Jurnal Riset Kimia
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Physical, Mechanical, and Antioxidant Properties of Edible Film from Jackfruit Seed Starch and Microcellulose with Addition of Green Tea Extract
Full text linkEdible films are gaining popularity as biodegradable alternatives to plastic packaging. Starch-microcellulose-based edible films are known to exhibit favorable physical and mechanical properties. However, enhancing their resistance to deterioration as food packaging is essential for extending shelf life of the product. This study aimed to develop edible films from jackfruit seed starch and microcellulose with the incorporation of green tea extract and to evaluate its effects on the films’ antioxidant activity, physical, and mechanical properties. Edible films were prepared with green tea extract at concentrations of 2.5%, 5%, 7.5%, and 10% (w/w of total starch). The produced films exhibited a smooth and elastic texture. The addition of green tea extract enhanced antioxidant properties, as indicated by an increase in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, with the highest activity observed at 10% extract concentration. Furthermore, the extract improved the films' thickness, density, tensile strength, and elongation while reducing water absorption and water vapor transmission rate. However, the mechanical properties did not yet meet the Indonesian National Standard for packaging materials
In-house Multiplex rRT-PCR Assay for Sars-Cov2 Detection in Indonesia using a new primer design
Full text linkDuring the COVID-19 pandemic, we attempted to develop an in-house rRT-PCR kit, utilizing custom primers targeting NSP14 and RdRp, with the RPP30 gene as an internal control. This kit will support Indonesian independence in enhancing COVID-19 diagnostics. The primer and probe were designed by a bioinformatics tool, determining primer specificity and sensitivity, optimizing probe concentrations, establishing LoD (Limit of Detection), LoQ (Limit of Quantification), and rRT-PCR efficiency, multiplex testing of the rRT-PCR kit on clinical samples, and testing the kit's stability. The in-house rRT-PCR kit can detect NSP14, RdRp, and RPP30 genes. The optimal concentrations for the NSP14, RdRp, and RPP30 probes are 1 μM, 1.5 μM, and 1.5 μM, respectively. The LoD and LoQ for the NSP14 are 0.22 ng/μL and 0.67 ng/μL, and for the RdRp are 1.08 ng/μL and 3.28 ng/μL. The rRT-PCR efficiencies for the NSP14, RdRp, and RPP30 are 80.3%, 100.6%, and 106%, respectively. Detection of ten clinical samples, comprising seven true positive and three true negative samples, showed Ct (Cycle threshold) values of 28–31 for the RPP30 gene, Ct 21–27 for the RdRp gene, and Ct 30–34 for the NSP14 gene. Stability testing of the rRT-PCR kit demonstrated promising results, where the kit stored at -20°C for seven days showed almost no difference in Ct values. This in-house multiplex rRT-PCR will support Indonesian independence in enhancing COVID-19 diagnostics, providing a dependable method for detecting SARS-CoV-2 in clinical samples
The Liquid Smoke from Empty Oil Palm Bunches (Elaeis Guineensis Jacq.) as a Natural Fungicide and Its Ability to Inhibit the Growth of Colletotrichum sp. Fungus
Full text linkThe primary pest of red chili plants is anthracnose disease. Anthracnose is caused by the fungus Colletotrichum sp. Anthracnose is controlled with synthetic fungicides, but their long-term usage can harm the environment by leaving residues in the soil that are difficult to degrade, causing environmental degradation and a severe impact on the health of human. The goal of this study was to see how much potential liquid smoke had as a natural fungicide in preventing Colletotrichum sp. growth. It is recognized that liquid smoke emitted by empty oil palm bunches includes antioxidant compounds that function as antifeedants, contact poisons, and stomach poisons against plant pests. These compounds have the ability to act as natural fungicides, preventing the rise of Colletotrichum sp. The pyrolysis process produces liquid smoke at temperatures ranging from 350°C to 450°C. Total phenol and total acid content are determined from the obtained liquid smoke. The total phenol a material was identified using the well diffusion method, and the findings were 12.57%. Meanwhile, the maximum total acid content was found in liquid smoke from pyrolysis at 450oC (38.4 mg/L) with a volume of liquid smoke produced of 790mL. The ideal liquid smoke concentrations for limiting the increasing number of Colletotrichum sp. fungus are 20% and 30%, with average values of 4.28 and 7.73 mm, respectively. With a very strong inhibitory response category
Phytochemical Screening, Antioxidant and Cytotoxic Activities of Ethyl Acetate Extract of Calotropis gigantea Flower
