Judul: Proses Pengolahan Asinan Salak Pondoh (Salacca edulis Reinw.)
Abstrak: Sallacca edulis Reinw. (pondoh snakefruit) is one of Indonesia’s tropical fruits commodities. It have character easily damage and short shelf life. However, the level of production snakefruits keeps increasing from year to year. Pickle as an alternative process for extend added value of salak. Water activity is important factor that influence shelf life of salak. The stage is determination the concentration of salt and pickle solution (sugar and vinegar). The results of chemical and physical analysis from the research showed the best concentration of salt and pickle solution is salt 12%, sugar 17%, and vinegar 3.5% with parameter the hardness is 18.25 mm/g.sec, vitamin C 0.0023 (mg/100 g), content of acid 0.015 (ml NaOH 0.1 N/100 g), value sensory of taste 4.026, dan water activity is 0.935. The value of water activity showed the formula not effective to prevent growth destroyed bacteri, yeast, and mold at salak pickle.
Keyword: shelf life, pickle, water activity

Judul: Pengaruh Ekstrak Lengkuas (Alpinia galanga L.Swartz) Terhadap Peningkatan Daya Simpan Buah Salak Pondoh (Sallacca edulis Reinw.)
Abstrak: Pondoh salacca fruit (Salacca edulis Reinw) is an Indonesia tropical seasonal fruit with non-climateric respiratory pattern and naturally perishable with 5 to 6 days of storage at the room temperature (Mahendra et al., 1993). Decrease the quality of fresh fruits generally occurs due to handling during harvest and post harvest inadequate, leading to various forms of mechanical damage, physiological, biological, and microbiological. The damage of salacca fruit especially caused by infection of yeast, the yeast grow in the skin of the fruit, the color of fruit flesh turn into brown, tender, wet, and even rotten, or, the skin of the fruit becomes very dry and hard, and this could caused problems when peeling it. Alpinia galangal (Alpinia galangal L. Swartz) is one of natural rhizome from Zingiberaceae Family that can be used as natural antimicrobes. In this study, to maintain the quality and to extend shelf life of Pondoh salacca fruit, immersion salacca fruit in Alpinia galangal extract, perforation packaging and low temperature storage were performed. The aim of this study is to determine the effect of Alpinia galangal extract to hamper the rotten of Pondoh salacca fruit, analyze physical and chemical conversion during storage and define the best temperature in effort to extend shelf life of Pondoh salacca fruit. This study applies MAP (Modified Atmosphere Packaging). The packages that were used in this study are holed polyethylene (PE) plastic bag sized 25 x 16 cm with 40 μm thickness. Design research that was used is completely randomized design in factorial pattern and four times repetition that were consist of Alpinia galangal concentration factor (consist of 3 levels that were A = 0% (v/v aquadest), B = 5% (v/v aquadest), and C = 10% (v/v aquadest). and storage temperature factor (consist of 3 levels that were T1 = 15oC (RH 85 – 90%), T2 = 22oC (RH 65 – 66%), and T3 = 31oC (RH 67-72%). The study result showed that the best treatment is salacca fruit immersion in 5% (v/v aquades) Alpinia galangal extract during 30 second and storage at temperature 15o C (RH 85-90%) could extend shelf life of Pondoh salacca fruit up to 21 days of storage with 8.33% damage percentage, 0.55% weight loss, 71.56% skin water rate percentage, 80.87% flesh water rate percentage, 17o brix total suspended solid, 0.18% total acid, and 25.83 mg vitamin /100 gram material. The result of organoleptic analysis showed that until the 30th day of storage, hardness, easiness-to-peel, color, flavor, and taste still generally could be accepted, while the black spot at fruit bottom and freshness parameter for salacca fruit that fruit immersion in 0% (v/v aquades) Alpinia galangal extract could not be accepted by panelist on 10 days of storage.
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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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