KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen <p><strong>KOVALEN: Jurnal Riset Kimia</strong> is a peer-reviewed journal of chemistry that published by the Chemistry Department, 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. KOVALEN has been established since 2015 with volume 1 no 1 (December 2015).</p> <p><strong>ISSN:&nbsp;<strong><strong>2477-5398 (electronic)</strong></strong></strong></p> <p>The Scope of this journal including:<br>1. Theoretical and environmental chemistry study<br>2. Material and biomaterial synthesis, including their application&nbsp;<br>3. Isolation, purification, and modification of the natural product<br>4. Development and validation of analytical methods<br>5. Isolation and application of enzyme</p> en-US jr.hardi0803@gmail.com (Jaya Hardi) pasjan82@gmail.com (Pasjan Satrimafitrah) Sat, 18 Apr 2020 12:02:09 +0000 OJS 3.1.2.4 http://blogs.law.harvard.edu/tech/rss 60 Efisiensi Mikroenkapsulasi Ekstrak Kulit Buah Naga Super Merah (Hylocereus costaricensis) Tersalut Maltodekstrin Berdasarkan Kecepatan Pengadukan https://bestjournal.untad.ac.id/index.php/kovalen/article/view/12647 <p>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 IC<sub>50</sub> values of 205.42 ppm for extracts and 246.32 ppm for microcapsules.</p> <p><strong>Keywords: </strong><em>Super red dragon fruit peel, freeze-drying, microencapsulation, maltodextrin</em></p> Jaya Hardi, Dian Citra, Syamsuddin, Dwi Juli Pusptasari Copyright (c) 2020 KOVALEN https://bestjournal.untad.ac.id/index.php/kovalen/article/view/12647 Sat, 18 Apr 2020 00:00:00 +0000 Pemisahan Logam Tanah Jarang dari Limbah (Tailing) Emas Poboya dengan Metode Pengendapan https://bestjournal.untad.ac.id/index.php/kovalen/article/view/13861 <p>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&nbsp; and used in various industries.</p> <p><strong>Keywords</strong>: <em>Gold tailings, rare earth metals (REM), destruction, precipitation</em></p> Arianto, Husain Sosidi, Prismawiryanti, Dwi Juli Pusptasari Copyright (c) 2020 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/13861 Sat, 18 Apr 2020 00:00:00 +0000 Isolasi dan Identifikasi Steroid dari Ekstrak N-Heksana Daun Afrika (Vernonia amygdalina Del.) https://bestjournal.untad.ac.id/index.php/kovalen/article/view/15032 <p>Isolation and identification of steroids from the n-hexane fraction of <em>Vernonia amygdalina </em>Del. was carried out. Separation and purification were performed using flash chromatographic and gravity chromatography. Based on the results of phytochemical tests supported by UV and FT-IR data analysis, the isolate obtained was a steroid (sterol type). Toxicity test results using the Brine Shrimp Lethality Test (BSLT) were known that the steroid has moderate toxicity with an LC<sub>50</sub> value of 48.39 ppm.</p> <p><strong>Keywords:</strong> <em>Vernonia amygdalina </em>Del.<em>,</em><em> Toxicity, BSLT, Sterol, Steroid</em></p> Evi Mashunah, Erwin, Saibun Sitorus Copyright (c) 2020 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/15032 Sat, 18 Apr 2020 00:00:00 +0000 Analisis Kadar Serat dan Protein Total Sereal Berbasis Tepung Ampas Kelapa dan Ikan Cakalang (Katsuwonus pelamis) https://bestjournal.untad.ac.id/index.php/kovalen/article/view/12788 <p>Research on the analysis of fiber and protein on cereal based on coconut pulp and skipjack tuna (<em>Katsuwonus pelamis</em>) 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.</p> <p><strong>Keywords</strong>: <em>S</em><em>kipjack tuna </em><em>flour, coconut pulp flour, cereal, fiber, protein</em></p> Nanda Novita, Nurhaeni, Prismawiryanti, Abd. Rahman Razak Copyright (c) 2020 KOVALEN https://bestjournal.untad.ac.id/index.php/kovalen/article/view/12788 Sat, 18 Apr 2020 00:00:00 +0000 Aktivitas Antibakteri Ekstrak Metanol dari Kulit Batang Kelor (Moringa oleifera Lam.) Terhadap Bakteri Staphylococcus aureus dan Escherichia coli https://bestjournal.untad.ac.id/index.php/kovalen/article/view/12854 <p>Antibacterial activity of <em>Moringa oleifera</em> Lam. stem bark has been tested against <em>Staphylococcus aureus </em>and <em>Escherichia coli</em>. The extraction of <em>Moringa oleifera</em> Lam. stem bark was used maceration method with methanol solvent and has obtained extract yield of 6.1%. The antibacterial activity test of <em>Moringa oleifera</em> stem bark extracts used a well diffusion method. The concentration of <em>Moringa oleifera</em> stem bark extract was varied to four concentrations of 1% 2% 3% 4% (w/v). The inhibition zone of methanol extract of <em>Moringa oleifera</em> stem bark against <em>Staphylococcus aureus</em> 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 <em>Moringa oleifera</em> stem bark at concentrations of 1%, 2%, 3%, and 4% could also inhibition of <em>Escherichia coli</em> growth with inhibition zone of 14.01 mm, 16.50 mm, 17.09 mm, and 17.10 mm, respectively.