scholarly journals Kinetika Reaksi Penurunan Kafein dan Asam Klorogenat Biji Kopi Robusta melalui Pengukusan Sistem Tertutup

2018 ◽  
Vol 38 (1) ◽  
pp. 105
Author(s):  
Sapto Kuncoro ◽  
Lilik Sutiarso ◽  
Joko Nugroho Wahyu Karyadi ◽  
Rudiati Evi Masithoh
Keyword(s):  
Chlorogenic Acid ◽  
Arrhenius Equation ◽  
Order Reaction ◽  
First Order Reaction ◽  
Chlorogenic Acids ◽  
First Order ◽  
Robusta Coffee ◽  
Coffee Beans ◽  
Energy Activation ◽  
Acid Reduction

This study was aimed to examine the correlation between temperature and duration of steaming on caffeine and chlorogenic acid reduction as well as to determine energy activation (Ea) according to Arrhenius equation. About 750 g of Robusta coffee was steamed by autoclaving at 100, 110, 120 °C for 1, 2, 3, 4, 5, 6 and 7 hours. The study was conducted in 3 replications. Analyses of caffeine and chlorogenic acid were performed using HPLC.  Steaming coffee beans at 100, 110 and 120 °C resulted in the highest decrease of caffeine and chlorogenic acids content for 7 hours by 13%, 18% and 25% for caffeine; and by 37%, 50% and 59% for chlorogenic acids. At all temperatures investigated, decaffeination and chlorogenic acid reduction followed first order reaction. The decaffeination equation at 100 °C, 110 °C and  120 °C followed equation of  y = -0.019x + 0.862, y = -0.023x + 0.820, and y = -0.033x + 0.759, respectively. Meanwhile, the chlorogenic acid reduction at 100 °C, 110 °C,  and 120 °C followed equation of y = -0.071x + 1.421, y = -0.089x + 1.271, and y = -0.120x + 1.201. Activation energies of decaffeination and chlorogenic acid reduction were 33,543.66 kJ/mol K and 31,934.91 kJ/mol K, respectively. ABSTRAKPenelitian ini bertujuan untuk mengkaji hubungan antara suhu dan lama pengukusan terhadap penurunan kandungan kafein dan asam klorogenat serta menentukan energi aktivasi (Ea) dengan pendekatan persamaan Arrhenius. Biji kopi Robusta masing-masing seberat 750 g dikukus dalam autoklaf (sistem tertutup) pada suhu 100, 110, dan 120 °C masing-masing selama 1, 2, 3, 4, 5, 6, dan 7 jam. Penelitian dilakukan dengan 3 kali ulangan. Analisis kafein dan asam klorogenat dilakukan menggunakan HPLC. Pengukusan biji kopi pada suhu 100, 110, dan 120 °C, menghasilkan penurunan kandungan kafein dan asam klorogenat tertinggi pada pengukusan selama 7 jam. Penurunan kandungan kafein selama 7 jam pada suhu pengukusan 100, 110, dan 120 °C berturut-turut 13%, 18%, dan 25%. Kandungan asam klorogenat mengalami penurunan 37%, 50%, dan 59% berturut-turut pada suhu 100, 110, dan 120 °C.  Pada semua suhu yang diuji, penurunan kafein dan asam klorogenat mengikuti reaksi orde satu. Penurunan kafein mengikuti persamaan y = -0,019x + 0,862,  y = -0,023x + 0,820, dan y = -0,033x + 0,759, sedangkan untuk asam klorogenat mengikuti persamaan y = -0,071x + 1,421,  y = -0,089x + 1,271, dan y = -0,120x + 1,201. Besarnya energi aktivasi penurunan kafein dan asam klorogenat berturut turut adalah 33.543,66 kJ/molK dan 31.934,91 kJ/Mok.

Leaching Kinetics of Atrazine and Inorganic Chemicals in Tilled and Orchard Soils

2014 ◽  
Vol 28 (2) ◽  
pp. 231-237 ◽  
Author(s):  
Lech W. Szajdak ◽  
Jerzy Lipiec ◽  
Anna Siczek ◽  
Artur Nosalewicz ◽  
Urszula Majewska
Keyword(s):  
Reaction Rate ◽  
Inorganic Compounds ◽  
Model Performance ◽  
Order Reaction ◽  
First Order Reaction ◽  
Order Kinetic ◽  
Time Data ◽  
First Order ◽  
Concentration Changes ◽  
Reaction Constants

Abstract The aim of this study was to verify first-order kinetic reaction rate model performance in predicting of leaching of atrazine and inorganic compounds (K+1, Fe+3, Mg+2, Mn+2, NH4 +, NO3 - and PO4 -3) from tilled and orchard silty loam soils. This model provided an excellent fit to the experimental concentration changes of the compounds vs. time data during leaching. Calculated values of the first-order reaction rate constants for the changes of all chemicals were from 3.8 to 19.0 times higher in orchard than in tilled soil. Higher first-order reaction constants for orchard than tilled soil correspond with both higher total porosity and contribution of biological pores in the former. The first order reaction constants for the leaching of chemical compounds enables prediction of the actual compound concentration and the interactions between compound and soil as affected by management system. The study demonstrates the effectiveness of simultaneous chemical and physical analyses as a tool for the understanding of leaching in variously managed soils.

