ALBERTA RIKA PRATIWI
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Isolation and Characterization of Silaffin that Catalyze Biosilica Formation from Marine Diatom Chaetoceros gracilis MANURUNG, AGNES IMELDA; PRATIWI, ALBERTA RIKA; SYAH, DAHRUL; SUHARTONO, MAGGY THENAWIDJAJA
HAYATI Journal of Biosciences Vol 14, No 3 (2007): September 2007
Publisher : Bogor Agricultural University, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (292.311 KB) | DOI: 10.4308/hjb.14.3.119

Abstract

The method of making silica in industries requires extreme conditions. The finding of proteins involved in the formation of biosilica from diatoms, has opened up an alternative way of production. Chaetoceros gracilis is one of the diatoms, which is potential in producing silaffin protein. This study aimed to isolate and to characterize the protein. We also analyzed the protein activity toward tetraethoxyorthosilicate (TEOS) substrate in in vitro reaction. Diatom biomass was harvested and further kept in 2% SDS/100 mM EDTA solution. Protein isolation was conducted by dissolving the silica and separating the protein by soaking in 2 M HF/8 M NH4F. Protein concentration was analyzed using Bradford method and the molecular weight was estimated through SDS-PAGE. Protein activity was observed by reacting it with TEOS substrate to form silica polymer and measured by colorimetric molibdate assay. Protein concentration was 1.20 mg/ml and appeared filamentous. The apparent molecular weights consisted of 12, 23, 42, 44 kDa. These protein was able to polymerize the silica at room temperature within 10 min. As much as 85.65 umol TEOS was polymerized per 1.4 x 106 silaffin protein per min. SEM analysis showed the formation of spherical, aggregate biosilica. Key words: Chaetoceros gracilis, silaffin protein, biosilica, polymerization
Fatty Acid Synthesis by Indonesian Marine Diatom, Chaetoceros gracilis PRATIWI, ALBERTA RIKA; SYAH, DAHRUL; HARDJITO, LINAWATI; PANGGABEAN, LILY MARIA GORETTI; SUHARTONO, MAGGY THENAWIDJAJA
HAYATI Journal of Biosciences Vol 16, No 4 (2009): December 2009
Publisher : Bogor Agricultural University, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (134.069 KB) | DOI: 10.4308/hjb.16.4.151

Abstract

Since the primary storage nutrients in diatoms consist of lipid, they are potential for the industrial fatty acid production. High value fatty acids include arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid. This study aimed to analyze fatty acid synthesis by Chaetoceros gracilis diatom during growth. There was a large increase in lipid yield from 4pg cell-1 mass of lipid per cell at the exponential phase to 283pg cell-1 at stationary phase. The lipid concentrations also increased significantly from the stationary phase to the death phase, but not significantly from the end exponential phase to the stationary phase. The relative percentage of saturated fatty acid (SAFA) of the total fatty acid was higher than that of monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) at all of growth phase. The highest PUFA was found at stationary phase at the same time when SAFA was being the lowest. The majority of SAFA was palmitic acid (24.03-40.35%). MUFA contained significant proportion of oleic acid (19.6-20.9%). Oleic acid, linoleic acid and α-linolenic acid were found at every stage growth. These fatty acids are considered as precursor for production of long chain PUFA-Docosahexaenoic acid (DHA/22:6ω3) through series of desaturation and elongation step with all of desaturase enzyme (Δ8-D, Δ9-D, Δ12-D, Δ15-D, Δ17-D, Δ6-D, Δ5-D, and Δ4-D) and elongase enzyme (E).         Key words: Chaetoceros gracilis, fatty acid, synthesis, saturated fatty acid (SAFA), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA)
BIOPRESERVATIF ALAMI DALAM PEMBUATAN EDIBLE FILM KARAGENAN Eucheuma cottonii DENGAN POLIETILEN GLIKOL SEBAGAI PLASTICIZER Caroline, Clementia; Pratiwi, Alberta Rika
JURNAL AGROTEKNOLOGI Vol 11 No 02 (2017)
Publisher : Faculty of Agricultural Technology, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (292.331 KB) | DOI: 10.19184/j-agt.v11i02.6523

