Judul: Characteristics and Antibacterial Activity Of Zno Nanoparticle-Fortified Probiotic Yogurt
Abstrak: Defisiensi zink merupakan prevalensi defisiensi mikronutrien yang paling umum terjadi di seluruh dunia, terutama di negara berkembang. Ada lebih dari 25% penduduk Indonesia yang telah menderita defisiensi zink. Zink merupakan mineral esensial yang dibutuhkan selama proses kehamilan hingga perkembangan anak, dan juga berperan penting dalam meningkatkan penyerapan usus, menjaga sistem imun, serta memiliki efek bakterisida. Untuk memenuhi asupan zink ini maka perli melakukan fortifikasi pangan dengan memanfaatkan mineral zink juga telah tersedia dalam bentuk nanopartikel berupa ZnO (zink oksida) yang telah dijamin aman untuk digunakan sebagai bahan tambahan pangan. Penelitian ini menguji karakteristik yoghurt yang difortifikasi dengan nanopartikel ZnO. Adapun pengujian yang dilakukan meliputi nilai pH, viskositas, total asam tertitrasi, serta dilakukan juga uji komposisi yoghurt, analisis mikrobiologi, analisis aktivitas antibakteri, dan uji organoleptik. Dalam pembuatan yoghurt, menggunakan starter Streptococcus thermophilus dan Lactobacillus bulgaricus, dan Lactiplantibacillus plantarum subsp. plantarum IIA-1A5 (Accession Number: OR473281). Penelitian ini diterapkan enam perlakuan yaitu (1) yoghurt plain, (2) yoghurt probiotik, (3) Yoghurt Probiotik + nano ZnO komersial, (4) Yoghurt Probiotik + nano ZnO sintetik (sudah ada kandungan pektin di dalamnya), (5) Yoghurt Probiotik + nano ZnO sintetik (tanpa pektin), (6) Yoghurt Probiotik + pektin. Setiap perlakuan dilakukan tiga ulangan. Data diolah dengan analisis ragam (ANOVA). Data diuji lanjut jika berbeda nyata (P<0,05) menggunakan Uji Tukey. Pengujian statistik data uji organoleptik diolah menggunakan uji non parametrik Kruskal-Walis. Hasil penelitian menunjukkan perbedaan berbeda nyata (P < 0.05) pada analisis viskostas, total bakteri asam laktat, dam mutu hedonik warna. Aktivitas antibakteri menunjukkan hasil sedang, dengan kisaran luas zona hambat di antara 5 sampai 10 mm. Berdasarkan hasil penelitian yang telah dilakukan, yoghurt yang difortifikasi dengan nanopartikel ZnO menunjukkan karakteristik fisikokimia dan BAL yang sesuai dengan standar SNI Yoghurt (2009)., Zinc deficiency is a prevalent global issue, particularly acute in developing nations, with over a quarter of the Indonesian population suffering from this micronutrient deficiency. Zinc, an essential mineral required from pregnancy through to child development, plays a critical role in enhancing intestinal absorption, maintaining the immune system, and exerting bactericidal effects. Fortification of food with zinc, including the use of zinc oxide (ZnO) nanoparticles, has been recognized as a safe and effective method to address this deficiency. This study examines the characteristics of yogurt fortified with ZnO nanoparticles. The research involved various tests including physicochemical assessments encompassing pH values, viscosity, total titratable acidity, as well as yogurt composition analysis, microbiological analysis, antibacterial activity evaluation, and organoleptic tests. The yogurt was prepared using starter cultures of Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactiplantibacillus plantarum subsp. plantarum IIA-1A5 (Accession Number: OR473281). Six treatments were applied: (1) plain yogurt, (2) probiotic yogurt, (3) Probiotic yogurt with commercial nano ZnO, (4) Probiotic yogurt with synthetic nano ZnO (containing pectin), (5) Probiotic yogurt with synthetic nano ZnO (without pectin), and (6) Probiotic yogurt with pectin. Each treatment was replicated thrice. Data were analyzed using Analysis of Variance (ANOVA) and further tested using Tukey's test for significant differences (P<0.05). Organoleptic test data were statistically evaluated using the non-parametric Kruskal-Wallis test. The results indicated significant differences (P<0.05) in viscosity, total lactic acid bacteria, and the hedonic quality of
Keyword: antibacterial, fortification, nanoparticle, yogurt, zinc, ZnO

Judul: Development of Zinc Rich Yogurt Based on Soy Milk (Glycine max L.), Pumpkin Fruit and Seeds (Cucurbita moschata)
Abstrak: Yogurt, susu kedelai dan labu kuning merupakan bahan pangan fungsional yang memiliki komponen biokimia yang baik bagi tubuh. Tujuan penelitian ini adalah untuk mendapatkan formula terbaik dari yogurt berbahan dasar susu kedelai dengan penambahan sari labu kuning dan susu biji labu kuning sebagai pangan tinggi zink dan β-karoten. Penelitian menggunakan Rancangan Acak Lengkap (RAL) dengan rasio sari labu kuning dan susu biji labu kuning yaitu (%) F1 (50:50), F2 (40:60), F3 (30:70). Nilai pH dan viskositas yogurt formula terpilih F3 adalah 3,85 dan 47,5 cP. Hasil organoleptik menunjukkan ketiga formula dapat diterima oleh panelis dan formula yang paling disukai adalah F3 yaitu yogurt susu kedelai dengan penambahan sari labu kuning 30% dan susu biji labu kuning 70%. Hasil analisis kimia yogurt formula terpilih F3 mengandung kadar air 80,61%, abu 1,67%, lemak 4,21%, protein 3,73%, karbohidrat 9,73%, zink 2,5 mg/100mL, dan β-karoten 144,37 µg/100 mL (28,8 RAE). Produk ini memenuhi klaim gizi tinggi zink 2,5 mg/100 mL dan harga jual produk per takaran saji (240 mL) adalah Rp6.700,00., Yogurt, soy milk, and pumpkin are functional food ingredients that have biochemical components that are good for the body. The purpose of this study was to obtain the best formula of soy milk-based yogurt with the addition of pumpkin juice and pumpkin seed milk as a food high in zinc and β-carotene. The study used a completely randomized design with the ratios of pumpkin juice and pumpkin seed milk, namely (%) F1 (50:50), F2 (40:60), and F3 (30:70). The pH value and viscosity of yogurt in the selected formula F3 are 3.85 and 47.5 cP. Organoleptic results showed that the three formulas were acceptable to panelists and the most preferred formula was F3, namely soy milk yogurt with the addition of 30% pumpkin juice and 70% pumpkin seed milk. The results of the chemical analysis of the selected formula F3 yogurt contained 80.61% moisture content, 1.67% ash, 4.21% fat, 3.73% protein, 9.73% carbohydrate, 2.5 mg zinc per 100 mL, and 144.37 µg/100 mL β-carotene (28.8 RAE). This product fulfills the nutrition claim of high zinc content (2.5 mg/100 mL) and the selling price of the product per serving size (240 mL) is IDR 6,700.
Keyword: provitamin A, pumpkin, soy milk, yogurt, zinc

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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