Judul: Physicochemical Characteristics, Antioxidant Activity, and Organoleptical Quality of Greek Yogurt with Addition of Pomegranate Peels Extract
Abstrak: Yoghurt termasuk produk pangan fungsional yang sering dimodifikasi salah satunya dengan penambahan sumber komponen bioaktif alami seperti ekstrak kulit delima (Punica granatum L.). Penelitian bertujuan untuk menganalisis karakteristik fisikokimia, aktivitas antioksidan, dan mutu organoleptik greek yoghurt dengan penambahan ekstrak kulit delima pada taraf berbeda. Greek yoghurt diberi penambahan ekstrak kulit delima sebanyak 0% (kontrol), 0,5%, 1,5%, dan 2,5% dari berat greek yoghurt kontrol. Penelitian dilakukan menggunakan rancangan acak lengkap (RAL) dengan penambahan ekstrak kulit delima sebagai perlakuan. Hasil penelitian menunjukkan bahwa penambahan ekstrak kulit delima pada greek yoghurt berpengaruh nyata (p<0,05) terhadap penurunan pH dan peningkatan aktivitas serta kapasitas antioksidan. Penambahan ekstrak kulit delima meningkatkan kesukaan panelis terhadap atribut rasa namun berlaku sebaliknya pada atribut warna. Makin besar taraf ekstrak kulit delima mengakibatkan kenaikan intensitas warna, aroma, dan rasa ekstrak kulit delima. Sebagai kesimpulan, penambahan 1,5% ekstrak kulit delima dapat memperbaiki karakteristik fisikokimia dan meningkatkan aktivitas antioksidan dengan mutu organoleptik greek yoghurt yang lebih baik., Yogurt is a functional food that is often modified by adding bioactive component such as pomegranate peel extract (Punica granatum L.). This study was aimed to analyze physicochemical characteristics, antioxidant activity, and organoleptical quality of greek yogurt with the addition of pomegranate peels extract at different levels. Greek yogurt was added by pomegranate peels extract at levels of 0% (control), 0,5%, 1,5%, and 2,5% of greek yogurt control's weight. The study was conducted using a completely randomized design (CRD) with the addition of pomegranate peel extract as a treatment. The results showed that pomegranate peels extract added to greek yogurt had significant effects (p<0.05) on decreasing pH and increasing antioxidant activity and capacity. Pomegranate peels extract addiction increased the taste preference but decreased the color preference. Higher level of pomegranate peels extract caused higher intensity of color, aroma, and taste of pomegranate peels extract. In conclusion, the addition of 1,5% pomegranate peels extract improved physicochemical characteristics and increased antioxidant activity with better organoleptic quality of greek yogurt.
Keyword: Antioxidant, Organoleptic, Physicochemical, Pomegranate peels, Yogurt

Judul: Physicochemical and Organoleptic Properties of Yoghurt With the Addition of Min Leaf Powder (Mentha piperita)
Abstrak: Susu dapat diolah menjadi salah satu pangan fungsional yang populer di masyarakat dan salah satunya diolah menjadi yoghurt. Pengembangan pengolahan yoghurt diantaranya dengan penambahan daun min sebagai bahan alami yang mempunyai manfaat, tetapi tidak berpengaruh buruk dalam proses pengolahan dan produk akhir yang dihasilkan. Penelitian ini bertujuan untuk menganalisis sifat fisikokimia dan organoleptik yoghurt yang diberi penambahan serbuk daun min. Rancangan yang digunakan dalam penelitian ini adalah menggunakan Rancangan Acak Lengkap (RAL) dengan perlakuan penambahan serbuk daun min dengan konsentrasi yang berbeda yaitu 1) Tanpa penambahan serbuk daun min; 2) Penambahan daun min 4,54%; 3) Penambahan serbuk daun min 9,08%. Pengujian fisikokimia adalah pH, viskositas, TAT, dan antioksidan. Pengujian sifat organoleptik yang dianalisis adalah warna, aroma, kekentalan, dan rasa. Hasil penelitian menunjukkan bahwa penambahan daun min berpengaruh sangat nyata (p<0,01) terhadap kandungan antioksidan yoghurt, namun tidak berpengaruh nyata terhadap warna, aroma, rasa, dan kekentalan. Uji hedonik menunjukkan bahwa penambahan daun min berpengaruh nyata (p<0,05) terhadap warna, aroma, dan rasa. Hasil uji mutu hedonik menunjukkan bahwa penambahan daun min terhadap yoghurt memberikan pengaruh nyata (p<0,05) terhadap warna, aroma, rasa, dan kekentalan. Dengan demikian dapat disimpulkan bahwa penambahan daun min memberikan peningkatan nilai antioksidan dan peningkatan jumlah daun min yang ditambahkan berbanding terbalik dengan nilai uji hedonik dan uji mutu hedonik., Milk can be processed into one of the functional foods that are popular in the community and many are developed into yogurt. One of the developments is by adding mint leaves into yoghurt as a natural ingredient that has benefits, but does not adversely affect the processing process and the final product produced. This study was aimed to analyze the physicochemical and organoleptic properties of yogurt with the addition of min leaf powder. This study was used a completely randomized design with the addition of mint leaf powder at different concentrations, namely 1) Without the addition of mint leaf powder; 2) Addition of 4.54% mint leaf powder; 3) Addition of 9.08% mint leaf powder.. The organoleptic properties analyzed were color, aroma, viscosity, and taste. The results showed that the addition of mint leaves had a very significant effect (p<0.01) on antioxidant level of yoghurt, but had no significant effect on color, aroma, taste, and viscosity. The hedonic test showed that the addition of mint leaves had a significant effect (p<0.05) on the color, aroma, and taste. The results of the hedonic quality test showed that the addition of mint leaves to yogurt had a significant effect (p<0.05) on the color, aroma, taste, and viscosity. Thus, it can be concluded that the addition of mint leaves increased the antioxidant level, but the increase in the number of mint leaves added was also inversely proportional to the value of the hedonic test and the hedonic quality test.
Keyword: antioxidant, yogurt, mint leaves

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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