The Kinetics of Glucose Decomposition with Sulfate Reduction in the Anaerobic Fluidized Bed Reactor

1993 ◽  
Vol 28 (2) ◽  
pp. 135-144 ◽  
Author(s):  
S. Matsui ◽  
R. Ikemoto Yamamoto ◽  
Y. Tsuchiya ◽  
B. Inanc
Keyword(s):  
Sulfate Reduction ◽  
Fluidized Bed ◽  
Kinetic Equations ◽  
Fluidized Bed Reactor ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Glucose Decomposition ◽  
Reaction Equations ◽  
Kinetics Of

Using a fluidized bed reactor, experiments on glucose decomposition with and without sulfate reduction were conducted. Glucose in the reactor was mainly decomposed into lactate and ethanol. Lactate was mainly decomposed into propionate and acetate, while ethanol was decomposed into propionate, acetate, and hydrogen. Sulfate reduction was not involved in the decomposition of glucose, lactate, and ethanol, but was related to propionate and acetate decomposition. The stepwise reactions were modeled using either a Monod expression or first order reaction kinetics in respect to the reactions. The coefficients of the kinetic equations were determined experimentally. The modified Monod and first order reaction equations were effective at predicting concentrations of glucose, lactate, ethanol, propionate, acetate, and sulfate along the beight of the reactor. With sulfate reduction, propionate was decomposed into acetate, while without sulfate reduction, accumulation of propionate was observed in the reactor. Sulfate reduction accelerated propionate conversion into acetate by decreasing the hydrogen concentration.

Complete monotonicity of entropy production in chemical reaction

1981 ◽  
Vol 46 (2) ◽  
pp. 452-456
Author(s):  
Milan Šolc
Keyword(s):  
Entropy Production ◽  
Equilibrium Constant ◽  
Chemical Reaction ◽  
Relative Entropy ◽  
Order Reaction ◽  
Complete Monotonicity ◽  
First Order Reaction ◽  
First Order ◽  
Completely Monotonic ◽  
Derivatives Of

The successive time derivatives of relative entropy and entropy production for a system with a reversible first-order reaction alternate in sign. It is proved that the relative entropy for reactions with an equilibrium constant smaller than or equal to one is completely monotonic in the whole definition interval, and for reactions with an equilibrium constant larger than one this function is completely monotonic at the beginning of the reaction and near to equilibrium.

Kinetics and Mechanism of Hexachloroiridate(IV) Oxidation of Arsenic(III) in Acidic Perchlorate Solutions

1992 ◽  
Vol 57 (7) ◽  
pp. 1451-1458 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Ionic Strength ◽  
Fractional Order ◽  
Activation Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
Intermediate Complex ◽  
Constant Ionic Strength ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of arsenic(III) by hexachloroiridate(IV) at lower acid concentrations and at constant ionic strength of 1.0 mol dm-3 have been investigated spectrophotometrically. A first-order reaction in [IrCl62-] and fractional order with respect to arsenic(III) have been observed. A kinetic evidence for the formation of an intermediate complex between the hydrolyzed arsenic(III) species and the oxidant was presented. The results showed that decreasing the [H+] is accompanied by an appreciable acceleration of the rate of oxidation. The activation parameters have been evaluated and a mechanism consistent with the kinetic results was suggested.

scholarly journals Determination of exothermic batch reactor specific model parameters

2019 ◽  
Vol 292 ◽  
pp. 01063
Author(s):  
Lubomír Macků
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Batch Reactor ◽  
Specific Model ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
First Order Reaction ◽  
Model Parameters ◽  
Reactor Model ◽  
First Order

An alternative method of determining exothermic reactor model parameters which include first order reaction rate constant is described in this paper. The method is based on known in reactor temperature development and is suitable for processes with changing quality of input substances. This method allows us to evaluate the reaction substances composition change and is also capable of the reaction rate constant (parameters of the Arrhenius equation) determination. Method can be used in exothermic batch or semi- batch reactors running processes based on the first order reaction. An example of such process is given here and the problem is shown on its mathematical model with the help of simulations.

scholarly journals N.M.R. studies of ligand exchange on acetylacetonatotrimethylplatinum(IV)

1975 ◽  
Vol 28 (4) ◽  
pp. 759 ◽  
Author(s):  
NS Ham ◽  
JR Hall ◽  
GA Swile
Keyword(s):  
Activation Energy ◽  
Quantitative Analysis ◽  
Ligand Exchange ◽  
Variable Temperature ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Cdcl3 Solution ◽  
Made In

A quantitative analysis of the variable-temperature 1H N.M.R. spectra of acetylacetonatotrimethyl-platinum(IV) has been made. In CDCl3 solution the exchange of acetylacetonate ligands is a first-order reaction and proceeds predominantly by dissociation of the dimer into two separated five-coordinate activated complexes. The activation energy is 61.5 � 0.8 kJ mol-1.

