Judul: Evaluasi Pengawet untuk Nira Kelapa (Cocos nucifera L.)
Abstrak: Palm sap obtained from tapping palm bunches of coconut flowers. Palm sap rich in sugar with it content apporiximately 11% that make it is easily fermented and decrease its quality. This study aims to obtain an effective antimicrobial formula used to inhibit degradation of palm sap quality. The preservatives used were of ethyl paraben, potassium sorbate, sodium sulfite, and nisin as a single agent or their mixture. Evaluation was done in following steps: (1) evaluation of single preservative toward lactic acid bacteria and yeast, (2) evaluation of preservatives toward lactic acid bacteria and yeast using coconut sap as medium, (3) evaluation the most efficacy preservative toward a mixture of lactic acid bacteria and yeast using coconut sap as medium. Based on the results, the mixture of ethyl paraben+potassium sorbate and ethyl paraben+sodium sulfite could inhibit the growth of yeast, and nisin could inhibit the growth of lactic acid bacteria, and preserve the pH value. When the initial contamination was high (±106 cfu/mL), the mixture of preservatives which could be used were: ethyl paraben 750 ppm + potassium sorbate 250 ppm + nisin 25 ppm; ethyl paraben 750 ppm + potassium sorbate 250 ppm + nisin 50 ppm; ethyl paraben 750 ppm + potassium sorbate 250 ppm + nisin 100 ppm; ethyl paraben 750 ppm + sodium sulfite 125 ppm + nisin 50 ppm; ethyl paraben 750 ppm + sodium sulfite 125 ppm + nisin 100 ppm. However, when initial contamination was lower (±104 cfu/mL), the following mixture of preservatives ethyl paraben 375 ppm + potassium sorbate 125 ppm + nisin 50 ppm were effective to preserve coconut sap.
Keyword: nisin, sodium sulfite, ethyl paraben, palm sap, preservative

Judul: Peningkatan Umur Simpan Produk Santan Kelapa (Cocos nucifera l.) dengan Aplikasi Bahan Tambahan Pangan dan Teknik Pasteurisasi
Abstrak: Coconut (Cocos nucifera L.) milk is very useful in Indonesian food consumption. There is a demand from the small industry to preserve coconut milk product by simple technology. The purpose of this research is to choose the most suitable food additives and thermal process in order to extend coconut milk shelf life. In preparing coconut prior extraction step, blanching with hot water gives better result. Main research consists of three stages: determination of the most suitable stabilizer and antioxidant, determination of preservative, and study of the influence of thermal process and coconut milk storage. The result of the research shows that the most effective combination of food additives for unheated coconut milk are CMC (carboxymethylcellulose), BHT (butilatedhidroxytoluene), and methyl parabens. While the most effective combination of food additives for heated coconut milk are carrageenan, BHT, and kalium sorbate. In room temperature storage, based on pH value, emulsion stability, free fatty acid content, and total of microbe parameters, pure coconut milk without treatment will be expired for less than 12 hours. Heating coconut milk will extend the shelf life to 48 hours, and by pasteurization treatment the shelflife will be longer up to 60 hours. Store in refrigerator for coconut milk without heating will extend the shelf life to 8 days. Coconut milk with and without pasteurization will expire less than 2 months. Use of food additives combination and pasteurization technique, supported by cool storage can extend the shelf life of coconut milk product significantly. Stability is 75.49%; free fatty acid is 0.84; the total of microba is 3.55x103 cfu /ml. Based on the experiment shows that pasteurization coconut milk has either best quality. Furthermore, from the research the best quality of coconut milk is by thermal process, with the heat 75oC, and pasteurization. And at the cool condition (refrigerator) storage will make the coconut milk keep fresh longer.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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