Penelitian ini bertujuan untuk mengetahui pengaruh jenis enzim dan waktu hidrolisis terhadap karakteristik hidrolisat protein kulit ikan kakap (Lutjanus sp.) dalam menghambat enzim α-glukosidase. Hidrolisis protein ikan (HPI) dilakukan secara enzimatis menggunakan dua jenis enzim proteolitik, yaitu papain dan alkalase, dengan variasi waktu hidrolisis selama 60, 90, 120, 150, dan 180 menit. Parameter yang diamati meliputi derajat hidrolisis, profil berat molekul protein, komposisi asam amino, serta nilai IC₅₀ terhadap penghambatan enzim α-glukosidase. Hasil penelitian menunjukkan bahwa jenis enzim dan waktu hidrolisis berpengaruh nyata terhadap semua parameter. Derajat hidrolisis tertinggi diperoleh pada penggunaan enzim alkalase selama 180 menit sebesar 77% dan enzim papain selama 150 menit sebesar 74%. Profil berat molekul HPI kulit ikan kakap  menghasilkan berat molekul  <10 kDa dengan enzim alkalase, sementara enzim papain menghasilkan berat molekul >15 kDa setelah waktu hidrolisis 60 menit. Komposisi asam amino juga dipengaruhi oleh jenis enzim dan waktu hidrolisis. Asam amino telah terbentuk pada waktu hidrolisis 60 menit dengan diperoleh asam amino hasil pemotongan enzim alkalase maupun papain, yang didominasi oleh prolin, glisin, alanin dan asam glutamat. Asam amino yang diperoleh sesuai dengan sisi pemotongan alkalase utamanya pada asam amino hidrofobik, adapun papain memotong pada asam amino sistin dan histidin.  HPI dengan enzim alkalase menunjukkan aktivitas penghambatan terhadap enzim α-glukosidase dengan nilai IC₅₀ sebesar 149,60 ppm tergolong lemah dan pada enzim papain sebesar 179,10 ppm tergolong sangat lemah. Hal tersebut menunjukkan HPI kulit ikan kakap mempunyai potensi bioaktivitas sebagai antidiabetes.

Kata kunci: hidrolisat protein, kulit ikan kakap, papain, alkalase, α-glukosidase

This study aims to determine the effect of enzyme type and hydrolysis time on the characteristics of snapper fish (Lutjanus sp.) skin protein hydrolysate in inhibiting the α-glucosidase enzyme. Fish protein hydrolysis (HPI) was carried out enzymatically using two types of proteolytic enzymes, namely papain, and alcalase, with variations in hydrolysis time for 60, 90, 120, 150, and 180 minutes. The parameters observed included the degree of hydrolysis, protein molecular weight profile, amino acid composition, and IC₅₀ value for inhibiting the α-glucosidase enzyme. The results showed that the type of enzyme and hydrolysis time significantly affected all parameters. The highest degree of hydrolysis was achieved using the alcalase enzyme for 180 minutes at 77% and the Papain enzyme for 150 minutes at 74%. The molecular weight profile of snapper skin HPI produces a molecular weight of <10 kDa with the alcalase enzyme, while the papain enzyme produces a molecular weight of >15 kDa after a hydrolysis time of 60 minutes. The amino acid composition is also influenced by the type of enzyme and hydrolysis time. Amino acids have been formed at a hydrolysis time of 60 minutes with the amino acids obtained from the cutting of the alcalase and papain enzymes, which are dominated by proline, glycine, alanine, and glutamic acid. The amino acids obtained according to the alcalase cutting side are mainly on hydrophobic amino acids, while papain cuts on the amino acids cystine and histidine. HPI with the alcalase enzyme shows inhibitory activity against the α-glucosidase enzyme with an IC₅₀ value of 149.60 ppm which is classified as weak and on the papain enzyme of 179.10 ppm which is classified as very weak. This shows that snapper skin HPI has the potential for bioactivity as an antidiabetic.

Keywords: protein hydrolysate, snapper skin, papain, alcalase, α-glucosidase.