Judul: Determination Total Phenol and Flavonoid and Antioxidant Activity of Soursop Leaf Extract (Annona muricata L.)
Abstrak: Daun sirsak (Annona muricata L.) mengandung senyawa fenolik dan flavonoid yang menunjukkan aktivitas antioksidan. Oleh karena itu, penelitian ini bertujuan mengevaluasi kadar fenolik dan flavonoid total pada ekstrak air dan etanol p.a. daun sirsak serta aktivitas antioksidannya berdasarkan dua metode, yaitu DPPH (2,2-difenil-1-pikrihidrazil) serta FRAP (ferric reducing antioxidant power). Kedua ekstrak ditentukan kadar fenolik dan flavonoid total, kemudian aktivitas antioksidan menggunakan metode DPPH dan FRAP. Metode DPPH menggunakan nilai IC50 sebagai parameter aktivitas antioksidan, sedangkan metode FRAP menggunakan kesetaraan terhadap asam askorbat (mg asam askorbat ekuivalen/mL ekstrak). Hasil kadar fenolik dan flavonoid total yang baik adalah ekstrak etanol p.a.. Hasil penentuan aktivitas menggunakan metode DPPH dengan ekstrak air dan etanol p.a. memiliki nilai IC50 secara berturut-turut sebesar 98,46 µg/mL dan 27,03 µg/mL. Hasil penentuan aktivitas menggunakan metode FRAP menunjukkan ekstrak air sebesar 1,72 mg AAE/mL ekstrak, sedangkan ekstrak etanol p.a. sebesar 4,15 mg AAE/L ekstrak. Hasil penelitian menunjukkan bahwa daun sirsak memiliki aktivitas antioksidan.
Keyword: Antioksidan, Daun Sirsak, DPPH, FRAP

Judul: Pengaruh Lama Penyimpanan dan Perebusan Daun Sirsak Segar (Annona muricata Linn) terhadap Aktivitas Antioksidan Sari Daun Sirsak.
Abstrak: Soursop (Annona muricata Linn) leaves have been used as traditional medicine. Antioxidant compounds contained in the soursop leaves are steroids or terpenoids, flavonoids, coumarins, alkaloids, saponins and tannins. The objectives of this research was to assess effect of storage time (0, 3, 7 and 14 days) at low temperature (4-8oC) and boiling time (5, 7 and 10 minutes) of fresh soursop leaves with boiling water (98oC) on antioxidant activity of soursop leaves extract. Analysis performed to the extracts were water content, pH, antioxidant activity (DPPH method), total phenolics and total flavonoids. The results analysis of variance showed that soursop leaves storage and boiling time gave significant (α<0.05) impact to antioxidant activity, total phenolics, total flavonoids and pH values. Fresh soursop leaves that stored in low temperature (4-8oC) longer have lower average value of antioxidant activity, total phenolics and total flavonoids of soursop leaves extract, but higher average value of pH. Moreover, longer boiling time resulted to higher average value of antioxidant activity, total phenolics and total flavonoids extract of soursop leaves, but lower average value of pH. The best treatment is based on the highest value of antioxidant activity, obtained from soursop leaves storage time treatment of day-zero with boiling time 10 minutes.
Keyword: Annona muricata Linn, antioxidant, boiling time, storage time

Judul: Implementasi Space Time Composite (STC) Data Model Menggunakan Model Data Relasional
Abstrak: The data model is a concept that describes the data stored in the database and the relationship between the data to the user in logic. Development of data models is very important in the design of the database as the basis of the stage of database design to be made. This study aims to apply the concept of Space Time Composite (STC) on the Model Data storage vector data types that can store enough information and describes the process of drafting objects and objects spatiotemporal evolution over time. From the results of the test queries on the data model that have been created, queries in a system are acquired that can help display the information preparation of objects from time to time and know the history of the object polygon and arc that has undergone changes in topology.
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