scholarly journals Polyphenols from Red Vine Leaves Using Alternative Processing Techniques

Processes ◽  
2018 ◽  
Vol 6 (12) ◽  
pp. 262 ◽  
Author(s):  
Simone Bachtler ◽  
Hans-Jörg Bart
Keyword(s):  
High Throughput Screening ◽  
Ph Value ◽  
Solvent Mixture ◽  
Total Phenol Content ◽  
Stirred Vessel ◽  
Alternative Processing ◽  
Assisted Extraction ◽  
Extraction Processes ◽  
Processing Techniques ◽  
Kinetics Of

The extraction kinetics of polyphenols, which are leached from red vine leaves, are studied and evaluated using a laboratory robot and nonconventional processing techniques such as ultrasonic (US)-, microwave (MW)-, and pulsed electric field (PEF)-assisted extraction processes. The robotic high-throughput screening reveals optimal extraction conditions at a pH value of 2.5, a temperature of 56 °C, and a solvent mixture of methanol:water:HCl of 50:49:1 v/v/v. Nonconventional processing techniques, such as MW- and US-assisted extraction, have the fastest kinetics and produce the highest polyphenol yield. The non-conventional techniques yield is 2.29 g/L (MW) resp. 2.47 g/L (US) for particles that range in size from 450 to 2000 µm and 2.20 g/L (MW) resp. 2.05 g/L (US) for particles that range from 2000 to 4000 µm. PEF has the lowest yield of polyphenols with 0.94 g/L (450–2000 µm), resp. 0.64 g/L (2000–4000 µm) in comparison to 1.82 g/L (2000 to 4000 µm) in a standard stirred vessel (50 °C). When undried red vine leaves (2000 to 4000 µm) are used the total phenol content is 1.44 g/L with PEF.

Low-temperature Mo-catalyzed growth of crystalline Si3N4 by CVD

1993 ◽  
Vol 51 ◽  
pp. 918-919
Author(s):  
K.L. More ◽  
R.A. Lowden ◽  
T.M. Besmann
Keyword(s):  
Vapor Deposition ◽  
Hot Isostatic Pressing ◽  
Chemical Vapor ◽  
Processing Method ◽  
Crystalline Material ◽  
Structural Ceramic ◽  
Alternative Processing ◽  
Strong Candidate ◽  
Hot Pressing Sintering ◽  
Processing Techniques

Silicon nitride possesses an attractive combination of thermo-mechanical properties which makes it a strong candidate material for many structural ceramic applications. Unfortunately, many of the conventional processing techniques used to produce Si3N4, such as hot-pressing, sintering, and hot-isostatic pressing, utilize significant amounts of densification aids (Y2O3, Al2O3, MgO, etc.) which ultimately lowers the utilization temperature to well below that of pure Si3N4 and also decreases the oxidation resistance. Chemical vapor deposition (CVD) is an alternative processing method for producing pure Si3N4. However, deposits made at temperatures less than ~1200°C are usually amorphous and at slightly higher temperatures, the deposition of crystalline material requires extremely low deposition rates (~5 μm/h). Niihara and Hirai deposited crystalline α-Si3N4 at 1400°C at a deposition rate of ~730 μm/h. Hirai and Hayashi successfully lowered the CVD temperature for the growth of crystalline Si3N4 by adding TiCl4 vapor to the SiCl4, NH3, and H2 reactants. This resulted in the growth of α-Si3N4 with small amounts of TiN at temperatures as low as 1250°C.

