https://bestjournal.untad.ac.id/index.php/kovalen/issue/feed KOVALEN: Jurnal Riset Kimia 2020-01-17T16:33:14+00:00 Jaya Hardi jr.hardi0803@gmail.com Open Journal Systems <p><strong>KOVALEN: Jurnal Riset Kimia</strong> 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.&nbsp;Publishing frequency 3 issues per year, in April, August, and December. KOVALEN&nbsp;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> https://bestjournal.untad.ac.id/index.php/kovalen/article/view/11540 UJI AKTIVITAS ANTIBAKTERI EKSTRAK n-HEKSAN, ETIL ASETAT DAN ETANOL KULIT BATANG KAYU EBONI (Diospyros celebica Bakh.) MENGGUNAKAN METODE DIFUSI 2020-01-17T16:28:39+00:00 Ni Luh Sumitriasih niluhsumitriasih@gmail.com Ahmad Ridhay ahmadridhay@yahoo.co.id Indriani indri.2707@gmail.com <p>A study was conducted on the antibacterial activity test on n-hexane, ethyl acetate, and ethanol extracts of ebony bark (<em>Diospyros celebica</em> Bakh.) using a diffusion method. The purpose of this research is to know the antibacterial activity of ebony bark against <em>Staphylococcus aureus</em> and <em>Escherichia coli</em> bacteria using <em>n</em>-hexane, ethyl acetate dan ethanol. The method of extraction used in this research was maceration method with three polarity levels of solvent. The antibacterial activity test was performed by diffusion-well test. The results showed that ethyl acetate extract gave the highest inhibition of 26.14 mm in gram-positive bacteria (<em>Staphylococcus aureus</em>) and ethanol extract of 25.97 mm in gram-negative bacteria (<em>Escherichia coli</em>).</p> <p><strong>Keywords</strong>: <em>Ebony (Diospyros celebica. </em>Bakh<em>), Tree Bark, Inhibitory, Antibacterial</em></p> 2019-12-31T00:00:00+00:00 Copyright (c) 2019 KOVALEN https://bestjournal.untad.ac.id/index.php/kovalen/article/view/11579 ANALISIS KADAR SERAT DAN KADAR PROTEIN SERTA PENGARUH WAKTU SIMPAN TERHADAP SEREAL BERBASIS TEPUNG AMPAS KELAPA DAN TEPUNG TEMPE 2020-01-17T16:29:35+00:00 Fitrianingsih Mozin fitrianingsih.mozin@gmail.com Nurhaeni eni_kimia64@yahoo.co.id Ahmad Ridhay ahmadridhay@yahoo.co.id <p>Research on dissolved protein and crude fiber flour based on coconut pulp and tempe flour has been performed. This study aims to determine the effect of shelf time on levels of dissolved protein and crude fiber flour-based cereal coconut pulp and tempeh flour. Cereals were made from coconut pulp flour and tempe flour as the main ingredients and the ratio of the ingredients was varied to 25:75; 50:50; and 75:25. The ratio of 25:75 produced the highest dissolved protein level of 3.88% and the 75:25 ratio produced the highest crude fiber of 21.96%.</p> <p><strong>Keywords</strong>: <em>Coconut pulp flour, tempe flour, dissolved protein, crude fiber</em></p> 2019-12-31T00:00:00+00:00 Copyright (c) 2019 KOVALEN https://bestjournal.untad.ac.id/index.php/kovalen/article/view/12573 ANALISIS KANDUNGAN NUTRISI MIE KERING YANG DISUBTITUSIKAN AMPAS KELAPA 2020-01-17T16:29:57+00:00 Sylvia Florensy Bawias sylviabawias@yahoo.com Syamsuddin syamsuddin_ssi@yahoo.com Prismawiryanti prismawiryanti@gmail.co.id Ni Ketut Sumarni syahparawan@gmail.com <p>Research has been carried out on the nutritional content of dried noodles substituted with coconut pulp. This study aims to determine the highest total protein content, highest crude fiber content and the highest water content and organoleptic quality of dried noodles substituted with coconut pulp. Dry noodles are made from wheat flour and coconut pulp as the main ingredients. The material ratio is varied to 90:10; 80:20; 70:30 and without the addition of coconut pulp flour. Dry noodles without the addition of coconut pulp flour produced the highest total protein content of 18.57%(b/b) and at the ratio of 70:30 the highest crude fiber was 17.55% (w/w) and the highest water content was 2.63% (w/w). Based on the quality of organoleptic dry noodles the most preferred is at the ratio of 90:10.