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Jaya Hardi
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KOVALEN: Jurnal Riset Kimia
Published by Universitas Tadulako
ISSN : -     EISSN : 24775398     DOI : https://doi.org/10.22487/kovalen
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Chemistry
KOVALEN: Jurnal Riset Kimia is a peer-reviewed journal of chemistry published by the Tadulako University, Indonesia. This journal concern with publishing the original research articles, review articles, and the current issues related to chemistry. Publishing frequency 3 issues per year, in April, August, and December.
Arjuna Subject : Kimia(semua kategori) - Kimia (Lain-Lain)
Articles 325 Documents
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Sintesis Metil Ester Asam Lemak dari Biji Alpukat (Parsea americana Mill) Menggunakan Polimer Penyangga Katalis Berbahan Dasar Eugenol: Synthesis of Fatty Acid Methyl Ester from Avocado Seeds (Parsea americana Mill) using Polymer Support Catalyst Based on Eugenol Sumarni; Erwin Abdul Rahim; Ni Ketut Sumarni; Ruslan; Hardi Ys.; Moh. Mirzan
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 3 (2020): Edisi Desember
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2020.v6.i3.13053

Abstract

Research on the manufacture of methyl esters from avocado seeds (Parsea americana Mill) with eugenol-based catalysts has been conducted. The aim is to determine the catalyst concentration used to produce methyl esters with the highest rendement and determine the composition of fatty acid methyl ester in avocado seeds. This study was used variations in concentrations of 0.25%, 1%, 1.75%, 2.25%, and 3%. The results of this study showed that the best concentration is 2.25% with the calculation of the results of 24.8% methyl esters in avocado seeds, namely lignoceric and octadecenoic acid methyl ester. Keywords: Avocado seeds, fatty acid methyl esters
Perubahan Bilangan Peroksida pada Blending VCO-Ekstrak Likopen Buah Tomat Berdasarkan Perbandingan Rasio dan Lama Penyimpanan: Peroxide Value Changes on Blending of VCO and Extract of Tomato Lycopene Based on Ratio Comparison and Storage Time Muqasyifah; Nurhaeni; Syamsuddin; Khairuddin
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 2 (2020): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2020.v6.i2.13132

Abstract

Utilizing of lycopene extract in VCO has serve as antioxidant agent that protected VCO from oxidation process during storage. Belnding of VCO and tomato lycopene extract has been done that purpose to determine changes in peroxide number in the mixture of VCO-lycopene extract tomatoes based on comparison of ratios and length of storage. Peroxide contents from the mixture of tomato extract with VCO were determined using a spectrophotometric method at a wavelength of 500 nm. The results showed that the best results were obtained at a ratio of 40: 3 (v/w) with peroxide numbers 0.08 meq O2/ kg, 1.38 meq O2/ kg, 1.84 meq O2/ kg, 3.21 meq O2/ kg, 3.46 meq O2/ kg and 3.83 meq O2/ kg respectively. Peroxide numbers increased with increasing storage time, the highest increase occurred at week 3 at a ratio of 40: 1 (v/w) which was equal to 9.62 meq O2/ kg. The addition of lycopene was better at reducing the VCO oxidation process than without the addition of lycopene. Keywords: peroxide value, VCO, lycopene, duration of storage, ratio comparison
Aktivitas Antioksidan Likopen Buah Tomat (Solanum lycopersicum L.) Terblending dalam Minyak Padat Ikan Lele (Clarias sp): Antioxidant Activity of Lycopene from Tomato (Solanum lycopersicum L.) Blended Into Frying Fat from Catfish Oil (Clarias sp) Eka Surya Wahyuningsih; Syamsuddin; Prismawiryanti; Dwi Juli Pusptasari
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 2 (2020): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2020.v6.i2.13651

Abstract

Research on the antioxidant lycopene of tomato fruit (Solanum lycopersicum L.) blended in frying fat from catfish (Clarias sp) oil has been done. The purpose of this research is to determine the antioxidant activity of tomato lycopene before and after being grounded into frying fat and determine the quality of frying fat after being grounded with tomato lycopene. The antioxidant activity of tomato lycopene is determined by the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. Analysis of frying fat quality includes determination of pH, determination of FFA (free fatty acid) levels, determination of total fat content, measurement of water content, peroxide number and organoleptic observation. Antioxidant activity of tomato lycopen was very high, namely with inhibition value of 89.79%; 90.34%; 91.49% and 92.10%. Frying fat analysis showed high antioxidant activity of lycopene tomatoes with 50.67% inhibition; 51.63%; 51.39% and 51.23%. The results of the analysis of the quality of frying fat are nearly same with SNI quality standards, except for peroxide numbers. Keywords: tomato, lycopene, antioxidants, frying fat, catfish, DPPH
Siklisasi Sitronelal Menggunakan Polimer Penyangga Katalis H2SO4 Berbahan Dasar Eugenol: Citronellal Cyclization Using Polymer Based-Eugenol Supported H2SO4 Catalyst Moh. Rifki Saputra; Erwin Abdul Rahim; Husain Sosidi; Ni Ketut Sumarni
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 1 (2021): Edisi April
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i1.13660

