cover
Article Per Year (5 Year)
All
Home Page
OAI Link
Editorial Team
Contact
Reviewer
Google Scholar
Contact Name
Jaya Hardi
Contact Email
jr.hardi0803@gmail.com
Phone
+6281341314717
Journal Mail Official
kovalen.journal@gmail.com
Editorial Address
Program Studi Kimia Fakultas MIPA, Uniiversitas Tadulako Jl. Soekarno-Hatta Km. 9, Tondo Palu, 94117
Location
Kota palu,
Sulawesi tengah
INDONESIA
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
 12   13   14   15   16 
PEMANFAATAN LIMBAH KULIT BUAH PISANG KEPOK (Musa paradisiaca) SEBAGAI BIOSORBEN ZAT WARNA RHODAMIN B Musafira Musafira; Nurfitrah M Adam; Dwi Juli Puspitasari
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 3 (2019): Edisi Desember
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (573.476 KB) | DOI: 10.22487/kovalen.2019.v5.i3.14629

Abstract

The investigation about the utilization of Banana peel (Musa paradisiaca) as biosorbent Rhodamine B dye has been done The purpose of this study was to determine the maximum contact time and to determine the adsorption capacity of kepok banana peel. Completely randomized design (CRD) was used in this research with two variables (the contact time and Rhodamine B concentration. Both variables were done in five levels i.e 10, 30, 60, 90, and 120 min and 2, 4, 6, 8 and 10 ppm respectively. The result showed that the maximum concentration of banana peel in adsorbing Rhodamine B was 6 ppm with 120 of contact time, and Rhodamine B adsorption capacity was 4.55mg/g. Keywords: Banana peel, Rhodamine B, biosorbent
APLIKASI EKSTRAK LIKOPEN DARI BUAH TOMAT APEL (Lycopersicum pyriforme) TERSALUT MALTODEKSTRIN PADA PENGOLAHAN MIE INSTAN FUNGSIONAL Dini Noviyandari; Jaya Hardi; Mappiratu Mappiratu
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 3 (2019): Edisi Desember
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (690.005 KB) | DOI: 10.22487/kovalen.2019.v5.i3.14799

Abstract

A research about the application of lycopene extract of tomato fruit (Lycopersicum pyriforme) coated with maltodextrin in functional instant noodle processing has been done. The aim of the research was to determine the effect of lycopene coated with maltodextrin concentration on the shelf life of functional instant noodle. The goal was reached by using various of lycopene coated with maltodextrin concentration i.e. 500 ppm, 1000 ppm, 1500 ppm, 2000 ppm and 2500 ppm. The functional instant noodle was kept at room temperature for 49 days and it was measured every 7 days. The result showed that the shelf life of functional instant noodle increased with the increase of lycopene coated with maltodextrin concentration. The longest shelf life (354.79 days) was found in 2500 ppm of maltodextrin concentration. Keywords: tomato, lycopene, instant noodle, shelf life
UJI AKTIVITAS ANTIOKSIDAN EKSRTRAK LUMUT HATI (Marchantia polymorpha) Nurhaeni Nurhaeni; Gladys; Jaya Hardi
KOVALEN: Jurnal Riset Kimia Vol. 5 No. 3 (2019): Edisi Desember
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (351.066 KB) | DOI: 10.22487/kovalen.2019.v5.i3.14981

Abstract

The research is about antioxidant activity of the liverworts (Marchatia polymorpha) extract based on the level of a polar solvent. This research was done by maceration of liverworts by using n-hexane, ethyl acetate and ethanol solvent. The n-hexane, ethyl acetate, and ethanol fraction were tested the antioxidant activity by using DPPH method. The result was obtained for antioxidant activity (IC50) on n-hexane extract, ethyl acetate, ethanol, and vitamin C is 1065.33 ppm, 1326.52 ppm, 1876.11 ppm, and 13.45 ppm, respectively. The liverworts extract was identified contains secondary metabolites compounds of flavonoid, tannins, polyphenol, alkaloid, and steroid. Keywords: Liverwort extract, antioxidant, IC50
Efisiensi Mikroenkapsulasi Ekstrak Kulit Buah Naga Super Merah (Hylocereus costaricensis) Tersalut Maltodekstrin Berdasarkan Kecepatan Pengadukan: Microencapsulation Efficiency of Super Red Dragon Fruit (Hylocereus costaricensis) Peel Extract Coated with Maltodextrin Based on Stirring Speed Jaya Hardi; Dian Citra; Syamsuddin; Dwi Juli Pusptasari
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 1 (2020): 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.2020.v6.i1.12647