</p> <p><strong>Keywords:</strong> <em>Moringa Oleifera </em>Lam., <em>Antiba</em><em>cteria</em><em>l</em>, <em>Staphylococcus aureus,</em> <em>Escherichia coli</em></p> Nurul Cholifah, Ahmad Ridhay, Pasjan Satrimafitrah, Ruslan, Hardi Ys Copyright (c) 2020 KOVALEN https://bestjournal.untad.ac.id/index.php/kovalen/article/view/12854 Sat, 18 Apr 2020 00:00:00 +0000 Penyerapan Ion Logam Merkuri Menggunakan Arang Aktif Limbah Kulit Pisang Kepok (Musa paradisiaca Formatypica) https://bestjournal.untad.ac.id/index.php/kovalen/article/view/15043 <p>This research aimed to determine the percentage of mercury metal ion adsorbed in kapok banana peel’s activated carbon. It was done by applying Completely Randomized Design (CRD) with 6 variations of contact time, pH, and mercury concentration (i.e 10, 20, 30, 40, 50, 60 minutes; pH of 1, 2, 3, 4, 5, 6; and concentration of 10, 20, 30, 40, 50, 60 ppm, accordingly). The result showed that the equilibrium time was reached at 30 minutes, the maximum pH was reached at pH 5 and the maximum of adsorbed mercury ion at 40 ppm of mercury ion concentration. The adsorption percentages of those parameters were 61%, 98%, and 99%, respectively.</p> <p><strong>Keywords: </strong><em>Kepok banana’s peel, charcoal, mercury metal ion.</em></p> Musafira, Dzulkifli, Fadrinah, Laila Qadrini Copyright (c) 2020 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/15043 Sat, 18 Apr 2020 00:00:00 +0000 Fermentasi Kelapa Parut Bebas Protein dengan Aspergillus niger untuk Menghasilkan Lipase https://bestjournal.untad.ac.id/index.php/kovalen/article/view/13052 <p>The research about the fermentation of protein-free grated coconut with<em> Aspergillus niger</em> 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.</p> <p><strong>Keywords</strong>: <em>Lipase enzyme, protein-free grated coconut</em>, <em>Aspergillus niger</em></p> Rifka Aulia, Syaiful Bahri, Meryany Ananda Copyright (c) 2020 KOVALEN https://bestjournal.untad.ac.id/index.php/kovalen/article/view/13052 Sat, 18 Apr 2020 00:00:00 +0000 Retensi Antosianin dari Ekstrak Daun Bayam Merah (Alternanthera amoena Voss) pada Pengolahan Mie Basah https://bestjournal.untad.ac.id/index.php/kovalen/article/view/14795 <p>Research about the retention of red spinach leaves extract (<em>Alternanthera amoena </em>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.</p> <p><strong>Keywords</strong>: <em>Retention, </em><em>anthocyanin, Alternanthera amoena </em>Voss.<em>, wet noodles</em></p> Betzy Eppang, Nurhaeni, Khairuddin, Ahmad Ridhay, Jusman Copyright (c) 2020 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/14795 Sat, 18 Apr 2020 00:00:00 +0000 Skrining Fitokimia, Uji Toksisitas dan Uji Peredaman Radikal DPPH Ekstrak Daun Gelinggang (Cassia alata L) https://bestjournal.untad.ac.id/index.php/kovalen/article/view/15045 <p><em>Cassia alata</em> L. (<em>Gelinggang</em>) one of the plants known as medicinal plants, especially for the treatment of skin diseases. The purpose of this study was to determine the type of secondary metabolites using phytochemical tests, toxicity with the BSLT method and antioxidant properties against DPPH radicals from the extract of the <em>Gelinggang</em> leaves. The results of the study showed extracts of <em>Gelinggang</em> leaves containing alkaloids, triterpenoids, steroids, and quinones. Based on the results of toxicity and antioxidant tests showed that <em>Gelinggang</em> leaves extract was very toxic to <em>Artemia salina</em> shrimp and it was a strong antioxidant against DPPH radicals with LC<sub>50</sub> and IC<sub>50 </sub>were 28.84 ppm and 73.57 ppm, respectively.</p> <p><strong>Keywords:</strong> <em>Gelinggang, Cassia alata </em>L.