Progress 10/01/03 to 09/30/08
Outputs
OUTPUTS: Experiments were performed that focused on the end-use properties of grains as influenced by environmental factors and genetics. In developing experiments, various analytical methods were developed and/or refined that measure grain and starch properties. Results were disseminated primarily via publications in scientific journals and through incorporation of knowledge learned in undergraduate curriculum and online materials. PARTICIPANTS: This project was managed by the listed PD/PI during the entire reporting period (D.S. Jackson). Numerous graduate students and several postdoctoral students participated in projects related to this activity; they are listed in the publications associated with this record. Additional laboratory assistance (and training) was received by undergraduate students that assist in the experimentation. Collaborators included grain researchers at Texas A&M University, Purdue University, Kansas State University and USDA. TARGET AUDIENCES: The target audiences for this work were agronomists, plant breeders, and grain scientists concerned with end-use quality, and food manufacturers that processes starch-containing grain-based food products. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Several significant changes in knowledge occurred for several specific grain processing unit operations: For Multiple End-Uses: The starch properties of grain are recognized as fundamental to many of its intended end-uses. Amylose content is one of those fundamental properties, but it is difficult to measure. A multi-wavelength iodine binding technique was developed that accurately measures amylose in grain and food systems. For Wheat Flour Tortilla Production: It was discovered that adding 10-20% waxy wheat flour into wild type flours would be ideal for restaurant (on-site) tortilla production and/or circumstances where tortillas are consumed shortly (within a day) after production. For Alkaline Processing: It can be concluded that corn losses may be reduced and dry solid yield increased by following proper cooking and steeping protocols that result in lower cooking temperatures coupled with longer steep times. Yields of product and product quality was also linked to specific by corn physical- chemical characteristics and that identifying sample growing locations would aid in screening samples for nixtamalization quality. For Wet Milling: It was determined that taking growing location into account when screening samples for wet milling may allow for selection of grain samples that would provide a higher starch yield. For ethanol production: It was determined that dry fractionation can be used to improve ethanol production economics, and that protease treated corn more quickly reached its maximum ethanol yield, and so could be used to shorten fermentation times. Ultimately, it was found that researchers, hybrid seed companies, and milling industries should collaborate to improve the grain quality measurement procedures.
Publications
- Zhu, T., Jackson, D.S., Wehling, R.L. and Gera, B. 2008. Comparison of Amylose Determination Methods and the Development of a Dual Wavelength Iodine Binding Technique. Cereal Chemistry 85(1):51-58.
- Kyung-Min Lee, Timothy J. Herrman, Lloyd Rooney, David S. Jackson, Jane Lingenfelser, Kent D. Rausch, John McKinney, Chris Iiams, Linda Byrum, Charles R. Hurburgh, Jr., Lawrence A. Johnson, Steven R. Fox. 2007. Corroborative Study on Maize Quality, Dry-Milling and Wet-Milling Properties of Selected Maize Hybrids. J. of Ag. and Food Chem. 55(26): 10751-10763.
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: Various laboratory experiments were conducted: We investigated the effect of decortication and protease enzyme addition pretreatments on corn ethanol production. Whole yellow dent corn and corn with 10% and 30% of the pericarp removed were used as raw materials. A slurry (containing 30% w/v solids) was prepared by mixing hammer milled corn (2mm mesh) and distilled water. The slurry was then partially liquefied using thermostable alpha-amylase and cooked on a hot plate for 1h from the time the slurry begins to boil. The samples were then cooled to 65C and additional alpha-amylase and amyloglucosidase was added for saccharification. The mash was then fermented by adding a yeast (Saccharomyces cerevisiae) innoculum. Samples were obtained from fermentation flasks over time, from 24h to 72h, and the ethanol concentration was determined. In separate work, we investigated the functionality of waxy and partially waxy wheat starch. These starches were compared when blended to a
specific amylose content (mixture of waxy granules and native granules) vs. having granules with a single amylose content (unmixed). Starch functionality was also assessed when chemically modified. Starches from each genotype of four partially waxy wheats grown at Yuma, AZ, during two crop years were isolated using AACC dough ball washing followed by flow table separation. Starch from fully waxy wheats and wild type wheats was also obtained. Amylose content of all native starches and blends was determined using a dual wavelength. Starches were chemically modified using a) 4.1%, dsb, propylene oxide, and b) cross-linking with 0.0165%, dsb, POCl3. Rapid Visco-analyses (RVA) were performed upon all native and modified starches using 25 gm of water and 2.5 gm starch. All samples were pasted in triplicate. The results of the experimentation outlined above were presented at the Annual Meeting of AACC International to academic and food industry scientists.
