Cereal Science

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Research from the Cereal Science program. The program website may be found at https://www.ag.ndsu.edu/cerealscience

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Effect of polyaccharides and proteins on refrigerated dough quality
(North Dakota State University, 2009) Zhang, Yu
Refrigerated dough is considered one of the most popular dough products in the food industry. Consumers appreciate the convenience, storage stability, and good organoleptic properties of refrigerated dough products. However, in practice, the quality of refrigerated dough can deteriorate during the storage as a result of liquid formation in dough, which is called "dough syruping". The objectives of this study were (1) characterization of the structural properties of dough components that affect dough syruping; (2) identification of rheological changes that occur during refrigeration, and as they relate to arabinoxylans (AX), starch and protein solubility. The data showed that AX solubilization and degradation occurred simultaneously with dough syruping. Nuclear magnetic resonance (NMR) spectroscopy analysis and the viscosity analysis of AX aqueous solution confirmed that AX solubilization and degradation resulted in the increase of low molecular weight fraction and the decrease of high molecular weight fraction in water extractable AX (WEAX). The pasting properties and thermal properties of starch changed during the storage: peak viscosity decreased up to 23.1 % compared to flour samples during 34 days refrigerated storage. Variation in starch granular morphology was detected. These results showed that physicochemical properties of starch changed during refrigerated storage. The rheological properties of dough changed dramatically during refrigerated storage, which may have significant impacts on endproduct quality. Both, the elastic modulus (G') and viscous modulus (G") decreased. Dough exhibited the major decrease on the moduli on day 3 and day 16. By comparing the viscoelastic properties of dough samples on day O and day 16, 50% decrease on the elastic modulus and a roughly 30% decrease in the loss modulus were observed. Changes in the protein fractions of dough samples were related to their rheological properties. Therefore, the physicochemical properties of polysaccharides and proteins appear to be directly correlated to dough syruping, which may result in the diminishment of rheological and organoleptic properties of refrigerated doughs.
Modeling and Analysis of Impacts of Right-Tum Lane Lengths
(North Dakota State University, 2010) Chevuri, Pavan Kumar
Turn lanes have been studied for several decades, with focus being on left-tum lanes and for urban areas. The need for right-turn lanes has been studied using the impact of such turn lanes on both safety and operational efficiency. However, the impacts of different right-turn lane lengths have not been studied well. The determinations of righttum lane lengths have been based primarily on the deceleration of the right-turning vehicles, which happens to be one of the many factors that should influence such decisions. In this study the impacts of the right-turn lanes on two-lane roads with no controls on major roads have been modeled and analyzed. In particular, the impacts on the space mean speed and the delays have been studied using both the analysis of field data from several intersections around Minnesota and the analysis of the results from simulation models developed using CORridor SIMulation (CORSIM®).
Effect of Amylase Content and Gluten on Gelatinization and Retrogradation of Starch Blends and Starch/Gluten Blends and on Bread Staling
(North Dakota State University, 2010) Matkovic, Kornelija;
Effect of amylase content and gluten on starch gelatinization and retrogradation properties, and consequently bread staling, still is not clear. In the case of starch and starch/gluten blends, information on the relationship between functional properties of starch blends and amylase and gluten contents is scarce. Effects of amylase content on baking and staling properties of bread were investigated by using 20, 30, and 40% blends of waxy spring (WS) or waxy durum (WD) wheat flour with non-waxy wheat flour. Crumbs with 30% and 40% waxy flour exhibited very open, porous structure. Retrogradation enthalpies and bread firmness were higher for waxy than for non-waxy crumbs and higher for WD than for WS crumbs at the end of storage (5 days), although waxy crumbs had a higher amount of soluble starch (especially WD crumbs) than non-waxy crumb. Results indicated that retrogradation and staling