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Co-pigmentation of Anthocyanin Jamblang Fruit (Syzygium cumini) with Acetic Acid and Alum Chintia N. Barani; Siti Nuryanti; Paulus H. Abram
Jurnal Akademika Kimia Vol. 10 No. 4 (2021)
Publisher : Universitas Tadulako

This study aimed to determine the effect of temperature on the stability of anthocyanin jamblang after co-pigmentation with acetic acid and alum. The extraction of Jamblang fruit used the maceration method with n-hexane, ethyl acetate, and ethanol-HCl 0.5% solvents. The total anthocyanin obtained was 70.64 mg/L. Anthocyanin of jamblang fruit was co-pigmented with acetic acid and alum in a concentration of 2.5%; 5%; 7.5%; and 10%, then be heated at various temperatures and heating times. At a temperature of 80 ℃ for 150 minutes, every 30 minutes, absorbance was measured. At a temperature of 60 ℃, the heating was carried out for 225 minutes, and every 45 minutes, absorbance was measured. At a temperature of 40 ℃, the heating was carried out for 300 minutes, and every 60 minutes, absorbance was measured. Absorbance measurements were taken using a UV-VIS spectrophotometer. The results showed that co-pigmentation of anthocyanin occurred proved by shifting λ max from 470 nm (unco-pigmented extract) to 500 nm (co-pigmented extract acetic acid) and 540 nm (co-pigmented extract alum). Acetic acid and alum co-pigments maintained the stability of anthocyanin jamblang at a heating temperature of 60 ℃. It can be seen from decreased absorbance, which is not so significant compared to the decrease at temperatures of 40 and 80 ℃, accompanied by anthocyanin's fading color, which is co-pigmented with acetic acid and alum during the heating process.

The Utilization of Acid as a Color Stabilizer in the Extraction of Anthocyanins from the Lakum (Cayratia trifolia L.) Peel Aryo E. Peluru; Paulus H. Abram
Jurnal Akademika Kimia Vol. 10 No. 4 (2021)
Publisher : Universitas Tadulako

Anthocyanins are a group of natural dyes (pigments) that give many colors to plants’ leaves, flowers, and fruits. Anthocyanins are generally acidic and more stable under acidic conditions. One of the plants that contain anthocyanin is the lakum (Cayratia trifolia L.) fruit ripe with a blackish-purple color. This study aimed to determine the best type of acid used to extract anthocyanins from the lakum fruit peel. The extraction process was carried out by maceration method using 96% ethanol solvent acidified with three types of acids, HCl 1%, citric acid 3%, and acetic acid 3%, with an average level of anthocyanin obtained of 283.88, 220.70, and 226.55 mg/L, respectively. This study indicated that the best acid used to extract anthocyanin from the lakum fruit peel with the highest total anthocyanin results was by adding HCl 1%.

Co-pigmentation of Anthocyanin Jamblang Fruit (Syzygium cumini) with Acetic Acid and Alum Chintia N. Barani; Siti Nuryanti; Paulus H. Abram
Jurnal Akademika Kimia Vol. 10 No. 4 (2021)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2021.v10.i4.pp237-246

This study aimed to determine the effect of temperature on the stability of anthocyanin jamblang after co-pigmentation with acetic acid and alum. The extraction of Jamblang fruit used the maceration method with n-hexane, ethyl acetate, and ethanol-HCl 0.5% solvents. The total anthocyanin obtained was 70.64 mg/L. Anthocyanin of jamblang fruit was co-pigmented with acetic acid and alum in a concentration of 2.5%; 5%; 7.5%; and 10%, then be heated at various temperatures and heating times. At a temperature of 80 ℃ for 150 minutes, every 30 minutes, absorbance was measured. At a temperature of 60 ℃, the heating was carried out for 225 minutes, and every 45 minutes, absorbance was measured. At a temperature of 40 ℃, the heating was carried out for 300 minutes, and every 60 minutes, absorbance was measured. Absorbance measurements were taken using a UV-VIS spectrophotometer. The results showed that co-pigmentation of anthocyanin occurred proved by shifting λ max from 470 nm (unco-pigmented extract) to 500 nm (co-pigmented extract acetic acid) and 540 nm (co-pigmented extract alum). Acetic acid and alum co-pigments maintained the stability of anthocyanin jamblang at a heating temperature of 60 ℃. It can be seen from decreased absorbance, which is not so significant compared to the decrease at temperatures of 40 and 80 ℃, accompanied by anthocyanin's fading color, which is co-pigmented with acetic acid and alum during the heating process.

