Judul: Karakteristik Yogurt Probiotik Susu Kambing Hasil Pemberian Pakan Campuran Garam Karbokslat Kering dengan Penambahan Ekstrak Kayu Manis sebagai Flavor
Abstrak: Goat milk enriched naturally by Omega-3 through feeding with a mixture of carboxylate salt dry (MCSD), has a complete nutrition, but contrairely had a more distinctive smell goaty and high risk off flavour of rancidity. It made goat milk less desirable for consumption. Yoghurt is a fermented milk product that can be balanced the intestinal microflora between pathogens and beneficial bacteria. Cinnamon (Cinnamon burmanii) is a spices aromatic that rich in flavour and antioxidant. The addition of cinnamon extract in goat’s milk probiotic yoghurt aims to minimized the goaty smell and to maintain quality of product. This research has purpose to studied the effect of addition cinnamon extracts with different concentrations (3%, 4%, and 5%) on goat’s milk probiotic yoghurt characteristic include physical, chemical, microbiological and sensorial. The results showed that the addition of cinnamon extract influence the acidity (decreased pH value and increased total acid titrable) and sugar content of product, but there isn’t effect on viscosity, protein and fat content of yoghurt. Extract cinnamon addition at 4%-5% stimulated the growth of lactic acid bacteria to 0.7 log10 – 0.8 log10 CFU/ml. The hedonic-test showed that addition cinnamon extract wasn’t influence yoghurt acceptability, but the goaty flavour found less detectable in fermented product with addition of cinnamon extract becaused of the flavour resulted from fermentation process and volatile acid from cinnamon extract. It could be conclude that the fermentation and the addition of cinnamon extract increased the acceptability of goat’s milk probiotic yoghurt.
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Judul: Optimation Formula Yoghurt of Goat Milk and Mushroom with Mixture Design and Potential Functional Properties
Abstrak: Etawah Breed goat milk has not been widely consumed in Indonesia because it has distinctive characteristic of prengus smell so that it is not appreciated by the public, and the lack of public knowledge concerning the benefits of goat’s milk. Milk fermentation process causes the formation of distinctive flavor as the result of activities from lactic acid bacteria, such as acetaldehyde and diacetyl compounds that can reduce or even eliminate the prengus smell. Conventionally, the bacteria commonly used in the formulation of yoghurt were Lactobacillus bulgaricus and Streptococcus thermophilus. However, it was later discovered that the bacteria are not sufficient to maintain the health of digestive tract. To increase the functional value of the yoghurt product, probiotic bacteria should be added. Lactobacillus acidophilus is one of probiotic bacteria that can be added in the making of yoghurt. White oyster mushrooms and shiitake mushrooms are two types of mushrooms well known by the people of Indonesia with affordable prices and potential prebiotic. The fiber and polysaccharides content in these two mushrooms, makes the mushrooms as potential prebiotic. Probiotic yoghurt enriched with the addition of prebiotics produces the product known as synbiotic yoghurt. The formulation of yoghurt can be performed by adding full cream and skim milk. Mixture design is a collection of mathematical and statistical techniques that are useful on modeling and analysis of the problem of the response that is influenced by several variables. The method serves to determine the optimum formula. Indonesia has a huge wealth of biodiversity, including medicinal plants and spices. The spices that have been known for a long time in Indonesia are ginger, cloves, anise and cinnamon. The addition taste in the form of spices syrup into yoghurt, will create a new taste variations. This research aims to assess the formulation of goat milk yoghurt to get the optimum formula using mixture design and determining the functional characteristics of yoghurt optimum formula based on resistance to gastric pH, antimicrobial activity based on E. coli, and amino acid content. This research also aims to examine the effects of spices syrup addition on the preference of the yoghurt. The result showed that the optimum formula was a mixture of 0.5% white oyster mushroom, 3% skim milk, 96% goat skim milk. The optimum formula has pH of 4.30, viscosity of 6200 cP, total titrated acid 1.08%, lactic acid bacteria 1.1 x 1010 cfu/ml. For a functional food criteria of 9.5 x 105 cfu/ml the yoghurt resists based on gastrointestinal tract pH, has 10.9 mm antimicrobial activity based on E.coli and content amino acid. The result of hedonic test that the addition of spices syrup as a topping that the highest score of the taste properties were 4.37 for 4 ml addition of ginger syrup; 4.13 for 6 ml addition of mixture of cloves-cardamom-anise syrup, and 4.23 for 6 ml addition of mixture of cloves-cardamom-cinnamon syrup. Based on these results, the consumer preference was still at the level of netral.
Keyword: goat milk, lactic acid bacteria, mixture design, mushrooms, yoghurt

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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