Full text linkThe investigation of phytochemical constituents and biological activities of natural extracts holds considerable potential in pharmacological research. Bioactive components derived from plants are often utilized in the development of novel therapeutic agents. The present study aimed to evaluate the phytochemical profile, antioxidant activity, and cytotoxic potential of Calotropis gigantea flower extract. The extraction was carried out using ethyl acetate as the solvent through maceration for 72 hours. Antioxidant activity was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, while cytotoxic activity was determined by the Brine Shrimp Lethality Test (BSLT). The ethyl acetate extract was found to contain alkaloids, flavonoids, tannins, and glycosides. It exhibited weak antioxidant activity (IC₅₀ = 329.74 mg/L) and moderate cytotoxic activity (LC₅₀ = 189.88 mg/L). These findings indicate that C. gigantea flowers possess diverse secondary metabolites with potential as antioxidant and anticancer properties
Harnessing Indigenous Fermentation: Probiotic Lactic Acid Bacteria from West Sumatera’s Dadih
Full text linkThe potential of lactic acid bacteria (LAB) isolated from dadih, a traditional fermented buffalo milk from West Sumatra, was explored as functional starter cultures for yogurt production. The use of local LAB is considered essential due to Indonesia’s dependence on imported cultures, which often exhibit inconsistent performance and suboptimal quality. This study selected bacterial isolates based on their ability to grow in highly acidic media and their tolerance to bile salt treatment. Molecular identification was conducted by amplifying the 16S rRNA gene using the PCR method. Specific LAB isolates with high probiotic potential were further characterized based on their tolerance to acid and bile salts. The results showed that several LAB strains from dadih, such as Lactococcus lactis, Weissella paramesenteroides, and Weissella sp., exhibited good probiotic properties. These isolates could effectively ferment milk and produce yogurt with organoleptic qualities comparable to commercial cultures. In addition, Serratia marcescens, known as an opportunistic pathogen, was also detected during the isolation process; some of its strains are known to participate in fermentation processes. These findings support the utilization of local LAB as an alternative to imported cultures, promoting local food production, improving the nutritional value of fermented dairy products, and preserving traditional culinary heritage
Green Coconut (Cocos nucifera L.) Husk Extract as Milk Freshness Indicator in Chitosan/ Polyvinyl Alcohol-based Smart Packaging Films
Full text linkThe growing demand for sustainable and eco-friendly food packaging has prompted research into innovative solutions that tackle environmental challenges and consumer health concerns. Food spoilage typically results from microbial activity, which is subsequently influenced by alterations in pH levels within the packaging environment. Plants, such as green coconut husk extract, contain anthocyanin, a water-soluble natural pigment with significant antioxidant and antibacterial properties, whose color changes in response to variations in the surrounding pH. This research focuses on the development of a pH-responsive packaging film utilizing chitosan and polyvinyl alcohol (PVA), integrated with green coconut (Cocos nucifera L.) husk extract, through a casting method to monitor milk freshness. An extraction procedure employing a maceration technique was conducted on green coconut husk utilizing methanol solvent with the incorporation of 1 % HCl (v/v). The thickness, mechanical properties, and pH-responsiveness of the resulting films with varying extract to chitosan volume ratios were examined in detail. The films were subsequently employed to monitor real-time applications concerning milk freshness. The results indicated that the addition of green coconut husk extract resulted in significant variations in the thickness, tensile strength, and elongation at the break of the film samples. The films exhibited thicknesses between 0.28 and 0.38 mm, demonstrating optimal mechanical properties at an extract-to-chitosan ratio of 4:1 (v/v), with tensile strength (TS) and elongation at break (EB) recorded at 4.65 MPa and 3.625%, respectively. The films exhibited a pH-sensitive color change from dark red to brown in acidic conditions. The findings indicate that the PVA/chitosan smart film, which contains green coconut husk extract, has the potential to serve as a deterioration indicator in packaged milk products
Hydrothermal and Coprecipitation Synthesis Design of BiVO4 for Methylene Blue Degradation