are complex processes that depend not only on amylase content, but also possibly on interactions of starch with other crumb components or interactions between two starches in a blend. To elucidate the effect of amylase content and gluten on properties of starch, blends of WD starch (0, 12.5, 25, 50, 75, and 100% w/w) and non-waxy starch, as well as starch blends combined with 30% gluten were studied. Gelatinization and retrogradation properties, as well as properties of soluble starch isolated from gels after 5, 10, 15, 20 days of storage and fractionated by gel permeation chromatography (GPC}, were studied. Gelatinization enthalpy (11H) was higher for blends with low than for blends with high amylase content. However, l).H was not significantly different between each consecutive blend although their amylase contents were different. Retrogradation enthalpy of starch blends (l).HaR) increased during 20 days of storage. On each storage day, M-laR was lower for low amylose blends than for high amylose blends, showing that low amylose content in starch blends slowed the process of retrogradation. Similar to t:.H, M-laR was not significantly different between each consecutive blend. Apparently, gelatinization and retrogradation properties of starch blends with different amylose contents were more complex than in single starches and could not be interpreted as a simple sum of contributions of individual components. Gluten did not affect gelatinization enthalpy of starch blends due to excess amount of water in the system. However, it significantly lowered the M-laR of low amylose blends (50, 75, 100% WO) compared to that of high amylose blends, especially on day 15 and day 20, which was interpreted as the result of gluten interacting with branched starch molecules. Analysis of GPC fractions of soluble starch showed that retrogradation patterns of O wx, 12.5 wx, and 25 wx blends were different, although their M-laR were similar. Low proportion of branched fraction in O wx soluble starch after day 5 and low ratio of blue value/total peak carbohydrate on days 15 and 20 indicated retrogradation due to reassociation of branched molecules with long chains. In 12.5 wx and 25 wx soluble starch, low values for the wavelength of maximum iodine absorption (Amax) of linear fraction indicated that some amylopectin fragments eluted with the linear fraction. Recrystallization of these molecules could have been facilitated by the presence of amylase in the fraction. Gluten affected retrogradation pattern of starch by promoting reassociation of branched molecules (reduction in A.max) at the beginning of storage. All starch/gluten blends had similar retrogradation patterns. Overall, amylose content affected gelatinization and retrogradation properties of starch significantly; however, in starch blends these properties were not simple averages of properties of two starches. In addition to the amylose content, properties of blends also could be governed by specific interactions between two starches or between starch and gluten.
Enhancing Bread Using High Temperature Extruded Lentil Flours
(North Dakota State University, 2010) Gupta, Abhay
Wheat proteins play a major role in determination of dough rheological properties and quality of baked bread. The main objective of this study was to evaluate the effects of extrusion speeds and lentil flour concentration in wheat flour on dough rheological properties, staleness and sensory attributes. Wheat flour was fortified with 5%, 10%, 15% and 20% lentil flour extruded at 350rpm, 400rpm and 450rpm extrusion speeds. The wheat flour sample ( control) was also fortified with non-extruded lentil flour to evaluate the effects of extruded and non-extruded lentil flours on bread characteristics. Bread staling was determined by measuring hardness of the crumb and samples were compared to control. Overall consumer acceptability was evaluated using a nine-point hedonic scale sensory analysis to determine the best wheat flour to lentil flour ratio. Extrusion speeds did not have any effects on overall acceptability of bread. Breads baked from wheat flour fortified with 10% lentil flour were most accepted by sensory panelists in terms of overall acceptability. Therefore, 10% lentil flour breads were tested for staleness and compared to the control sample. Lentil breads had no significant difference in staleness on day one as compared to the control sample. However, on day four and day six, it was observed that lentil breads staled faster than the control bread. It can be concluded that bread with lentil flour had poorer shelf life as compared to breads with only wheat flour.