Abstract

Research on citronellal cyclization using a polymer based on eugenol supported H2SO4 catalyst has been carried out. The study aim was to determine the ratio of the addition of polymer based-eugenol supported H2SO4 catalyst used to produce the highest isopulegol. Citronellal cyclization was carried out using variations of catalyst concentration (1, 2, 3, 4, and 5%) and reaction time (30, 60, and 90 minutes). The results have obtained a yield of 50.67% found in the catalyst concentration of 1% and 90 minutes reflux time. From the results of GC-MS analysis, 29 compounds were read and among them isopulegol which was read at retention time 19.703 at peak 9 and peak area 4.76%. And the isopulegol results obtained are 11.34%.
Aktivitas Antioksidan Akar Bawang Merah Lokal Palu (Allium cepa Var Aggergatum L.) dengan Berbagai Kepolaran Pelarut: Antioxidant Activity of Local Shallot Roots (Allium cepa Var Aggregatum L.) in Palu City with Various Solvent Nur Faidah; Nurhaeni; Ahmad Ridhay; Jusman; Abd. Rahman Razak; Syaiful Bahri
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 3 (2020): Edisi Desember
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2020.v6.i3.13662

Abstract

Research on the antioxidant activity of the local onion roots of Palu (Allium cepa Var Aggregatum L.) with various polarity solvents has been carried out. This study aims to determine the potential of Palu local shallot root extract as an antioxidant and determine the IC50 value of the Palu local shallot root antioxidant activity. The method applied in this research is maceration using n-hexane, ethyl acetate, and ethanol. The extracts from each solvent were tested for their antioxidant activity by the DPPH method. The results of the study showed that the IC50 value in n-hexane extract, ethyl acetate extract, and ethanol extract were 579.98 ppm, 518.28 ppm 315.83 ppm and as a comparison used ascorbic acid obtained IC50 of 53.69 ppm. Based on the results obtained, the best antioxidant activity is in polar solvents (ethanol extract) compared to other solvents. Keywords: Antioxidants, roots, Palu local shallots, Allium cepa Var Aggregatum L.
Adsorpsi Logam Merkuri (Hg) dari Limbah Tanah Tercemar Menggunakan Tanaman Sawi (Brassica juncea L) pada Berbagai Waktu Tanam: Adsorption of Mercury (Hg) from Contaminated Soil Waste Using Sawi Plants (Brassica juncea L) in Various Planting Times Khairuddin; Wiranto Wengkau; Dwi Juli Puspitasari; Husain Sosidi; Nov Irmawati Inda
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 1 (2021): Edisi April
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i1.13666

Abstract

Mercury (Hg) as a gold extractor can cause environmental pollution, therefore, hyperaccumulator plants are needed, such as mustard greens (Brassica juncea L). Research on the effect of planting time of mustard greens on the adsorption of mercury (Hg) metal ion on contaminated soil waste has been carried out. The purpose of this research was to determine the concentration and adsorption mechanism of Hg metal ion from contaminated soil at roots and canopy of mustard plants at various planting times. Amount of Hg metal ion adsorbed on the roots and canopy of mustard greens at 2, 4, and 6 weeks of planting times were analyzed using Atomic Absorption Spectrophotometry (AAS). The results showed that the average levels of Hg metal ion adsorption at various planting time of 2, 4, and 6 weeks at roots were 156.611 μg/g, 810.256 μg/g, and 888.711 μg/g, respectively, and at the canopy were 69.486 μg/g, 134.580 μg/g, and 60.416 μg/g, respectively. The planting time of 6 weeks resulted in the highest adsorption ability of Hg at the roots. The results of the bioconcentration factor (BCF) test showed that the adsorption of Hg in the roots and canopy of the mustard plant took place using a phytoextraction mechanism (BCF < 1).
Ekstraksi dan Uji Stabilitas Zat Warna Alami dari Bayam Merah (Alternanthera amoena Voss): Extraction and Stabilization of Natural Dyes from Red Spinach (Alternanthera amoena Voss) Khairuddin; Joy Noldy Baciang; Indriani; Nov Irmawati Inda
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 3 (2020): Edisi Desember
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2020.v6.i3.13670