Abstract

Flavored edible film can be made from carrageenan with addition of spices such as sugar, salt, garlic, pepper, and nutmeg. Flavored edible film is an instant spice product innovation to reduce plastic packaging waste. This study aims to determine the effect of adding spices to flavor, solubility, shelf life, antibacterial activity, and fungus growth on edible film. Sensory analysis was to determine the most preferred formulation. Solubility analysis used solution at 75°C and 100°C with oil and without oil. Shelf life analysis used the Accelerared Shelf-Life Testing method at 25°C, 35°C, and 40°C at 75% RH. Antibacterial activity used paper disc diffusion method with Bacillus cereus and Salmonella. Analysis of fungus growth was done with incubation for 24 hours. Flavored edible film consisting of 4 grams of sugar, 4 grams of salt, 1 grams of garlic, 0.2 grams of pepper and 0.2 grams of nutmeg has the highest score of taste and aroma attribute score of 2.20 ± 0.45. Flavored edible film had a significant difference solubility in oil treatment and no significant difference in temperature treatment. Flavored edible film had a shelf life 17 days. Flavored edible film could not inhibit bacterial activity. There was no fungal growth on flavored edible film. Keywords: flavored edile film, carrageenan, sensory, solubility, shelf life, antimicrobial activity, fungus growth
Pengaruh Deep-Fat Frying terhadap Kandungan Asam Glutamat pada Bumbu Penyedap Granul Spirulina sp. Larasati, Bernadeta Pingkan; Ananingsih, Victoria Kristina; Hartayanie, Laksmi; Pratiwi, Alberta Rika
Jurnal Aplikasi Teknologi Pangan Vol 8, No 2 (2019): Mei 2019
Publisher : Faculty of Animal and Agricultural Sciences, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (150.849 KB) | DOI: 10.17728/jatp.3347

Abstract

AbstrakPenelitian ini bertujuan mengetahui pengaruh deep-fat frying terhadap kandungan asam glutamat bumbu penyedap granul Spirulina sp. yang telah diaplikasikan ke dalam adonan tepung terigu. Penelitian pendahuluan dilakukan untuk menghasilkan tiga formulasi bumbu penyedap granul Spirulina sp berdasarkan kadar gula dan kadar garam bumbu 3 produk komersial. Tiga formulasi penyedap granul Spirulina sp diaplikasikan ke dalam tepung terigu yang kemudian digoreng dengan metode deep-fat frying pada suhu 140, 160, dan 180oC hingga matang. Adonan sebelum dan sesudah penggorengan dianalisis warnanya menggunakan chromameter. Kandungan asam glutamat adonan setelah penggorengan kemudian dianalisis menggunakan L-glutamate assay kit dan diuji spektrofotometer pada panjang gelombang 492 nm. Hasil penelitian menunjukkan bahwa proses penggorengan menyebabkan perubahan warna pada adonan. Peningkatan suhu penggorengan dari 140 ke 180oC menyebabkan penurunan nilai L* dari ±47 ke ±39, penurunan nilai b* dari ±26 ke ±19, serta peningkatan nilai a* dari ±8 ke ±10. Hasil penelitian juga menunjukkan peningkatan suhu penggorengan 140 ke 180oC yang menyebabkan penurunan kandungan asam glutamat adonan bumbu penyedap granul Spirulina sp. dari ±8 menjadi ±3 mg/100g. Kesimpulannya, peningkatan suhu penggorengan menyebabkan perubahan warna dan penurunan kandungan asam glutamat pada semua formulasi bumbu penyedap yang diimplentasikan pada adonan tepung terigu.Effect of Deep-Fat Frying to The Glutamic Acid Content in Spirulina sp. Granule Flavor EnhancerAbstractThis research aims to determine the effect of deep-fat frying on the content of glutamic acid in Spirulina sp. granule flavor enhancer that has been applied to the flour dough. Preliminary research was produced three formulas of Spirulina sp. granule flavor enhancer, that were formulated based on sugar and salt content on three commercial seasoning brands. Thus, three formulas were applied to wheat flour then fried with deep-fat frying method at 140, 160, and 180oC until cooked well. The color of doughs before and after frying were analyzed using chromameter. The glutamic acid content were analyzed using L-glutamate assay kit and tested by spectrophotometer at 492 nm. As results, frying process changed the color of the dough. The increase in the frying temperature from 140 to 180oC caused a decrease in value of L from ± 47 to ±39, value of b* from ± 26 to ±19, and increase the value of a* from ±8 to ±10. The increase in the temperature of frying from 140 to 180oC caused a decrease in glutamic acid content of Spirulina sp. from ±8 to ±3 mg/100 g. As conclusion, increase in the frying temperature might cause a change in color and decreased content of glutamic acid in the doughs.