Optimized hydrolysis of tuna viscera by a spray-dried cell-free crude enzyme preparation from Staphylococcus sp. isolated from fermented fish
Year: 2025
Type: article
Abstract: Proteolytic enzymes are used to produce hydrolysates from fish processing wastes to recover protein or lipid for various applications. Tuna processing also generates these by-products which contributes to post-harvest losses and environmental pollution. Thus, this study was aimed at optimizing the proteolytic activity on yellow fin tuna (Thunnus albacares) viscera (YFTV) of a spray-dried cell-free crude enzyme extracted from the culture of Staphylococcus sp. strain L1 which was isolated from fermented sardines and identified using 16s rRNA gene analysis. To prepare the enzyme, the isolate was grown in a protease-producing medium supplemented with casein and peptone. The culture supernatant was harvested following fermentation and was spray-dried. For the hydrolysis, the process was optimized to produce hydrolysates with high total soluble protein (TSP) and high degree of hydrolysis (DH). Utilizing the central composite design of the Response Surface Methodology (RSM), YFTV protein hydrolysis was conducted at varying enzyme concentrations (0.5-1.5%, w/v), temperature (40-60°C) and hydrolysis times (60 to 180min). According to the RSM-generated model, the optimal conditions for achieving the highest TSP were 60 min, 40°C and 1.5% enzyme concentration. For the highest DH, the optimal conditions were 60 min, 60°C and 0.5% enzyme concentration. The predicted optimum values using the generated linear and quadratic equations were 3.68 mg/ml TSP and 30.67% DH. The lack of fit test for both responses yielded an insignificant value (p > 0.05), indicating that the regression coefficient was adequate for estimating both responses under various conditions. The optimized protein hydrolysis conditions for YFTV using protease from Staphylococcus sp. could be effectively applied in food production systems, particularly in downstream processing. Furthermore, the utilization of tuna viscera as protein hydrolysates could substantially contribute to waste management in the processing industry.
Source: Sustainable Aquatic Research
Authors: Jhovian, Lee G. Joseco, Nuñal, Sharon
Language: English
Subfield: Food Science
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W7117295950