PARTICIPANTS: This project is conduced by the PI/PD, a post doctoral research associate, and graduate students. Additional laboratory assistance (and training) is received by undergraduate students that assist in the experimentation. Collaborators include USDA scientists (waxy wheat).
TARGET AUDIENCES: The target audiences for this work are food manufacturers that processes starch-containing grain-based food products.
Impacts
A change in knowledge occurred: Specifically, 1) Decortication did not result in loss of ethanol yield, 2) Protease treated corn more quickly reached its maximum ethanol yield, and so could be used to shorten fermentation times, 3) RVA pasting curves showed that amylose dispersed within a waxy wheat native granule increases the viscosity of the paste beyond that of mechanically mixed native granules at nearly the same % amylose. 4) Hydroxypropylation "stabilizes" the final viscosity of mechanically blended waxy wheat starches and higher amylose genotypes. and 5) Cross-linked genetically blended waxy wheat amylose viscosity is depressed compared to mechanically blended amylose. These results suggest that unique starch viscosity characteristics can be obtained from waxy wheats and partially waxy wheats. Blends of waxy and wild type wheats (compared to an amylose content similar to a partially waxy wheat) is not likely to result in the same viscosity profile. Food
processors can use waxy wheats, blends, or partially waxy wheats to obtain starches with the specific viscosity profile they desire, potentially allowing for the production of improved food and industrial products.
Publications
- Kaye, N.M., S.C. Mason, D.S. Jackson and T.D. Galusha. 2007. Crop rotation and soil amendment alters sorghum grain quality. Crop Science: 47:722-727.
- Lee, K.-M., Herrman, T. J., Bean, S. R., Jackson, D. S. and Lingenfelser, J. 2007. Classification of Dry-Milled Maize Grit Yield Groups using Quadratic Discriminant Analysis and Decision Tree Algorithm. Cereal Chemistry 84(2):152-161.
- Ratnayake, W. S, Wassinger, A.B., and Jackson, D.S. 2007. Extraction and characterization of starch from alkaline cooked corn masa. Cereal Chemistry 84(4):414-420.
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Progress 10/01/05 to 09/30/06
Outputs
Wet milling performance and quality characteristics of dent corn (Zea mays L) and sorghum (Sorghum bicolor L. Moench) were investigated. Corn wet milling starch yield was somewhat high (67.8%, 94% starch recovery) compared to results reported by other researchers; sorghum wet milling starch yield averaged 60.6% (85% starch recovery) due to difficulty in separating sorghum starch from the pericarp. Measured grain quality characteristics included hardness, density, starch properties (pasting, thermal, and crystalline), and protein properties (total nitrogen, and prolamine contents). Corn starch yield was most highly correlated with starch content (r=0.704), starch pasting properties (r=0.227 to 0.733), and starch thermal properties (r=0.457 to 0.681). Sorghum starch yield was most highly correlated with protein content (r=-0.723), starch content (r=0.476), and kernel diameter (r=-0.476). Significant regression equations were developed for both corn starch yield
(R2=0.76, P<0.05) and sorghum starch yield (R2=0.58, P<0.05). TADD hardness, RVA, starch content, and protein content tests were recommended for screening samples for corn wet milling. Starch content, protein content, RVA, kernel weight, and kernel diameter tests were recommended for screening samples for sorghum wet milling. A subset of 5 sorghum hybrids grown in Nebraska, Kansas, and Texas were analyzed to determine the effects of genetic and environmental factors. Texas sorghum had significantly higher protein content, starch gelatinization temperature (as measured by DSC), DSC enthalpy, and significantly lower prolamine content, RVA peak viscosity, and RVA breakdown (P<0.05). Starch content was also significantly lower for Texas sorghum (P=0.09). Sorghum hybrids had significantly different starch contents, SKCS hardnesses, kernel weights, kernel diameters, RVA setbacks, and RVA hydration rates across locations (P<0.05). Sorghum wet milling starch yields were significantly
different for both locations and hybrids (P<0.05). Taking growing location into account when screening samples for wet milling may allow for selection of grain samples that would provide a higher starch yield.