</p> <p><strong>Keywords: </strong><em>Dry noodles, coconut pulp flour, total protein content, crude fiber content, water content, organoleptic quality</em></p> 2019-12-31T00:00:00+00:00 Copyright (c) 2019 KOVALEN https://bestjournal.untad.ac.id/index.php/kovalen/article/view/12662 TRANSESTERIFIKASI IN SITU BIJI KELOR (Moringa oleifera Lam) MENGGUNAKAN POLIMER BERBAHAN DASAR EUGENOL SEBAGAI PENYANGGA KATALIS H2SO4 2020-01-17T16:30:14+00:00 achmad rihday achmadrihday050796@gmail.com Erwin Abdul Rahim erwin_abdulrahim@yahoo.com Syaiful Bahri caniagos@yahoo.com Dwi Juli Pusptasari lilik56@ymail.com <p>A study of <em>in situ</em> transesterification of Moringa (<em>Moringa oleifera</em>) seeds with polymer based on eugenol catalyst support have been carried out. The aim of the study is to determine the concentration of eugenol-based polymer support catalyst which was used to produce fatty acid methyl esters with the highest yield, and best time and to determine the composition of fatty acid methyl esters found in transesterification <em>in situ</em>. The results showed that the catalyst concentration of 1% with a reflux time of 150 minutes resulted in a yield of 12.04% methyl ester. The results of analysis of methyl esters using GC-MS contain methyl stearate and methyl-9,12-octadecanoate compounds. The characteristics of methyl ester are water content of 1.23%, acid number of 11.60 mgKOH/gram, saponification number of 0 mg NaOH/gram, and pour point of 16˚C.</p> <p><strong>Keywords</strong>: <em>Moringa seed,</em> <em>eugenol as a catalyst support H<sub>2</sub>SO<sub>4</sub>,&nbsp; transesterification</em></p> 2019-12-31T00:00:00+00:00 Copyright (c) 2019 KOVALEN https://bestjournal.untad.ac.id/index.php/kovalen/article/view/14037 PENGARUH JENIS PELARUT TERHADAP EKSTRAKSI DARI KULIT BUAH NAGA MERAH (Hylocereus polyrhizus) 2020-01-17T16:30:43+00:00 Amalia Noviyanty amalianoviyanti@ymail.com Chitra Anggriani Salingkat chitrasalingkat@yahoo.co.id Syamsiar Syamsiar syamsiarrachmat@yahoo.co.id <p>This study aims to determine the effect of the type of solvent on extract yield, total phenolics and IC50 values of the skin of red dragon fruit and also obtain the best type of solvent that provides extract rendement, total phenolics and the highest or best IC50 value for extracting red dragon fruit peels. There are 3 types of solvents used (95% ethanol, ethyl acetate and acetone: water (7: 3) with a sample-solvent ratio (5:1 v/b).&nbsp; The data obtained were analyzed using a Completely Randomized Design that was applied to observations of extract rendemen, phenolics total and IC<sub>50</sub> values, if the treatment had a very significant or significant effect followed by continued BNJ test at 1% or 5% level. The results showed that the solvent ratio very significantly affected the extract rendemen, phenolics total and IC<sub>50</sub> value of red dragon fruit peel extract.&nbsp; Ethanol 95% solvent is the best solvent for extracting dragon fruit peels because it has the highest yield (26.15%), total phenolic (64.75 ppm) and antioxidant activity (IC<sub>50</sub> value) (120.53 ppm) highest or best.</p> <p><strong>Keywords</strong> : <em>IC<sub>50</sub>, the red dragon fruit skin, solvent ratio, extract yield, phenolics total</em></p> 2019-12-31T00:00:00+00:00 Copyright (c) 2019 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/14029 PENGARUH RASIO PELARUT TERHADAP EKSTRAKSI DARI KULIT BUAH NAGA MERAH (Hylocereus polyrhizus) 2020-01-17T16:31:13+00:00 Amalia Noviyanty amalianoviyanty@untad.ac.id Chitra Anggriani Salingkat Chitrasalingkat@yahoo.co.id Syamsiar Syamsiar syamsiarrachmat@yahoo.co.id <p>This study aims to determine the effect of the ratio of solvents to extract yield, phenolics total and IC<sub>50</sub> values ​​of red dragon fruit peel and also get the optimal solvent ratio to obtain extract yield, phenolics total and the highest or best IC<sub>50</sub> values ​​of red dragon fruit peel extracts. The solvent ratio used there are 6 levels of the ratio: 2:1; 3:1; 4:1; 5:1; 6:1 and 7:1 (v/w). The data obtained were analyzed using a Completely Randomized Design that was applied to observations of extract yield, phenolics total and IC<sub>50</sub> values, if the treatment had a very significant or significant effect followed by continued Tukey HSD test at 1% or 5% level. The results showed that the solvent ratio very significantly affected the extract yield, phenolics total and IC<sub>50</sub> value of red dragon fruit peel extract.&nbsp; The solvent ratio of 4:1 (v/w) produced extract yield, phenolics total and IC<sub>50</sub> values the highest or best i.e&nbsp; 26.22%, 71.56 ppm, and 124.62 ppm.