Chemical Characterization, Functionality, and Baking Quality of Intermediate Wheatgrass (Thinopyrum intermedium), a Novel Perennial Crop
Citra Rahardjo, Kristin Whitney, Senay Simsek, Tonya Schoenfuss, and Baraem Ismail
Department of Food Science and Nutrition, University of Minnesota, Twin Cities, 1334 Eckles Avenue, St. Paul, MN 55108 http://swbiodiversity.org/seinet/taxa/index.php?taxon=1288
ABSTRACT MATERIALS AND METHODS RESULTS DISCUSSION • Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). SDS-PAGE • All IWG samples had higher protein and total dietary fiber content when compared to Intermediate Wheatgrass (IWG) or Thinopyrum intermedium, is a perennial was carried out to visualize the protein distribution in all 19 samples. Dough Stability Time (seconds) wheat controls (Figures 1 and 2). 700 crop of interest to agronomists due to its extensive root system that result in • Starch Pasting Properties. Determined by Rapid Visco Analyzer (RVA). 600 • % Ash was higher in IWG samples (due to higher bran to endosperm ratio), but % fat was reduced soil and water erosion, and increased nitrogen fixation. However, • Rheological Properties. Farinograph was used to determine the maximum water 500 similar to that of wheat controls. farmers will be reluctant to plant this crop without an established market, absorption, dough development time, and dough stability (AACCI method 54-21.02). 400 • Total starch content among IWG were slightly lower than that of controls, but amylose to 300 which relies on the characterization of IWG grains for parameters relevant Kieffer method was used to determine the resistance to extension as well as extensibility of 200 amylopectin ratio was similar (Figure 3). to food use. the dough using a texture analyzer. 100 • Despite the high protein content, IWG samples were deficient in HMWG (Figure 4). 0 • Bread Making and Quality Parameters Measurement. AACCI method 10-09.01 was Since HMWG is important for dough functionality especially for dough strength and Therefore, the objective of this study was to analyze lines of IWG for the used to produce the bread samples. Bread volume measurement was done following the elasticity, this may affect its properties and limit its applications in bread making. grains’ chemical composition, functionality, and baking properties. rapeseed displacement method (AACCI method 10-05.01). C-Cell Bread Imaging System • According to the farinograph data (Figures 5 and 6), the functionality of HRW dough was used for scanning of bread samples. Figure 5. Farinogram of hard red wheat, Figure 6. Farinograph Dough Stability Time Results sample was superior when compared to IWG samples. HRW sample had higher stability Sixteen IWG lines along with one bulk IWG sample and wheat controls bulk IWG, and IWG L4-1. All analyses of 17 IWG samples and two wheat controls. All time compared to IWG samples. were analyzed for proximate composition, dietary fiber, starch composition, were performed in duplicate. analyses were performed in duplicate and reported in • Kieffer analyses were also conducted to compare the resistance to extension and and gluten forming proteins, following standard analytical procedures. ± standard deviation (SD). extensibility of the dough samples (Figure 7). The data generated showed that wheat Starch pasting properties were monitored using a rapid visco analyzer. RESULTS control samples were superior in terms of resistance to extension, followed by bulk IWG Dough rheology was assessed using farinograph and Kieffer. Bread baking sample – Kernza, then the other 16 IWG samples. While for extensibility, one wheat tests were also performed following AACCI method. Resistance to Extension (mN) Extensibility (mm) control sample (Arapahoe) is noticeably higher, followed by HRW and bulk IWG 450 25 (Kernza). Protein Content (%)– Wet Basis 400 Compared to wheat controls, IWG samples had higher protein and dietary 25 350 20 • Starch pasting temperature (Figure 8) is inversely proportional to the total starch content, fiber contents, yet were deficient in high molecular weight glutenins 300 which may happen due to higher protein and fiber that compete for water. On the other 15 250 (HMWG), an important protein component responsible for dough strength 20 hand, the final viscosity is directly proportional to the total starch content. 200 10 and elasticity. Slight variation in protein profile was observed among the 150 • Bread volume was generally higher for wheat samples - especially for Arapahoe, when 15 different lines. The fat and ash content of IWG samples were similar to 100 5 compared to the IWG samples (Figure 9). those of the wheat controls. Both farinograph and Kieffer showed weaker 50 • When comparing bread pictures (Figure 10), wheat controls had bigger air holes and 10 0 0 IWG dough strength compared to that of controls. These findings suggest rounded tops; while IWG samples appeared denser and some of them had flat surface. that IWG has a superior nutritional profile, but poses challenges for baked 5 products that require dough rising properties. These results can be explained by the lack of gluten network formation, and the higher fiber 0 Figure 7a and 7b. Dough resistance to extension and extensibility for all 19 samples, obtained content that competes with protein and starch for water. through Kieffer method. CONCLUSIONS