Abstract

Extract of super red dragon fruit peel has an antioxidant activity that can prevent free radicals from outside and its activity can be maintained by the coating of super red dragon fruit peel extract with maltodextrin The coating efficiency of super red dragon fruit peel extract with maltodextrin can be controlled with the speed of stirring during microencapsulation experiment. In order to obtain the highest microencapsulation efficiency and compare the antioxidant activity of super red dragon fruit peel extract before and after microencapsulation experiment. The study of coating efficiency has been done with microencapsulation that was carried out using the freeze-drying technique. During the microencapsulation of super red dragon fruit peel extract with freeze-drying technique, stirring speed in the microencapsulation process was 600 rpm, 800 rpm, 1000 rpm, 1200 rpm, and 1400 rpm respectively. From the microencapsulation process of super red dragon fruit peel extract coated with maltodextrin, it was obtained the highest microencapsulation efficiency at stirring speed of 800 rpm, which was 66.85% and had a particle size of 14.24 µm. It can be concluded that the antioxidant activity before and after encapsulation included a very weak category with IC50 values of 205.42 ppm for extracts and 246.32 ppm for microcapsules. Keywords: Super red dragon fruit peel, freeze-drying, microencapsulation, maltodextrin
Perbandingan Kadar Albumin Ikan Gabus (Channa striata) dari Proses Perebusan dan Pengukusan dengan Menggunakan Uji Biuret: Comparison of Cork Fish (Channa striata) Albumin Content from Boiling and Steaming Process by Using Biuret Test Sulfitri Suardi; Syaiful Bahri; Khairuddin; Ni Ketut Sumarni; Erwin Abdul Rahim
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 1 (2020): 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.2020.v6.i1.12699

Abstract

Cork Fish (Channa striata) is a freshwater fish that was spread throughout most of Indonesia and it contains albumin that was beneficial to the human body. Albumin was easily dissolved in water during the cooking process both boiled and steamed. This study aims to determine the influence of boiling and steaming times at 100oC against albumin content of cork fish that lost and left in fish meat. The times of boiling and steaming that was used to processing the fish were 10, 15, and 20 minutes. The albumin concentration that lost and left in for the boiling and the steaming process was determined by the biuret test that used a UV-Vis spectrophotometer at albumin maximum wavelength of 530 nm. The results showed that albumin content that lost for 10 minutes boiling process (62 mg/10g) was smaller than the other boiling times and albumin left in fish meat was 164 mg/10g. The same result was also obtained at 10 minutes steaming process which results left in albumin content of 167 mg/10g and lost albumin of 62 mg/10g. The albumin content that lost or dissolved in water for the steaming process was smaller than the boiling process, therefore the steaming process is more efficient than the boiling process at cork fish processing. Keywords: Cork fish, albumin, boiling, steaming.
Analisis Kadar Serat dan Protein Total Sereal Berbasis Tepung Ampas Kelapa dan Ikan Cakalang (Katsuwonus pelamis): Analysis of Fiber Content and Total Protein of Cereal Based on Coconut Pulp and Skipjack Tuna (Katsuwonus pelamis) Flour Nanda Novita; Nurhaeni; Prismawiryanti; Abd. Rahman Razak
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 1 (2020): 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.2020.v6.i1.12788