Abstract

Research on the extraction and stability test of natural dye from red spinach (Alternanthera amoena Voss) has been carried out. This study aims to determine the effect of pH and length of sun exposure on the stability of the dye from red spinach. Extraction using the maceration method with ethanol solvent and measurement using a UV-Vis spectrophotometer. Stability testing is carried out at pH 2-5 and sun exposure for 1-4 hours using a dark and light container. The results obtained, at pH 2 and pH 3, anthocyanins were more stable, compared to pH 4 and 5 which had greater color degradation. In exposure to sunlight, dark containers with a degradation percentage of 31.70% were better than clear containers with a percentage of 48.78%. Keywords: Anthocyanin, red spinach, natural dyes stability.
Pengaruh Konsentrasi Asap Cair Terhadap Mutu, Total Bakteri, dan Waktu Simpan Ikan Cakalang (Katsuwonus pelamis) Asap: Effect of Liquid Smoke Concentration on Quality, Total Bacteria, and Shelf Life of Smoked Skipjack Fish (Katsuwonus pelamis) Angria Deswika Malambu; Syaiful Bahri; Hardi Ys.; Prismawiryanti; Abd. Rahman Razak
KOVALEN: Jurnal Riset Kimia Vol. 7 No. 1 (2021): Edisi April
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2021.v7.i1.14238

Abstract

Liquid smoke contains acid, carbonyl, and phenolic compounds, so it is very appropriate to be used as a preservative. Traditional smoking can be replaced with liquid smoke because it is safer and more practical. The study of the use of coconut shell liquid smoke has been used in skipjack fish to determine the effect of liquid smoke concentration and storage time on dissolved protein content and total bacteria in smoked fish. The quality of smoked fish was determined by two treatments, namely the variation in the concentration of liquid smoke (2, 3, 4, and 5%) and storage time (2, 4, 6, 8, and 10 days). The results showed that the best concentration of liquid smoke to produce smoked skipjack fish is 3% with a water content of 62.41% and dissolved protein content of 17.58%. The maximum storage time of smoked skipjack tuna is 6 days with a total plate count (TPC) value or total bacteria 1.8 x 105.
Penurunan Kadar Asam dalam Kopi Robusta (Coffea canephora) dari Desa Rantebua Kabupaten Toraja Utara dengan Teknik Pemanasan: Reduce Acid Levels in Robusta Coffee (Coffea canephora) from Rantebua Village, North Toraja District by Heating Techniques Syahruddin Kasim; Syarifuddin Liong; Ruslan; Alprianto Lullung
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 2 (2020): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2020.v6.i2.15133

Abstract

Robusta coffee (Coffea canephora) is the most widely produced coffee in Indonesia. The relatively high acid content causes robusta coffee to be less attractive to both local and international consumers. Acid levels in coffee can be reduced by heating techniques using water as a solvent because it is cheap and easy to obtain and water is also a safe solvent and has no side effects for health. Coffee bean water content was analyzed by heating to constant weight by the oven method, acid content by titration technique, and followed by organoleptic testing. The results of the analysis of water content for dry treatment of 10.02%, wet treatment of 10.35% and on heating for 15, 30, 45, 60, 75, and 90 minutes respectively at 9.99%; 10.34%; 9.70%; 10.40%; 11.65% and 11.36%. The results of the analysis of acid levels for the treatment of dry processing amounted to 3.65%, wet processing amounted to 3.42%, and for heating for 15, 30, 45, 60, 75, and 90 minutes respectively 3.03%; 2.76%; 2.51%; 2.39%; 2,32% and 2,28%. Organoleptic test results showed that the decline in the quality of coffee occurs when heating above 45 minutes. Based on research data it was concluded that the heating method can reduce acid levels in coffee beans with a maximum heating time of 45 minutes to maintain the quality of taste in coffee. Keywords: Coffea canephora, organoleptic, warming up, titration.
Sintesis Nanopartikel Perak Menggunakan Ekstrak Daun Eceng Gondok (Eichornia crassipes) Sebagai Bioreduktor: Synthesis of Silver Nanoparticles Using Leaves Extract of Water Hyacinth (Eichornia crassipes) As a Bioreductor Syahruddin Kasim; Paulina Taba; Ruslan; Romi Anto
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 2 (2020): Edisi Agustus
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2020.v6.i2.15137

Abstract

Nanoparticles was done by adding water hyacinth leave extract to AgNO3 2mM solution with a ratio of 1:40. Formed silver nanoparticles were analyzed using UV-Vis spectrophotometer, SEM, XRD, PSA, and FTIR to determine its characteristics. Results showed that absorbance value increased if reaction time is increased. Maximum absorption was obtained at wavelength 432-446 nm by using UV-Vis spectrophotometer. Result of PSA analysis shows that the average size of silver nanoparticles formed is 93.2 nm while XRD analysis shows that the average crystal size of silver nanoparticles is 50.11 nm, with round shape and amorphous. Result of FTIR analysis to determine functional group that contributes to nanoparticle synthesis shows the contribution of OH group. Keywords: reduction method, silver nanoparticles, Eichornia crassipes, bioreductor

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