This study was aimed at determining the effects of selenium on the contents of vitamin C, amino acid, total water-soluble solids and tea polyphenol, and whether the antioxidant activity of selenium-enriched green tea is enhanced compared with regular green tea by linoleic acid oxidation and the lard oxidation method. The contents of selenium, vitamin C and tea polyphenol in green teas were greatly increased by foliar application of selenium-enriched fertilizer. No significant differences of the contents of vitamin C, amino acid and tea polyphenol were observed between green tea treated with sodium selenite and that without selenium. The selenium-enriched green tea exhibited significantly higher antioxidant activity than regular green tea, both in linoleic acid oxidation and in the lard oxidation system. These results suggest that the antioxidant activity of green tea is significantly enhanced by the combination of selenium and green tea constituents compared with that of regular green tea.

Atomic fluorescence spectrophotometry was used to determine the selenium (Se) concen-tration in 30 rice products of different species from Southern China. The Se level ranged from 0.015 to 0.0461μgg-1. Considering the average daily individual consumption of rice products in Southern China, the average dietary intake of Se supplied by this source is only 6-18μg day-1 for an adult. This low Se intake from rice products is mainly responsible for the low total Se intake of inhabitants in Southern China. Foliar spraying ofSe-enriched fertiliser or sodium selenite with 14-18g Seha-1 in the heading stage of rice growth increased the Se content to 0.178-0.421μgg1 in rice products. The concentration and amount ofSe-enriched fertiliser can be varied to achieve an optimum concentration of Se in rice products. The authors suggest that these Se-enriched rice products can contribute an increase in Se intake of 50-100μgday-1 on average if their Se concentration is controlled in the region of 0.15-0.50μg g-1.

This research was to determine the effect of foliar application of selenium on increasing the antioxidant activity of tea harvested during the early spring tea producing season using a R,R-diphenyl-

The polysaccharide and flavonoid concentrations of two-, three-, and four-year-old Aloe vera were determined, and their antioxidant activities were evaluated compared to BHT and R-tocopherol by the DPPH radical scavenging method and the linoleic acid system at 100

activities of extracts derived from sesame seed by supercritical carbon dioxide (SC-CO2) extraction and by n-hexane were determined using R,R-diphenyl-â-picylhydrazyl (DPPH) radical scavenging and linoleic acid system methods. The highest extracted yield was given at 35℃, 40MPa, and a CO2 flow rate of 2.5mL min-1 by an orthogonal experiment. The yields of extracts increased with increasing pressure, and yields at 40 and 30MPa were higher than that by solvent extraction at 46.50%. Results from the linoleic acid system showed that the antioxidant activity follows the order: extract at 3℃, 20MPa>BHT>extract at 55℃, 40MPa>extract at 55℃, 30MPa>Trolox>solvent extraction>R-tocopherol. The SC-CO2 extracts exhibited significantly higher antioxidant activities comparable to that by n-hexane extraction. The extracts at 30MPa presented the highest antioxidant activities assessed in the DPPH method. At 20MPa, the EC50 increased with temperature, which indicated that the antioxidant activity was decreased in a temperature-dependent manner. The significant differences of antioxidant activities were found between the extracts by SCCO2 extraction and n-hexane. However, no significant differences were exhibited among the extracts by SC-CO2 extraction. The vitamin E concentrations were also significantly higher in SC-CO2 extracts than in n-hexane extracts, and its concentrations in extracts corresponded with the antioxidant activity of extracts.