The Utilization of Acid as a Color Stabilizer in the Extraction of Anthocyanins from the Lakum (Cayratia trifolia L.) Peel Aryo E. Peluru; Paulus H. Abram
Jurnal Akademika Kimia Vol. 10 No. 4 (2021)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2021.v10.i4.pp254-259

Anthocyanins are a group of natural dyes (pigments) that give many colors to plants’ leaves, flowers, and fruits. Anthocyanins are generally acidic and more stable under acidic conditions. One of the plants that contain anthocyanin is the lakum (Cayratia trifolia L.) fruit ripe with a blackish-purple color. This study aimed to determine the best type of acid used to extract anthocyanins from the lakum fruit peel. The extraction process was carried out by maceration method using 96% ethanol solvent acidified with three types of acids, HCl 1%, citric acid 3%, and acetic acid 3%, with an average level of anthocyanin obtained of 283.88, 220.70, and 226.55 mg/L, respectively. This study indicated that the best acid used to extract anthocyanin from the lakum fruit peel with the highest total anthocyanin results was by adding HCl 1%.

Analysis of Nitrogen and Potassium in Liquid Organic Fertilizer from Rice Washing and Mature Coconut Water Pinkan K. Bolang; Vanny M. A. Tiwow; Paulus H. Abram; Yuli Nurmayanti
Jurnal Akademika Kimia Vol. 14 No. 2 (2025)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2025.v14.i2.pp64-69

Mature coconut and rice washing water contain nitrogen and potassium, which are helpful for plants. This study aims to determine the levels of nitrogen and potassium in liquid organic fertilizer from a mixture of mature coconut water and rice washing water. Nitrogen content was analyzed using the Kjeldahl method. Potassium levels were analyzed using a flame photometer. The results indicated that the best nitrogen and potassium levels were obtained in liquid organic fertilizer with a mixture ratio 50:50, namely N 1.26% and K 1.27%. The highest nitrogen content was obtained in liquid organic fertilizer (LOF) with a mixture ratio of 25:75, 1.40%, and the highest potassium content was obtained in liquid organic fertilizer with a mixture ratio of 50:50, 1.27%. When mixed, the increase in nitrogen and potassium levels was caused by the bacteria in the liquid organic fertilizer, which breaks down protein during digestion.

Epoxidation of Eugenol from Clove Oil (Syzygium aromaticum) Using H₂O₂ Oxidizer and H₃PO₄ Catalyst Walburga E. Gheje; Paulus H. Abram; Maria V. Tiwow; Sitti Rahmawati
Jurnal Akademika Kimia Vol. 14 No. 2 (2025)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2025.v14.i2.pp77-82

Clove oil (Syzygium aromaticum) contains 80–90% eugenol. Eugenol is a pale yellow liquid with several active functional groups, such as hydroxyl, aromatic rings, and allyl groups, which allow it to be modified to produce various eugenol derivative compounds. This study aims to characterize eugenol epoxy resin synthesized from clove oil eugenol using hydrogen peroxide (H₂O₂) and phosphoric acid (H₃PO₄) as a catalyst. The resulting eugenol epoxide was in the form of a yellowish-white gel with a distinctive clove aroma. It was soluble in benzene and chloroform but insoluble in ethanol. FTIR analysis showed that the epoxy compound contained an ether group (C-O-C) at absorption peaks of 1266.07 cm⁻¹ to 1018.66 cm⁻¹, a hydroxyl group (─OH) at 3347.08 cm⁻¹, a methyl group (-CH₃) at 1470 cm⁻¹ to 1350 cm⁻¹, an alkene group (C=C) at 1637.39 cm⁻¹, and a vinyl group at 910.2 cm⁻¹.

Implementation of Locally Oriented PBL Devices on The Other Reaction to the Students' Critical Thinking Ability Jenny I. Laroni; Afadil Afadil; Paulus H. Abram
Jurnal Akademika Kimia Vol. 13 No. 4 (2024)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2024.v13.i4.pp125-132

This study aims to determine the validity, practicality, and effectiveness of the application of problem-based learning tools with local wisdom-oriented material on the rate of reaction to the critical thinking skills of students of SMAN 1 Pamona Utara. The research design used a one-group pretest-posttest design. The population of all class XI MIPA students at SMAN 1 Pamona Utara. The research sample consisted of 54 people, comprising 27 class XI MIPA 1 students and 27 class XI MIPA 2 students, with the two classes serving as the experimental classes. Experts carried out the validation of learning tools, and the score of each validity item of the research instrument in the form of lesson plans and worksheets, calculated according to a Likert scale, was 74.10%, indicating that the lesson plans and worksheets were declared valid and fit for use based on validity by the validator. For the practicality assessment instrument, the implementation of the RPP Problem-Based Learning has been carried out well, resulting in a score of 91.3%, which falls in the very high category. In contrast, the assessment instrument for the effectiveness of critical thinking skills is very high, which is divided into Interpretation, Evaluation, and Analysis, namely, class XI MIPA 1 scored 93%, 96.25%, and 96.5%, and class XI MIPA 2 had scores of 95%, 95.50%, and 96.5%. The value of student learning outcomes is evident in the N-gain values for both classes XI MIPA 1 and 2, which are 0.76 and 0.74, respectively, placing them in the high category. In LKPD based on local cultural wisdom, students are expected to improve their conceptual understanding of the subject matter.

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