Upcoming Event: Practical Farmers of Iowa Conference
The Practical Farmers of Iowa Annual Conference will be held on January 19-20. Where: Scheman Building, ISU, Ames, Iowa. We will have a table at the expo. Stop by and say hello.
Evaluation of Three GEI Specialty Corns
We recently underwent an evaluation of the nutritional value of the grain of three GEI specialty corns:
GEI 101 lys: High lysine corn
GEI 411C: High anthocyanin corn
GEI 2318: High carotenoid corn
Objective: The grain of normal corn is considered to have a limited nutritive value because of the deficiency of essential amino acids in the protein, especially lysine and tryptophan. Specialty corns with enhanced nutritive values for the food and feed markets have been developed by Genetic Enterprises International. The company considered it important to conduct a substantive analysis of three of the most popular and important grain specialties considered for food and feed applications focusing on the strength of each specialty.
Materials and Methods: Specialty hybrids: GEI 101 lys (high lysine corn), GEI 2318 (high carotenoid) and GEI 411C (high anthocyanin) were planted side by side in 8 row wide strips in Luther, IA. Cross pollination was minimized by planting the late hybrid, GEI 2318, on each side of the early hybrids. 10 representative ears of each hybrid were harvested, dried and shelled in bulk . Representative samples were taken from each bulk for analysis. Grain purity was insured by removing contaminant kernels from each bulk.
| Learn more about GEI 101 lys | Learn more about GEI 411C |
| Learn more about GEI 2318 | Additional Specialty Corns |
Evaluation of Specialty Corns: Tests Conducted
The following tests were conducted: NIR testing to determine % moisture % protein, % oil, % starch, and density.Total protein and amino acid analysis of proteins were conducted on the three hybrid samples and total anthocyanin content on GEI 411 C at the ESCL Analytical Services, University of Missouri The hybrid corn GEI 2318 was analyzed for Provitamin A components and β carotene at the ISU Department of Food Science and Human Nutrition lab using GLC method.
Evaluation of Specialty Corns: NIR Results
Analysis : Results obtained with the NIR analysis show that GEI 2318 is higher in % protein and % oil compared to GEI 101 lys and GEI 411C. Hybrid GEI 101 lys is lower in protein but higher in % oil and % starch compared to GEI 411C. Kernel density is highest for GEI 2318 compared to the other two hybrids. The high lysine hybrid has the lowest kernel density and falls in the range category of the soft texture floury corn types.
Because of these characteristics, the grain requires a shorter cooking and steeping time for the nixtamalization and processing into dough for the manufacture of corn chips, corn tortillas or other snack products. GEI 411C has a density similar to typical corn dent types (density 1.25-1.28) and responds well to common nixtamalization practices and processing schedules used for dent corn types in the density range indicated.
Evaluation of Specialty Corns: Amino Acid Results
Amino Acid Analysis & Protein Quality
Analysis : Protein quality is determined by the relative concentration of essential amino acids in the protein. It has been well established that the protein of normal corn is deficient in essential amino acids, especially lysine and tryptophan. Studies conducted on normal and high lysine corn proteins have shown the following % amino acids concentrations that can be used as reference for comparison purposes.
Normal corn High lysine corn
Percent of protein
Lysine 2.5 3.5-4.5
Tryptophan 0.6 0.9
Methionine 1.6 1.6
Reference: Quality protein maize, edited by Edwin T. Mertz; 1992 by the American Association of Cereal Chemist, Inc.
The results of the amino acid analysis of the three specialty hybrids show that GEI 101 lys and GEI 411C had 4.28% and 3.46 % lysine of protein, respectively. Both hybrids fall in the high lysine amino acid range for this type of hybrids; likewise the tryptophan level is somewhat similar for both hybrids, (0.88,0.72 ). GEI 2318 % lysine of protein is 2.70 and 0.58 for tryptophan, in the amino acid range of normal endosperm corn.
The leucine : isoleucine : valine ratio are approximately in a ratio of 2:1:1, indicating that these amino acids are in the recommended favorable ratio for muscle development. With respect to the % methionine in the proteins, GEI 411C and GEI 2318 are much higher than in the protein constitution of the lysine hybrid GEI 101 lys. This indicates that the potential use of these two specialties with the appropriate protein supplementation could have good results in poultry diets.
The data of the % amino acid per 100 grams of grain indicate the % amino acid available in the grain for formulating a food or feed product. The relative values of amino acids present in the grain of each hybrid show the effect of the protein quantity in the grain irrespective of the quality of the protein. GEI 2318 has similar values to the high lysine hybrid types, but this protein requires supplementation with a higher protein source such as soybean oil meal for better functionality.
Total Anthocyanin Level
Total Anthocyanin level of GEI 411C (high anthocyanin corn) was determined at the ESCL Analytical Services, University of Missouri using the method of Li, et al (2011).
GEI 411C had a Total Anthocyanin content (TAC ) of 69.94 mg/100g. This value compares well with the TAC results of an average of 49.6 mg/100 g with a range of 17.6 to 65.1mg/100 g reported for 8 cultivars of blue corn types reported in the paper Grain and Nutritional Quality Traits of Southwestern U.S. Blue Maize Landraces by Amol Nankar, et al, Cereal chemistry 94(6):950-955
Evaluation of Specialty Corns: Provitamin A Results
β carotene and Provitamin A content of GEI 2318
β carotene analysis was conducted at the ISU Department of Food Science and Human Nutrition lab using GLC method.β carotene equivalents were calculated applying the following formula: Provitamin A= total β carotene+0.5(β-cryptoxanthin + α-carotene )
Recipe for the Season: Caramel Popcorn
Measure out 10 cups of popped corn (air popped works well) and put this in a kettle in a warm oven. Next mix 1 1/3 cup sugar with 1 cup of butter or margarine and ½ cup of corn syrup in a pot. Stirring constantly, heat the mixture until a candy thermometer registers 265°. Remove from heat and add 1 teaspoon of vanilla. Working quickly, pour the syrup over the warmed popcorn (works better if the kettle is in your sink). Stir the mixture carefully coating all the corn kernels. Pour out the coated popcorn onto a cookie sheet and separate the kernels with two forks.