Browsing by Subject "Intermediate Wheatgrass"

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    Developing Agronomics of Intermediate Wheatgrass as a Perennial Grain
    (2017-08) Frahm, Charles
    The forage species intermediate wheatgrass (Thinopyrum intermedium L.; IWG) is being developed for use as a perennial grain crop. Field tests have shown that improved IWG populations are suitable for many food applications, creating demand for IWG grain. A lack of understanding of IWG characteristics related to grain production has limited the ability for researchers to recommend best management practices for increasing grain yields. By describing IWG development through quantitative modeling, useful information was generated to apply practical management decisions in future production of IWG. A production challenge limiting IWG grain production is stem lodging, which hinders pollination, grain fill, and reduces overall grain quantity. The second objective of this research was to measure the effect of plant growth regulators (PGRs) on IWG grain yield. Results show that applying PGRs at rates recommended for other grass species has the potential to increase IWG grain yields.
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    Effect Of Steam Treatment On Chemical Changes Over Storage Of Intermediate Wheatgrass (Thinopyrum Intermedium) Refined, Partially Refined, And Whole Flour
    (2020-03) Hayek, Jenny
    Intermediate wheatgrass (IWG, Thinopyrum intermedium) is a perennial grain that has great environmental benefits such as reduced soil and water erosion due to its extensive root system. IWG has shown promise in its development as a food ingredient with high nutritional value. An understanding of its grain storage stability is essential to its commercial viability and success in food use. Grains are typically processed into flour and stored until use. While whole grains can be stored for eight to twelve years, flour has a significantly shorter shelf life. The storage stability of IWG flour has not yet been addressed. IWG has a relatively high fat content compared to wheat, which poses a potential issue regarding shelf life, as over time rancidity and decreases in antioxidant activity may occur. Thermal treatment, such as steaming, may be beneficial to increase grain shelf life by inactivating enzymes that are involved in lipid rancidity, namely lipase and lipoxygenase. Additionally, reducing the bran content via refinement may also prolong shelf life by decreasing fat content, but this would also reduce dietary fiber and antioxidant content, negatively affecting the praised nutritional value of IWG. An understanding of IWG flour storage stability and ascertaining methods to improve its stability is necessary for IWG’s commercialization and success. The objective of this work was to determine the effect of steam treatment, bran content, prior grain storage, and relative humidity on enzymatic activity, antioxidant content, antioxidant activity, and measures of hydrolytic and oxidative rancidity over IWG flour storage. Compositional analysis of IWG and hard red winter wheat (HRW) samples, harvested in 2016 and 2017, was conducted prior to storage using standard AOAC and AACCI methods. IWG grains were subjected to steam treatment in a sieve over a boiling water bath (100°C for 120 seconds), and then were left to equilibrate at room temperature for 24 hours. IWG grains (those that were steamed and those left as-is) were milled into whole, partially refined (75% bran), and refined flour. HRW grains were milled into whole and refined flour. Flour samples were stored at ambient temperature at 43% and 65% relative humidity (RH) for up to nine months. Samples were analyzed periodically for changes in enzymatic activity, antioxidant content and activity, and measures of hydrolytic and oxidative rancidity. Over storage, lipase (determined spectrophotometrically), and lipoxygenase (ferrous oxidation-xylenol orange assay) activities were evaluated. Carotenoid and hydroxycinnamic acid contents were determined by high performance liquid chromatography (HPLC). Antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and leucomethylene blue (LMB) assays. Hydrolytic rancidity was evaluated by measuring free fatty acids (FFA, titration), meanwhile oxidative rancidity was evaluated by measuring peroxide value (acetic acid-chloroform method), and hexanal content (static headspace gas chromatography). Compared to HRW, IWG had significantly higher protein, insoluble fiber, total dietary fiber, antioxidant content, and fat content. IWG had higher lipase yet lower lipoxygenase activity compared to HRW. The direct steam treatment utilized resulted in a significant reduction in lipase and lipoxygenase activity, without a significant reduction in antioxidant content. Overall, direct steam treatment and partial refinement had a positive effect on