Dough rheology and wet milling of hard waxy wheat flours

Microstructures of Starch Granules with Different Amylose Contents and Allomorphs as Revealed by Scattering Techniques

In this study, as-is (ca. 12% moisture by mass) and hydrated (50% water by mass) granules of waxy potato (WP), waxy wheat (WW), waxy maize, normal maize, and high-amylose maize (HAM) starches were investigated by using small-angle neutron and X-ray scattering (SANS and SAXS), wide-angle X-ray scattering, and ultra-small-angle neutron scattering. The SANS and SAXS data were fitted using the two-phase stacking model of alternating crystalline and amorphous layers. The partial crystalline lamellar structures inside the growth rings of granules were analyzed based on the inter-lamellar distances, thicknesses of the crystalline lamellae and amorphous layers, thickness polydispersities, and water content in each type of layer. Despite having a longer average chain length of amylopectin, the WP and HAM starches, which had B-type allomorph, had a shorter inter-lamellar distance than the other three starches with A-type allomorph. The WP starch had the most uniform crystalline lamellar thickness. After hydration, the amorphous layers were expanded, resulting in an increase of inter-layer distance. The low-angle intensity upturn in SANS and SAXS was attributed to scattering from interfaces/surfaces of larger structures, such as growth rings and macroscopic granule surfaces. Data analysis methods based on model fitting and 1D correlation function were compared. The study emphasized─owing to inherent packing disorder inside granules─that a comprehensive analysis of different parameters was essential in correlating the microstructures with starch properties.

Familiarization with White Whole Wheat Improves Acceptability of Whole Grain-Based Baked Products Made with White Whole Wheat Among College Students

Research corroborates that high whole grain intake is associated with lower risk for obesity, type 2 diabetes, cardiovascular diseases, and cancers. Unfamiliarity with, and negative sensory appeal of whole grains limit voluntary food choices to increase their consumption. This study aimed to explore the effectiveness of familiarization with white whole wheat, to improve college students’ acceptability of shortened cakes, muffins, and yeast breads made with white whole wheat flour (WWWF). All-purpose flour (APF) was replaced with WWWF in standardized recipes, and the products scored by 102 college students. Independent t-test was used to analyze if sensory scores for appearance, taste, texture, and overall acceptability between APF and WWWF products were statistically significant. Before familiarization with WWWF, all three APF products scored significantly higher than whole grain counterparts ( P < .05). When participants were familiarized with health benefits and expected sensory profile of whole grain products, sensory scores for appearance, taste, and overall acceptability of WWWF products did not significantly differ from APF counterparts ( P > .05). Familiarization significantly increased overall acceptability scores of WWWF products ( P < .05). Familiarization also increased proportion of students willing to bake with WWWF. Results underscore that familiarization can improve acceptability of WWWF in baked products and students’ willingness to incorporate it in baking, with potential to stimulate dietary modifications.

Study of Noodle Quality Based on Protein Properties of Three Wheat Varieties

Waxy wheat offers unique benefits in food processing, including improving the smoothness and performance of the product. However, waxy wheat is not yet commercially available. The protein characteristics, including the protein content, subunit distribution, secondary structure, chemical interactions, and microstructure of the gluten, were explored to realize the full potential of waxy wheat. The results showed that the noodles prepared from waxy wheat had a gentle and glutinous texture compared with GY2018 and YM13. Partial-waxy and waxy wheat had a lower gluten index and glutenin macropolymer (GMP) content than GY2018, indicating a reduced gluten strength. Confocal laser scanning microscopy (CLSM) images showed that the starch granules were not securely attached to the partial-waxy and waxy wheat protein matrix. In addition, the waxy protein chains appeared more elongated and they weakened the protein network. In particular, HMW-GS subunit 2 + 12 may be the essential cause of the weak dough from SKN1. Compared with GY2018 and YM13, SKN1 had the highest number of free sulfhydryl groups. Rather than ionic bonds, hydrophobic interactions increased the gluten network in GY2018, YM13, and SKN1. The weak molecular forces in the gluten will result in a soft noodle texture.

Grain Yield Performance and Quality Characteristics of Waxy and Non-Waxy Winter Wheat Cultivars under High and Low-Input Farming Systems