Physicochemical Properties of Pre-Harvest Sprouted Hard Spring Wheat
(North Dakota State University, 2011) Lu, Haiyan
Pre-Harvest Sprouting (PHS) can cause severe economic loss in wheat grown across many areas of the world. Prolonged rainfall before harvest and high temperatures can contribute to the occurrence of PHS. Grain growers prefer wheat genotypes with low susceptibility to PHS. The objective of this study was to examine the physicochemical properties of Hard Red Spring Wheat (HRSW) and Hard White Spring Wheat (HWSW) affected by PHS. Physicochemical properties of the starch and protein in HRSW and HWSW were significantly affected by PHS. α-Amylase was determined using an Azurine-crosslinked amylose substrate (AZCL-Amylose; Megazyme Co., Ltd). Endo-protease activity was determined using an Azurine-crosslinked substrate (Protazyme AK tablet; Megazyme Co., Ltd). Mean value of α-amylase of PHS damaged wheat (2.00 CU/g) was 17 times greater than sound wheat (0.12 CU/g). Mean value of endo-protease of PHS damaged wheat (2.30 A_{590}/g/h) was 1.6 times higher than sound wheat (1.44 A_{590}/g/h). PHS increased both α-amylase and endo-protease activities, resulting in the hydrolysis of starch and protein molecules. However, the increased endo-protease activity was not as significant as the increase in the α-amylase activity in PHS wheat. In a scale of 1.0-9.0, the wheat genotypes had significantly different sprouting scores ranging from 2.5 to 7.8, which had positive correlations with α-amylase and endoprotease activities (P<0.001 ). Consequently, genotypes showed differences in degradation of starch and protein molecules. The endo-protease activity of PHS samples had greater correlation (r= 0.78) with protein degradation measured by High Performance Size Exclusion Chromatography (HPSEC) than with sprouting score (r = 0.57). The degree of protein degradation was better estimated by the endo-protease activity than sprouting score in PHS samples. The pasting properties of starch were measured by Rapid Visco Analyzer (RVA). Mean value of peak viscosity of PHS damaged wheat decreased up to 96% compared to that of sound wheat sample. HPSEC was used to detect the starch molecular weight distribution. PHS damaged wheat had lower molecular weight for high molecular weight amylopectin (HMW-AP) and higher molecular weight for low molecular weight amylopectin (LMW-AP) and amylose. This result indicated that PHS had changed the molecular weight distribution of starch. Sodium Dodecyl Sulfate (SDS) buffer extractable proteins (EXP) and un-extractable proteins (UNP) were analyzed by HPSEC. Some portion of UNP had changed to EXP. The result indicated that the molecular weight distribution of protein had been changed due to PHS.
Evaluation of Pea Protein and Modified Pea Protein as Egg Replacers
(North Dakota State University, 2012) Hoang, Hieu Duy
Native yellow pea (Pisum sativum) protein isolates (PPIs) showed good foaming and emulsifying properties but a poor gelling characteristic. However, this can be corrected by Transglutaminase (TGase) treatment. PPIs were obtained using alkaline extraction method in which extracting pH, precipitating pH, flour–to–water ratio, and extraction time were optimized to obtain maximum yields and least change in protein functionalities. Extraction pH of 10.0, precipitating pH of 4.3, flour–to–water ratio of 1:6, and 30 minute extraction time were found to be optimum values for pea protein extraction. SDS–PAGE gels showed that the PPI had a very similar protein molecular weight profile as its original flour. TGase treatment was applied on PPIs at different pH levels from 4.3 to 7.0. The SDS–PAGE and RVA tests showed that treatment at pH 6.0 provided the best overall functionality. Large molecular weight (MW) proteins (~ 90,000 Da) and medium MW proteins (~50,000 – 80,000 Da) were the main substrates for TGase catalyzed reaction whereas most low MW the proteins (< 45,000 Da) were not involved. RVA results indicated that treatments at pH 6.0 and 7.0 had the highest viscosities but the treatment at pH 6.0 had better stability and consistency. Functionality tests indicated that modified PPIs possessed a better viscosity profile than the native PPIs but no improvement in gelling capacity and only minor impact on foaming and emulsifying properties. PPIs performance greatly depended on their final pHs. The foaming capacity, foaming stability, and emulsion capacity were significantly improved when the final pH of PPIs was adjusted from 4.3 to 7.0. The overall sensory evaluation results suggested that TGase–treated PPIs and PPIs were not yet able to replace egg in the cake system. Only PPI can replace egg in the cookie system. TGase–treated samples had a lower acceptability due to an “off–taste” and a “strange” flavor. Future work, therefore, should study TGase combined with other treatments to further improve PPIs functionalities. Purification should be integrated into extraction process and other food systems should also be included to extent the scope and role of modified PPIs in food industry.
