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RAFFLESIA JOURNAL OF NATURAL AND APPLIED SCIENCES, Departement Of chemistry, Faculty Of Mathematics And Natural Sciences, University Of Bengkulu, Jalan WR Supratman, Kandang Limun, Kota Bengkulu, 38371, 0736(20919).
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Rafflesia Journal of Natural and Applied Sciences (RJNAS)
Published by Universitas Bengkulu
ISSN : -     EISSN : 28083806     DOI : 10.33369/rjna.v4i1.34652
Core Subject : Health, Science,
Biochemistry, Genetics & Molecular Biology Chemistry Materials Science & Nanotechnology Medicine & Pharmacology Public Health
Rafflesia Journal of Natural and Applied Sciences (RJNAS) with e-ISSN: 2808-3806 is an open access and peer reviewed journal published by Department of Chemistry, Universitas Bengkulu, Indonesia. This journal is published two times per year (April and October). RJNAS publishes research papers, review and short communication in field of Chemistry, Natural, and Applied Sciences. RJNAS accept articles written in Bahasa Indonesia and English (preferable).
Arjuna Subject : Kimia(semua kategori) - Kimia Organik
Articles 6 Documents
 1 
Search results for , issue "Vol. 2 No. 2 (2022): Oktober" : 6 Documents clear
Analysis of total phenolics and flavonoids content from methanol extract of Caesalpinia bonduc (L.) Roxb. seeds and antioxidant activity assay Samriani Samriani; Hasnah Natsir; Seniwati Dali; Abdul Wahid Wahab; Nunuk Hariani Soekamto; Paulina Taba
RAFFLESIA JOURNAL OF NATURAL AND APPLIED SCIENCES Vol. 2 No. 2 (2022): Oktober
Publisher : UNIB Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/rjna.v2i2.23929

Abstract

Caesalpinia bonduc (L.) Roxb. seed is known as gorek seed contain secondary metabolites such as alkaloids, tannins, flavonoids, and phenolics, due to the content of these secondary metabolites so that this plant has antioxidant activity. This study aimed to determine total phenolic and flavonoid contents of methanol extract of gorek C. bonduc seeds as well as antioxidant activity. Extraction of gorek C. bonduc seeds was carried out with methanol, then quantitative determination of total phenolic by the Folin-Ciocalteu method as Gallic Acid Equivalent (GAE)/gram of extract, flavonoid content by AlCl3 method as Quercetin Equivalent (QE)/gram of extract, and in vitro antioxidant activity with DPPH (2,2-diphenyl-1-picrylhydrazyl) method was in IC50 (inhibition concentration). Based on the results of research, the phytochemical screening of methanol extract of gorek C. bonduc seeds showed alkaloids, flavonoids, saponins, tannins, and phenolics. The determination of the total phenolic and flavonoid content were obtained 0.55 ± 0.02 mgGAE/g and 0.50 ± 0.02 mgQE/g, respectively. The antioxidant activity of methanol extracts and ascorbic acid showed IC50 values were 3770.77 ppm and 3.36 ppm respectively.
Synthesis of porous Hydroxyapatite (HAp) from Laying Chicken Waste Eggshells Agung Rimayanto Gintu; Elizabeth Betty E. Kristiani; Yohanes Martono
RAFFLESIA JOURNAL OF NATURAL AND APPLIED SCIENCES Vol. 2 No. 2 (2022): Oktober
Publisher : UNIB Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/rjna.v2i2.23931

Abstract

Hydroxyapatite (HAp) was the type of bioceramics synthesized from the compound which rich Calcium (Ca) contains, these bioceramics commonly used to repair the damage of hard tissues. In this study threatened the synthesis of HAp from laying chicken eggshells, the characterization of the eggshells showed that the contains of Calcium 0,9809 ± 0,0118g/g; Phosphate 0,0236 ± 0,0009g/g; and ratio of Ca/P 2,0840%. The synthetic process by base precipitation method showed the yield 77,5786 ± 0,3509%; and from the synthetic obtained the HAp with contains of Calcium 0,1522 ± 0,0047g/g; Phosphate 0,01354 ± 0,0019g/g; and ratio of Ca/P 0,9162%. The Biochemical characterization of the HAp showed that the Porosity 70,5940 ± 0,4104%; Biodegradability 16,1879 ± 0,1362%; and swelling Ability 28,0549 ± 0,1054%. The entire result of the research concluded that the sample eggshells potentially became one of the sources of HAp, and the HAp synthesized from the eggshells potentially to apply as remineralization agents.
Effect of Liquid Rubber Compound on the Physicochemical Properties of Particle Board from Coconut Frond Powder Teja Dwi Sutanto; Charles Banon; Bambang Trihadi
RAFFLESIA JOURNAL OF NATURAL AND APPLIED SCIENCES Vol. 2 No. 2 (2022): Oktober
Publisher : UNIB Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/rjna.v2i2.23932

