Fish Scale Valorization by Hydrothermal Pretreatment Followed by Enzymatic Hydrolysis for Gelatin Hydrolysate Production

Abstract

Protein hydrolysates from fish by-products have good process suitability and bioavailability in the food industry. The objective of this work was to develop a method for protein recovery from fish scales and evaluate the hydrolysis of the scale protein. The effect of the hydrothermal process on protein recovery, degree of hydrolysis (DH) and structural properties of the hydrolysates was investigated. Results showed that hydrothermal treatment could enhance protein recovery of tilapia scales without demineralization and dramatically improve the DH of the hydrolysates. The hydrothermal treated scales showed a better protein recovery (84.81%) and DH (12.88%) and released peptides more efficiently than that of the conventional treated samples. The obtained gelatin hydrolysates mainly distributed in the range of 200–2000 Da with an angiotensin I-converting enzyme (ACE) IC50 value of 0.73 mg/mL. The ACE inhibitory activity of gelatin hydrolysates was stable under high temperature, pH and gastrointestinal proteases. Hydrothermal treatment followed by enzymatic hydrolysis offers a potential solution for preparation of gelatin hydrolysates for food ingredients from fish processing by-products.

Optimization of enzymatic hydrolysis of red tilapia scales (Oreochromis sp.) to obtain bioactive peptides

“…In this sense, the Km value obtained for the substrate is greater than the obtained for Alcalase® 2.4 L in other substrates such as tilapia viscera (1.9 g/L) [ 61 ] and Salmon muscle (4 g/L) [ 30 ]. This is possibly due to the difference in the scale's structure, which has a higher mineral content, partially comprised of hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 [ 62 ], which makes it a protease resistant structure [ 63 ].…”

The potential application of the protein hydrolysates of three medicinal plants: cytotoxicity and functional properties

“…The degree of hydrolysis (DH) was determined according to the described previously method with slight modifications (Nielsen, Petersen, & Dambmann, 2001; Zhang, Tu, Shen, & Dai, 2019). The amount of α‐amino nitrogen was measured with the o‐phthaldialdehyde (OPA) method and the total nitrogen of each sample was determined by the Kjeldahl method.…”

Antioxidant and Cryoprotective Effects of Bone Hydrolysates from Bighead Carp (Aristichthys nobilis) in Freeze-Thawed Fish Fillets

“…The molecular weight (MW) distribution of the hydrolysates was analyzed on a TSK-Gel G2000 SW XL column (7.8 mm × 300 mm, Tosoh, Tokyo, Japan) using a Waters e2695 HPLC system according to Zhang et al [ 22 ]. The eluent was 45% acetonitrile solution containing 0.1% trifluoroacetic acid (TFA).…”