Optimization of Enzymatic Hydrolysis of Mackerel (Rastrelliger sp.) Muscle Protein Hydrolysate Using Response Surface Methodology

Abstract Mackerel (Rastrelliger sp.) is a widely distributed epipelagic species in South East Asia. Mackerel has a high amount nutrient such as protein (20.83 %) and fat (1.03 %). The high amount of protein and low amount of fat will allow it to be used as a material to produce a good protein hydrolysate. The aim of this study is to determine the optimal enzymatic hydrolysis conditions (time, temperature, and pH) using Response Surface Methodology (RSM). Mackerel Protein Hydrolysate (MPH) was prepared using commercial Flavourzyme. Optimization of MPH was performed by employing Box Behnken Design method of RSM. SN-TCA method was used to calculate the degree of hydrolysis (DH) which is the key parameter in hydrolysis reaction. Optimum hydrolysis conditions were obtained at pH 7, temperature 55°C and 60 min of process. Under these conditions the DH obtained was 17.7293 % with 4% enzyme to substrate ratio. The suggested model for the hydrolysis process is quadratic with the desirability factor of 1. The MPH was further assessed for its amino acid composition using High Performance Liquid Chromatography (HPLC). The hydrolysis process increases the amino acid amounts namely L-Glutamic Acid (19.77%), L-Valin (14.20%), L-Aspartic Acid (11.42%), Glycine (11.04%), L-Alanin (14.20%), L-Prolin (16.80%), and L-Histidin (27.06%). The study suggested that mackerel muscle can be considered to be utilized as fish protein hydrolysis materials.