Physicochemical Properties of Commercial Gums and their Effects on Processing and Cooking Quality of Nontraditional Pasta
(North Dakota State University, 2012) Sandhu, Gurleen Kaur
Processing characteristics and quality of pasta made from durum flour and semolina and the physicochemical properties of commercial gums and their effects on processing and cooking quality of nontraditional pasta was investigated. An initial experiment was conducted using semolina and durum flour fortified with nontraditional ingredients (soy flour or oat flour, 10% w/w) and xanthan, guar or locust bean gums (2% w/w). A second set of experiments were conducted to determine the effect of commercial source of food gums on their effect on the processing and cooking quality of nontraditional pasta. Proper hydration of nontraditional ingredient blends was more easily achieved with durum flour than semolina. This was attributed to the smaller particle size of durum flour compared to semolina. Nontraditional ingredients tended to over hydrate semolina resulting in large aggregates that adhered to metal surfaces, all of which made mixing and pasta processing difficult. Initially, dough strength was greater with durum flour than with semolina, but semolina had better dough stability over time. Soy and oat flours reduced dough strength. Xanthan and guar gums increased dough stability, particularly with durum flour. Pasta made with durum flour generally had greater cooking loss and lower cooked firmness than pasta made from semolina. Soy and oat flours reduced cooked firmness and increased cooking loss. Guar and locust bean gums did not affect cooking quality of pasta. Xanthan gum increased cooked firmness of pasta. Samples of each gum were obtained from three different commercial vendors. For each food gum, samples varied in bulk density, molecular weight, viscosity in distilled water and the magnitude of effect on dough strength with commercial source. The effect of xanthan, guar and locust gums on hydration, dough strength, and cooking quality was not affected by commercial source. The magnitude of the increase in dough strength caused by xanthan and guar gums varied among their respective commercial sources.
White Bread and Whole Wheat Bread: Comparison of End-Product Quality, Starch Characteristics and Nutritional Quality
(North Dakota State University, 2012) Whitney, Kristin Lynn
Wheat, an important crop in North Dakota and the United States, is often used for bread. Health concerns related to chronic diseases have caused a shift towards consumption of whole wheat bread. This research investigated the differences between white and whole wheat bread related to the endproduct and nutritional quality. Flours were milled from Glenn grown in Casselton in 2010, and Barlow, Glenn and Prosper grown in Casselton in 2012. White and whole wheat flours and breads were evaluated for chemical composition, baking quality by AACC method 10-09.01 and estimated glycemic index (eGI) by the Englyst assay. Whole wheat breads had significantly (P<0.05) lower loaf volumes than white breads. Whole wheat breads had significantly (P<0.05) higher mineral, protein and phenolic acid contents, as well as, significantly (P<0.05) lower eGI. Overall, several factors in the whole wheat bread composition can be found to affect the quality and starch hydrolysis.
Application of Response Surface Methodology in the Development of Gluten-Free Bread with Yellow Pea Flour Addition
(North Dakota State University, 2012) Jeradechachai, Thunyaporn
Yellow pea (Pisum sativum L.) flour fortified gluten-free (GF) bread formulation was optimized by response surface methodology (RSM) and the final product was evaluated for shelf life and sensory acceptability. A second-order model was fitted to the precooking temperature of pea flour (PTPF), water level, and proof time as the factors. Higher PTPF and lower proof time significantly (P<0.05) reduced the brightness of bread crumb. Crumb firmness was influenced by the PTPF, water level and proof time. The optimized parameters for PTPF, water level, and proof time were 156.9 °C, 523.8 g, and 18.0 min, respectively. The optimized bread had a brightness (L* value), specific volume, crumb firmness, and cell diameter of 68.2, 2.6 ml/g, 174.2 gf, and 3.81 mm, respectively. The optimized GF bread had longer shelf-life, but had significantly (P<0.05) lower acceptance scores, than the commercial premix bread product.
