Inhibitory effects of volatile antioxidants found in various beans on malonaldehyde formation in horse blood plasma.

This study investigates the effectiveness of aroma extracts from various beans (soybeans, mung beans, kidney beans, and azuki beans) in inhibiting malonaldehyde formation in horse blood plasma, a process involved in oxidative stress. They found that the extracts do have antioxidant properties, with soybeans showing the highest antioxidant activity.

Research Methodology

• The researchers undertook a comprehensive evaluation to determine the inhibitory effect of aroma extracts isolated from dried soybeans, mung beans, kidney beans, and azuki beans on malonaldehyde (MA) formation in horse blood plasma.
• MA formation, which is an indicator of oxidative stress in the body, was induced using Fenton’s reagent, a solution of hydrogen peroxide with ferrous iron, which helps to create highly reactive free radicals that would cause oxidation.
• The degree of the inhibitory effect was determined by utilizing gas chromatography (GC) which was coupled with a nitrogen-phosphorus detector (NPD). GC is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. The NPD is a highly sensitive and selective detector for the analysis of nitrogen- and phosphorus-containing compounds.

Findings

• The aroma extract of soybeans showed the strongest antioxidant activity amongst the four tested, inhibiting MA formation by 58% at the level of 400 microg/mL. Followed by mung beans with a 47% inhibitory effect, azuki beans with 40%, and kidney beans with 23%.
• These results were compared to alpha-tocopherol (a form of Vitamin E) and BHT (butylated hydroxytoluene, a common food preservative) which are known antioxidants. They inhibited MA formation by 52% and 70%, respectively, at the same level. This shows the effectiveness of the bean extracts in inhibiting MA formation, albeit with varying degrees.
• Separate aroma chemicals found in the aroma extracts of beans were also examined. These include maltol, eugenol, benzyl alcohol, 1-octen-3-ol, butyrolactone, and 1-methyl-2-pyrrolidone. Among these, the antioxidant activity decreased in the following order: eugenol> maltol> 1-octen-3-ol> benzyl alcohol> butyrolactone> 1-methyl-2-pyrrolidone.

Implications

• The finding that aroma extracts from soybeans, mung beans, kidney beans, and azuki beans have demonstrable inhibitory effects on MA formation may yield potential benefits in food preservation and human health due to their antioxidant properties.
• These antioxidant properties could be adapted for use in food and pharmaceutical industries to inhibit oxidation, which is a common cause of food spoilage and has been implicated in a number of human health conditions such as cancer, heart disease, and other disorders related to ageing.