Judul: Nanoenkapsulasi Ekstrak Kelopak Bunga Rosella (Hibiscus sabdariffa) Hasil Ekstraksi Berbantu Gelombang Mikro Sebagai Bahan Antibakteri dan Antioksidan
Abstrak: Roselle has used as medicine because they contain bioactive medicine because they contain bioactive compound such as phenols. The present study was designed to develop Microwave Assisted Extraction (MAE) on phenolics extraction from roselle calyx which gave maximum yield, higher antioxidant and antibacterial activity, and maintain stability of roselle bioactive compounds through the application of nano-encapsulation technology. Scope of this research was divided in three stages of experimental activities. Firstly, investigated of solvent influence on characteristics of toxicity, antibacterial and antioxidant activities. Secondly, determined the optimum condition of Microwave Assisted Extraction and characterized the extract on optimum conditions, and thirdly, applied of nano-encapsulation technique to improved the stability roselle extract. The aims of the first research was to find solvent with the best extract characteristics of toxicity, antibacterial and antioxidant activity. Qualitative method was used to determine the phytochemical calyx content, Brine Shrimp Lethality for toxicity tests. Antibacterial tests were done against Staphylococcus aureus and Escherichia coli using disc diffusion method. Total antioxidant activity was determined by the ferric thiocyanate method. The results showed that bioactive compounds in Roselle calyx were flavonoid, phenolic compounds, tannin, alkaloid, and steroid. Ethanol 70% could extract the phenolics 19.45 + 0.32 mg/g compared with ethyl acetate and hexane, which only could extract the fenolik compound respectively 7.51 + 0.49 mg/g and 2.73 + 0.31 mg/g. It means that ethanol 70% is more effective than the other solvents. The ethanol 70% extract was found to be potential against brine shrimp with LC50 value below 1000 ppm, 510.613 ppm. On the other hand with ethyl acetate and hexane were respectively 1241.983, and 1718.446 ppm. Ethanol 70% and ethyl acetate extract had antibacterial activity, showed by inhibitory zone 7.7 + 2,01b mm and 7,53 + 2,19 bmm for S aureus and 13.28 + 3,30b mm, 12,35 + 3,13b mm against to E coli. There was no inhibitory zone for crude hexane extract. EC50 value for ethanol 70%, ethyl acetate and hexane were 4393.2; 5879,16 ;4813,92 ppm respectively. Roselle calyx was an excellent source of phenolic compounds. In this study, microwave-assisted extraction was employed to extract the phenols from Roselle calyx. The aims for the second stage were to determined the optimum condition of microwave assisted extraction, and characterized of the antibacterial and antioxidant activity extract from optimum condition. For the efficiency of extraction by using response surface methodology, the effects of microwave output power, ethanol concentration, and extraction time on total phenols yield were investigated and the optimal conditions were determined as follows: microwave output power 250 W, etanol concentration 78,36% and extraction time 4.91 min. The estimated values for total fenoliks yield, 24,61 mg/g was obtained at those conditions. A verification experiment at the optimum condition, consisting of 4 runs, was performed and the practical yield of 23.77 + 0.25 mg/g total fenoliks was higher than using conventional method 19.84 + 0.46 mg/g.. Compared with conventional method, total phenolics, antosianin, and vitamin C and yield of microwave assisted extraction were 23.77 + 0.25, 14.80 + 0.08, 10.74 + 0,14 mg/g and 22.09 + 3.3 % which are higher
Keyword: roselle, antibacterial, antioxidant, toxicity, phenolics

Judul: Process engineering of langsat fruit peel (Lansium domesticum var. langsat) extraction as antibacterial and antioxidant
Abstrak: Langsat, a fruit plant in the family of Meliaceae, has long been used in traditional medicine to treat fever, diarrhea, malaria, and tumor. This study aims to obtain the optimum extraction condition and method of langsat fruit peel with the best antibacterial and antioxidant activities. The methods used to determine activities were agar diffusion method, dillution method for MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) for antibacterial and DPPH (1,1-diphenyl-1-picrilhydrazyl) for antioxidant activity. Solvents used in the maceration extraction were hexane (non polar), ethyl acetate (semi-polar) and ethanol (polar). Solvent that gave the best antibacterial and antioxidant activity was further used for the microwave extraction. Conventional extraction methods namely reflux and maceration were then compared to microwave extraction. The microwave power and extraction time was determined based on the highest total phenol extract of langsat fruit peel. The best extraction method was used to optimize the extraction process with response surface method to determine the optimal conditions for the extraction of langsat fruit peel. The results showed that ethanol extracts have the highest antibacterial and antioxidant activity compared to other extracts. The MIC and MBC values of ethanol extracts were 62.5 and 125 ppm for bacteria S. aureus, while the bacteria E. coli with value of 500 and 1000 ppm, respectively. The antioxidant activity of ethanol extract DPPH method has IC50 value of 77.60 ppm. Microwave with power of 400 watt for 3 minutes, produced the highest total phenol extract. Extraction with microwave produced phenol with a total of 13.92% and 22.64%, higher than extraction with reflux and maceration. The optimum extraction of langsat fruit peel was obtained at the microwave power of 336.56 watts and for extraction time of 3.24 minutes, which resulted in a total phenolic extract of the langsat fruit peel 44.07 mg TAE/g. The validation results experimentally showed the value of total phenols 0.66% smaller than predicted. Validation results showed an increase in antibacterial and antioxidant activity than before the optimization, the MIC and MBC values for S. aureus were 31.25 and 62.5 ppm, whereas E. coli with value of 125 and 250 ppm. The antioxidant activity of the validation result has IC50 value of 47.44 ppm.
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Judul: Analisis Struktur Atas Gedung Diploma IPB terhadap Beban Gempa Berdasarkan SNI 03-1726-2002 dan SNI 03-1726-2012
Abstrak: Gedung Diploma IPB masih menggunakan SNI 03-1726-2002 dalam perencanaan strukturnya. SNI tersebut kemudian diubah seiring dengan keluarnya peraturan baru yang termuat dalam SNI 03-1726-2012. Tujuan dari penelitian ini adalah mengetahui ketahanan struktur atas gedung Diploma IPB terhadap beban gempa ditinjau berdasarkan waktu getar alami dan partisipasi massa, mengetahui besarnya gaya geser dasar seismik, dan membandingkan besarnya simpangan berdasarkan kedua SNI. Partisipasi massa arah X yang dihasilkan yaitu sebesar 0.9417 pada modal ke 9 dan 0.9006 pada modal ke 12 pada arah Y. Kedua nilai tersebut telah memenuhi kedua standar SNI. Waktu getar alami telah memenuhi standar SNI 2002, namun belum memenuhi standar SNI 2012. Gaya geser dasar dinamik yang dihasilkan berdasarkan SNI 2012 sebesar 1599.6606 kN akibat gempa arah X dan 1223.5794 kN akibat gempa arah Y, sedangkan berdasarkan SNI 2002 untuk arah X sebesar 1544.5109 kN dan untuk arah Y sebesar 1544.8304 kN. Simpangan antar lantai telah memenuhi persyaratan kedua standar SNI. Struktur Gedung Diploma IPB telah memiliki kekakuan yang cukup dan terhitung boros, sehingga seharusnya dapat direncanakan dengan lebih hemat biaya.
Keyword: beban gempa, gaya geser dasar, simpangan, struktur atas