Judul: The Potential to Prevention Hypertension and  Sensory Profile of Seaweed Salt Sargassum polycystum and Ulva lactuca
Abstrak: Penyakit hipertensi termasuk silent killer yang menyumbang angka kematian terbesar di Indonesia. Tingginya risiko terkena penyakit ini disebabkan oleh pola hidup yang tidak sehat salah satunya, yaitu kelebihan konsumsi garam/natrium. Alternatif pencegahan yang dapat dilakukan salah satunya melalui konsumsi garam rendah natrium. Rumput laut dapat dimanfaatkan sebagai bahan baku pembuatan garam rendah natrium yang dapat dikonsumsi penderita hipertensi dan memiliki karakteristik sensori yang unik. Penelitian ini bertujuan untuk menentukan potensi garam rumput laut dalam mencegah hipertensi melalui parameter kadar NaCl, rasio Na/K, keberadaan senyawa antioksidan fenolik, dan Angiotensin Converting Enzyme-Inhibitor (ACE-I) serta menentukan tingkat keasinan relatif dan profil sensori garam rumput laut. Penelitian ini terdiri dari pembuatan tepung dan garam rumput laut Sargassum polycystum dan Ulva lactuca, pengujian komposisi kimia dan fisikokimia, pengujian in vitro ACE-I, pengujian tingkat keasinan relatif, dan profil sensori. Data dianalisis menggunakan independent sample t-test dengan taraf kepercayaan 95%. Hasil penelitian menunjukkan garam S. polycystum memiliki potensi sebagai pencegah hipertensi yang lebih baik dengan karakteristik kadar NaCl 43,77±0,54%, rasio Na/K 0,50, total fenolik 381±0,002 mg GAE/g sampel, total flavonoid 479±0,003 mg QE/g sampel, total phlorotannin atau florotanin 270±0,001 mg PGE/g sampel, dan nilai penghambatan ACE (IC50) 128,32±1,35 μg/mL. Tingkat keasinan relatif larutan garam rumput laut lebih rendah dibandingkan larutan standar NaCl 0,54% sehingga diperlukan konsentrasi larutan garam rumput laut yang lebih tinggi untuk dapat memberikan stimulus yang sama dengan larutan NaCl 0,54%. Larutan garam S. polycystum konsentrasi 0,85% dan garam U. lactuca konsentrasi 0,89% memiliki rasa asin yang setara dengan larutan NaCl 0,54%. Garam S. polycystum memiliki profil sensori yang lebih bersih dengan hasil focus group discussion didapatkan tujuh atribut sensori, yaitu mineral, eggy/sulfur, seaweed, salty, bitter, umami, dan sensasi astringent. Tingkat kesukaan sensori garam S. polycystum secara overall disukai panelis (5,08 dari skala 6) dan garam U. lactuca agak disukai panelis (4,78 dari skala 6)., Hypertension is a silent killer disease with the largest mortality rate in Indonesia. The high risk of developing this disease is caused by an unhealthy lifestyle, one of which is excess consumption of salt/sodium. Alternative prevention that can be done through the consumption of low sodium salt. Seaweed can be used as a raw material for production low sodium salt which can be consumed by people with hypertension and it has unique sensory characteristics. This study aimed to determine the potential of seaweed salt in preventing hypertension through parameters of NaCl content, Na/K ratio, presence of phenolic antioxidant compounds, and Angiotensin Converting Enzyme-Inhibitor (ACE-I) and to determine the relative saltiness level and sensory profile of seaweed salt. This study was consisted of preparation of flour and salt from Sargassum polycystum and Ulva lactuca, determination of chemical and physicochemical characteristics, in vitro testing of ACE-I, and determination relative saltiness level and sensory profiles. Data analysis used independent sample t-test with 95% confidence level. The results showed that S. polycystum salt had the best potential for preventing hypertension with the characteristics NaCl level of 43.77±0.54%, Na/K ratio of 0.50, phenolic total 381±0,002 mg GAE/g sample, flavonoid total of 479±0,003 mg QE/g sample, phlorotannins total of 270±0,001 mg PGE/g sample, and ACE-I (IC50) of 128.32±1.35
Keyword: Angiotensin-I-converting enzyme inhibitory, low sodium salt, Sargassum polycystum, Ulva lactuca

Judul: Antioxidant Activity and Characteristics of Ulva lactuca Combination Salt, Antioxidant Activity and Characteristics of Ulva lactuca Combination Salt
Abstrak: Rumput laut hijau Ulva lactuca dapat dimanfaatkan sebagai sumber bahan baku garam rumput laut yang memiliki aktivitas antioksidan. Penelitian ini bertujuan menentukan kombinasi filtrat dan residu terbaik garam rumput laut yang memiliki karakteristik sesuai dengan standar mutu garam konsumsi yang dianjurkan untuk pasien hipertensi. Garam rumput laut diperoleh dari filtrat ekstraksi tepung Ulva lactuca dengan pelarut akuades rasio 1:10. Garam dari filtrat murni (K) yang diperoleh ditambahkan residu dengan rasio garam filtrat dan residu 1:1 (A), 1:2 (B), dan 2:1 (C). Garam yang dihasilkan dilakukan uji komposisi mineral, kontaminan logam berat, rasio Na:K, kadar NaCl, kadar serat pangan, kadar iodium (KIO3), uji sensori garam, dan uji antioksidan. Garam K memiliki rasio Na:K 1,45, kadar NaCl 17,87%, dan residu logam berat di bawah standar maksimum SNI garam diet. Kadar serat pangan tertinggi dihasilkan pada garam B sebesar 35,63%. Aktivitas antioksidan menggunakan metode uji ABTS diperoleh nilai tertinggi pada garam C sebesar 55,07 ppm dan kapasitas antioksidan dengan metode uji CUPRAC diperoleh nilai tertinggi pada garam filtrat sebesar 21,57 μmol trolox/g., Ulva lactuca green seaweed can be used as raw material source for seaweed salt which has antioxidant activity. This study aims determine the best combination of filtrate and residue of seaweed salt which has characteristics in accordance with the standard of consumption salt quality which recommended for hypertensive patients. Seaweed salt was obtained from the extraction filtrate of Ulva lactuca flour with a 1:10 ratio of distilled water as a solvent. The salt from the pure filtrate (K) obtained was added to the residue with the ratio of the filtrate salt to the residue of 1:1 (A), 1:2 (B), and 2:1 (C). The resulting salt was tested for mineral composition, heavy metal contaminants, Na: K ratio, NaCl content, dietary fiber content, iodine content (KIO3), salt sensory test, and antioxidant test. The salt K has a Na: K ratio of 1.45, NaCl content of 17.87%, and heavy metal residues below the SNI maximum standard for dietary salt. The highest content of dietary fiber was produced in salt B of 35.63%. The antioxidant activity using the ABTS test method obtained the highest value for the C salt of 55.07 ppm and the antioxidant capacity with the CUPRAC test method obtained the highest value for the filtrate salt of 21.57 μmol trolox/g.
Keyword: antioxidants, NaCl, Na: K ratio, Ulva lactuca, seaweed salt

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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