Quality Improvement of Soymilk Processed from Two Soybean Varieties
(North Dakota State University, 2012) Zhang, Yan
Five soymilk quality-related characteristics were investigated as affected by different grinding, heating, extraction methods and varieties. The five characteristics are (1) protein and solid recovery, (2) trypsin inhibitor activity, (3) antioxidant compounds and antioxidant capacity, (4) soy odor, and (5) isoflavone content and profile. The two varieties were Prosoy and black soybeans. The results show that significant differences existed among the three grinding methods (ambient grinding, cold grinding, and hot grinding). Ambient grinding gave the best protein and solid recoveries. Hot grinding showed the best results for the other four parameters. Cold grinding gave the poorest performance, with the exception of the odor profile. The three heating methods (traditional stove cooking, one-phase UHT, two-phase UHT) also resulted in significant differences in the chemical compounds and properties of the soymilk. In many cases, the effects of heating methods were closely related to grinding methods and varieties. Our results clearly demonstrated that a UHT processor equipped with a vacuum chamber was a very efficient way to reduce or eliminate some undesirable soy odors, especially in conjunction with hot grinding. Our results also demonstrated that many complex reactions occurred during thermal treatment. Because of different seed characteristics, the two different varieties behaved differently during processing. For both varieties, extraction with okara washing water from last batch (Method #2) gave the highest solid and protein recoveries.
Variability in Arabinoxylan, Xylanase Activity and Xylanase Inhibitor Levels in Hard Spring Wheat
(North Dakota State University, 2012) Mendis, Mihiri Marini
Arabinoxylans (AX), xylanase, and xylanase inhibitors have an important role in many cereal food processing applications. The effect of growing location (L), genotype (G), and their interactions (L ×G) on AX, apparent xylanase and apparent xylanase inhibition activities of Triticum aestivum xylanase inhibitor (TAXI) and xylanases inhibiting protein (XIP) of wheat was studied using six hard red spring wheat and six hard white spring wheat genotypes. Total AX content was largely dependent on L×G. In bran, xylanase activity, 25% of the variability could be attributed to L×G interaction. Genotype contributed 72% to the variability in TAXI activity indicating TAXI activity in wheat bran is largely under genetic control. The bran TAXI level and XIP level varied by a factor of 700 and 3000, respectively, among genotypes. These results enable the industry to choose between different wheat varieties with varying xylanase activities to complement its intended use.
Iron Biofortification Potential of Field Pea (Pisum Sativum L.)
(North Dakota State University, 2012) Amarakoon, Amarakoon Rajapakse Wasala Mohotti Mudiyanselage Darshika
Iron (Fe) deficiency affects more than 3 billion of the global population. The objectives of this study were to (1) determine the genetic and environmental variation of seed Fe concentration and food matrix factors that govern Fe bioavailability in field peas (Pisum sativum L.) grown in North Dakota, USA in 2010 and 2011, and (2) determine the genetic variation of Fe uptake by field pea grown under greenhouse conditions with different Fe treatments. Seed Fe concentration in field pea samples from the field study ranged between 46-53 mg/kg with a mean of 51 mg/kg. Mean concentrations of the food matrix factors in those field peas were as follows: phytic acid=5.1 mg/g, xanthophyll=17.3 mg/100 g, canthaxanthin=86.8 mg/100 g, beta-carotene=516.8 μg/100 g, kestose=1697 mg/100g, quercetin=54.3 mg/100 g, and ferulic acid=46.9 mg/100 g. DS Admiral and CDC Golden showed high concentrations of Fe promoter compounds and low concentrations of phytic acid. DS Admiral showed high Fe uptake with increasing Fe fertilizer rates in the greenhouse study. Therefore, DS Admiral and CDC Golden could be potential field pea genotypes for future Fe biofortification efforts.
Effect of Flaxseed Fiber on Bread Quality Obtained from Frozen Dough
(North Dakota State University, 2012) Schlepp, Emily Beth
Fiber in frozen bread dough is thought to reduce the loss of yeast vitality and improve nutrition and quality of bread. The objective of this study was to determine the applicability of flaxseed fiber in frozen bread dough. Fiber was extracted from two sources of brown flaxseed and added to bread formulas at 0%, 1% and 3%. Dough was blast chilled and kept frozen until thawed at scheduled intervals. Thawed dough was proofed, baked into bread. Bread was tested analytically and by a sensory panel. Loss of overall quality was observed overtime. Breads containing flaxseed fiber had significantly larger loaf volumes (cc) and reduced firmness (g). A trained sensory panel detected significantly lower crumb firmness and stale flavors in breads containing flaxseed fiber. These results suggest flaxseed fiber has the potential to improve the perceived quality of frozen bread dough.
