Judul: Karakterisasi Peptida Inhibitor Angiotensin Converting Enzyme (ACE) Hidrolisat Daging Kambing Kacang (Capra aegagrus hircus Linn) dalam Potensinya sebagai Ingredien Pangan Fungsional
Abstrak: The kacang goat (Capra aegagrus hircus) is indigenous to Indonesia and Malaysia, and is common throughout in Southeast Asia. The negative issue facing Indonesian people is that consumption of goat meat can lead to hypertension. Natural angiotensin converting enzyme (ACE) inhibitory peptides from animal protein are considered as an alternative antihypertensive agent. ACE inhibitory peptide could be generated by hydrolysis the protein sources by using the proteolytic enzymes. The purpose of this research was to obtain the water soluble fraction of protein hydrolysates derived from kacang goat in their inhibition of ACE and antihypertensive activities. This study used ten male of kacang goats aged 8-24 months from a local farm in East Java were brought to Bogor by Mitra Tani Farm, West Java Indonesia. The goats divided into two slaughter ages, namely < 1.5 years old and >1.5 years old. Kacang goats are generally slaughtered for consumption at these ages. The body part used for this research was the carcass leg. The contents of protein, fat, moisture, ash, and amino acid in the goat meat were not different on both of slaughter ages. The dominant amino acids found in the goat meat were glutamic acid, aspartic acid, leucyne and lysine. Protein hydrolysate of kacang goat meat was generated by adding endoprotease into homogenate (minced meat to distilled water, 1:3) with several concentrations (0.5%, 1.0%, 1.5% w/w of the total substrate) and hydrolyzed for 60 min. The next hydrolysis was conducted by adding protease complex at several concentrations (0.5%, 1.0%, 1.5% w/w of the total substrate) to the first hydrolysate. Digestion proceeded for 1, 3, and 5 h. The pH of homogenate was kept constant by addition of 6 N NaOH and was monitored every 30 min during hydrolysis. The water soluble fraction (WSF) of hydrolysate was obtained by separating the supernatant and its residue. The crude hydrolysates were charactherized by analysis the ACE inhibitory activity, degree of hydrolysis, soluble protein content, peptide content and yield percentage. The ACE inhibitory activity of crude hydrolysate at 0.5 mg/mL and 1.0 mg/mL ranged between 21.2-45.2% and 48-58%, respectively. The crude hydrolysates had degree of hydrolysis ranged between 10.4-26.3%, soluble protein contents ranged between 534.7 - 579.9 mg/g, peptide contents 400.4-520.8 mg/g and the yield percentage ranged between 49.9-76.0%. The highest ACE inhibitory activity resulted from a hydrolysate digested for 4 h with 5 g kg-1 of both enzymes. The hydrolysate was further fractionated gradually to determine the sequence of ACE inhibitory peptide. Fractionation of protein hydrolysate was started by concentrating the hydrolysate through ultrafiltration system by using centrifugal filter membrane (molecular weight cut-off, MWCO; 3 kDa). Furthermore, an active fraction was separated on a Sephadex G-10 column. The most active fraction was then purified by high performance liquid chromatography- reversed phase (HPLC-RP) gradually with two different types of columns and was obtained an ACE inhibitory peptide with a molecular weight of 478 Da. The ACE inhibitory peptide from most active fraction with IC50 : 12.91 mg/mL (27.0 μM) was identified as tetra-peptide, Phe-Gln-Pro-Ser. Protein hydrolysate and Phe-Gln-Pro-Ser demonstrated the potent antihypertensive activities in spontaneous hypertensive
Keyword: ACE inhibitor, peptida bioactive, protein hydrolysate, meat of kacang goat, antihypertensive

Judul: Analysis of Angiotensin-Converting Enzyme (ACE) Inhibitor Activity of Bioactive Peptides from Etawah Crossbreed Goat Milk