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

Robustness versus Performance Assessment for Different Gamma-TiAl Processing Routes

2011 ◽  
Vol 1295 ◽  
Author(s):  
Marc Thomas
Keyword(s):  
High Performance ◽  
Cost Effective ◽  
Processing Route ◽  
Transportation Industry ◽  
Tial Alloys ◽  
Alternative Processing ◽  
Aerospace Applications ◽  
Robust Processing ◽  
Processing Techniques ◽  
Robust Process

ABSTRACTOne of the main driving force for the development of advanced structural materials is weight saving especially in the transportation industry in order to reduce CO2 emission. The utilization of gamma aluminides, as good candidates for aerospace applications, is strongly related to the development of a cost-effective and robust processing route, as far as possible. It is well established that the processing route, i.e. cast, wrought or PM, has a dramatic effect on the microstructure and texture of gamma-TiAl alloys. Therefore, significant microstructural variations through post-heat treatments coupled with compositional modifications can only guarantee a proper balance of desired properties. However, a number of metallurgical factors during the processing steps can contribute to some scattering in properties. This review will highlight several critical process variables in terms of the resulting g-TiAl microstructures. Of primary importance is the as-cast texture which is difficult to control and may contribute to prefer some alternative processing routes to ensure a better repeatability in mechanical results. Some innovative processing techniques for controlling the structure will then be presented. The main point which will be discussed in this paper is whether an approach leading to a robust process would not be at the expense of the high performance of the structural material.

scholarly journals Optimization of Ultrasonic Cellulase-Assisted Extraction and Antioxidant Activity of Natural Polyphenols from Passion Fruit

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2494
Author(s):  
Wei Wang ◽  
Yu-Ting Gao ◽  
Ji-Wen Wei ◽  
Yin-Feng Chen ◽  
Qing-Lei Liu ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Extraction Method ◽  
Ph Value ◽  
Soxhlet Extraction ◽  
Passion Fruit ◽  
Total Phenol Content ◽  
Extraction Temperature ◽  
Scavenging Activity ◽  
Solid Ratio ◽  
Dpph Scavenging

In this paper, ultrasonic cellulase extraction (UCE) was applied to extract polyphenols from passion fruit. The extraction conditions for total phenol content (TPC) and antioxidant activity were optimized using response surface methodology (RSM) coupled with a Box-Behnken design (BBD). The results showed that the liquid-to-solid ratio (X2) was the most significant single factor and had a positive effect on all responses. The ANOVA analysis indicated quadratic models fitted well as TPC with R2 = 0.903, DPPH scavenging activity with R2 = 0.979, and ABTS scavenging activity with R2 = 0.981. The optimal extraction parameters of passion fruit were as follows: pH value of 5 at 30 °C for extraction temperature, 50:1 (w/v) liquid-to-solid ratio with extraction time for 47 min, the experimental values were found matched with those predicted. Infrared spectroscopy suggested that the extract contained the structure of polyphenols. Furthermore, three main polyphenols were identified and quantified by HPLC. The results showed the content of phenolic compounds and antioxidant activity of the optimized UCE were 1.5~2 times higher than that determined by the single extraction method and the Soxhlet extraction method, which indicates UCE is a competitive and effective extraction technique for natural passion fruit polyphenols.

Kinetics of Solvent Extraction Processes

1997 ◽  
Vol 17 (1-4) ◽  
pp. 205-226 ◽  
Author(s):  
GEOFFREY W. STEVENS ◽  
JILSKA M. PERERA
Keyword(s):  
Solvent Extraction ◽  
Extraction Processes ◽  
Kinetics Of

scholarly journals Pengaruh Waktu Steam Blanching dan Suhu Pengeringan terhadap Karakteristik Kimia serta Sensori Teh Daun Bambu Tabah (Gigantochloa nigrociliata BUSE-KURZ)

2019 ◽  
Vol 8 (2) ◽  
pp. 271
Author(s):  
I Nyoman Cahyadi Purnama ◽  
Pande Ketut Diah Kencana ◽  
I Made Supartha Utama
Keyword(s):  
Water Content ◽  
Ph Value ◽  
Raw Materials ◽  
Acid Value ◽  
Total Phenol ◽  
Total Phenol Content ◽  
Total Acid ◽  
Drying Temperature ◽  
Bamboo Leaves ◽  
Randomized Design