scholarly journals Daya Hambat Ekstrak Biji Kopi Robusta (Coffea Canephora) terhadap Bakteri Porphyromonas gingivalis (in vitro)

2021 ◽  
Vol 18 (2) ◽  
pp. 69
Author(s):  
Rr. Nektara Titan Dianastri ◽  
Pudji Astuti ◽  
Rendra Chriestedy Prasetya
Keyword(s):  
Porphyromonas Gingivalis ◽  
Inhibition Zone ◽  
Coffea Canephora ◽  
Negative Control ◽  
Growth Media ◽  
Coffee Bean ◽  
Chlorogenic Acids ◽  
Robusta Coffee ◽  
Coffee Beans

Periodontitis is mostly caused by plaque and Pophyromonas gingivalis bacteria as the main cause. The outer membrane layer of the Porphyromonas gingivalis wall produces pathogenic virulence factors, such as lipopolysaccharides which will activate inflammatory cells and cause phagocytosis of antigens thereby triggering free radicals. Robusta coffee beans naturally contain caffeine, phenolic compounds, trigonellin, and chlorogenic acids as antibacterial and anti-inflammatory. The purpose of this study was to determine the inhibition of Robusta (Coffea canephora) coffee bean extract 0.5%; 0.75%; 1%; 1.25%; 1.5% and 3% on the growth of Porphyromonas gingivalis in vitro and to find out the lowest concentration of Robusta (Coffea canephora) coffee bean extract which has inhibitory effect on the growth of Porphyromonas gingivalis. In this study were divided into 8 treatment groups namely positive control, negative control, 0.5% robusta coffee bean extract, 0.75%, 1%, 1.25%, 1.5% and 3%. Petridish dishes containing TSA media that have been sterilized, added P. gingivalis suspension with density according to Mc standard. Farland Then a sterile white test blank with a diameter of 6 mm that is still sterile is placed on top of the bacterial growth media in accordance with the placement of the treatment group and dropped with all 8 treatment materials. After 24 hours incubated in a desiccator, the inhibition of robusta coffee bean extracts against the growth of Porphyromonas gingivalis bacteria was observed and data collection was done by measuring the inhibition zone using calipers. The results obtained robusta coffee bean extract at concentrations of 3%, 1.5%, 1.25% and 1%, have an antibacterial power which is suspected because Robusta coffee beans naturally contain ingredients such as caffeine, polyphenols and chlorogenic acids which have antibacterial activity while the robusta coffee bean extract with a concentration of 0.5% and 0.75% does not have antibacterial power against Pophyromonas gingivalis. Robusta coffee bean extract with a concentration of 1% is the smallest concentration of Robusta (Coffea canephora) coffee bean extract which can inhibit the growth of Porphyromonas gingivalis.

scholarly journals OPTIMASI FOTODEGRADASI METIL ORANYE MENGGUNAKAN FOTOKATALIS TiO2/Al2O3 MONTMORILONIT

2015 ◽  
Vol 10 (2) ◽  
Author(s):  
Iwan Sumarlan
Keyword(s):  
Methyl Orange ◽  
Order Reaction ◽  
First Order Reaction ◽  
Impregnation Method ◽  
First Order ◽  
Pillared Montmorillonite ◽  
Methyl Orange Concentration

Abstrak: Dispersi TiO2 ke dalam montmorilonit terpilar aluminium (PILM) telah sukses dilakukan. Fotokatalis dibuat dengan menginterkalasikan Al13 ke dalam montmorilonit alam kemudian dikalsinasi pada temperatur 500oC. Dispersi TiO2 ke dalam montmorilonit terpilar aluminium (PILM) dilakukan dengan menggunakan metode impregnasi dengan konsentrasi teoritis 0,4%, 0,8% 1% dan 3%. Fotodegradasi metil oranye optimum diperoleh pada Ti/PILM 1%, pH 10, konsentrasi metil oranye 1,5 M dan konsentrasi katalis 1 gram/liter dengan laju konstanta orde satu sebesar 21,77x10-3 per menit.Kata kunci : Metil Oranye, Montmorilonit,Optimasi, Fotokatalis, TiO2Abstract: Dispersion of TiO2 on montmorillonite pillared aluminium has been done successfully. The photocatalyst were prepared by intercalation of Al13 onto natural montmorillonite and then calcined at 500oC. Titania dispersion onto aluminium pillared montmorillonite was carried out by impregnation method at the theoritic concentration of 0.4%, 0.8%, 1% and 3% titania. Photodegradation optimum of methyl orange was found to be at Ti/PILM 1%, pH 10, methyl orange concentration 1.5 M and concentration of photocatalyst 1 gram/litre. The photodegradation follows first order reaction with constan rate of 21.77x10-3 per minutes.Key Word: Methyl Orange, Montmorillonite, Optimation, Photocatalyst, TiO2

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