Abstrak: Peptida bioaktif merupakan hasil pemecahan protein yang bermanfaat untuk kesehatan dengan bekerja sebagai antioksidan, antidiabetes, dan antihipertensi. Salah satu mekanisme dari sifat antihipertensi peptida bioaktif adalah inhibisi angiotensin-converting enzyme (ACE). Penghambatan ACE dengan inhibitor alami menjadi alternatif untuk menghindari efek samping obat sintetik. Penelitian ini bertujuan untuk mengetahui pengaruh proses hidrolisis terhadap kadar protein, inhibisi ACE, dan profil protein susu kambing peranakan Etawa. Dalam penelitian ini, susu kambing yang telah dipisahkan lemaknya dihidrolisis enzim papain dengan aktivitas spesifik 1,48 ± 0,04 U/mg pada suhu 55 oC selama 1, 4, dan 24 jam. Analisis kadar protein dilakukan dengan metode Bradford, aktivitas inhibitor ACE dengan ACE Kit-WST, dan profil protein dengan SDS-PAGE. Susu kambing yang dihidrolisis mengalami penurunan kadar protein dan peningkatan inhibisi ACE yang signifikan. Waktu hidrolisis yang lebih lama juga meningkatkan inhibisi ACE. Pada larutan susu kambing konsentrasi 7,5 mg/mL, hidrolisat 24 jam menunjukkan aktivitas tertinggi sebesar 95,01 ± 1,13% dibandingkan nonhidrolisis sebesar 84,49 ± 0,93%. Obat kaptopril sebagai kontrol positif menunjukkan aktivitas sebesar 101,25 ± 0,56% pada konsentrasi ≥ 0,1 µg/mL. Hasil elektroforesis susu kambing menunjukkan enam pita protein dengan berat molekul 11-84 kDa. Setelah proses hidrolisis, hidrolisat protein hanya menunjukkan dua pita protein 11 dan 16 kDa, menunjukkan bahwa hidrolisis memotong protein berukuran besar menjadi peptida dengan berat molekul lebih kecil. Penelitian ini berpotensi pada pengembangan pangan fungsional yang dapat mencegah dan mengobati hipertensi. Kata kunci: antihipertensi, inhibitor ACE, peptida bioaktif, susu kambing, Bioactive peptides are the result of protein breakdown which are beneficial for health by working as antioxidant, antidiabetic, and antihypertensive. One mechanism of the antihypertensive properties from bioactive peptides is the inhibition of angiotensin-converting enzyme (ACE). Inhibiting ACE with natural inhibitors is an alternative to avoid the side effects of synthetic drugs. This study aims to determine the effect of hydrolysis on protein content, ACE inhibition, and the protein profile of Etawah crossbreed goat milk. In this study, goat milk that has had its fat separated was hydrolyzed by papain enzyme with specific activity of 1.48 ± 0.04 U/mg at 55 oC for 1, 4 and 24 hours. Analysis of protein content was carried out using the Bradford method, ACE inhibitor activity with ACE Kit-WST, and protein profile with SDS-PAGE. Hydrolyzed goat milk had a significant decrease in protein content and increase in ACE inhibition. Longer hydrolysis time also increases ACE inhibition. In the goat milk solution with a concentration of 7.5 mg/mL, 24-hour hydrolysate showed the highest activity at 95.01 ± 1.13% compared to non-hydrolysis at 84.49 ± 0.93%. The captopril as positive control showed activity at 101.25 ± 0.56% at a concentration of ≥ 0.1 µg/mL. The result of goat milk electrophoresis showed six protein bands with a molecular weight of 11-84 kDa. After hydrolysis, the protein hydrolysates only showed two protein bands of 11 and 16 kDa, indicating that hydrolysis cleaves large protein into peptides with smaller molecular weight. This research has the potential to develop functional foods that can prevent and treat hypertension. Keywords: ACE inhibitor, antihypertensive, bioactive peptide, goat milk
Keyword: ACE inhibitor, antihypertensive, bioactive peptide, goat milk

Judul: Simulasi persamaan keadaan bintang dengan pendekatan klasik dan relativistik
Abstrak: Komposisi bintang yang selalu berubah akanmempengaruhi massa dan radius bintang itu sendiri. Dimana semakin tua sebuah bintang, maka bintang akan didominasi oleh unsur-unsur berat. Dengan persamaan politrop dan metode Runge-Kutta orde 4 didapatkan radius dan massa bintang semakin berkurang seiring berkurangnya nilai Ye, sedangkan kerapatan semakin meningkat. Pendekatan terbaik terdapat pada nilai Ye sebesar 0.5 dimana didapatkan bahwa massa bintang katai putih sebesar 1.4Mo sesuai dengan massa Chandrasekhar dengan radius bintang 5000 km dan nilai kerapatan bintang sebesar 5.31x 106 g cm-3. Untuk massa bintang neutron diperoleh nilai 0.05Modan radius bintang sebesar 2300 km, sedangkan kerapatannya bintang neutron diperoleh sebesar 1.84 x 107 g cm-3 dengan menggunakan pendekatan relativistic. Pendekatan relativistic terbukti lebih baik untuk menentukan radius dan massa bintang, dengan pendekatan terbaik pada nilai Ye sebesar 0.5 yaitu pada bintang katai putih
Keyword: Composition of the stars, density of the stars, mass of the stars, radii of the stars