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ARS Home » Southeast Area » Griffin, Georgia » Plant Genetic Resources Conservation Unit » Research » Publications at this Location » Publication #409842
Research Project: An Integrated Approach for Plant Genetic Resources Conservation, Characterization, Evaluation, Documentation, and Distribution

Location: Plant Genetic Resources Conservation Unit

Title: Evaluating galactomannan concentrations in ten Guar (Cyamopsis tetragonoloba (L.) Taub.) genotypes over 2 locations for potential use as a healthy nutraceutical source

Author
item Morris, John - Brad
item Tonnis, Brandon
item Wang, Ming

Submitted to: Current Topics in Phytochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2024
Publication Date: 6/10/2024
Citation: Morris, J.B., Tonnis, B.D., Wang, M.L. 2024. Evaluating galactomannan concentrations in ten Guar (Cyamopsis tetragonoloba (L.) Taub.) genotypes over 2 locations for potential use as a healthy nutraceutical source. Current Topics in Phytochemistry. 19:97-105.

Interpretive Summary: Guar gum is an important food ingredient and has recently been shown to have gut health effects. Some guar plants may contain lower amounts of guar gum in seeds than others, therefore a study needed to be done on looking at the amount of guar gum in several guar plants. Several guar plants showed higher amounts of guar gum in the seeds than others. These guar types can and should be used to develop varieties with higher amounts of guar gum in the seeds.

Technical Abstract: Guar (Cyamopsis tetragonoloba L.) is used as a food additive, vegetable, and in the oil and gas industries in the U.S.A and other countries worldwide. However, this study focused on its potential functional vegetable use. Guar may contain significant concentrations of galactomannan gum for potential use as a healthy and functional nutraceutical. Ten guar genotypes were selected from the USDA, ARS, Plant Genetic Resource Conservation Unit’s cold storage at -18' during 2019. Information for percent mannose, galactose, galactomannan, and the mannose to galactose ratio (M:G) as well as seed and endosperm weight plus years in storage prior to planting would add value to these guar genotypes for use as a nutraceutical. The overall means for seed and endosperm weight, galactose, mannose, galactomannan %, and the mannose to galactose (M:G) ratio were 33.40 mg, 13.7 mg, 25.23%, 53.26%, 78.03%, and 2.12, respectively. The Congolese and Pakistan genotypes, PI 263406 and PI 262153 produced the highest seed weight averaging 39.77 mg. However PI 263406 and PI 165511 (India) produced the highest endosperm weight averaging 16.22 mg. Using high performance liquid chromatography (HPLC), the genotypes, PI 263698 (Sudan), PI 253182 (Maryland, U.S.A.), and PI 268229 (Iran) produced the highest mean of 26.5% and 80.33% for galactose and galactomannan, respectively. The Indian genotypes, PI 164299, PI 164477, and PI 263698 produced the highest mean concentration for mannose (54.8%), but not significantly. The lowest M:G ratios were found in PI 165511, PI 263698, and PI 268229 averaging 2.01 indicating higher solubility. Several correlations were found and both galactose and galactomannan % showed significant negative correlations (r = -0.524* and r = -0.536*, respectively) indicating that galactose and galactomannan % decreased in the seeds stored the longest (from 12 – 36 years) at -18'. These results can be used by scientists for guar cultivar development with high galactomannan concentrations.