Purwandaru, Kresna and Maulida, Nurul Istikomah (2023) Studi Waktu Adsorpsi Batch Terhadap Kadar Tanin Ekstrak Daun Stevia (Stevia rebaudiana)”. Sarjana thesis, Universitas Brawijaya.
Abstract
Ekstrak daun stevia (Stevia rebaudiana) merupakan tanaman compositae perdu basah yang sangat berpotensi untuk dikembangkan skala besar sebagai alternatif bahan pemanis alami karena memiliki tingat kemanisan 300 kali dari gula sukrosa. Namun ekstrak daun stevia umumnya masih mengandung rasa pahit yang disebabkan adanya kandungan tanin. Oleh karena itu perlu dilakukan tahap pemurnian dahulu untuk menurunkan kandungan tanin dan meningkatkan rasa manisnya, salah satunya yakni dengan adsorpsi batch menggunakan adsorben karbon aktif teraktivasi NaOH 1M. Penelitian ini bertujuan untuk mengetahui pengaruh waktu adsorpsi batch terhadap kadar tanin ekstrak daun stevia dan menentukan model adsorpsi isoterm yang sesuai. Variabel bebas yang digunakan pada penelitian ini yakni waktu adsorpsi 5 hingga 180 menit dan sampel diambil setiap 5 menit. Adsorben karbon akif yang digunakan dihaluskan menjadi 100 mesh dan diaktivasi menggunakan larutan NaOH 1M selama 24 jam. Metode penentuan kadar tanin dilakukan dengan reagen folin-ciocalteu 0,5 ml dan larutan Na2CO3 35% 1 ml serta diukur absorbansinya menggunakan spektrofotometer Uv-Vis pada gelombang maksimal 735 nm. Kadar tanin dinyatakan dalam satuan mg/gr TAE (Tannic Acid Equivalent). Hasil penelitian ini menunjukkan terdapat 3 kondisi kadar tanin yang berbeda, yakni pada waktu adsorpsi 5-90 menit kadar tanin menurun, pada 95-120 menit kadar tanin konstan (setimbang) dan pada 125-180 menit kadar tanin meningkat. Waktu kesetimbangan adsorpsi tanin ekstrak daun stevia dicapai pada rentang waktu 95-120 menit dan didukung dengan analisis akurasi menggunakan perhitungan koefisien variasi yang didapatkan sebesar 4,17%. Kadar tanin ekstrak daun stevia sebelum adsorpsi didapatkan sebesar 0,910 mg/gr TAE dan terendah sebesar 0,040 mg/gr TAE pada waktu 100 menit dengan efisiensi maksimal mencapai 95,6%. Adsorpsi tanin ekstrak daun stevia dapat terjadi karena adanya gugus polar seperti gugus hidroksil (O-H) yang membentuk ikatan hidrogen, terdapat interaksi gaya van der waals dengan gugus fungsi karbon aktif, adanya peningkatan luas permukaan dan diameter pori adsorben karbon aktif yang tergolong mesopori (5,33 nm), serta peristiwa tegangan permukaan. Model adsorpsi isoterm yang sesuai adalah Freundlich dengan nilai R2 = 0,9998 dan KF = 25,293 [(mg/gr)(L/mg)1/nf], serta jenis adsorpsi yang terjadi adalah fisika.
English Abstract
Stevia leaf extract (Stevia rebaudiana) is a wet shrub Compositae plant which has the potential to be developed on a large scale as an alternative natural sweetener because it has a sweetness level of 300 times that of sucrose. However, stevia leaf extract generally still contains a bitter caused by the tannins content. Therefore it is necessary to carry out the purification to reduce the tannin content and increase the sweetness, one of which is by batch adsorption using activated carbon. This research to determine the effect of batch adsorption time on the tannin content of stevia leaf extract and determine the appropriate adsorption isotherm model. The independent variables used in this study were adsorption time from 5 to 180 minutes and samples were taken every 5 minutes. The carbon adsorbent used was ground to 100 mesh and activated using NaOH 1M solution during 24 hours. The tannin content determination method was carried out with 0.5 ml of folin-ciocalteu reagent and 1 ml of 35% Na2CO3 solution and the absorbance was measured using a Uv-Vis spectrophotometer at a maximum wave of 735 nm. Tannin levels are expressed in units of mg/gr TAE (Tannic Acid Equivalent). The results of this study showed were 3 different tannin content conditions, decreasing condition at 5-90 minutes, constant at 95-120 minutes, and increasing at 125-180 minutes. The adsorption equilibrium time of stevia leaf extract tannins was reached at 95-120 minutes and was supported by an analysis using a coefficient of variation calculation is 4.17%. The tannin content of stevia leaf extract before adsorption was 0.910 mg/gr TAE and the smallest was 0.040 mg/gr TAE at 100 minutes with a maximum efficiency of 95.6%. Adsorption of tannins in stevia leaf extract can occur due to the presence of polar groups such as hydroxyl groups (O-H) which form hydrogen bonds, interaction of van der waals forces with the site of activated carbon adsorbent, increase surface area and pore diameter of adsorbent be mesopore (5,33 nm), and surface tension. The suitable adsorption isotherm model is the Freundlich adsorption isotherm with a value of R2 = 0.9998 and KF = 25.293 [(mg/gr)(L/mg)1/nf], and the type of adsorption that occurs is physics.
| Item Type: | Thesis (Sarjana) |
|---|---|
| Identification Number: | 0523070047 |
| Uncontrolled Keywords: | adsorpsi batch, ekstrak daun stevia, karbon aktif, tanin, waktu adsorpsi |
| Divisions: | Fakultas Teknik > Teknik Kimia |
| Depositing User: | agung |
| Date Deposited: | 11 Jan 2024 02:29 |
| Last Modified: | 11 Jan 2024 02:29 |
| URI: | http://repository.ub.ac.id/id/eprint/207880 |
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