Effects of Preliminary and Preservation Methods on the Quality of Radix et Rhizoma Salviae miltiorrhizae | Chapter 6 | Current Research Progress in Agricultural Sciences Vol. 4

Preliminarily preparing and preserving Radix et Rhizoma Salviae mitiorrhzae  (Danshen) has been done for a long time. However, the processing method is simple, manual and based on experience. The effect of pretreatment, drying and storage methods on maintaining the quality of Rhizome and roots of Salvia miltiorrhiza Bunge postharvest was studied. The purpose of the study is to reduce the effect of fungi, maintain the quality of medicinal plants after storage time, limit the increasing of moisture content, keeping a good sensory quality by using organic acid in combination with low pressure. Salvia miltiorrhiza Bunge grown in Hoa Binh is harvested with enough growing time and highly active elements. The experiments used organic acids as acid citric and sodium bisulfate solutions to evaluate the pretreatment of Radix et Rhizoma Salviae mitiorrhzae. Danshen were pretreated and dried by convection drier and heat pump drier and were preserved by low-pressure. The results showed that dipping acid citric solution pH 2.5-3 for 30 minutes restricted the development of total microorganisms. Using a heat pump drier resulted in good sensory quality and retaining tanshinone IIA, salvianolic acid content in Radix et Rhizoma Salviae mitiorrhzae. The method of preserving Radix et Rhizoma Salviae mitiorrhzae by the low pressure of 200 mmHg, and 400 mmHg after 9 months at ambient temperature (25-30 oC), humidity (80-85%) maintained better quality than the control. Besides, the moisture medicine, tanshinone IIA, salvianolic acid content, and total microorganisms in the experiment samples changed slowly during the storage period.

 

Author (s) Details

 

Nguyen Thu Huyen
National Institute of Medicinal Material, Vietnam.

 

Cu Thi Hang
National Institute of Medicinal Material, Vietnam.

 

Phan Thi Thu
National Institute of Medicinal Material, Vietnam.

 

Nguyen Thi Yen Chi
Hanoi-Amsterdam High School for the Gifted, Vietnam.

 

Quach Anh Kiên
Phan Dinh Phung High School, Vietnam.

 

Nguyen Minh Nha
Quang An Secondary School, Vietnam.

 

 

Please see the book here:- https://doi.org/10.9734/bpi/crpas/v4/2530

 

Microwave Cavities Generated Active Species in Plasmas | Chapter 3 | Plasmas Afterglows with N2 for Surface Treatments synthesis 2024

Microwave plasma sources are described from low Ar gas pressure (< 1 Torr) to high gas pressures (> 10 Torr up to the atmospheric gas pressure) in N2 and Ar. At low gas pressure, the plasma diameter is over 1 cm, typically 2.6 cm and at high gas pressure, it needs discharge tubes < 1cm, down to 0.1 cm. The microwave plasmas have been studied from low to atmospheric gas pressure in rare gases (mainly Ar) and gas mixtures containing N2. At low gas pressure, it is found the surface wave plasmas, produced by patented launchers Surfatron and Surfaguide, which were developed by Michel Moisan in the Plasmas Lab. of the Montreal Univ. in 1975 [1] (see note). At high gas pressure from a few Torr up to the atmospheric gas pressure, the SW plasmas Surfatron at low power and Surfaguide at high power are still operating. It is also given the results obtained by a resonant cavity in N₂ − xO₂ with 𝑥 = 0−20%. It is presently reported the detection of plasma active species obtained by optical spectroscopy. The main used frequency was 2450 MHz. The plasma power could vary from a few Watts (surfatron) up to a few 103 Watts (Surfaguide, resonant cavity). The plasma can be produced in a static gas flow, mainly at low gas pressure and up to several liters per minute (slpm) at high gas pressures. The optical spectroscopy was set up first to obtain the spatial distribution of radiative species, mainly in Ar gas at low gas pressure in the perspective to characterize the SW plasmas. Then the radial distribution of Ar metastable density was obtained by resonant optical absorption. At medium (a few Torr) up to the atmospheric gas pressure, flowing HF plasmas (resonant cavity) and SW plasmas were produced in gas mixtures with N₂ to produce N -atoms and other active species such as N2 metastable molecules and N₂ +ions which are studied inside the plasma and in afterglow conditions. It discusses the kinetics reactions relating the 𝑁₂(𝑋,𝑣),𝑁₂(𝐴,𝑣′),𝑁₂(𝐵,𝑣′),𝑁₂(𝐶,𝑣′),𝑁₂ + (𝑋,𝑣′) and N₂ + (𝐵,𝑣′) interfering in the radiative emissions of N₂ (𝐵,𝑣′),𝑁₂(𝐶,𝑣′) and N₂ +(𝐵,𝑣′) states. At atmospheric gas pressure, the plasmas are mainly in Ar dominant gas, easier to ionize. In these conditions, the plasmas are characterized by the electron density and the gas temperature which will be reported for specific microwave plasmas sources. Depending on plasma parameters such as powers, flow rates and exit tube diameters, the plasmas were more and less near the Local Thermodynamic Equilibrium (LTE) as demonstrated in Montreal Univ., Lisbon IST and Cordoba Univ. The conclusion was that the N₂ excited states are mainly produced from the N2 ground state by electron collisions in a resonant microwave cavity. It was estimated that the LTE was nearly reached in a 100 Torr, 300-500 W N₂ plasma in a quartz tube of i.d.10 mm. with equality of vibrational and rotational temperatures.

 

Author (s) Details

 

André Ricard

LAPLACE, Université de Toulouse, CNRS, INPT, UPS, 118 route de Narbonne, 31062 Toulouse Cedex 9, France.

Please see the book here:- https://doi.org/10.9734/bpi/mono/978-93-49473-93-5/CH3