storage stability of flours from freshly harvested grains. Positive effects included reduced enzymatic activities and lower contents of rancidity products over storage, as well as preserved antioxidant content and activity over storage. The free fatty acid content increased over storage, but to a lesser extent in flour from steamed grains, confirming that steam treatment was effective in partial inactivation of lipase. Similarly, hydroperoxides increased over storage, but flour from steamed grains had lower hydroperoxide contents over time compared to flour from not steamed grains, confirming that steam treatment was effective in delaying oxidation product formation due to partial lipoxygenase inactivation and reduced level of free fatty acids. Partial refinement resulted in significantly lower measures of rancidity over storage, with lower enzymatic activities, compared to whole flours. Antioxidant content and activity were not greatly impacted by steaming or partial refinement, and were mostly preserved during storage. Results demonstrated that in comparison to HRW, IWG’s superior antioxidant content and activity contributed to the delayed appearance of oxidative rancidity measures. Results also demonstrated that flours stored at 43% RH had a slower progression of rancidity compared to samples stored at 65% RH. In IWG flours from one-year-old grains, steam treatment had a positive impact with regard to storage stability, preserving antioxidant contents and delaying the development of rancidity. However, with regard to lipase and lipoxygenase activity and antioxidant activity as measured by DPPH and LMB, steam treatment and refinement did not have a consistent, significant impact. The impact of grain storage prior to milling was positive in general, with lower enzymatic activities and similar antioxidant contents at the beginning and end of storage, and overall lower contents of free fatty acids, hydroperoxides, and hexanal at the end of storage in the resultant flour compared to flour from freshly harvested grains. Overall, the reduction of enzymatic activity by steam treatment resulted in lower contents of hydrolytic and oxidative rancidity products over storage. Partial refinement also resulted in lower contents of rancidity products and enzymatic activities over storage, while also retaining benefits linked with bran including dietary fiber and antioxidant content. Additionally, flours stored at 43% RH had a slower progression of rancidity compared to those stored at 65% RH. Thus, both steam treatment and partial refinement, combined with low RH storage conditions, may be useful to prolong the shelf life of IWG flour.
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    The Effects Of Different Wheat Types On Colon Cancer Risk
    (2020-08) Thyne, Vanessa
    Colon cancer is the third most common cancer and the second leading cause of cancer-related deaths in the United States (1). A variety of risk factors play a role in the etiology of this disease, including environmental risk factors (2, 3). Because of this, considerable research has gone into finding ways to increase consumption of foods that have an inverse association with colon cancer (4). While several epidemiological studies have shown an association between a diet high in whole grains and a lower risk of colon cancer, experimental studies have been inconsistent. This study looks at the effects of wheat class on colon carcinogenesis during the post-initiation stage of colon cancer development in rats. It also examined whether intermediate wheatgrass (IWG) commercially known as Kernza TM, a perennial grass being developed as an alternate to wheat, modifies colon cancer risk in a way similar to red wheat. A major endpoint of this study was enumeration of colonic phenotypic markers known as aberrant crypt foci (ACF), an early pre- cancerous lesion. Additionally, based on previous findings indicating that the type and amount of mucin production is a marker for dysplasia (5), changes in mucin production was examined as well. Finally, CD44, a putative marker of cancer stem cells, was determined immunohistochemically as an additional indicator of colon cancer risk. It was found that there was a significantly greater number of sialomucin-stained ACF (SIM_ACF), and mucin-depleted ACF (MDF) staining in white wheat and vs. red wheat, indicating a higher degree of dysplasia in white wheat. This shows a greater protective effect of red wheat vs. white wheat in the ACF of the colon. Moreover, staining for CD44 was found to be higher in ACFs of white wheat and IWG vs. red wheat. The correlation between the two, indicated by a dysplasia score, 0.7029 (p<0.0001) demonstrates a positive relationship between CD44 and dysplasia. The reduced number of dysplastic markers along with a higher dysplasia score in white wheat and IWG vs. red wheat supports a protective effect of red wheat.
