Yuni Kusumastuti

The valorization of cacao shells offers high added value because of the rich content of bioactive compounds. This study investigated the application of cacao shell waste as an antibacterial agent through green extraction processes. The extraction was carried out by integrating SAE-DES (sonication-assisted and deep eutectic solvent) with a choline chloride-lactic acid-based solvent. The parameters of extraction, including temperature, solid-to-solvent ratio, and DES concentration, were optimized applying a Box–Behnken design in RSM (response surface methodology). The optimum conditions were found to be 80 °C, a solid-to-solvent ratio of 1 : 10, and a DES concentration of 62.65%, with TPC (total phenolic content) and TFC (total flavonoid content) of 4.94 ± 0.10 g GAE per g sample and 5.97 ± 0.09 g RE per g sample, respectively. Additionally, the mass transfer coefficient (k_ca) and equilibrium constant (H_s) range from 8.73 × 10⁻³ to 14.80 × 10⁻³ min⁻¹ and 0.56 × 10⁻³ to 41.91 × 10⁻³ g solid per cm³, respectively. FTIR analysis confirmed the presence of significant functional groups of phenolic compounds in the extract. Furthermore, the extract was effective against Escherichia coli and Staphylococcus aureus.

The development of seaweed-derived products, particularly carrageenan, is increasingly prioritized in Indonesia to support sustainability and strengthen the local economy. Despite extensive studies on carrageenan extraction, systematic comparisons between locally extracted carrageenan and specific local commercial products remain limited. This study addresses this gap by directly comparing carrageenan extracted from Eucheuma cottonii harvested in Lombok, Indonesia, with a locally produced commercial carrageenan as a quality benchmark. Carrageenan extraction was performed using alkaline KOH treatment followed by ethanol precipitation. The extracted carrageenan exhibited a relatively high viscosity (61.16 cP) and a low sulfate content (11.58%). FTIR analysis confirmed the presence of sulfate ester groups and 3,6-anhydrogalactose units, indicating a κ-carrageenan structure. In addition, the extracted carrageenan exhibited a crystallinity index of 31.27% and a gel strength of 539 Pa. The yield, rheological behavior, and total phenolic content (TPC) were also evaluated. Notably, the extracted carrageenan demonstrated structural and functional properties comparable to those of the local commercial product. These findings provide direct evidence that carrageenan derived from Indonesian seaweed meets commercial performance benchmarks, highlighting its potential as a sustainable, competitive raw material for pharmaceutical applications as well as drug delivery.

The growing demand for eco-friendly food packaging has driven the development of biodegradable active films. This study developed novel agar-based films incorporating phenolic-rich cocoa pod husk (CPH) extract (10 - 25% w/w) and glycerol (30–50% w/w) using green deep eutectic solvent (DES) extraction. The optimal formulation (25% w/w CPH, 40% glycerol) demonstrated exceptional functionality. The antioxidant activity of bioplastics added with phenolic compounds of cocoa pod husk extract at 10, 15, and 25% w/w, analysed by the DPPH method, obtained results of 45.72 ± 0.27, 47.45 ± 0.06, and 56.85 ± 0.06, respectively, and the water vapour permeability was 907.26 g/m ² day. The hydrogen bonding interaction among the components of the blend films led to enhanced structural, barrier, thermal stability, miscibility, antioxidant properties, and smooth surface morphology of the blend films. Characterization showed hydrogen bonds such as -OH between agar, glycerol, and phenolic CPH, C=O ester groups (FTIR), and homogeneous microstructure (SEM). DES extraction preserved bioactivity better than conventional methods. This study demonstrates the potential of agar/CPH films as sustainable active packaging for perishable foods, combining antioxidant/antimicrobial properties with mechanical strength, while addressing both food preservation and environmental sustainability challenges through circular economy principles.

