Judul: Antioxidant Activity of Bioactive Peptides Produced by Goat Milk Protein Hydrolysis Using Papain Protease Enzyme
Abstrak: Fresh goat's milk has the main nutritional content of protein which is composed of peptides with biological abilities whose activation occurs after the hydrolysis process. This study aims to test the hydrolyzate of goat's milk, especially the Etawa breed (PE), which is hydrolyzed with papain enzymes to produce bioactive peptides with antioxidant activity along with protein profiles before and after hydrolysis. Goat milk was hydrolyzed at 37°C and 55°C for 1, 4, and 24 hours, followed by analysis of protein content with the Bradford method, antioxidant activity with the DPPH and P-FRAP methods, and measurement of molecular weight with the SDS-PAGE method. Papain activity was obtained at 1.23 × 103 U/mL with a specific enzyme activity value of 1.86 × 103 U/mg. The protein content of goat's milk was 7.95 ± 0.01 mg/mL, but after being hydrolyzed at 55°C for 24 hours, the lowest value was 1.21 ± 0.02 mg/mL. The highest antioxidant activity of goat's milk peptides occurred at hydrolyzate at 55°C for 24 hours, increasing 94% by 62.86 ± 1.17 % RSA against DPPH and 11.96% by 131.72 ± 1.04 mgAAE/mL in P-FRAP compared to non-hydrolyzed. The molecular weight of goat's milk is 8-84 kDa, the hydrolyzate is found to be 7-24 kDA in size which is suspected to be β-casein (24 kDa) and αs2-casein (<10 kDa) as easily digestible proteins. Statistical data analysis showed that the antioxidant activity of goat's milk bioactive peptides was significantly different (P>0.05) on temperature and hydrolysis time by papain enzyme., Susu kambing segar memiliki kandungan gizi utama protein yang tersusun atas peptida dengan kemampuan biologis yang aktivasinya terjadi setelah proses hidrolisis. Penelitian ini bertujuan menguji hidrolisat susu kambing khususnya Peranakan Etawa (PE) yang dihidrolisis dengan enzim papain untuk menghasilkan peptida bioaktif dengan aktivitas antioksidan beserta profil protein sebelum dan setelah hidrolisis. Susu kambing dihidrolisis dengan suhu 37°C dan 55°C selama 1, 4, dan 24 jam, dilanjutkan analisa kadar protein dengan metode Bradford, aktivitas antioksidan dengan metode DPPH dan P-FRAP, dan pengukuran berat molekul dengan metode SDS-PAGE. Aktivitas papain diperoleh sebesar 1,23×103 U/mL dengan nilai aktivitas spesifik enzimnya sebesar 1,86×103 U/mg. Kadar protein susu kambing diperoleh sebesar 7,95±0,01 mg/mL, namun setelah dihidrolisis suhu 55°C selama 24 jam mendapatkan nilai terendah sebesar 1,21±0,02 mg/mL. Aktivitas antioksidan peptida susu kambing tertinggi terjadi pada hidrolisat suhu 55°C selama 24 jam, meningkat 94% sebesar 62,86±1,17 %RSA terhadap DPPH dan 11,96% sebesar 131,72±1,04 mgAAE/mL pada P-FRAP dibandingkan non-hidrolisis. Berat molekul susu kambing sebesar 8-84 kDa, didapatkan hidrolisatnya berukuran 7-24 kDa yang diduga β-kasein (24 kDa) dan αs2-kasein (<10 kDa) sebagai protein mudah cerna. Nilai analisis data statistik menunjukan aktivitas antioksidan peptida bioaktif susu kambing berbeda nyata secara signifikan (P>0,05) terhadap suhu dan waktu hidrolisis oleh enzim papain.
Keyword: SDS-PAGE, papain enzymes, goat milk, bioactive peptides, antioxidant