Judul: A Meta-Analysis on The Effect of pH on Curcumin Natural Dye Halochromic
Abstrak: It is recorded in much previous research that curcumin has been used to monitor the changes in pH in some products. However, a quantitative study in analyzing and combining results from various research, especially on the effect of pH in halochromic curcumin natural dye against the color characteristics, has not been studied yet. A preliminary study was done to know the trend of halochromic natural dye in Scopus. As the result, carotenoids and curcumin were the top two trending topics from 2017 to 2021 as proven by 18,704 and 16,279 journals respectively talking about these natural dyes. Meta-analysis in this research was carried out by searching “curcumin”, “pH indicator”, and “freshness monitoring” as keywords in the database from 2012 to 2022 with google scholar, crossref, and science direct. The data obtained were from 18 journals with 29 studies and 211 sample data. Firstly, the data was examined throughout its collinearity to ensure each variable was independent thus the model will result in highly reliable statistical inferences. Then, the data were further analyzed using parameters, such as the L* value, a* value, b* value, total color difference, chroma, and hue by applying a linear mixed model. The visual color of halochromic curcumin natural dye turns from bright yellow to dark red color as pH increases. The results of the analysis model with pH between 1 to 14 had a highly significant impact with P≤0.001 in the decreasing of L* value, b* value, total color differences, hue, and chroma. On the contrary, pH brought a significant impact on the increasing of a* value with P≤0.001. The addition of the matrix to curcumin natural dye affects the intensity of color changes. The results of the independent t-test statistical analysis showed a significant effect (P≤0.05) with a visible reduction of the L* value, b* value, total color difference, and chroma, while the a* value and hue had no significant (P>0.05) effect with respectively an invisible increasing and decreasing.
Keyword: curcumin, natural colorant, pH-responsive indicator, smart packaging

Judul: Evaluasi Kadar Kurkuminoid Rimpang Temulawak (Curcuma xanthoriza Roxb.) Menggunakan Analisis Citra Berbasis Red Green Blue
Abstrak: Turmeric (Curcuma xanthoriza Roxb.) is one of the important natural product in Indonesia. Quality of turmeric is dictated by content of curcuminoid. The curcuminoid content could be determined by spectrophotometry, titration volumetry, or chromatography, but those analytical methods are destructive to the material and need long time. One of rapid and nondestrucive method is image analysis. The objectives of this research were to evaluate content of curcuminoid using image analysis based on red green blue (RGB). Picture taking for image analysis was using USB Digital Microscope with enlargement 800x and curcuminoids were measured using spectrophotometry Uv-Vis at wavelength of 420 nm. The data showed that RGB value is equivalent with the content of curcuminoid. The result can be used as parameter to differentiate turmeric with harvest age 3, 6, and 9 months. The obtained equation of predicted content of curcuminoid is y = - 0,22 - 0,0062 R + 0,0643 G - 0,0330 B, R² = 96,1%.
Keyword: turmeric., RGB, curcuminoid, image analysis

Judul: Pemanenan Energi Listrik dari Kincir Angin Vertikal
Abstrak: Usaha pemanenan energi angin di Indonesia masih sedikit. Sampai Tahun 2016 hanya 3.54 MW alat pemanenan energi angin yang sudah terpasang. Kendala utamanya ialah dibutuhkan investasi yang besar untuk membuatnya. Pembuatan kincir angin dengan ukuran yang lebih kecil dengan bahan yang dapat dibeli di pasar lokal menjadi solusi agar pembuatan kincir angin lebih ekonomis. Pembuatan kincir vertikal tipe Savonius dapat menjadi solusinya. Kincir vertikal Savonius dapat beroperasi pada kecepatan < 3 m/s dan ketinggian < 50 m. Kincir angin ini terdiri dari tiga sistem, yaitu generator, rotor kincir dan transmisi pulley-belt. Generator dibuat dari modifikasi motor AC dan magnet neodymium. Rotor kincir dibuat dari pipa PVC 4”, pipa alumunium ¾”, dan papan polikarbonat. Transmisi pulley-belt dibuat dari plastik dan karet. Kincir ini membutuhkan gaya minimal 3 N untuk dapat berputar atau torsi minimalnya 0.75 Nm. Kecepatan angin yang dibutuhkan untuk merotasikannya sebesar 1.9 m/s. Daya maksimal yang dapat dihasilkan ialah 5.76 watt berupa tegangan sebesar 36 volt dan arus 160 mA.
Keyword: energi terbarukan, generator, motor AC, sudu Savonius