In a simple and instant procedure for detecting fish freshness, a hydrogel and hydrophilic pectin matrix membrane was used successfully as an optical pH sensor by immobilizing the chromoionophore ETH 5294 (CI), which is very selective and sensitive for the membrane. The Pe/CI optical pH sensor exhibited excellent linearity between pH 5 and pH 9, with a sensor response time of 5 min and reproducibility of 1.49% relative standard deviation (RSD). The sensor showed response stability for 15 days and a response reduction of 8.6%. The sensor’s capability was demonstrated by the detection of fish freshness for 17 days at 4 °C.

Pectin from Arabica Gayo coffee pulp has been successfully isolated using citric acid as a solvent. The pectin extracted from the coffee pulp is determined by the extraction conditions. This study aims to produce pectin from dried coffee extract using citric acid using two factors, namely the difference factor of citric acid (1: 5 and 1: 20 b/v) and extraction time 75 and 150 minutes. The optimum ratio of Arabica Gayo coffee pulp with citric acid was 1:20 b/v with rendemen 7,8 % with 125 minute extraction time and at the temperature of 80 °C and pH 4. The methoxyl content of isolated pectin was 12.71 % and has been determined as high methoxyl pectin (HMP). The result of analysis with FTIR is known that the extract produced is pectin with comparison with pectin standard. The pectin has been used as a matrix membrane and showed its smooth surface gel form and smaller diameter from scanning electron microscopy (SEM).1

Essential oils are oils derived from plants that are aromatic. Numeg leaves are part of plant that containing essential oil. Each of essential oils from different plants will have different physical properties. In this study, the essential oil is produced using steam distillation method. The purpose of this study was to determine the physical properties of essential oils of nutmeg leaves South Aceh. The physical properties of essential oils can be evaluated from the percentage of moisture content, ash content, aroma, color, and rendemen. The results showed that the essential oil of nutmeg leaves are pale yellow, has a characteristic smell of nutmeg, the percentage of moisture content and ash, viscosity, density is respectively 6.8%, 2.1%, 0.4% yield density, 3.8 P, 0576 g/cm3. The essential oil of nutmeg leaves South Aceh can be used as pharmaceuticals. But the density of leaf nutmeg oil does not comply with ISO Standard.

Gastropods have an important role in an ecosystem that is directly involved in the food chain system and can be used as a bioindicator of water quality because it is sensitive to water pollution. This study was conducted to analyze the quality of the waters of Krueng Aceh by identifying the diversity of the Gastropod community and analyzing the COD and BOD content in the waters. The study used a purposive sampling method by applying 5 sampling stations along the study area. Gastropod samples are taken using Ponal Grab, which is 23 cm x 23cm and sieved from the substrate using a mesh filter. The results showed that the highest abundance index was obtained at station 1, which is 15 ind/m2. The results of identification in the study area are 15 Gastropod Species. Furthermore, the most widely found Gastropod species is Snail tiger, while the least is Margarites. This result informs that the highest diversity index is found at station 1, which is 2.51 categorized as moderate pollution and on the other hand the dominance index level is less than 0.50 or no one dominates at each station.

Study on the biosynthesis of copper nanoparticles has been carried out employing the green synthesis method using methanol extract of Sugar-Apple leaf (Anonnaceae squamosa) as a reducing agent and stabilizer. The results of the reduction reaction of Cu2+ ions were confirmed using a UV-Vis Spectrophotometer, Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM). The results of the characterization analysis showed that the nanoparticles formed were Cu, CuO2, Cu2O, and CuO, with crystal size of 38.17 nm, 27.82 nm, 15.59 nm, and 37.08 nm respectively. The obtained copper nanoparticles were tested for their antioxidant activity using the 1,1-diphenyl-2-picrihydrazil (DPPH) method. The antioxidant test results from the formed copper nanoparticles showed an IC50 value of 263.35 ppm, while vitamin C was 5.81 ppm. The previous study on the antioxidant activity of the methanol extract of Sugar-Apple leaf showed an IC50 value of 5.6 ppm. Therefore, it can be concluded that the antioxidant activity of the formed nanoparticles has a weak inhibitory power against 1,1-diphenyl-2-pycrilhydrazil (DPPH) radicals.