Full text linkThis study investigated the characteristics and photocatalytic activity of BiVO4 photocatalyst synthesized using hydrothermal and coprecipitation methods for methylene blue (MB) degradation under visible light. The variation of synthesis parameters, including pH, calcination temperature, and pH of MB solution, affects the crystal structure, morphology, and photocatalytic efficiency of the material. XRD characterization results show that the hydrothermal method produces BiVO4 with pure scheelite(m-s) monoclinic phase and high crystallinity, while the coprecipitation method produces a combination of scheelite(m-s) monoclinic and orthorhombic Bi4V2O11 phases, which contributes to enhanced photocatalytic activity through better charge separation. The average crystal size of the hydrothermal method is 17.85 nm, larger than that of coprecipitation (11.41-14.71 nm), which gives the coprecipitated material a surface area advantage. SEM analysis showed rod-like morphology in hydrothermal, while coprecipitation produced sphere-grape-like particles. UV-Vis DRS results show that hydrothermal synthesized BiVO4 has a band gap energy of 2.28 eV, smaller than BiV(4)(400) (2.46 eV) and higher than BiV(4)(550) (2.07 eV) synthesized using coprecipitation method. This smaller band gap energy indicates that the interaction of Bi³⁺ and VO₄³- ions in the hydrothermal material is better, thus favoring visible light absorption. The highest photocatalytic activity was obtained from the coprecipitated material with a degradation efficiency of 89.32% at pH 11 within 150 min, higher than the hydrothermal material which reached 76.06% under similar conditions. This photocatalytic activity was dominated by OH* and O2-* radicals, which play a role in MB degradation. This study shows that designing synthesis pH parameters (4-7), calcination temperature (400), and coprecipitation method produced a material with optimum photocatalytic performance, making BiVO4 a superior candidate for colored wastewater treatment applications
Bioactivity of Red Leaf Extract of Pucuk Merah Plant (Syzygium myrtifolium Walp.)
Full text linkSyzygium myrtifolium Walp. is an ornamental plant traditionally used as an herbal medicine. Ethanol extract of Syzygium myrtifolium Walp. has been reported to have activities as an antioxidant, anticancer, and antimicrobial. In this study, Syzygium myrtifolium Walp is extracted. Leaves were carried out using a multistage maceration method using methanol, ethyl acetate, and hexane solvents. Antioxidant, antimicrobial, and toxicity tests were performed, and secondary metabolite compounds, total flavonoid content, and total phenolic content were identified on red leaf extract. Total phenolic content was tested using the Folin-Ciocalteau reagent, total flavonoids with the AlCl3 reagent, antioxidants with the DPPH method, antimicrobial using the disc diffusion method, and toxicity tested using the BSLT method. The result showed that Syzygium myrtifolium Walp. Red leaf extract contained a secondary metabolite of triterpenoids, steroids, phenolics, flavonoids, alkaloids, and coumarins. The ethyl acetate and methanol extract's total phenolic and flavonoid content were 311.0520 and 420.360 mg GAE/g extract and 211.788 and 105.360 mg QE/g extract. Antioxidant activity of ethyl acetate and methanol showed that the extracts were highly antioxidant with IC50 of 19.606 and 12.0656 mg/L. The antimicrobial activity showed that the hexane extract was resistant to the bacteria Staphylococcus aureus and Propionibacterium acnes and the fungus Candida albicans. However, no inhibition zones were produced for Pseudomonas aerigunosa and Escherichia coli bacteria. The toxicity test showed that the hexane and ethyl acetate extract had strong toxic properties with LC50 of 56.65 and 16.79 mg/L, and the methanol extract was toxic with LC50 of 224.2846 mg/L
Development and Testing of a Portable Air Purifier with Chemical and UV-C Filtration for Virus and Pollutant Removal
Full text linkCOVID-19 has profoundly impacted global health due to its severe respiratory effects. Similarly, respiratory issues are also triggered by pollutants such as O3, SO2, NO2, and CO. In response to these challenges, this study developed a portable air purifier called APMIKAV, incorporating sodium lauryl sulfate, activated carbon, and UV-C light as filter components. APMIKAV fabrication aimed to build a portable air purifier and study its effectiveness in filtering air containing viruses and pollutants into clean air. The APMIKAV utilized a three-stage filtration process that included a surfactant filter for pollutant removal and virus lysis, an activated carbon filter for pollutant adsorption, and a UV-C filter to deactivate viral DNA and RNA. Methods included designing, assembling, and testing. Antiviral testing was carried out with GeNose C19 on patients who tested positive for COVID-19, while air parameters were analyzed using an NDIR analyzer for CO and an air sampling impinger for O3, SO2, and NO2. Test with GeNose C19 showed negative results. Pollutant concentrations post-filtration average efficiency were 98.17%, 68.84%, 49.29%, and 66.34%, for NO2, O3, SO2, and CO, respectively. Overall, the multi-stage filtration process provided a robust solution for enhancing air quality in environments susceptible to both pollution and viral transmission, which confirmed APMIKAV's effectiveness in providing cleaner and safer air