Impacts
Producers, grain elevators, and processors have more definitive testing procedures for selecting corn and/or sorghum hybrids best suited for wet milling for starch and/or ethanol. These selections are best made knowing the geographic location of the source grain. All players in the marketing chain can use this information to maximize income; processors can selected gain that minimizes process waste and maximizes end-product quality.
Publications
- Ratnayake, W. S. and Jackson, D. S. 2006. Gelatinization and solubility of corn starch during heating in excess water: New insights. Journal of Agricultural and Food Chemistry 54:3712-3716.
- Jaeger, S. L., M. K. Luebbe, C. N. Macken, G. E. Erickson, T. J. Klopfenstein, W. A. Fithian, and D. S. Jackson. 2006. Influence of corn hybrid traits on digestibility and the relationship to efficiency of feedlot cattle.. J. Anim. Sci. 84(7): 1790-1800.
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Progress 10/01/04 to 09/30/05
Outputs
Dent corn (Zea mays L) and sorghum (Sorghum bicolor L. Moench) sample sets representative of commonly grown hybrids were analyzed for nixtamalization performance. The influence of kernel characteristics including hardness, density, starch properties (thermal, pasting, and crystallinity), starch content, protein content, and prolamine content on nixtamalization performance was also determined. Corn nixtamal moisture content was lower for hard, dense kernels with high protein contents; sorghum nixtamal moisture content was lower for kernels with low moisture contents and low starch relative crystallinities. Significant regression equations showed that corn nixtamal moisture content (R2=0.64, P<0.05) was influenced by TADD, kernel moisture content, starch content, and protein content; sorghum nixtamal moisture content (R2=0.63, P<0.05) was influenced by starch relative crystallinity, kernel moisture content, and abrasive hardness index. Pericarp removal was not strongly
correlated with kernel characterization tests. DML was only slightly correlated with corn moisture content (r=-0.248) and sorghum starch relative crystallinity (r=0.375) (P<0.05). A subset of 5 sorghum hybrids grown in 3 locations was analyzed to determine the effects of genetic and environmental factors. Location and hybrid factors influenced most kernel characteristics and nixtamalization processing variables. Identifying sample growing locations would aid in screening samples for nixtamalization.
Impacts
Producers, grain elevators, and processors have more definitive testing procedures for selecting corn and/or sorghum hybrids best suited for nixtamalization (alkaline cooking) for tortillas and snack chips. These selections are best made knowing the geographic location of the source grain. All players in the marketing chain can use this information to maximize income; processors can selected gain that minimizes process waste and maximizes end-product quality.
Publications
- Yglesias, R. and Jackson, D.S. 2005. Evaluation of liquid nitrogen freeze drying and ethanol dehydration as methods to preserve partially cooked starch and masa systems. Cereal Chem. 82(6):702-705.
- Yglesias, R., Parkhurst, A.M. and Jackson, D.S. 2005. Development of laboratory techniques to mimic industrial scale nixtamalization. Cereal Chem. 82(6):695-701.
- Lee, K.-M., Herrman, T.J., Lingenfelser, J., and Jackson, D.S. 2005. Classification and prediction of maize hardness-associated properties using multivariate statistical analyses. J of Cereal Sci. 41(1):85-93.
- Ozcan, S. and Jackson, D.S. 2005. Functionality Behavior of Raw and Extruded Corn Starch Mixtures. Cereal Chem. 82(2):223-227.
- Duarte, A.P., Mason, S.C., Jackson, D.S. and Kiehl, J. de C. 2005. Grain Quality of Brazilian Maize Genotypes as Influenced by Nitrogen Level. Crop Sci. 45(5):1958-1964.
