traits with the exception of flour protein concentration. No waxy entries statistically equaled the highest ranking nonwaxy entry for grain volume weight, falling number, flour yield, or mixograph mix time. No waxy lines numerically exceeded or equaled the mean of the nonwaxy controls for falling number, flour yield, or mixograph mix time. For grain and flour protein related variables, however, many waxy lines were identified well within the range of acceptability, relative to the nonwaxy controls used in this study. Approximately 50% of the waxy lines did not differ from the highest ranking nonwaxy cultivar for grain and flour protein concentrations. Forty‐three (86%) of the tested waxy lines were not sig‐nificantly different from the nonwaxy line with the highest mixograph mixing tolerance, 22/50 (44%) of the waxy wheat lines did not differ from the highest ranking nonwaxy line in gluten index scores, and 17/50 (34%) did not differ from the highest ranking nonwaxy line in extracted wet gluten. All waxy experimental lines produced gluten via Glutomatic washing. The quality of the gluten, as measured both by mixograph and gluten index, varied widely among the waxy lines tested. These observations suggest that weak gluten is not a natural consequence of the waxy trait, and waxy cultivars with acceptable gluten properties can be developed.

Physical, Textural, and Antioxidant Properties of Extruded Waxy Wheat Flour Snack Supplemented with Several Varieties of Bran.

Wheat represents a ubiquitous commodity and although industries valorize 10% of wheat bran, most of this antioxidant-rich byproduct gets fed to livestock. The objective of this study was to incorporate wheat bran into an extruded snack. Bran samples from hard red spring, soft white club cv. Bruehl, and purple wheat lines were added to cv. Waxy-Pen wheat flour (Triticum aestivum L.) at replacement concentrations of 0%, 12.5%, 25%, and 37.5% (w/w; n = 10). Extrudates were evaluated for antioxidant capacity, color, and physical properties. Results showed that high fiber concentrations altered several pasting properties, reduced expansion ratios (P < 0.0001), and created denser products (P < 0.0001), especially for white bran supplemented extrudates. Purple bran supplemented extrudates produced harder products compared to white and red bran treatments (P < 0.0001). Extrudates produced with 37.5% (w/w) of each bran variety absorbed more water than the control with no added bran. The oxygen radical absorption capacity assay, expressed as Trolox Equivalents, showed that extrudates made with addition of red (37.5%) and purple (37.5%) bran had higher values compared to the other treatments; the control, red, and white bran treatments had less antioxidant activity after extrusion (P < 0.0001) compared to purple bran supplemented extrudates. Purple and red brans may serve as viable functional ingredients in extruded foods given their higher antioxidant activities. Future studies could evaluate how bran variety and concentration, extruded shape, and flavor influence consumer acceptance.