This study employed response surface methodology (RSM) to optimize alcalase-enzymatic hydrolysis conditions for the production of an angiotensin I-converting enzyme (ACE) inhibitory peptide from Shortfin scad (Decapterus Macrosoma) skin gelatin (SSGH). Using Central Composite Design (CCD) with four factors and three levels, a statistical modeling equation was developed to predict effects from the following variables:(i) temperature (40, 50, 60°C); pH (7, 8, 9);(ii) enzyme/substrate (E/S) concentration (1, 2, 3%); and (iii) hydrolysis time (60, 120, 180 min) with respect to yield, degree of hydrolysis (DH) and ACE-inhibitory activity. Optimum hydrolysis conditions obtained were 60°C, pH 9, 2.92% and 114.56 minutes. Experimental yield for SSGH was higher (90.05%) than the predicted value of 54.38%. The degree of SSGH hydrolysis (DH = 90.48%) was also higher than the RSM predicted value of 72.04%. Experimental SSGH ACE inhibitory activity (79.61%) was lower than predicted (89.19%).This study demonstrates the viability of using RSM to optimize conditions for the enzymatic hydrolysis of SSGH to yield gelatin with high ACE inhibitory peptide activity.
This study investigates effects from different drying methods (vacuum oven dried vs. freeze dried) on the rheological, functional and structural properties of chicken skin gelatin compared to bovine gelatin. Vacuum oven dried chicken skin samples showed a higher gelatin yield (12.86%) than freeze-dried samples (9.25%). The latter showed a higher melting temperature (32.64oC) and superior foaming capacity (176%) as well as foaming stability (166.67%). Vacuum oven dried samples demonstrated greater fat binding capacity (5.5 ml/g) and emulsion stability (55.79%). There were no significant differences (p >0.05) in emulsion and water holding capacity for three gelatins. Bovine gelatin did hold the lowest of all functional properties studied. A Fourier Transform Infrared (FTIR) spectrum analysis of chicken skin gelatin under both drying methods presented structures similar to those of bovine gelatin. Collectively, this findings indicated no significant differences (p >0.05) in rheological, functional and structural properties for chicken skin gelatins prepared by either drying method. Hence, to save costs and maintain gelatin quality, vacuum oven drying offers potential as an alternative means of production.
Enzymatic hydrolysis of proteins is an important bioprocess method to prepare bioactive peptides with many functionality and health benefits. The aims of the present work were to prepare and determine the physicochemical characteristics of gelatine hydrolysate from skin of shortfin scad (SSGH) via hydrolysis using alcalase. Analyses on chemical composition, molecular weight by SDS PAGE, protein concentration, amino acid composition, Fourier Transform Infrared Spectroscopic features, and solubility of SSGH were thus performed. The yield of SSGH obtained was 51.01% (d.b.). The chemical compositions of SSGH for moisture, protein, fat, and ash were 13.82%, 90.05%, 1.95%, and 12.48%, respectively. SSGH showed low molecular weight (