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Najmah Najmah
Gorontalo State University
Chemistry Education

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Antioxidant Activity of Tilapia (Oreochromis niloticus) Bone Protein Hydrolysate Using the ABTS Method Nurain Dano; Deasy N. Botutihe; Nita Suleman; Nurhayati Bialangi; Najmah Najmah
Jurnal Akademika Kimia Vol. 15 No. 2 (2026)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2026.v15.i2.pp121-128

Abstract

Tilapia (Oreochromis niloticus) bones are a fishery by-product whose use remains limited, despite containing proteins that can be processed into bioactive peptides with antioxidant activity. This study aims to evaluate the characteristics of protein hydrolysate and antioxidant activity from raw and cooked tilapia bones using the ABTS method. Enzymatic hydrolysis was performed using papain at concentrations of 4%, 6%, and 8% (b/v) at pH 7 and 55°C for 4 hours. The parameters analyzed included qualitative amino acid tests, dissolved protein levels determined by the Kjeldahl method, degree of hydrolysis based on dissolved proteins in 10% TCA, and antioxidant activity expressed as IC₅₀ values. The results showed that all samples tested positively for amino acids, including aromatic amino acids. The lowest IC₅₀ value was observed in the treatment of a ripe sample with an enzyme concentration of 8% (6.89 mg/mL), indicating the highest antioxidant activity among the treatments. This is in line with an increase in the degree of hydrolysis to 84.53% under the same conditions, as well as an increase in dissolved protein levels to up to 32.78%. These findings indicate that tilapia bone protein hydrolysate has the potential to serve as a natural source of antioxidants, particularly under optimal hydrolysis conditions.
Antioxidant Activity of Hydrolysate Protein in Skipjack Fish (Katsuwonus pelamis) Using the ABTS Method Fou F. Muksin; Deasy N. Botutihe; Erni Mohamad; Hendri Iyabu; Najmah Najmah
Jurnal Akademika Kimia Vol. 15 No. 2 (2026)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2026.v15.i2.pp142-149

Abstract

Skipjack tuna (Katsuwonus pelamis) bones are a byproduct of the fishing industry that are rich in protein and have potential as a source of bioactive peptides. This study aimed to determine the antioxidant activity of protein hydrolysates from raw and cooked skipjack tuna bones using the ABTS method. Hydrolysis was performed using bromelain at concentrations of 4%, 6%, and 8% at 55 °C for 4 hours pH 7.0), followed by enzyme inactivation at 85 °C for 20 minutes. Antioxidant activity was measured by IC50 determination using a UV-Vis spectrometer at 734 nm. The results showed that the antioxidant activity of skipjack tuna bone samples with the highest total protein content was observed at an enzyme concentration of 8%, namely 35.55% (raw fish bones) and 36.24% (cooked fish bones). The highest degree of hydrolysis in the raw fish bone sample reached 82.15 % and in the cooked fish bone sample reached 86.81 % with 8 % enzyme. Qualitative amino acid tests (ninhydrin, Biuret, xanthoprotein, and Millon) yielded positive results, indicating the presence of aromatic amino acids (tyrosine, tryptophan, phenylalanine) that contribute to antioxidant activity. The lowest IC50 value was obtained in the raw fish bone sample at an 8 % concentration, namely 10.03 mg/ml, and in the cooked fish bone sample at 6.19 mg/ml at an 8 % enzyme concentration. The higher the enzyme concentration, the higher the antioxidant activity.
Co-Authors Deasy N. Botutihe Erni Mohamad Fou F. Muksin Nita Suleman Nurain Dano Nurhayati Bialangi