Determination of antioxidant properties of aroma extracts from various beans

Formation of genotoxic dicarbonyl compounds in dietary oils upon oxidation

Dietary oils--tuna, salmon, cod liver, soybean, olive, and corn oils--were treated with accelerated storage conditions (60 degrees C for 3 and 7 d) and a cooking condition (200 degrees C for 1 h). Genotoxic malonaldehyde (MA), glyoxal, and methylglyoxal formed in the oils were analyzed by GC. Salmon oil produced the greatest amount of MA (1070+/-77.0 ppm of oil) when it was heated at 60 degrees C for 7 d. The highest formation of glyoxal was obtained from salmon oil heated at 60 degrees C for 3 d. More glyoxal was found from salmon and cod liver oils when they were heated for 3 d (12.8+/-1.10 and 7.07+/-0.19 ppm, respectively) than for 7 d (6.70+/-0.08 and 5.94+/-0.38 ppm, respectively), suggesting that glyoxal underwent secondary reactions during a prolonged time. The amount of methyglyoxal formed ranged from 2.03+/-0.13 (cod liver oil) to 2.89+/-0.11 ppm (tuna oil) in the fish oils heated at 60 degrees C for 7 d. Among vegetable oils, only olive oil yielded methylglyoxal (0.61+/-0.03 ppm) under accelerated storage conditions. When oils were treated under cooking conditions, the aldehydes formed were comparable to those formed under accelerated storage conditions. Fish oils produced more MA, glyoxal, and methylglyoxal than did vegetable oils because the fish oils contained higher levels of long-chain PUFA, such as EPA and DHA, than did the vegetable oils. A statistically significant correlation (P < 0.05) between the alpha-tocopherol content and the oxidation parameters was obtained from only MA and fish oils heated at 60 degrees C for 3 d.

New legume sources as therapeutic agents

This review evaluates the potential health benefits of three legume sources that rarely appear in Western diets and are often overlooked as functional foods. Fenugreek (Trigonella foenum graecum) and isolated fenugreek fractions have been shown to act as hypoglycaemic and hypocholesterolaemic agents in both animal and human studies. The unique dietary fibre composition and high saponin content in fenugreek appears to be responsible for these therapeutic properties. Faba beans (Vicia faba) have lipid-lowering effects and may also be a good source of antioxidants and chemopreventive factors. Mung beans (Phaseolus aureus, Vigna radiatus) are thought to be beneficial as an antidiabetic, low glycaemic index food, rich in antioxidants. Evidence suggests that these three novel sources of legumes may provide health benefits when included in the daily diet.

Inhibition of malonaldehyde formation from blood plasma oxidation by aroma extracts and aroma components isolated from clove and eucalyptus

The inhibitory effect of aroma extracts isolated from clove buds [Syzygium aromaticum (L.) Merr. et Perry] and eucalyptus leaves (Eucalyptus polyanthemos Schauer) on malonaldehyde (MA) formation from horse blood plasma oxidized with Fenton's reagent was determined by gas chromatography. Aroma chemicals such as eugenol, thymol and benzyl alcohol, identified in the aroma extracts, were examined for their inhibitory effect on the same system. Between the two aroma extracts tested, clove exhibited the most potent antioxidant activities. Extracts of eucalyptus and clove inhibited MA formation by 23 and 48%, respectively, at the level of 400 microg/ml, whereas, alpha-tocopherol and BHT inhibited MA formation by 52 and 70%, respectively, at the same level. Eugenol, thymol and benzyl alcohol inhibited MA formation by 57, 43 and 32%, respectively, at the level of 400 microg/ml.