Bambu " tabah " adalah salah satu varietas bambu yang hanya ditemukan di pulau Bali . " Tabah " daun bambu memiliki potensi untuk dikembangkan sebagai bahan baku untuk membuat teh yang dapat menghasilkan minuman dengan berbagai manfaat. Jika dimanfaatkan secara optimal, daun bambu " tabah " dapat diolah sebagai produk yang akan memberikan keuntungan. Penelitian ini bertujuan untuk mengetahui pengaruh proses blanching dan pengeringan uap terhadap aktivitas kadar air, pH, asam total, fenol total, dan teh daun bambu " tabah " organoleptik . " Tabah "Daun bambu diperlakukan dengan waktu blanching uap dengan variasi waktu, yaitu selama 10 menit, 15 menit dan 20 menit. Setelah steam blanching, daun bambu" tabah "dikeringkan menggunakan oven dengan variasi suhu pengeringan 50 ° C, 60 ° C, dan 70 ° C. Metode penelitian yang digunakan adalah metode eksperimen dengan pola faktorial Rancangan Acak Lengkap (RAL) yang terdiri dari dua faktor dan diulang tiga kali. Faktor pertama adalah waktu blansing uap dan faktor kedua adalah suhu pengeringan.Hasil menunjukkan bahwa kombinasi terbaik dari perawatan berdasarkan penerimaan keseluruhan tes hedonis yang dihasilkan pada " tabah”Teh daun bambu adalah perlakuan waktu blansing uap 15 menit dengan suhu pengeringan 60 ° C (W2S2) yang menghasilkan 7,03% kadar air untuk kadar air SNI 8%, nilai pH 6,40, nilai asam total 0,94, total kadar fenol 54,95 , tes skor warna 4,47, tes skor aroma 4,87, tes skor rasa 4,60 dan tes keseluruhan penerimaan hedonis 4, 67.     Bamboo “tabah” is one of the bamboo variety of which finds only in Bali island. "Tabah" bamboo leaves have the potential to be developed as raw materials for making tea that can produce drinks with various benefits. If utilized optimally, "tabah" bamboo leaves can be processed as a product that will provide an advantage. This study aims to determine the effect of steam blanching and drying process on the activity of water content, pH, total acid, total phenol, and organoleptic " tabah" bamboo leaf tea. "Tabah" bamboo leaves are treated with steam blanching time with a variation of time, namely for 10 minutes, 15 minutes and 20 minutes. After steam blanching, the "tabah" bamboo leaves are dried using an oven with variations in the drying temperature of 50 ° C, 60 ° C and 70 ° C. The research method used was an experimental method with a completely randomized design (CRD) factorial pattern consisting of two factors and repeated three times. The first factor is the steam blanching time and the second factor is the drying temperature. The results showed that the best combination of treatments based on the overall acceptance of hedonic tests produced on “tabah” bamboo leaf tea is the treatment of 15 minutes steam blanching time with a drying temperature of 60 ° C (W2S2) which produces 7.03% water content for SNI water content 8%, pH value 6.40, total acid value 0.94, total phenol content 54.95, color scoring test 4.47, aroma scoring test 4.87, taste scoring test 4.60 and overall acceptance hedonic test 4, 67.

scholarly journals Сitric acid influence on electroreduction processes in low concentrated Cu(NO3)2 solutions

2017 ◽  
Vol 5 (2) ◽  
pp. 136-143
Author(s):  
Alla Pravda ◽  
Vasil Larin
Keyword(s):  
Citric Acid ◽  
Ph Value ◽  
Reduction Reaction ◽  
Copper Electrodeposition ◽  
Nitrate Ions ◽  
Low Concentrations ◽  
Physico Chemical ◽  
Influence Of Ph ◽  
Kinetics Of ◽  
Cathode Reduction

Physico-chemical regularities citric acid influence on processes of copper and nitrate-ions reduction in low concentrated nitrate solutions were established. An influence of pH value on inhibitor action of low concentrations of the additive according to cathode reduction reaction of nitrate-ions, on kinetics of copper electrodeposition, on structure of the precipitates obtained was shown. Polarization measurements show us changes of copper electrodeposition at introduction of citric acid in Cu(NO3)2 solution. By the methods of traced elements and extraction into aqueous phase the reversible inclusion complexes into electrolytic copper, was established that proves participation of complexes in cathode process.

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