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Progress 10/01/03 to 09/30/04
Outputs
New efforts were started to characterize, in a collaborative effort, corn and sorghum hybrids grown in the Midwest / Great Plains. Grain sorghum and maize was obtained as identity maintained lots of at least 5 kg from a variety of sources and growing locations. Sources included university and commercial yield trials throughout the Corn Belt and Texas (for sorghum). In addition, commercial grain aggregators, with capabilities to maintain and/or identify particular lots, supplied samples. Several grain quality tests and analytical methodologies were performed rapidly on the samples of grain. To reduce sample numbers for more complex testing and end-use processing, test data including NIR spectra, floaters, protein, true density, tests weight, sieve analysis, and TADD were analyzed using principal component analysis (PCA). Of a large number of samples, preliminary evaluation allowed us to select (via PCA) approximately 100 corn samples and 40 sorghum samples that are
representative of the genetic and environmental diversities associated the grain collected for this study. These samples are currently undergoing wet milling, dry milling (at KSU), and alkaline processing. In addition, starch testing is also being performed. Data on physical and compositional analysis will be related to end-use performance characteristics. A common alkaline cooking quality test, pericarp removal, was evaluated. When the traditional May-Greenwald staining procedure was performed significant differences between hybrids and cook times (p less than 0.0001, n=8) were found, but the overall mean coefficient of variation was 16.8% with a range from 4.9 to 29.6 for each cook time. Three additional methods for determining ease of pericarp removal were developed and compared: (1) Hunter Lab colorimeter values were measured on dyed and non-dyed samples; (2) computer software (ImageJ) was used to measure stained pericarp area from a digital image; and (3) pericarp was physically
separated from the kernel and quantified. Results from the colorimeter and physical separation methods demonstrated less ability to distinguish between hybrids than the dye-staining method, while results from the computer software method were similar to the dye-staining method.
Impacts
Both producers and processors will be provided with detailed information and testing procedures to aid in identification of the best sorghum and corn (maize) hybrids for particular end-uses. Improved information will enable breeders to select improved hybrids, producers to identify contract markets for increased profitability, and processors to produce grain-based food and industrial products with increased yields and low waste/by-product generation.
Publications
- No publications reported this period
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Progress 10/01/02 to 09/30/03
Outputs
Fourteen (14) flour blends of two natural wild type wheat (Triticum aestivum L.) flours, 'Nuplains' and 'Centura,' blended with one waxy flour sample were characterized and processed to Asian salted noodles. The flour amylose content ranged from <1% to 29%. Damaged starch contents were 10.4%, 7.0%, and 6.6% for the waxy wheat, Nuplains, and Centura, respectively. The waxy flour Farinograph water absorption was as high as 79.5%, ?20% higher than the wild type flours. Because two types of starch granules (wild type and waxy type) existed in the flour blends, two peaks at 82 C (waxy) and 95 C (wild type) were found in the RVA pasting curves. Reduced amylose content caused high flour swelling volume/power and low falling number. Significant effects of flour amylose content on noodle processing and textural (eating) qualities were found in the study. Noodle qualities, as reflected in covariate analysis, were not significantly impacted by the flour blend's protein content,
SDS-sedimentation volume, Mixograph dough development time, or Mixograph tolerance score. The absence of covariate (protein quantity and quality) effects for the food system (flour) used in this study is a very desirable design for the functional studies of starch components. The optimal flour amylose content range for Asian salted noodle products was 21%-24%. Fourteen flour blends with amylose content ranges between <1% and 29% were also used to study tortilla production and quality parameters. Reduced amylose contents decreased dough stickiness and pliability; low amylose doughs were also very smooth in appearance. Very low flour amylose content was associated with earlier tortilla puffing and poor machinability during baking, darker color, low opacity, larger diameters, and reduced flexibility after storage. Tortilla texture analysis indicated that lowering amylose content gave fresh tortillas higher extensibility; after three or more days storage, however, low amylose flours
required more force to break the tortillas and the rupture distances became shorter. These results, as reflected in covariate analysis, were not significantly impacted by the flour blend's protein content, swelling volume/power, SDS-sedimentation volume, Mixograph dough development time, or Mixograph tolerance score. Based on our observation of an initial increase in extensibility with reduced-amylose tortillas, adding 10-20% waxy flour into wild type flours should be ideal for restaurant (on-site) tortilla production and/or circumstances where tortillas are consumed shortly (within a day) after production. The optimal flour amylose content for hot-press wheat tortilla products is 24-26%.
Impacts
Nebraska wheat breeders are studying the applicability of waxy wheat for Midwestern producers. This study documents the usefulness of waxy wheat flours in two food products. This information will aid breeders and food processors in developing better food products, and help improve the export potential of specialty wheat grown in Nebraska.
Publications
- Guo, G., Jackson, D.S., Graybosch, R.A., and Parkhurst, A.M. 2003. Asian salted noodle quality: Impact of amylose content adjustments using waxy wheat flour. Cereal Chem. 80(4):437-445.
- Guo, G., Jackson, D.S., Graybosch, R.A., and Parkhurst, A.M. 2003. Wheat flour tortilla quality: Impact of amylose content adjustments using waxy wheat flour. Cereal Chem. 80(4):427-436.