<em>, toxicity, antioxidants, DPPH</em></p> Izkia Mawaddah, Erwin E, Chairul Saleh Copyright (c) 2020 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/15045 Sat, 18 Apr 2020 00:00:00 +0000 Perbandingan Kadar Albumin Ikan Gabus (Channa striata) dari Proses Perebusan dan Pengukusan dengan Menggunakan Uji Biuret https://bestjournal.untad.ac.id/index.php/kovalen/article/view/12699 <p>Cork Fish (<em>Channa striata</em>) 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 100<sup>o</sup>C 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.</p> <p><strong>Keywords</strong>: <em>Cork fish, albumin, boiling, steaming</em>.</p> Sulfitri Suardi, Syaiful Bahri, Khairuddin, Ni Ketut Sumarni, Erwin Abdul Rahim Copyright (c) 2020 KOVALEN https://bestjournal.untad.ac.id/index.php/kovalen/article/view/12699 Sat, 18 Apr 2020 00:00:00 +0000 Analisis Kualitatif dan Kuantitatif Metabolit Sekunder Ekstrak Etanol Buah Okra (Abelmoschus esculentus L. Moench) dengan Metode Spektrofotometri UV-Vis https://bestjournal.untad.ac.id/index.php/kovalen/article/view/15044 <p>This study aims to determine the content of secondary metabolites and the levels of total secondary metabolites in ethanol extract of Okra (<em>Abelmoschus esculentus</em> L. Moench) fruit with UV-Vis Spectrophotometry method. Okra (<em>Abelmoschus esculentus</em> L. Moench) fruit extract was prepared by maceration method with 96% ethanol. The extract was concentrated using a rotary evaporator that followed by a qualitative test for alkaloids, flavonoids, saponins, and tannins using suitable reagents with the test parameters, while for the qualitative assay using a UV-Vis Spectrophotometry. Qualitative analysis of alkaloids using test parameters of total alkaloids equivalent to quinine, flavonoid using parameter of total flavonoids equivalent to quercetin, saponin using parameters of standard saponins total from the Quillaja Bark, and tannin using test parameters of total tannins equivalent to tannic acid. Qualitative test results indicated that the ethanol extract of Okra fruit tested positive for alkaloids content wich characterized by the orange deposition, flavonoids characterized by the formation of an orange-yellow color, a stable foam for saponins and tannins marked in black. The quantitative analysis resulted alkaloids of 2228.06 mg/gram, flavonoids of 2.79 mg/gram, saponins of 10.03 mg/gram, and tannins of 1973.27 mg/gram.</p> <p><strong>Keywords: </strong><em>Okra fruit, secondary metabolites, UV- Vis spectrophotometry, qualitative, quantitative</em>.</p> Joni Tandi, Bella Melinda, Anita Purwantari, Agustinus Widodo Copyright (c) 2020 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/15044 Sat, 18 Apr 2020 00:00:00 +0000 Isolasi dan Identifikasi Metabolit Sekunder dari Ekstrak Etil Asetat Batang Nangka (Artocarpus heterophyllus Lmk.) dan Aktivitasnya Sebagai Antibakteri https://bestjournal.untad.ac.id/index.php/kovalen/article/view/15047 <p>Isolation and identification of secondary metabolite of ethyl acetate extract of jackfruit stem (<em>Artocarpus heterophyllus</em> Lmk.) as well as its activity as antibacterial have been carried out. The purpose of this study was to know the characterization and antibacterial activity of secondary metabolites from ethyl acetate extract of the Jackfruit stem. Ethyl acetate extract was fractionated and purified using several chromatographic techniques. The identification of the isolated compound was elucidated by spectroscopic UV-Vis, IR, and NMR. Based on data analysis of UV, IR, and NMR spectra showed that the isolated compound was a flavonoid derivative. Antibacterial activity test of the isolated compound to <em>Escherichia coli</em> and <em>Staphylococcus aureus</em> was done by a well diffusion method. The inhibitory zone values of flavonoid compound in concentration series of 1000 µg/ml, 3000 µg/ml, and 5000 µg/ml against <em>E. coli</em> were 9.65 mm, 10.25 mm, and 11.00 mm, respectively. While, the inhibitory zone values in the same concentration series against&nbsp; <em>S. aureus</em> were 9.00 mm, 10.75 mm, and 11.38 mm.</p> <p><strong>&nbsp;</strong><strong>Keywords</strong>: <em>Jackfruit</em>, <em>Artocarpus heterophyllus Lmk</em>.,<em> flavonoid, antibacterial activity.</em></p> Indriani, Iswan Copyright (c) 2020 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/15047 Sat, 18 Apr 2020 00:00:00 +0000