Skin waste from tuna processing needs to be utilized, such as extraction of its collagen and gelatin. Their functional properties can be improved by enzymatic hydrolysis for conversion to peptides. Thus, the research objectives were to examine the characteristics and antioxidant activity of collagen, gelatin, and the derived peptide from yellowfin tuna skin. Collagen was extracted using 0.75 M acetic acid at 4 °C, while gelatin was prepared using 0.25% citric acid and extracted at 65 °C. Hydrolysis was carried out with 2% Alcalase, followed by fractionation with a molecular weight cut off sieve for both collagen and gelatin. Collagen yield was 22.6% with pH value of 6.63 and whiteness of 96.7%. Gelatin yield was 20.0% with pH value of 4.94 and whiteness of 51.0%. Hydrolysis for three hours resulted in 52.7% and 45.2% degree of hydrolysis for collagen and gelatin, respectively. The molecular weights of collagen peptides ranged from 2.94 to 11.93 kDa, while those of gelatin peptides ranged from 3.54 to 16,620 kDa. Antioxidant activities of these peptides were higher than those before hydrolysis. The high antioxidant activity (IC50) of collagen peptides were found in <3, 3–10, and 10–30 kDa fractions as well as in the gelatin peptides.

Aflatoxin B1 is a toxigenic and carcinogenic compound produced by Aspergillus flavus and Aspergillus parasiticus. An approach to prevent aflatoxin contamination in feed was carried out by using Saccharomyces cerevisiae (Sc) and Rhizopus oligosporus (Ro). Aspergillus flavus was cultured together with Sc, Ro and their combination (ScRo) in chicken feed. The aflatoxin B1 content was observed at day 0, 5, 10 and 15. The result showed that aflatoxin B1 contaminations in feed were reduced by Sc, Ro and ScRo addition. The highest reduction of aflatoxin B1 content was shown at day 5 for all treatments with Sc, Ro and ScRo. The best activity of reducing aflatoxin B1 was shown by Ro. Although the ability of reducing aflatoxin B1 of Sc, Ro or ScRo was not significantly different, Sc or Ro gave the better result than ScRo and they are better used individually.

<p class="abstrak2">Sumbawa horse milk is claimed to cure some diseases such as asthma, hypertension, diabetes and gastrointestinal disorder but its potential bioactive peptide has not been explored. The aims of this study are to evaluate bioactivities peptides from Sumbawa horse milk protein hydrolysate and to analyzethe physio-chemical properties of selected peptides. The milk protein was hydrolyzed by Bacillus thuringiensis protease, the peptide produced were sequential fractionated and then analyzed for antibacterial and antioxidant activities. The peptide fraction &lt;3 kDa was then sequenced using LCMS-MS and the physio-chemical properties of the peptides were analyzed. The result showed that peptides fraction &lt;3 kDa from the 30 min hydrolysis was the most active as antibacterial and more active to Gram negative bacteria.  For antioxidant, scavenging activity of the fraction per µg protein/mL were 83% to ABTS and 31% to DPPH radicals. The values were similar with vitamin C 12.5 µg/mL for ABTS and 14.5 µg/mL for DPPH. Peptide <tt>HPYFYAPELLYYANK with molecular weight prediction </tt>1887.92 Da and isoelectric point 7.47 has high therapeutic index prediction (64.75). The result showed that peptides from Sumbawa horse milk hydrolyzed by Bacillus thuringiensis protease was active as antibacterial and antioxidant. Peptide <tt>HPYFYAPELLYYANK from fraction &lt;3 kDa was potential as antibacterial.</tt></p><p><strong>Key Words:</strong> <em>Bacillus thuringiensis</em>, Bioactive Peptide, Horse Milk</p>

