Judul: Effect of Over Fermentation Period Tempeh with The Addition of Seaweed on Chemical Composition and Bioactive Components
Abstrak: Tempe yang difermentasi dengan waktu yang lebih panjang memiliki karakteristik berbeda dengan tempe segar. Perubahan akibat lama fermentasi dan penambahan rumput laut memberikan pengaruh terhadap komposisi kimia dan komponen bioaktif. Penelitian ini bertujuan untuk mengevaluasi pengaruh lama waktu fermentasi terhadap karakteristik tempe rumput laut dengan waktu fermentasi berlebih dan mengidentifikasi komposisi kimia serta komponen bioaktif pada tempe dengan penambahan rumput laut pada fermentasi berlebih. Lama waktu fermentasi yang dilakukan pada penelitian ini adalah selama 48, 60, 72, dan 84 jam. Komposisi kimia tempe dengan penambahan rumput laut memiliki kadar air berkisar 64,03-65,62%, kadar abu berkisar 1,50-1,71%, kadar lemak 1,39-2,31%, dan kadar protein berkisar 15,99-16,94%. Senyawa metabolit yang terkandung adalah alkaloid, steroid, saponin, dan fenol. Komponen bioaktif mengalami kenaikan pada tempe rumput laut fermentasi 48 jam dan fermentasi 84 jam dengan total fenol berturut-turut sebesar 9,04 mg GAE/g dan 10,75 mg GAE/g serta nilai antioksidan masing-masing sebesar 199,30 ppm dan 167,17 ppm.
Keyword: Fermentasi, Rumput Laut, Tempe

Judul: Utami, Rahayu
Abstrak: Tempe is a fermented soybean food in Indonesia. Tempe was commonly produced about 24-48 hours fermentation. Tempe is referred as over-fermented tempe after the 48 hours fermentation has been completed. The over-fermented tempe known as tempe semangit and tempe bosok. Tempe semangit is over-fermented tempe (slightly overriped) which is obtained by lengthening the fermentation 48-72 hours longer than fresh tempe fermentation, whereas tempe bosok (overripe tempe) needs more than 72 hours of over-fermentation. Therefore, over-fermented tempe has a brown color, pungent odor, and soft textures compared to the white compact cake of fresh tempe. Over-fermented tempe is popular in Javanese culture as an umami seasoning in traditional foods. Over-fermented tempe have been prepared by several different periods including : 0, 24, 48, 72 and 96 hours after the tempe production. Over-fermented tempe was extracted to obtain water soluble extracts (WSEs). The water soluble extracts (WSEs) were analyzed for crude proteins, total acids, total sugars, pH value, total amino acids, free amino acids, HPLC profile, taste activity value and umami taste dilution factors. Analysis of variance (ANOVA) was performed on crude protein, total acids, total sugars and pH value. As shown by ANOVA, crude protein and pH value were not statistically different between the fermentation periods, but were statistically different on total acids and total sugars. Free amino acids were characterized for their tasting and taste activity values. Based on the taste activity value, the taste of WSEs was umami and bitter. WSE from sample with 72 hours over-fermentation had umami taste activity value higher than bitter taste activity. The ratios of umami and sweet taste activity value to bitter taste activity were found between 1.2-1.6 in the mentioned WSE. There was a positive correlation between the taste rasio and umami taste dilution factor (r = 0.843 dan p = 0.002). The umami taste dilution factor was the result of sensory analysis of 5 times concentrated WSE. The highest ratio 1.6 belongs to WSE with 72 hours over-fermentation which had the highest dilution factor 256. Umami taste intensity WSE with 72 hours fermentation was determined with the existence of umami and bitter tasting free amino acids. In general HPLC profile indicated the composition in WSE’s fractions. Fraction 2 of each WSE of over-fermented tempe dominantly consisted of hydrophilic components, in contrast Fraction 3 of each WSE of over-fermented tempe was dominated by hydrophobic components. Fraction dominantly consisted of hydrophilic components having a higher intensity of umami taste.
Keyword: bitter taste, free amino acids, umami taste, over-fermented tempe, water soluble extract

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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