The performance of a method that could accelerate the sorption process of biological materials was evaluated with respect to rapidness (expedition of sorption), comparability of equilibrium moisture content (EMC) values with the control (conventional static method) and effect of specific airflow rates on the rate of sorption, EMC, and sorption rate constant. For this purpose, a simple, compact, and inexpensive experimental setup was fabricated with a facility to agitate the conditioned air around the sample. Different forms of raw and parboiled rice kernels (rough rice, brown rice, and milled rice) of an Indica variety were used as sample material. Both adsorption and desorption processes were investigated under conditions of high humidity (80.27%) and tropical temperature (30°C). Sorption rate constants based on a first-order kinetic model showed a faster rate of sorption by the accelerated method compared to the control for determining the equilibrium moisture content (EMC). The accelerated method required 40-60% less time compared to the control method (static) to reach sorption equilibrium. Specific airflow rates of 79.14m³/min-m³ and lower showed the most similar EMC values to those of the control. The results showed that this method can be applied in order to expedite the sorption process.

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We examined the phenolic contents of 45 species of vegetables and their radical scavenging activities for 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·). High contents of phenolic compounds and strong DPPH·scavenging activities were observed in extracts from Nishiyomogi, Ryukyuyomogi, Aojiso, Moroheiya, Hosobawadan, Bajiru, Ensai, Yaeyamakazura, Suizenjina, Botanbouhuu and Uikyou. Eight of these vegetables are traditional foods in Okinawa. These showed strong radical scavenging activities for the superoxide radical (O₂^-·) and tert-butylhydroperoxyl radical (t-BuOO·). We found five antioxidative phenolic compounds, D(+)-chicoric acid, chlorogenic acid, caffeic acid, luteolin 7-O-β-D-glucopyranoside, and luteolin 7-O-β-D-glucuronide, in Hosobawadan (Crepidiastrum lanceolatum Nakai). Their detailed structures were determined using ¹H-NMR, ¹³C-NMR, MS, and UV spectrometry.

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L-Ascorbic acid (AsA) has numerous biological activities. It is known that AsA is unstable under neutral and alkaline conditions, degrading almost completely within several hours, whereas it is relatively stable under acidic conditions. The present study investigated the effect of grape seed extract (GSE), which contains proanthocyanidins, on the stability of AsA under neutral and alkaline conditions. The addition of GSE to AsA solution in 3,3′-dimethylglutaric acid-tris(hydroxymethyl)aminomethane-2-amino-2-methyl-1,3-propanediol (GTA) (50mM, pH 7.0 or 10.0) buffer significantly increased the remaining amount of AsA and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, compared with those of AsA alone. In particular, it was clarified that GSE contributed to the stability of AsA at an alkaline pH. We also investigated the effect of GSE on the stability of AsA under quasi-physiological conditions. It was revealed that GSE stabilized AsA in simulated intestinal juice (pH 8.5) at 37°C. DPPH radical-scavenging activity was closely correlated with the remaining amounts of AsA. The present results, although not directly transferable to in vivo conditions, suggest that GSE may stabilize AsA under neutral and alkaline conditions and affect the physiological activity of AsA.

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