ARS | Publication request: Phytochemical composition and antioxidant capacity of modified-lipoxygenase soybeans grown in maryland

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 18, 2011
Publication Date: December 28, 2011
Citation: Whent, M., Lv, J., Lutterodt, H., Kenworthy, W., Yu (Lucy), L., Luthria, D.L. 2011. Phytochemical composition and antioxidant capacity of modified-lipoxygenase soybeans grown in maryland. Journal of Agricultural and Food Chemistry. 59:12902-12909.

Interpretive Summary: This paper describes the phytochemical composition and antioxidant capacity of modified-Lipoxygenase soybeans grown in Maryland. Although recognized as a health-enhancing food, soybeans and foods produced from them can develop sensory properties that make them less desirable to consumers. Lipoxygenase (linoleate: oxygen oxidoreductase, EC 1.13.11.12) is a catalyst for oxidation of polyunsaturated fatty acids that contain a cis,cis-1,4-pentadiene moiety. This enzyme is contained in soybean seed, and after homogenization the reaction leads to formation of secondary volatile carbonyl compounds. The enzyme can be inactivated by heat, and this method is typically used in food processing as it also reduces anti-nutritional factors contained in soybean. However, there is interest in reducing the lipoxygenase content in soybean seeds through breeding, in order to further reduce the possibility of poor odors or flavors. The results obtained from the current research demonstrated that modification of the LOX trait did not necessarily alter the lipid or isoflavone composition of the experimental soybean lines when compared with a non-modified cultivar. The data presented in this manuscript will be of interest for the soybean food product producers. This work was done in collaboration with University of Maryland, College Park.

Technical Abstract: Maryland-grown soybean lines modified for low lipoxygenase (LOX) content and a traditional non-modified cultivar were analyzed for fatty acid composition, total phenolic content (TPC), isoflavone composition, relative DPPH• scavenging capacity (RDSC), and hydroxyl radical scavenging capacity (HOSC). Soybean lines included black, brown, and yellow soybeans. TPC of all soybean lines ranged from 2.84 to 4.74 mg gallic acid equivalents (GAE)/ g flour. Total isoflavones were between 2.78 and 8.66 µmol/ g flour. RDSC of all lines was between 0.48 and 14.62 µmol TE/ g flour, and HOSC ranged from 53.57 to 135.52 µmol TE/ g flour. Some modified-LOX genotypes demonstrated antioxidant capacity and/or isoflavone content that was similar to or higher than the non-modified cultivar (P < 0.05). Black colored soybeans demonstrated higher TPC and RDSC than most yellow soybean lines, although did not have higher isoflavone content. The results demonstrate that modification of the LOX trait did not necessarily alter the lipid or isoflavone composition of the experimental soybean lines when compared with a non-modified cultivar. These soybean lines may be studied further for nutraceutical properties and use in functional foods.