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Progress 10/01/01 to 09/30/02
Outputs
Plant breeders are actively developing grains with novel starch and other characteristics. In order to screen new germplasm, small-scale processing operations must be developed that mimic industrial procedures and products. A small-scale laboratory method for Asian salted noodle processing was developed. Thirty-five (35) grams of flour were mixed into a dough, rested, sheeted and cut into noodles. Six (6) hard red winter wheat (Triticum aestivum L.) varieties planted in Nebraska (1999) were selected to compare laboratory and pilot-plant production methods and the resulting salted noodle products. Flour protein content ranged between 9.3%-10.7% (14%MB), and the Mixograph dough mixing tolerance scores were between 2.3-3.0 based on a 0-7 scale. Raw noodle color and discoloration after 24 hours storage was tested. Cooking loss and weight gain were measured as the noodle cooking properties. Cooked noodle hardness, springiness, cohesiveness, adhesiveness, gumminess, and
chewiness were analyzed with a TA-XT2 Texture Analyzer. All these properties, except springiness, were highly correlated between laboratory and pilot-plant products. Both methods were reproducible and had high precision. Data analysis indicated that the laboratory method was comparable to the pilot-plant method. When the quality of noodles made using the different wheat varieties was ranked, similar rankings were obtained for both the pilot-plant and laboratory Asian salted noodle processing methods.
Impacts
The development of small-scale processing procedures that mimic larger industrial processing techniques is vital to the efficient breeding of cereal grains. This research used an advanced statistical tool to screen wheat varieties for further study, and proved that a laboratory processing method could be used to screen varieties for noodle making. The statistical procedures will prove useful in developing similar tests for corn and other grains, while the specific wheat noodle test will allow for targeted breeding of US wheats for improved Asian noodles. More competitive high quality US wheats will help increase exports to Asian countries.
Publications
- Shandera, D.L. and Jackson, D.S. 2002. Corn Kernel Structural Integrity: Analysis Using Solvent and Heat Treatments. Cereal Chem. 79(2):308-316.
- Guo, G. 2002. Asian salted noodle and wheat tortilla quality: impact of amylose content adjustments using waxy wheat flour. Thesis (Ph.D.)--University of Nebraska-Lincoln.
- Zhu, T. 2002. Evaluation and development of several amylose determination methods. Thesis (M.S.)--University of Nebraska-Lincoln.
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Progress 10/01/00 to 09/30/01
Outputs
The starch properties of grain are recognized as fundamental to many of its intended end-uses. Amylose content is one of those fundamental properties; unfortunately, the accurate measurement of amylose is difficult. In order to determine the best procedure to analyze for amylose content, starch samples with 10%, 20%, 30%, 50%, and 80% amylose content were obtained by mixing purified amylose and amylopectin fractions from corn, rice, wheat or potato starch. Amylose content was determined using differential scanning calorimetry (DSC), high performance size exclusion chromatography (HPSEC) and colorimetric iodine binding methods. Standard curves generated using the DSC procedure were linear. Standard curve slopes did not show significant differences between rice, corn and wheat; potato starch's slope was significantly different. A single standard equation can be used for measuring percent amylose from cereal sources. It was also possible to employ a single standard curve
for cereal starches when percent amylose was determined by iodine binding; a different standard curve was required when measuring potato starch. An iodine binding procedure using both 620nm and 505nm increases the method's precision vs. that using only the standard 620nm wavelength. When HPSEC was used to determine percent amylose, calculations based on dividing the injected starch mass and amylose peak mass rather than calculations of the amylose/amylopectin ratio, enhanced accuracy. All starch types can be analyzed similarly using HPSEC. Each method, depending upon the number of samples and availability of amylose standards, has its own unique benefits and limitations. The DSC procedure, because of its small sample-size requirement, is ideal for measuring the amylose content of breeders samples (early generation lines) of corn; grain starch characteristics can even be measured using a single kernel that can subsequently be planted.
Impacts
Plant breeders are increasingly developing corn lines with novel starch characteristics. The accurate screening of amylose content in these lines has proven difficult. The application of the DSC method studied in our laboratory will allow easier screening for starches with different amylose contents early in the breeding cycle, resulting in the faster introduction of corn lines with unique amylose properties and thus unique end-use properties.