Waxy starch with a modified amylose-to-amylopectin ratio is desired for a range of applications in food and non-food industries; however, yield performance and grain quality characteristics of waxy wheat cultivars are usually inferior in comparison to advanced non-waxy cultivars. In this study, we compared waxy (‘Eldija’, ‘Sarta’) and non-waxy (‘Skagen’, ‘Suleva DS’) winter wheat cultivars grown under high and low-input farming systems over two cropping seasons by evaluating their yield and grain quality, including flour, dough, and starch physicochemical properties. The yield of waxy cv. ‘Sarta’ was significantly lower compared to the non-waxy cultivars across all trials; however, waxy cv. ‘Eldija’ had a similar yield as non-waxy cultivars (except under high-input conditions cv. ‘Skagen’). Moreover, no significant differences were observed between protein and gluten content of waxy and non-waxy cultivars. Low amylose content typical for waxy wheat cultivars highly correlated (r ≥ 0.8) with lower falling number, flour yield and sedimentation values, lower nitrogen % used for grain, higher flour water absorption and flour particle size index. In general, properties dependent on starch structure demonstrated consistent and significant differences between both starch types. The prevailing heat waves during the grain filling period decreased grain test weight but increased protein and gluten content and caused gluten to be weaker. Dough development time at these conditions became longer, dough softening lowered and starch content decreased, but A-starch, starch peak and final viscosity values increased. Low-input farming had a negative effect on grain yield, grain nitrogen uptake and grain test weight but increased phosphorus content in grain. The unique dough mixing properties of waxy cultivar ‘Eldija’ suggest that it could be used in mixtures along with non-waxy wheat for dough quality improvement.

Properties of flour from pearled wheat kernels as affected by ozone treatment

Two different pearling degrees of wheat kernels (lightly-pearled: 14.4% and heavily-pearled: 38.9%) and un-pearled kernels were treated with ozone and evaluated for flour compositions and properties. Ozonation did not change main compositions and damaged starch content of three kernels' flours. Flour brightness of all three kernels was improved after ozone treatment. Ozonation enhanced the dough strength of the flours from un-pearled and pearled kernels and the effect elevated with increasing pearling degree. Ozone treatment increased the peak viscosity of flour and the level of increase in heavily-pearled kernels was greater than un-pearled and lightly-pearled. Ozonation resulted in an increase in the insoluble protein polymer content of heavily-pearled kernels' flour, but only had a slight effect on un-pearled lightly-pearled kernels. After ozone treatment, un-pearled and lightly-pearled kernels exhibited increases in molecular weight of starch, but heavily-pearled resulted in the opposite trend.

Settling volume and morphology changes in cross-linked and unmodified starches from wheat, waxy wheat, and waxy maize in relation to their pasting properties

Normal wheat, waxy wheat and waxy maize starches were cross-linked with 0.01, 0.03 and 0.06% (sb) phosphorus oxychloride. The objective of this study was to correlate the morphology changes and settling volume to the pasting properties of those cross-linked and unmodified starches. Pasting and microscopic data for waxy maize starch and its cross-linked products was similar to waxy wheat starch, except changes occurred at ∼5 °C higher in temperature. At 6% solids, waxy wheat starch cross-linked with 0.01% POCl₃ had a greater settling volume and a higher pasting viscosity than the cross-linked waxy maize starch, but at 7 and 8% solids, waxy maize starch cross-linked with 0.03% and 0.06% POCl₃ had a higher pasting viscosity. At 6% starch solids, particle volume fraction appeared to be the dominant factor controlling consistency, but at higher starch solids contents, the deformability (rigidity) of swollen granules became important in controlling viscosity.

Lipases as Processing Aids in the Separation of Wheat Flour into Gluten and Starch: Impact on the Lipid Population, Gluten Agglomeration, and Yield

Three lipases with different hydrolysis specificities were tested in a laboratory-scale dough-batter wheat flour separation process in two concentrations. Lipolase specifically hydrolyzed nonpolar flour lipids. At the highest concentration tested, it significantly improved gluten agglomeration and yield, also when combined with a xylanase with hydrolysis specificity toward water-extractable arabinoxylan. We hypothesize that its action is due to the release of adequate levels of free fatty acids, which, because at least a part of them is dissociated, act as anionic surfactants. Lipolase at the lowest concentration, Lecitase Ultra, hydrolyzing both nonpolar and polar lipids, and YieldMAX, which specifically hydrolyzed phospholipids, had no or a negative impact on gluten agglomeration and yield. In conclusion, this study demonstrated that lipases with hydrolysis specificity toward nonpolar lipids can be used as processing aids in wheat flour separation in the absence or presence of added xylanases to maximize gluten agglomeration and yield.

High levels of sugars and fructan in mature seed of sweet wheat lacking GBSSI and SSIIa enzymes

Sweet wheat (SW), which lacks functional granule-bound starch synthase I (GBSSI) and starch synthase IIa (SSIIa), accumulates high levels of free sugars in immature seeds. Here, we examined the effects of the lack of these two enzymes on mature kernel composition. Whole grain flour of SW had higher levels of sugars, particularly maltose, slightly higher ash and protein content, approximately two to three times higher lipid levels, and about twice as much total dietary fiber as parental or wild-type lines. Considerably higher levels of low-molecular-weight soluble dietary fiber (LMW-SDF), largely consisting of fructan, were also detected in SW. Although there were no differences in total amino acid levels, the free amino acid content of SW was approximately 4-fold higher than that of wild type, and the levels of certain free amino acids such as proline were particularly high. Thus, we were able to clearly demonstrate that the lack of GBSSI and SSIIa caused dramatic changes in mature seed composition in SW. These compositional changes suggest that SW flour may provide health benefits when used as a food ingredient.