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    Effects of Dough Conditioners on Rheology and Bread Quality of Intermediate Wheatgrass
    (2018-07) Banjade, Jaya
    Studies have shown the detrimental effect of agricultural practices on the environment. One solution to combat those problems would be to focus on alternatives that would lead to sustainable environmental benefits, like cultivating perennial crops. While annual crops are dominating current agricultural production, cultivating perennial crops would contribute to several environmental benefits like reduced nitrogen losses, and soil erosion. With expanding global food insecurity, using perennial crops for food would offer an alternate to diminishing food supply. Among the several perennial crops screened for domestication, intermediate wheatgrass (Thinopyrum intermedium, IWG) has been considered a promising crop to be used as food. The aim of this study was to evaluate IWG of same genetic material, cultivated at two location in Minnesota- Rosemount (RM) and Roseau (RS) for chemical and functional characteristics of dough and breads as affected by refinement (bran removal) and the use of dough conditioners. Five dough conditioners were used- wheat protein isolate, (WPI), vital wheat gluten (VWG), ascorbic acid (AA), Powerbake (a commercial enzyme mix) (PB) and transglutaminase (TG). While IWG kernels were studied for kernel physical properties, IWG flour at three refinement levels - 0 %bran (0B), 50 %bran (50B) and 100 %bran was investigated for proximate composition and dietary fiber following respective standard methods. Dough extensibility and resistance to extension were measured with the texture analyzer equipped with Kieffer extensibility rig, and dough stickiness was measured with a texture analyzer equipped with Chen-Hoseney stickiness cell. Baked breads were evaluated for dimensions, specific volume, crumb firmness, and crumb grain characteristics. Controls consisted of annual hard red winter wheat (W) and IWG dough without conditioners (N). IWG kernels were thinner, with lower weight, volume and bulk density in comparison to wheat. Results from proximate composition indicated an increased fat, protein and ash content with increasing bran concentration, and a decrease in moisture and carbohydratecontents. While there was no difference between IWG and wheat at 0B for moisture and carbohydrate, for the remaining two bran concentrations, wheat had higher moisture and carbohydrate, and lower protein, fat and ash content than IWG. IWG had higher dietary fiber content than wheat at 50 and 100B refinement levels, the difference attributed to insoluble dietary fiber, as no differences was observed in soluble fiber between wheat and IWG at all bran concentrations. At all bran concentrations, extensibility of wheat dough was higher than for the dough made with IWG from both locations. Adding dough conditioners did not improve extensibility for any samples. Some differences were noted between the two locations- 50B-N, 50B and 100B with WPI, 100B with VWG, 50B and 100B with AA, 50B and 100B with PB and 0B and 100B with TG. At 0B and 50B, resistance to extension of wheat dough was higher than for dough made with IWG from both locations, however, for 100B, IWG from RM N, with AA, and PB and IWG from RS N, with WPI, VWG, AA and PB were different. TG increased resistance to extension for IWG from RM at 0B and 50B; for IWG from RS at all refinement levels. At all bran concentrations, stickiness of wheat dough was lower than for dough made with IWG from both locations. Adding PB and TG to 100B IWG from RM reduced stickiness to match values of wheat, however, no such effect was seen in IWG from RS. Adding WPI and VWG reduced stickiness of 0B IWG samples from both locations, in addition, TG also reduced stickiness of 0B RM IWG dough. While no conditioners reduced stickiness of 50B IWG from RS; WPI, VWG, PB and TG reduced stickiness of 50B IWG from RM. While dough conditioners did not reduce stickiness of 100B samples from RM; WPI, VWG and TG reduced stickiness of 100B samples from RS. Bread results indicated a negative effect of bran on dimensions, specific volume and crumb grain characteristics. While WPI, VWG, AA and PB improved or did not change the bread dimensions, TG always reduced them. The effect of dough conditioners was more pronounced for length and width than for height; indicating IWG expanded more than rose. While none of the conditioners increased the specific volume of RS IWG samples at any refinement level, PB increased the volume of 0B IWG from RM. TG decreased the specific volume of all samples. At 0B concentration, controls and breads with WPI and VWG demonstrated collapse when in oven. A noticeable surface smoothing effect was observed for 0B samples with AA and PB. AA and PB improved the crumb grain properties with uniform air cells distribution for 0B samples. Bran negatively affected the air cells count, and adding dough conditioners did not improve the crumb grain characteristics. While there was no effect of TG on 0B samples; cell count, cell area and cell size decreased with TG addition for higher bran contents. The breads were unacceptably dense and the effect was pronounced at higher bran concentrations. This work provides insight on ways to improve functionality and product quality of IWG breads. AA and PB produced loaf of consistent appearance with smoother surface and uniformly distributed gas cells in the crumb. WPI and VWG exhibited expansion before the dough collapsed and thus, the loafs were unable to hold gas. Adding starch or other functional ingredients to increase viscosity would help in retaining the gas, and is thus recommended. This research would facilitate future efforts towards using IWG as a standalone flour for breads, as well as help breeders for markers selections towards developing IWG bread flour.