Abstract

Research on the analysis of fiber and protein on cereal based on coconut pulp and skipjack tuna (Katsuwonus pelamis) flour has been carried out. The purpose of this study was to determine the ratio of coconut pulp flour and skipjack tuna flour which produced the highest fiber content and protein content in cereal processed products and to know the preference level of panelists for cereal processed products. The ratio of coconut pulp and skipjack tuna flour used in this study, namely 25:75, 50:50, 75:25 (w/w), and without the addition of coconut pulp flour and skipjack tuna flour. The results showed that cereal with the highest fiber content was obtained at a ratio of 75:25 i.e. 10.52% and the lowest fiber content was obtained at the cereal without the addition of coconut pulp flour and skipjack tuna flour i.e. 1.19%, whereas the highest protein content of cereal was obtained at a ratio of 25:75 i.e. 26.02% and the lowest protein content was obtained at the cereal without the addition of coconut pulp flour and skipjack tuna flour i.e. 9.17%. The highest preference level (5.57) of the panelists for the cereal flour of coconut pulp and skipjack tuna flour is the 75:25 ratio. Keywords: Skipjack tuna flour, coconut pulp flour, cereal, fiber, protein
Aktivitas Antibakteri Ekstrak Metanol dari Kulit Batang Kelor (Moringa oleifera Lam.) Terhadap Bakteri Staphylococcus aureus dan Escherichia coli: Antibacterial Activity of Methanol Extracts from The Stem Bark of Moringa oleifera Lam. Against Staphylococcus aureus and Escherichia coli Nurul Cholifah; Ahmad Ridhay; Pasjan Satrimafitrah; Ruslan; Hardi Ys
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 1 (2020): 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.2020.v6.i1.12854

Abstract

Antibacterial activity of Moringa oleifera Lam. stem bark has been tested against Staphylococcus aureus and Escherichia coli. The extraction of Moringa oleifera Lam. stem bark was used maceration method with methanol solvent and has obtained extract yield of 6.1%. The antibacterial activity test of Moringa oleifera stem bark extracts used a well diffusion method. The concentration of Moringa oleifera stem bark extract was varied to four concentrations of 1% 2% 3% 4% (w/v). The inhibition zone of methanol extract of Moringa oleifera stem bark against Staphylococcus aureus at extract concentrations of 1%, 2%, 3%, and 4% was 10.08 mm, 11.8 mm, 15.00 mm, and 17.02 mm, respectively. The methanol extract of Moringa oleifera stem bark at concentrations of 1%, 2%, 3%, and 4% could also inhibition of Escherichia coli growth with inhibition zone of 14.01 mm, 16.50 mm, 17.09 mm, and 17.10 mm, respectively. Keywords: Moringa Oleifera Lam., Antibacterial, Staphylococcus aureus, Escherichia coli
Fermentasi Kelapa Parut Bebas Protein dengan Aspergillus niger untuk Menghasilkan Lipase: Fermentation of Protein-Free Grated Coconut with Aspergillus niger to Produce of Lipase Rifka Aulia; Syaiful Bahri; Meryany Ananda
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 1 (2020): 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.2020.v6.i1.13052

Abstract

The research about the fermentation of protein-free grated coconut with Aspergillus niger to produce of crude lipase enzyme has been carried out. This study aims to determine the effect of water content on fermentation medium and the incubation time which results lipase enzyme extract with the highest activity. This study used a Completely Randomized Design (CRD) consisting of 2 factors, i.e. variations of water content in medium of 40%, 50%, 60%, and 70% and incubation times of 48, 96, 144, and 192 hours. The parameters observed were lipase enzyme activity produced in each treatment. The results showed that the highest medium water content was 70% with the lipase enzyme activity 4.33 µmol/mL.minute and the best incubation time was 96 hours with the lipase enzyme activity of 0.83 µmol/mL.minute. Keywords: Lipase enzyme, protein-free grated coconut, Aspergillus niger
Pemisahan Logam Tanah Jarang dari Limbah (Tailing) Emas Poboya dengan Metode Pengendapan: Separation of Rare Earth Metals from Poboya Gold Waste (Tailings) by Deposition Method Arianto; Husain Sosidi; Prismawiryanti; Dwi Juli Pusptasari
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 1 (2020): 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.2020.v6.i1.13861