Cacao shells contain bioactive compounds such as phenolic acids and flavonoids. This study investigated the potential of bioactive compound extraction in cacao shells using conventional and green solvents like deep eutectic solvent (DES) (choline chloride: lactic acid). Specifically, it investigated the extraction kinetic models and parameters, which are critical to scale up the extraction process. The extraction of cacao shell was conducted using various conventional solvents (ethanol, methanol, n-hexane, and water) and DES (100 % and 70%) in which the result showed that DES 100% had the highest total phenolic content of 337.92?±?9.55 mg GAE/g dry weight. Meanwhile, pseudo-second order and Peleg’s model provided the best fit for the experimental data with higher R2 values. DES 70% showed a higher total flavonoid content of 76.51?±?1.59 mg RE/g dry weight. FT-IR and Raman spectroscopy confirmed the presence of bioactive compounds in DES-based extracts, which revealed characteristic vibrational bands associated with polyphenolic structures. These include bands corresponding to hydroxyl (–OH), carbonyl (C=O), and aromatic C=C stretching—functional groups commonly found in quercetin and other bioactive compounds.

This study aimed to synthesize magnetite mesoporous silica nanoparticles using local iron sand obtained from natural resources as magnetite core. The process was carried out in four stages, namely synthesis of magnetite nanoparticles, coating with silica, surfactant templating, silica incorporation, and surfactant removal. The particles were characterized by Scanning Electron Microscopy-Energy Dispersive X-ray spectroscopy (SEM-EDX), X-ray Diffraction (XRD), Particle Size Analyzer (PSA), Vibrating Sample Magnetometer (VSM), Fourier Transform Infrared (FTIR), and Brunauer-Emmett-Teller (BET). The results showed that magnetite mesoporous silica nanoparticles with a 2 g concentration of CTAB contained Fe3O4 and SiO2 compounds, without the chemical bonds related to CTAB. This material showed a smaller particle size distribution of 698.0 nm and a larger saturation magnetization value of 4.76 emu/g, with paramagnetic properties. Furthermore, the surface area, average pore diameter, and volume were 912.950 m2/g, 3.0706 nm (mesoporous), and 0.83 cm3/g, respectively. These magnetite mesoporous silica nanoparticles showed potential for application as hyperthermia agents and drug carriers to specific locations.

Microalgae is attractive biomass to produce biofuels due to the depletion of fossil fuel existence. However, one of the problems in its application is in t Microalgae is attractive biomass to produce biofuels due to the depletion of fossil fuel existence. However, one of the problems in its application is in t

Copper nanoparticles (CuNPs) play an active role in the field of optics, textiles, electrical conductors, catalytic, biochemical sensors, oxidative capacity, ph

Salah satu permasalahan yang muncul di lapangan pembangkit listrik panas bumi (PLTP) adalah terjadinya silica scaling dalam sistem pemipaaan akibat konsentrasi padatan terlarut yang tinggi pada air geotermal (geothermal brine). Silica scalling dapat menyebabkan penurunan efisiensi pembangkitan energi listrik dari panas bumi. Pada penelitian ini lumpur silika yang dihasilkan dari lapangan pembangkit listrik panas bumi akan dimanfaatkan sebagai raw material sintesis silica gel. Silica gel disintesis menggunakan metode sol-gel dengan variasi rasio natrium silikat dan air (1:3 ; 1:4 ; dan 1:5) dan konsentrasi asam klorida ( 0,5 M ; 1 M; dan 2 M). Karakteristik silica gel dilihat menggunakan analisis Forier Transform Infra Red (FTIR). Secara umum, pita serapan yang muncul pada spektra sample silica gel menunjukkan bahwa gugus fungsional yang terdapat pada silica gel adalah gugus silanol (Si-OH) dan gugus siloksan (Si-O-Si). Panjang gelombang 1055,86 cm-1­ menunjukkan gugus Si-O, yang mengindikasikan adanya vibrasi SiO4 dan polimerisasi Si-O-Si saat pembentukan silica gel. Selain itu, kapasitas penjerapan air oleh silika gel menunjukkan bahwa sampel dengan kode A7 memiliki kapasitas penjerapan air terbesar, yaitu mencapai 0,9331 gr air/ gram silica gel. Analisis Response Surface Methodology (RSM) mengindikasikan bahwa konsentrasi asam memberikan pengaruh singnifikan terhadap pembentukan silica gel dibandingkan dengan variasi pengenceran natrium silikat.