RESUMO
Objective: To explore the suitable drying methods for Rhei Radix et Rhizoma (RRR) with color, drying time, drying rate, and content of active ingredients as indexes. Methods: Rheum palmatum was used in the test and the color of RRR was studied according to Chinese Pharmacopeia 2010. The extract was obtained by hot-dip method. The contents of anthraquinone, gallic acid, and catechin were determined using HPLC. Results: RRR treated with oven-drying, shade-drying, sun-drying, and fumigated with sulfur-drying below 65 °C showed good color and the cross-section was claybank. The cross-section of RRR treated with oven-drying over 65 °C showed dark brown. The highest contents of extract and anthraquinone in RRR treated by sun-drying were 34.32% and 1.90% and followed by those treated by oven-drying at 45 °C with 33.53% and 1.68%, respectively. High temperature caused the decrease of anthraquinone in RRR. The contents of gallic acid and catechin reduced with the increase of temperature under the constant temperature oven-drying process. Conclusion: The suitable drying method for RRR is oven-drying at constant 45 °C or sun-drying.
RESUMO
Objective: To explore the suitable packaging methods for Rhei Radix et Rhizoma (RRR) with the contents of active ingredients, quality loss before and after storage, shelf life, and economic benefit as indexes. Methods: Rheum palmatum was used in the experiment and the color of RRR was studied according to Chinese Pharmacopeia 2010. The extract was obtained by hot-dip method, and the contents of anthraquinone, gallic acid, and catechin were determined using HPLC. Results: The moisture capacity of RRR package had the significant effect on the active constituents, the highest content of extracting substances (31.36%) was obtained with the moisture content of 24%, and the lowest content was obtained with the moisture content of 14%. The highest anthraquinone content (1.893%) was obtained with the moisture content of 14%, and the highest in catechin and gallic acid contents were 1.492% and 0.400% with the moisture content of 20%. The contents of RRR extract and anthraquinone were the highest (33.47% and 1.891%) with vacuum packing, while those with common package were the lowest (28.30% and 1.539%). The highest contents of gallic acid and catechin (0.323% and 2.022%) were obtained with deoxidizer packaging. The mildew and infestation observation and the quality determination of one-year stored RRR showed that the vacuum packing had no mildew with the moisture content of less than 20%. Conclusion: The vacuum packing is an optimal atmosphere packaging method, which could increase the revenue of farmers and the moisture content of RRR during storage.
RESUMO
A digital beamformer in medical ultrasound imaging systems conventionally requires that the returning signals received by transducers are sampled at a rate significantly higher than the Nyquist rate. This paper presents a digital beamformer that employs zero padding followed by digital interpolation filtering to achieve vernier beamformer delays. The experimental results show that the digital interpolation beamformer can greatly decrease the complexity of A/D converter circuitry.