Abstract

Gold tailings are waste generated from gold mining activities and contain minerals and rare-earth metals (REM) that are much needed in current technological developments. This research was conducted to determine the REM content contained in Poboya gold tailings, through the destruction process using sulfuric acid and precipitation using ammonium hydroxide. The results were showed that the level of REM contained in Poboya gold tailings was 6-7%. REM oxide content analysis performed with Scanning Electron Microscopy - Energy Dispersive X-Ray Spectroscopy (SEM-EDS) obtained 6 types of REM with the main REM levels namely Terbium (Tb): 77-80% dan Lanthanum (La): 13%, as well as other rare-earth metals with smaller amounts of Europium (Eu): 4-5%, Cerium (Ce): 2%, Neodymium (Nd): 0.02% and Gadolinium (Gd): 0.02%. Poboya gold waste can be used by the community as a source of REM and used in various industries. Keywords: Gold tailings, rare earth metals (REM), destruction, precipitation
Retensi Antosianin dari Ekstrak Daun Bayam Merah (Alternanthera amoena Voss) pada Pengolahan Mie Basah: Retention of Anthocyanin from Red Spinach Leaves Extract (Alternanthera amoena Voss) in Processing Wet Noodles Betzy Eppang; Nurhaeni; Khairuddin; Ahmad Ridhay; Jusman
KOVALEN: Jurnal Riset Kimia Vol. 6 No. 1 (2020): 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.2020.v6.i1.14795

Abstract

Research about the retention of red spinach leaves extract (Alternanthera amoena Voss) as a natural coloring and preservative in wet noodles has been done. The study aim is to determine the anthocyanin retention of red spinach leaves extract in the processing of wet noodles and determine the organoleptic quality of wet noodles by adding pigment red spinach leaves extract. The extraction method used the maceration method by ethanol solvent. Anthocyanin levels on an extract that obtained by using a UV-Vis spectrophotometer were 33.34%. Anthocyanin retention of red spinach leaves extract on wet noodle processing at storage times of 0, 6, 12, 18, 24, 30, 36, 42, and 48 hours was 100%, 75.87%, 75.37%, 74.95%, 74.62%, 74.12%, 73.28%, 71.70%, and 70.61%. Organoleptic quality of wet noodles that was added with extract has “like” to “really like” grade with score detail of the best color of 4.37 at 18 hours storage, whereas the odor, texture, and taste for 0 hours storage have the highest score of 4.63, 4.63, and 4.57, respectively. The wet noodles with red spinach leaves extract more preferred than the noodles without extracts. Keywords: Retention, anthocyanin, Alternanthera amoena Voss., wet noodles

Page 14 of 33 | Total Record : 325

 12   13   14   15   16 

Filter by Year

2015 2025


Reset
Filter By Issues
All Issue Vol. 11 No. 2 (2025): December Edition Vol. 11 No. 1 (2025): August Edition Vol. 10 No. 3 (2024): December Edition Vol. 10 No. 2 (2024): August Edition Vol. 10 No. 1 (2024): April Edition Vol. 9 No. 3 (2023): December Edition Vol. 9 No. 2 (2023): August Edition Vol. 9 No. 1 (2023): April Edition Vol. 8 No. 3 (2022): December Edition Vol. 8 No. 2 (2022): August Edition Vol. 8 No. 1 (2022): April Edition Vol. 7 No. 3 (2021): Edisi Desember Vol. 7 No. 2 (2021): Edisi Agustus Vol. 7 No. 1 (2021): Edisi April Vol. 6 No. 3 (2020): Edisi Desember Vol. 6 No. 2 (2020): Edisi Agustus Vol. 6 No. 1 (2020): Edisi April Vol. 5 No. 3 (2019): Edisi Desember Vol. 5 No. 2 (2019): Edisi Agustus Vol. 5 No. 1 (2019): Edisi April Vol. 4 No. 3 (2018): Edisi Desember Vol. 4 No. 2 (2018): Edisi Agustus Vol. 4 No. 1 (2018): Edisi April Vol. 3 No. 3 (2017): Edisi Desember Vol. 3 No. 2 (2017): Edisi Agustus Vol. 3 No. 1 (2017): Edisi April Vol. 2 No. 3 (2016) Vol. 2 No. 2 (2016) Vol. 2 No. 1 (2016) Vol. 1 No. 1 (2015) More Issue