Judul: Pengaruh Lama Perebusan terhadap Kandungan Gizi dan Komponen Bioaktif Keong Matah merah (Cerithidea obtusa)
Abstrak: Indonesia has a great potential with marine life, matah merah snail is one from many marine life is used to consume. People generally serve matah merah snail using boiling manner. This study aims to determine the effect boiling time on nutrition and bioactive components of matah merah snail. The design of the research is completely randomized design (CRD) with 1 factor and 4 levels, there was fresh (M0), boiling (M1), boil + 10 minutes (M2), boil + 20 minutes (M3) with 2 replications. The test that conducted was proximate test, phytochemical test and BSLT test . Data were analyzed by analysis of variance, if the analysis of variance significant effect on the level of 5%, then the test is continued by real difference test. Based on the results of the statistical analysis of variance factor treatment were not significant effect on moisture, ash and fat. The significant results of statistical analysis on the protein content gained followed by Duncan test, the results are treatment M0 is significantly different to the treatment M1, M2, and M3. Phytochemical test results, the M0 metanol extract compounds contains ninhydrin, flavonoids, alkaloids, tanins and terpenes. Compounds that Contained on M1 and M2 are ninhydrin, flavonoids, alkaloids, tanins and terpenes, while the M3 contains flavonoids, ninhydrin, alkaloids and terpenes. The M0 ethyl acetate extract containing flavonoids and ninhydrin, alkaloids and terpenes weak. M1 contains ninhydrin, polyphenols and terpenes, whereas in M2 and M3 contains ninhydrin, alkaloids and terpenes. Hexan extract M0 contains flavonoids, terpenes, saponins, while the M1, M2 and M3 contains terpenes and saponins. LC50 values in the M0, M1, M2, and M3 metanol extract are 15.58; 22.54; 25.68; 39.8 ppm. Ethyl acetate extract M0, M1, M2, and M3 LC50 values at 40.08; 364.58; 146.12; 130.27 ppm. N-hexane extract M0, M1, M2, and M3 have LC50 values of 1100.43; 352.5; 90.49; 14.95 ppm.
Keyword: bioactive compounds, gastropods, matah merah snails, nutrition

Judul: Pengaruh metode pengolahan terhadap kandungan mineral keong matah merah (Cerithidea obtusa)
Abstrak: Unsur mineral merupakan salah satu komponen zat gizi penting yang sangat diperlukan oleh tubuh disamping karbohidrat, lemak, protein dan vitamin. Mineral berfungsi sebagai zat pembangun dan pengatur di dalam tubuh. Pemenuhan kebutuhan mineral pada manusia dapat diperoleh dengan cara mengkonsumsi bahan pangan baik yang berasal dari nabati maupun hewani. Keong matah merah mengandung nilai gizi terutama mineral yang tinggi. Pada umumnya keong matah merah dikonsumsi oleh masyarakat setelah mengalami proses pengolahan. Proses pengolahan sangat berpengaruh terhadap kelarutan mineral dan gizi bahan pangan karena terjadi kerusakan bahan pangan oleh panas yang berakibat menurunnya nilai gizi sehingga perlu dilakukan penelitian mengenai pengaruh metode pengolahan tersebut. Tujuan umum penelitian ini adalah menentukan jumlah mineral makro dan mikro pada keong matah merah, sedangkan tujuan khusus adalah menganalisis pengaruh pengolahan terhadap kandungan mineral dan kehilangan mineral, menganalisis kelarutan mineral (natrium, kalsium, fosfor dan magnesium) akibat pengolahan serta menentukan metode pengolahan terbaik yang memberikan kehilangan mineral terendah dan kelarutan mineral tertinggi pada keong matah merah.
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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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