This data will assist breeders in their screening and future breeding efforts Before Thermal Treatment After Thermal Treatment • Our data indicated that there are some challenges for the use of IWG in baked Figure 1. Protein content of 17 IWG samples and two wheat controls. All analyses were for the development of IWG lines suitable for food applications. products. performed in triplicate and reported in ± standard deviation (SD). Gin MGin Enhancement of IWG’s protein functionality, determining the effect of fiber Min At • Compared to the wheat controls, IWG is higher in fiber and protein content, which mAu on dough development, and the impact of dough conditioners need to be mAu 256nm makes it an attractive ingredient targeted toward health conscientious consumers. studied. However, it is deficient the gluten component that is responsible for strength and Total Dietary Fiber Content (%)– Wet Basis Minutes Minutes elasticity5. Thus, IWG may pose challenges for use in baked goods. 20 SDF IDF Gin • Our findings demonstrated the need to investigate ways to enhance the protein 18 After Thermal MGin At P34min functionality of IWG, for baked product applications, by varying constituents such as 16
Treatment mAu 323nm fiber content, and formulating at optimum conditions while using dough conditioners. 14 26% 26% INTRODUCTION 27% 25% 28% 27% 27% 24% 28% 29% 28% 29% 29% 29% 12 26% 28% 30% 28% Minutes • IWG is a novel perennial crop, native to Asia and Europe, and got 10 33% 1 introduced to the US in 1932 . 8
• The environmental benefits of perennial crops in comparison to annual 6 FUTURE WORK crops include reduced soil and water erosion, reduced soil nitrate 4 leaching, increased carbon sequestration, and reduced inputs of energy 2 • Investigate the types of interactions that stabilize the gluten network in IWG doughs. 1. 67% 72% 73% 73% 76% 72% 75% 71% 74% 74% 72% 71% 74% 71% 72% 71% 72% 72% 70% and pesticide 0 Figure 8. Starch pasting properties visualization • Monitor formation intermolecular β-sheet structure at different moisture contents, Hard Red WheatArapahoe Bulk IWGIWG L4-1IWG L4-3IWG L4-29IWG L4-32IWG L4-57IWG L4-72IWG L4-84IWG L4-85IWG L4-103IWG L4-105IWG L4-139IWG L4-154IWG L4-157IWG L4-159IWG L4-160IWG L4-172 • According to World Wildlife Fund (WWF),“Half of the topsoil on the of hard red wheat, bulk IWG, and IWG L4-1. various mixing temperatures, above glass transition, and stability during relaxation. Figure 2. Total Dietary Fiber content of 17 IWG samples and two wheat controls. All analyses planet has been lost in the last 150 years,”and not only it does affect the • Monitor dough strength upon addition of dough conditioners. were performed in duplicate and reported in ± standard deviation (SD). amount of available soil, but also the quality of the current Bread Volume (cm3) by Rapeseed Displacement Method • Determine the effect of fiber content, or degree of refinement on gluten formation. “ • Research different product applications that do not require rising properties during soil. Compaction, loss of soil structure, nutrient degradation, and soil 120 salinity,”are several of many examples of soil quality degradation that baking, such as cookies, pancakes, breakfast cereal, and crackers. Total Starch Content (%) - Wet Basis 100 currently is happening2. Pacific Institute also mentions that water supply 70 80 is continually degrading and that many“major rivers –including the Amylose Amylopectin Colorado River in the western United States and the Yellow River in 60 60 50 ” 26% 40 China – no longer reach sea in most years, which proves the water 26% ACKNOWLEDGEMENT 23% 22% 40 22% 23% 23% 23% 23% 22% 24% 23% 23% 22% 24% shortage that the world is currently facing3. 22% 24% 25% 24% 20 30 • IWG traditionally has only been used as animal feed1. However, current 0 This project was supported through research grants provided by the Forever Green 20 research shows promising potential for food use & biofuel4. Initiative and Minnesota Department of Agriculture, as well as a gift fund by the Land 10 • From a consumer perspective, the engagement in purchasing habits that 74% 74% 78% 78% 77% 76% 77% 77% 76% 78% 75% 77% 76% 76% 77% 77% 78% 78% 76% Institute. North Dakota State University Wheat Quality and Carbohydrate Laboratory 0 under Dr. Senay Simsek and USDA-ARS Cereal Crops Research Unit under Dr. Jae-Bom can improve the environment is gaining prominence. The use of perennial Figure 9. Bread Volume for all samples were performed in duplicate and reported in ± standard Ohm provided great help and collaboration with data generated. IWG lines were kindly crops in food products will allow consumers to feel good about their deviation (SD). purchase, and their role in supporting a sustainable agricultural system. provided by Dr. James Anderson and his research group from the Agronomy/Plant Figure 3. Total Starch content of 17 IWG samples and two wheat controls. All analyses were Genetics Department at the University of Minnesota. performed in triplicate and reported in ± standard deviation (SD). MATERIALS AND METHODS REFERENCES Materials. 16 different IWG lines that are crossed based on their superior genetic characterization, a bulk species of IWG, along with two controls of 1. Barkworth, and D.R. Dewey. "INTERMEDIATE WHEATGRASS Thinopyrum wheat species (Hard Red Wheat (HRW) and Arapahoe) were grown and Intermedium."United States Department of Agriculture (Contributor: USDA, NRCS, provided by the Agronomy/ Plant Genetics Department at the University of Idaho State Office). Web. 3 Apr. 2015. Minnesota. 2. "Soil Erosion and Degradation." World Wild Life. Web. 3 Apr. 2015. https:// www.worldwildlife.org/threats/soil-erosion-and-degradation. • Protein Quantification. Determined by a nitrogen analyzer following the 3. "Sustainable Water Management – Local to Global." Pacific Institute. Web. 3 Apr. AOAC Dumas method. 2015.