Abstract

Particle board research made from coconut frond powder with various concentration of liquid rubber compound has been done. First particle board was made by mixing 50 mesh of coconut front powder with various concentration of liquid rubber compound there are 25; 30; 35; 40 and 45 % to obtain a particle board with the length, width and height of 5 x 10 x 7.5 cm and then dried by drying. Subsequently the particle board pressed to a thickness of 2.5 cm and then tested the modulus of rupture (MOR), the modulus of elasticity (MOE), the Screw Hold Strength and water absorption. The results indicated that the best condition was obtained on the use of 45 % of liquid rubber compound. In this condition, the value of MOR, MOE, screw hold strength and water absorption are 1436.16 g/ mm2, 2354.38 g/ mm2, 5.2708 N/ cm2 and 41.85% respectively.
Antibacterial Edible Coating of Ipomea batatas Incorporated with Lactobacillus acidophilus Miksusanti miksusanti; Najmatul Asriah; Indah Solihah; Dina Permata Wijaya
RAFFLESIA JOURNAL OF NATURAL AND APPLIED SCIENCES Vol. 2 No. 2 (2022): Oktober
Publisher : UNIB Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/rjna.v2i2.23933

Abstract

This study was conducted to analyze the effect of variations concentration of Lactobacillus acidophilus in edible coatings and their antibacterial activity against E. coli using the well diffusion method. This study used an edible coating of Prebiotic from purple sweet potato starch and Lactobacillus acidophilus with dilution variations (10-6, 10-7, 10-8, 10-9) as probiotics. In this study physical properties were tested for edible coatings such as color tests with visual observations, water content by the gravimetric method and viscosity using Viscometer Ostwald. The content of organic acids in edible coating solutions was measured using the HPLC method. Organoleptic test was conducted with taste and color parameters on the A-E scale of 30 respondents. Research results showed edible coating discoloration before and after incorporation from deep purple to brown. The value of water content and viscosity also changed from 62,8% to 71,4% and 569,97 cp to 486,64 cp respectively. The best antibacterial activity of edible coating incorporation with Lactobacillus acidophilus was 263,76 mm2. Organoleptic test on grapes that have been coated with edible coating showed that covered with edible coating contains probiotics (Lactobacillus acidophilus) has no effect on respondents' perception. Lactic acid and acetic acid were exist in edible coating which were incorporated with Lactobacillus acidophilus.
Storage modeling standard Cr(VI) solution based on comparison of time regression value with UV-Vis spectrophotometry FACHRURRAZIE; Elfiwani
RAFFLESIA JOURNAL OF NATURAL AND APPLIED SCIENCES Vol. 2 No. 2 (2022): Oktober
Publisher : UNIB Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/rjna.v2i2.23934

Abstract

Chromium (Cr) compounds are found in nature in two forms, Cr (III) and Cr (VI). Analysis of Cr (VI) was determined using spectrophotometer UV-vis. A standard solution must be fresh as a standard that is usually not used repeatedly in the measurement. This study aims to determine whether the standard solution of Cr (VI) be used for a certain period until it must be disposed of. This idea is based on Cr (VI) compounds that were categorized as hazardous and toxic materials. In this study, the shelf life of standard Cr (VI) was carried out with controlled temperature and humidity in a refrigerator at 4 ℃ during the test period of two days. In this study, there was found that every hour of storage of standard Cr (VI) will observe a change in the gradient value of the regression. The model then compared with p-value resulted in only up to 7 hours of storage with a deviation of regression slope and intercept compared with initial time (T0–T7) is 0.0062 and 0.0019 which and its increases over time. From the result, it can be concluded that standard regression can be used as a model for determining the maximum storage time by comparing the regression values each time so that the seven hours storage time is the limit where the Cr (VI) that can no longer be used as a measurement standard. It concerned that standard regression could be used as a model for determining the maximum storage time by comparing the regression values each time. Keywords: Cr (VI), Modeling, Regression, Spectrophotometry UV-vis, T-Test
Chemical characteristic of Fly ash and Bottom ash as potential source for synthesis of Aluminosilicate-based materials Elda ALYATIKAH; Siswo; Riaa Safitri; Tety Wahyuningsih Manurung; Rendy Muhamad Iqbal
RAFFLESIA JOURNAL OF NATURAL AND APPLIED SCIENCES Vol. 2 No. 2 (2022): Oktober
Publisher : UNIB Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/rjna.v2i2.23935

Abstract

The world's population has reached 7 billion or doubled from the previous half-century and continues to increase every year. This increase in population is directly proportional to the increase in electrical energy consumption. Electricity needs in Indonesia are mostly met by Steam Power Plants. Unfortunately, the use of coal as an energy source in Steam Power Plants can cause environmental pollution, namely the waste generated by fly ash and bottom ash. However, even though it is classified as hazardous materials, silica (SiO2) and alumina (Al2O3) content in the waste are high enough so that it can be used for the synthesis of aluminosilicate-based materials. The ash waste in this study was obtained from the Steam Power Plant in Kapuas Regency, Central Kalimantan Province which was tested according to the ASTM D93-10 standard. The composition of SiO2, Al2O3, Fe2O3, and CaO in fly ash was 56.44; 31.31; 0.51; 0.78%. The compositions of SiO2, Al2O3, Fe2O3 and CaO in the bottom ash were 66.66; 17.09; 0.31; 5.40%. Based on its composition, fly ash and bottom ash are classified as type F ash. In addition, fly ash and bottom ash have SiO2/Al2O3 ratios of 3.90 and 1.80, respectively. It can be concluded that fly ash and bottom ash has the potential to be used as basic materials for the manufacture of aluminosilicate-based materials such as geopolymers, zeolites, and others.

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