Growth of Fusarium Graminearum on Wheat Bran/Agar Cultures in Relation to Fusarium Head Blight Susceptibility
(North Dakota State University, 2012) Abeyratne, Meliza Stephnie
Research investigates the chemical basis for Fusarium head blight (FHB) resistance and initiating development of a screening test for resistant wheat genotypes. The focus is on minimizing cost of screening and gaining chemical approach against FHB. Wheat bran/agar plates (8% bran, w/v) prepared from hard red spring wheat with different susceptibility to FHB were inoculated with F. graminearum. Fusarium plaque diameters and ergosterol levels after 4 days of growth were significantly lower (p< 0.05) on plates prepared from genotypes with low FHB susceptibility than from high FHB susceptible genotypes. F. graminearum growth was lower, when methanol-soluble compounds (MSC) extracted from a low FHB susceptibility genotype, Glenn, were added to high susceptibility genotype, Samson. Wheat bran/agar plates enriched with linoleic acid significantly (p<0.05) reduced the growth rate of F. graminearum in both Glenn and Samson genotypes. Oxygenated fatty acids, including monohydroxy- and dihydroxy- fatty acids were identified in the MSC.
Prebiotics in Lentil (Lens Culinaris L.)
(North Dakota State University, 2013) Johnson, Casey Ray
Prebiotic carbohydrates are an important component of healthy diet. The objectives of this study were (1) to compare the concentrations of prebiotic carbohydrates in different lentil genotypes and growing locations and (2) to compare the concentrations of prebiotic carbohydrates in lentil under various processing and preparation procedures. Mean concentrations of prebiotics in lentil genotypes were as follows: raffinose-family oligosaccharides (RFO) (raffinose + stachyose, 2509 mg; verbascose, 1562 mg), fructo-oligosaccharides (nystose, 62 mg), sugar alcohols (sorbitol, 1220 mg; mannitol, 203 mg), and resistant starch (RS), 7.5 g 100 g-1. Modest RFO concentration reductions were observed with cooking, cooling, and reheating. Mean RS concentration in raw, cooked, cooled, and reheated lentil were 3.0, 3.0, 5.1, and 5.1 g/100g respectively, clearly demonstrating cooling-induced synthesis of RS. Study results suggest that lentil contains nutritionally significant concentrations of prebiotics and that those concentrations may be enhanced through breeding, locational sourcing, and cooking and preparation procedures.
Effects of Pasteurization (Heating) on Milled Flaxseed Quality
(North Dakota State University, 2013) Turner, Cody Troy
Current food industry practices include the use of pasteurization (heat treatment) as a means to reduce the microbial counts of flaxseed (Linum usitatissimum). Flaxseed was pasteurized using a dry air heat treatment of 148 °C for 16.25 minutes and the oxidative stability was observed over a 20 week storage period. Flaxseed quality was measured using peroxide value, percent free fatty acid (as oleic), and propanal content. Peroxide values of the pasteurized milled flaxseed were found to significantly increase (P ≤ 0.05) by week 2. Propanal formation coincided with peroxide value development over 20 weeks of storage. Pasteurized flaxseed milled under refrigerated temperatures (10 – 18 °C) did not exhibit any significant (P > 0.05) improvement in oxidative stability. Flaxseed pasteurization at 148 °C for 16.25 minutes using dry heat was found to be detrimental to the oxidative stability flaxseed once milled.
Assessing Microbial Stability and Quality of Green Beans Using Various Home Canning Methods
(North Dakota State University, 2013) Kuchynski, Jenny
Today many consumers follow processing methods recommended either from family members or the internet, which they interpret as being safe. Processing temperature profiles, survival of B. stearothermophilus spores, texture, and color of green beans processed under four home canning methods were assessed. The products were processed using pressure, boiling water bath, steam, or oven canning methods. Pressure canning produced the greatest microbial reductions but this method resulted in the lowest bean quality. The boiling water bath, steam, and oven canning were found to be less safe because the product temperature never achieved 100°C and the resulting microbial counts, >1.7 log CFU/ml, were observed after processing. However, green bean quality was better than pressure canning, with beans from steam canning having the firmest texture and best green color. Although better green bean quality results were observed from internet or family based methods, their safety is questionable considering the high microbial survival.
