Location: Grain Quality and Structure Research
2020 Annual Report
Accomplishments
1. Sorghum polyphenols exhibit anti-microbial activity. Sorghum grain is known to have high levels of phenolic compounds that have many beneficial human health attributes. However, less is known about other benefits sorghum phenolic compounds may have. To further identify valuable properties of compounds in sorghum grain, ARS scientists in Manhattan, Kansas, in collaboration with researchers at Kansas State University, investigated the anti-microbial properties of extracts from sorghum grain. This research revealed that extracts from high polyphenol sorghum grain were able to reduce the growth of legionella infection inside mouse immune cells by activating specific immune signals. This study demonstrates the potential antimicrobial properties of sorghum phenolics and provides research to support new utilization of high polyphenol sorghum grain.
2. Combining proteins improves adhesive performance and reduces costs. Proteins can be used as adhesives to reduce the amount of formaldehyde used in the production of pressed wood products such as plywood. Probably the widest researched protein for adhesive use has been isolated soy proteins. While showing promise for use as adhesives, soy is a valuable food and feed ingredient and isolated soy proteins can be expensive for use as adhesives. As a simple and direct method to improve protein-based adhesives and reduce their cost, ARS scientists in Manhattan, Kansas, and collaborators at Kansas State University investigated the use of mixtures of sorghum, canola and soy proteins as adhesives. Using a mixture of these three proteins was found to improve adhesive performance substantially compared to using soy proteins alone. The optimum formula contained 50% soy and 50% sorghum – canola proteins, thus reducing the amount of soy protein needed. This in turn potentially reduced the cost of the adhesive and competition between food uses of soy and non-food uses. This research provides a simple and direct way to improve protein-based adhesives, while providing new avenues for utilization of proteins from other sources such as sorghum grain.
3. Insect feeding on sorghum flour milling fractions. It is well known that stored product insects can feed on wheat flour milling fractions and therefore thrive in flour mills. These insects can cause severe economic impact in flour mills and identifying flour milling fractions they can feed on is an important step in devising appropriate measures to control the insects. Due to the increasing interest in sorghum flour, it is possible this type of insects could also infest sorghum flour mills. To investigate this, ARS researchers in Manhattan, Kansas, along with collaborators at Kansas State University, monitored growth and development of the red flour beetle on six sorghum flour milling fractions. The red flour beetle survived and developed on all flour milling fractions, identifying that flour mill sanitation at all steps of sorghum flour milling would be critical in controlling this insect pest.
4. Sorghum varieties influence resistance to stored product insects. Stored product insects can cause severe economic damage by feeding on stored grains. Previous research has shown that the lesser grain borer survives well on stored sorghum grain. However, past research has been conducted on limited types of sorghum grain. Due to the increasing interest in various types of sorghum grain for human food uses, it would be valuable to know if different grain types vary in how well stored product insects can feed and survive on them. To address this question, ARS researchers in Manhattan, Kansas, tested four different sorghum varieties for resistance to the lesser grain borer. Insect production and feeding damage was generally lowest on the sorghum line with waxy starch. This research demonstrated that sorghum grain composition may influence resistance of sorghum to stored product insects.
5. Correction of near infrared spectrum to allow analysis of weathered sorghum grain. Sorghum grain grows in an exposed head on top of the sorghum plant. This type of growth allows the grain to be exposed to the elements and can result in the grain being damaged, often referred to as weathered grain. Weathered grain may be discolored and have altered chemical composition. Such changes to the grain impact the use of rapid, non-destructive near infrared (NIR) spectroscopic analysis for determining protein content. This in turn often means such samples are difficult to work with and analyze. To overcome this problem, ARS scientists in Manhattan, Kansas, along with collaborators at Kansas State University investigated the use of statistical methods to correct spectra from weathered grains when analyzed by NIR. Statistical corrections improved the accuracy of the NIR method and allowed for weathered grains to be analyzed and thus still useful in studies of sorghum grain composition.