</p> <p><strong>Keywords</strong> : <em>IC<sub>50</sub>, the red dragon fruit skin, solvent ratio, phenolics total</em></p> 2019-12-31T00:00:00+00:00 Copyright (c) 2019 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/14309 KARAKTERISASI SILIKA DARI ABU AMPAS TEBU 2020-01-17T16:31:41+00:00 Tifa Paramitha tifa.paramitha@polban.ac.id Tri Reksa Saputra tri.reksa@polban.ac.id Amelia Nur Aliah amelnuraliah@yahoo.com Arijan Vevayose Tarigan vevayosetarigan@gmail.com Mukhtar Ghozali mukhtar.ghozali@polban.ac.id <p>Silica has been successfully extracted from sugarcane bagasse ash by using alkali method. Extraction was carried out using sodium hydroxide solution to obtain sodium silicate solution and solid residue. Then, hydrochloric acid solution was added to sodium silicate solution until pH of solution was 7 and silica was formed. Furthermore, silica was heated in oven at 150 ˚C and calcined at 700 ˚C. Variation of this study were extraction time (1, 2 and 3 hours). The synthesized silica were characterized functional groups, acidity level, water adsorption ability and adsorption ability of Cu<sup>2+</sup> ion. The results of FTIR analysis showed that all silica contain siloxane group. Silanol group did not appear because during calcination process occured the condensation reaction of silanol group. Other characterization results showed that silica with extraction time of 2 hours had highest acidity level, water adsorption ability and adsorption ability of Cu<sup>2+ </sup>ion, which were 6.201 mmol/gram, 86.41% and 92.55%.</p> <p><strong>Keywords : </strong><em>bagasse ash, extraction, silica, siloxane</em></p> 2019-12-31T00:00:00+00:00 Copyright (c) 2019 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/14628 KAJIAN AKTIVITAS ANTIOKSIDAN MIKROKAPSUL EKSTRAK KULIT TERONG UNGU (Solanum melongena L) 2020-01-17T16:32:04+00:00 Efin Lestari efinlestari@gmail.com Ni Ketut Sumarni syahparawan@gmail.com Mappiratu Mappiratu mappiratu@yahoo.com <p>Study about antioxidant activity of microcapsule of purple eggplant (<em>Solanum melongena</em> L) peel extract has ben done. The research aimed to find the best pH and coating ratio for yielding microcapsule with the highest antioxidant activity. It was done by applying 5 levels of both pH variation of &nbsp;2, 3, 4, 5, 6 and maltodextrin ratio of 1:1, 2:1, 3:1, 4:1, 5:1 (w/v). The determination of antioxidant activity was done by DPPH method. The result showed that at pH 2 and 1:1 of maltodextrin coating ratio were the best condition to yield the highest antioxidant activity i.e 32.54 % and 96.31 %, respectively.</p> <p><strong>Keywords: </strong><em>Purple eggplant </em><em>peel</em><em>, maltodextrin, microcapsule, antioxidant activity</em></p> 2019-12-31T00:00:00+00:00 Copyright (c) 2019 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/14629 PEMANFAATAN LIMBAH KULIT BUAH PISANG KEPOK (Musa paradisiaca) SEBAGAI BIOSORBEN ZAT WARNA RHODAMIN B 2020-01-17T16:32:33+00:00 Musafira Musafira Musafira77@yahoo.com Nurfitrah M Adam adamvhyta@gmail.com Dwi Juli Puspitasari lilik56@ymail.com <p>The investigation about the utilization of Banana peel (<em>Musa paradisiaca</em>) 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 &nbsp;4.55mg/g.</p> <p><strong>Keywords</strong>: <em>Banana peel, Rhodamine B, biosorbent</em></p> 2019-12-31T00:00:00+00:00 Copyright (c) 2019 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/14981 UJI AKTIVITAS ANTIOKSIDAN EKSRTRAK LUMUT HATI (Marchantia polymorpha) 2020-01-17T16:32:54+00:00 Nurhaeni Nurhaeni eni_kimia64@yahoo.co.id Gladys gladyspatoki@gmail.com Jaya Hardi jr.hardi0803@gmail.com <p>The research is about antioxidant activity of the liverworts (<em>Marchatia polymorpha</em>) 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 (IC<sub>50</sub>) 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.</p> <p><strong>Keywords</strong><strong>:</strong> <em>Liverwort extract, antioxidant, IC<sub>50</sub></em></p> 2020-01-18T00:00:00+00:00 Copyright (c) 2019 KOVALEN: Jurnal Riset Kimia https://bestjournal.untad.ac.id/index.php/kovalen/article/view/14799 APLIKASI EKSTRAK LIKOPEN DARI BUAH TOMAT APEL (Lycopersicum pyriforme) TERSALUT MALTODEKSTRIN PADA PENGOLAHAN MIE INSTAN FUNGSIONAL 2020-01-17T16:33:14+00:00 Dini Noviyandari diniharun17@ymail.com Jaya Hardi jr.hardi0803@gmail.com Mappiratu Mappiratu mappiratu@yahoo.com <p>A research about the application of lycopene extract of tomato fruit (<em>Lycopersicum pyriforme</em>) 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 <em>i.e.</em> 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.</p> <p><strong>Keywords: </strong><em>tomato, lycopene, instant noodle, shelf life</em></p> 2019-12-31T00:00:00+00:00 Copyright (c) 2019 KOVALEN: Jurnal Riset Kimia