Characterization of Edible Bean Flours: Properties and Functionality
(North Dakota State University, 2013) Simons, Courtney W.
Consumption of pulses is considered part of a healthy diet. Therefore, the opportunity exists for development of new pulse-based ingredients. However, a better understanding of their properties is necessary. The compositional and functional properties will vary depending on the bean type, their physical form (pre-cooked, raw flour, starch or protein fractionates) and growing location. In this study, edible bean flours (pinto, navy, black and small red) were subjected to extrusion cooking to produce snacks and texturized high-protein flour. The extrudates were studied to determine the effect of extrusion on the physical, physicochemical, chemical, sensory, and digestibility properties. Texturized high-protein flour was used in a bread formulation study. Finally, a preliminary study of location effect on production of grassy compounds, e.g. hexanal and hexanol, in pinto beans was conducted to determine importance of growing environment on flavor development during storage. The results of these studies showed that bean flours generally had excellent extrusion properties (good expansion and texture). However, pre-cooked flours had much lower expansion and textural integrity compared to raw bean flours and starch fractionates. Nutritional content (protein, total starch, fiber and ash) of flours were generally retained after extrusion. Lipids and resistant starch (RS) however were significantly reduced. Significant reduction in RS resulted in snacks having high glycemic index. Extrudates had 20% lower raffinose content suggesting reduced potential for flatulence after extrusion processing. Sensory evaluation of pinto, navy and black bean snacks indicated good overall acceptability. Pinto bean high-starch fraction differed in composition and functionality (viscosity and thermal properties) compared to its raw whole flour and extruded form. Adding 5% texturized pinto bean protein to bread increased its lysine content by 50%; without significantly affecting bread quality. A significant statistical interaction between growing location and storage time on hexanol and hexanal concentrations was observed for pinto beans grown in Forest River, Johnstown and Hatton North Dakota. This Dissertation will help processors understand the potential for beans as a food ingredient. Applications may include use in breads and other baked products, extruded puffed snacks, pasta, and soups. Bean flours can improve nutritional quality and provide unique functionality to food systems.
Effect of Operational Parameters on Laboratory Determination of Malt Fermentability
(North Dakota State University, 2013) Sehrawat, Jaidev
Prediction and variability in malt fermentability is a concern for breeders and brewers. The primary purpose of this study was to determine the variation in fermentability using two different laboratory mash methods. Another experiment was conducted to develop a relationship between malt/wort parameters and malt fermentability with addition of adjunct. The prediction of malt fermentability was achieved by using stepwise multiple linear regression analysis to evaluate which quality factors were able to best explain the observed variation in fermentability. The hot water extract (HWE) mash protocol showed a wider range of fermentability values than did the Congress mash. However, hot water extract mash method clearly showed better discriminative power. Diastatic Power (DP) explained about 50% of the variation in fermentability when using the Congress mash with all malt (i.e. 100%) and also with adjunct. While in case of HWE extract protocol, limit dextrinase activity was able to explain 32% of variation in fermentability with all malt and also with adjunct.
Quality and Estimated Glycemic Index of Bread Fortified with Soy Protein Isolate
(North Dakota State University, 2014) Fujiwara, Natsuki
More than 25 and 79 million individuals in the U.S. have diabetes and pre-diabetes, respectively. Many individuals are required to monitor blood glucose levels. Glycemic index (GI), a measurement of how a food affects the blood glucose level, is a method for selecting foods by diabetic populations. The effect of soy protein isolate (SPI) on the glycemic response of bread was determined, including the quality characteristics of bread made with various SPI percentages. Lower loaf volumes, firmer texture and open grain structure were observed in breads as the level of SPI increased. Estimated GI (eGI) significantly decreased (p<0.05) with increased SPI levels and also a significant correlation (p<0.05) was found between these indices and SPI concentrations. This indicates that fortification of SPI in the bread can reduce eGI and possibly provide a health benefit to the diabetic population. This experiment provided useful insights into SPI effect on eGI and bread quality characteristics.

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