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The thermal and acid stability of Oryza sativa rice albumin (RA), which suppresses postprandial hyperglycaemia, was evaluated for its use in foods. RA showed high thermal stability, with a peak temperature (Tp) of 100.8 °C by differential scanning calorimetry measurement. However, its Tp shifted to 52.0 °C with the addition of dithiothreitol, suggesting that the heat resistance of RA is attributed to its rigid structure supported by intermolecular disulphide bonds. The a-amylase inhibitory activity of RA was retained even after heating to 100 °C, although it gradually decreased with longer heating times or increasing concentrations of RA. RA showed high nitrogen solubility and surface properties, such as emulsifying and foaming properties, even under acidic conditions, as opposed to other common food proteins (i.e., casein, soy protein isolate, and dried egg white). These findings suggest that RA can be used as an additive in various foods. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the antioxidative activity of 68 culinary herbs and spices, and to evaluate the hepatoprotective effects of highly antioxidative plants (selected after an in vitro study) on carbon tetrachloride-induced oxidative stress in rats. Six Lamiaceae plants (oregano, common thyme, peppermint, lemon balm, sweet marjoram and rosemary) were found to be among the top 10 plants showing high total oxygen radical absorbance capacity (T-ORAC: sum of hydrophilic and lipophilic ORAC (H- and L-ORAC)). Their T-ORACs were composed of > 90% H-ORACs. Next, we prepared hydrophilic fractions of three selected Lamiaceae plants (peppermint, lemon balm and rosemary), in which bitterness and lipophilic odorants were reduced. Oral administration of these fractions in rats decreased aspartate aminotransferase and alanine aminotransferase activities in serum, inhibited lipid peroxidation, and restored superoxide dismutase and glutathione 5-transferase activities in carbon tetrachloride-treated rats. Antioxidants in plants could exert a hepatoprotective effect by scavenging free radicals. [ABSTRACT FROM AUTHOR]