Goat milk is highly nutritious foodstuffs that b eneficial for improving health. The milk contains b ioactive peptides which produced b y hydrolysis process. The aim of this study was to ABSTRAKSusu kambing merupakan bahan pangan bernutrisi tinggi yang bermanfaat untuk meningkatkan kesehatan. Susu mengandung peptida bioaktif yang dapat dihasilkan melalui proses hidrolisis. Tujuan dari penelitian ini adalah untuk mengevaluasi aktivitas antibakteri dan antioksidan hidrolisat yang dihasilkan dari hidrolisis protein susu kambing dengan bromelin. H idrolisis protein susu kambing dilakukan menggunakan ekstrak kasar bromelin (0,1 U/mL) pada pH 6, 50°C selama 60 menit. Hidrolisat difraksinasi menggunakan membran molecular weight cut off 10 kDa. Hidrolisat sebelum dan sesudah fraksinasi diuji kemampuan antibakteri dan antioksidannya. Toksisitas hidrolisat dan hasil fraksinasinya ditentukan dengan uji hemolisis. Hasil menunjukkan bahwa hidrolisat sebelum dan sesudah fraksinasi dapat menghambat pertumbuhan E. coli, S. Typhimurium dan L. monocytogenes. Hidrolisat setelah fraksinasi mempunyai aktivitas antibakteri lebih tinggi yang mengindikasikan bahwa fraksinasi dapat meningkatkan aktivitas antibakteri. Fraksi hidrolisat juga menunjukkan aktivitas netralisasi radikal ABTS dan DPPH. Fraksi <10 kDa mempunyai aktivitas antioksidan yang paling tinggi terhadap radikal ABTS dan DPPH. Uji hemolisis menunjukkan bahwa hidrolisat sebelum dan sesudah fraksinasi tidak menimbulkan lisis pada sel darah merah menandakan aman untuk diaplikasikan. Kedua fraksi <10 kDa dan >10 kDa tidak hanya menunjukkan ketidakberadaan hemolisis tetapi juga dapat menurunkan autol isis pada sel darah merah. Hasil tersebut menunjukkan bahwa susu kambing yang dihidrolisis dengan bromelin dapat berfungsi sebagai antibakteri dan antioksidan.Kata kunci: antibakteri, antioksidan, bromelin, hidrolisat, susu kambing PENDAHULUAN 1Susu merupakan bahan pangan bernutrisi tinggi yang ditandai dengan keseimbangan asam

Susu mempunyai nilai nutrisi tinggi dan mengandung protein sebagai sumber peptida bioaktif yang berguna bagi kesehatan. Penelitian ini bertujuan untuk mengeksplorasi potensi peptida bioaktif dari susu kambing sebagai antimikroba dan antioksidan. Susu dihidrolisis menggunakan enzim tripsin, kimotripsin, pepsin atau protease Bacillus sp. E.13. Peptida yang diperoleh dipilah untuk aktivitas antimikroba dengan mencampurkan peptida dan bakteri Staphylococcus aureus, Listeria monocytogenes, Salmonella thyphimurium dan Escherichia coli sebanyak 10 6 CFU/mL dan diinkubasi pada suhu 37°C selama 2 jam dan ditumbuhkan pada Mueller Hinton agar. Aktivitas antimikroba ditentukan dengan membandingkan jumlah koloni bakteri yang tumbuh pada cawan dengan dengan jumlah koloni bakteri kontrol tanpa penambahan peptida. Aktivitas antioksidan ditentukan melalui uji 2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid (ABTS) dan 2,2-diphenyl-1-picrylhydrazyl (DPPH). Aktivitas antimikroba terlihat pada peptida hasil hidrolisis susu kambing oleh pepsin pada suhu 37°C, pH 2 selama 90 menit dan protease Bacillus sp. E.13 pada suhu 55°C, pH 11 selama 30 and 60 menit tetapi aktivitas tersebut tidak terdeteksi pada peptida hasil hidrolisis protein dengan tripsin dan kimotripsin. Peptida dari hidrolisis protein oleh protease Bacillus sp. E.13 dapat menghambat Listeria monocytogenes, Salmonella thyphimurium dan Escherichia coli sampai 5 siklus log. Peptida antimikroba tersebut juga dapat meredam radikal ABTS sampai 86% dan radikal DPPH 9% pada konsentrasi 68 μg protein/mL. Hasil tersebut mengindikasikan bahwa protein susu kambing yang dihidrolisis dengan protease Bacillus sp. E.13 berpotensi sebagai antimikroba sekaligus sebagai antioksidan.