6. Encapsulation of fish oil using sorghum protein particles. It is well known that fish oil contains nutrients important to human health. Despite the health benefits of fish oil, consumption remains low. One way to increase consumption of fish oil is by adding fish oil to other food products. Directly adding fish oil to other food products however can cause problems with off-flavors and off-odors. To overcome these issues, fish oils can be encapsulated within a shell that protects the fish oil from forming undesirable flavors and odors. ARS researchers in Manhattan, Kansas, collaborated with scientists at the University of Granada, Spain to investigate whether isolated sorghum grain proteins could be successfully used as the shell material to encapsulate fish oil. By using a technique called electrospraying, sorghum proteins were found to work very well at encapsulating fish oil and had an encapsulation efficiency of about 94%. This research shows the potential for sorghum proteins to be used as encapsulating agents for the food industry and opens new avenues and markets to increase the value of sorghum grain.
Review Publications
Girard, A.L., Bean, S.R., Tilley, M., Adrianos, S.L., Awika, J.M. 2017. Interaction mechanisms of condensed tannins (proanthocyanidins) with wheat gluten proteins. Food Chemistry. 245:1154-1162. https://doi.org/10.1016/j.foodchem.2017.11.054.
Pontieri, P., Troisi, J., Bean, S.R., Tilley, M., Di Salvo, M., Boffa, A., Pignon, D., Del Giudice, F., Alifano, P., Del Giudice, L. 2019. Comparison of methods for extracting Kafirin proteins from food-grade sorghum cultured in a Mediterranean environment. Australian Journal of Crop Science. 13:1297-1304. https://doi.org/10.21475/ajcs.19.13.08.p1695.
Arthur, F.H., Bean, S.R., Smolensky, D., Cox, S.R., Lin, H., Peiris, S., Petersen, J. 2020. Development of Rhyzopertha dominica (Coleoptera: Bostrychidae) on sorghum: quality characteristics and varietal susceptibility. Journal of Stored Products Research. https://doi.org/10.1016/j.jspr.2020.101569.
Bean, S.R., Zhu, L., Smith, B.M., Wilson, J.D., Ioerger, B.P., Tilley, M. 2018. Starch and protein chemistry and functional properties. In: J.R.N. Taylor and K. Duodu, editors. Sorghum and Millets: Chemistry and technology. 2nd edition. San Diego, CA: Elsevier. p. 131-170.
Liu, H., Bean, S.R., Sun, X. 2018. Camelina protein enhanced by polyelectrolyte interaction and its plywood bonding properties. Industrial Crops and Products. 124:343-352. https://doi.org/10.1016/j.indcrop.2018.07.068.
Ioerger, B.P., Bean, S.R., Tilley, M., Lin, H. 2020. An improved method for extraction of sorghum polymeric protein complexes. Journal of Cereal Science. https://doi.org/10.1016/j.jcs.2019.102876.
Peiris, K., Bean, S.R., Tilley, M., Jagadish, K. 2020. Analysis of sorghum content in corn-sorghum flour bioethanol feedstock by near infrared spectroscopy. Journal of Near Infrared Spectroscopy. https://doi.org/10.1177/0967033520924494.
Kaufman, R.C., Wilson, J.D., Bean, S.R., Galant, A.L., Perumal, R.R., Tesso, T., Herald, T.J., Shi, Y.C. 2018. Influence of genotype and environmental interaction on sorghum (Sorghum bicolor (L) Moench) grain chemistry and digestibility. Agronomy Journal. https://doi.org/10.2134/agronj2017.09.0561.
Xu, S., Shen, Y., Chen, G., Bean, S.R., Li, Y. 2019. Antioxidant characteristics and identification of peptides from sorghum kafirin hydrolysates. Journal of Food Science. 84:2065-2076. https://doi.org/10.1111/1750-3841.14704.
Gilchrist, A., Smolensky, D., Cox, S.R., Perumal, R., Noronha, L.E., Shames, S. 2020. High-polyphenol extracts from Sorghum bicolor attenuate replication of Legionella pneumophila within RAW 264.7 macrophages. FEMS Microbiology Letters. https://doi.org/10.1093/femsle/fnaa053.