Publications
- Sahai, D., Mua, J.P., Surjewan, I., Buendia, M.O., Rowe, M. and Jackson, D.S. 2001. Alkaline processing (Nixtamalization) of white mexican corn hybrids for tortilla production: Significance of corn physico-chemical characteristics and process conditions. Cereal Chem. 78(2):116-120.
- Sahai, D. and Jackson, D.S. 2001. A novel enzymatic nixtamalization process for producing corn masa flour. Cereal Foods World: 46:240-246.
- Sahai, D., Buendia, M.O. and Jackson, D.S. 2001. Analytical Techniques For Understanding Nixtamalized Corn Flour: Particle Size and Functionality Relationships in a Masa Flour Sample. Cereal Chem. 78(1):14-18.
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Progress 10/01/99 to 09/30/00
Outputs
Five white corn hybrids were processed (nixtamalized) using ten different processing conditions; tortillas were prepared to establish relationships between corn composition, physical characteristics and nixtamalization process or product properties. Corn hybrids were characterized by proximate analysis and by measuring Stenvert hardness, Wisconsin breakage, percent floaters, TADD overs, 1000 kernel weight and test weight. Corn characteristics were correlated with process/product variables (effluent dry matter loss and pH; nixtamal moisture and color; masa moisture, color and texture; and tortilla moisture, color and rollability). Process and product variables such as corn solid loss, nixtamal moisture, masa texture, and tortilla color, were not only influenced by processing parameters (cook temperature, cook time and steep time) but also depended on corn characteristics. Significant regression equations were developed for nixtamalization dry matter loss (P<0.05,
r2=0.79), nixtamal moisture (P<0.05, r2=0.78), masa gumminess (P<0.05, r2=0.78), tortilla texture (P<0.05, r2=0.77), tortilla moisture (P<0.05, r2=0.80), tortilla calcium (P<0.05, r2=0.93), and tortilla color `a' value (P<0.05, r2=0.87).
Impacts
Tortilla and snack production is increasing rapidly in the US. Yields of product and product quality is determined both by corn physical- chemical characteristics and processing conditions. Process conditions typically have the greatest influence on product yields and quality; several factors such as corn composition and hardness characteristics also critically influence nixtamalization properties.
Publications
- Sahai, D. Mua, J.P., Surjewan, I., Buendia, M.O., Rowe, M. and Jackson, D.S. 1999. Assessing degree of cook during corn nixtamalization: Impact of processing variables. Cereal Chem. 76:850-854.
- Osman, M.G., Sahai, D. and Jackson, D.S. 2000. Oil absorption characteristics of a multi-grain extrudate during frying: Impact of extrusion temperature and screw speed. Cereal Chem. 77(2):101-104.
- Sahai, D., Surjewan, I., Mua, J.P., Buendia, M.O., Rowe, M., and Jackson, D.S. 2000. Dry matter loss during nixtamalization of a white corn hybrid: Impact of processing parameters. Cereal Chem. 77(2):254-258.
- Shandera, Jr. D. 2000. Understanding corn endosperm morphology through solvent and heat treatments. University of Nebraska--Lincoln Ph.D. Dissertation. 211 p.
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Progress 10/01/98 to 09/30/99
Outputs
This work was designed to systematically study the impact of processing parameters on corn dry matter loss and effluent pH generated during nixtamalization by using response surface methodology. In the ranges studied, corn dry matter loss varied between 3.17 - 9.82%. Most of the dry matter loss was in nejayote (4.12 - 6.55%), while DML in wash varied between 1.08 to 2.23%. Cook temperature and percentage of lime added during nixtamalization, were the most critical factors influencing total DML. Total corn dry matter loss increased during steeping, however, most of the loss occurred during the first 6-8 hours of steeping. It is evident from this response surface study that cooking accounted for most of the solid loss, while steeping accounting for a relatively smaller portion of the loss. DML did not linearly increase on steeping for 12 hours, but leveled off after about 6-8 hours of steeping. Similar observations were made when other corn hybrids, including softer
yellow corn hybrids, were investigated for dry matter loss during steeping (data not shown).
Impacts
It can be concluded that corn DML may be reduced and dry solid yield increased by following proper cooking and steeping protocols.Cooking of corn at high temperature long time with no or minimal steeping is common in commercial masa and instant masa flour production facilities. It appears from this response surface study that such a practice would result in a higher dry matter loss as compared to nixtamalization at lower temperature with an extended steep time.
Publications
- No publications reported this period
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