Preparation of rapeseed protein hydrolysates with ACE inhibitory activity by optimization and molecular weight distribution of hydrolysates

Objective:The main purpose of this study was to screen effective proteolytic enzymes for producing hydrolysates from rapes protein, and to optimize hydrolysis conditions using response surface design to prepare hydrolysates with maximum ACE inhibitor activity.Methods:RSM design was successfully applied to the hydrolysis conditions on the basis of single factor experiments which further derived a statistical model for experimental validation. The molecular weight distribution of rapeseed protein hydrolysates with different degree of hydrolysis was also investigated.Results:All the proteolytic enzymes tested produced hydrolysates that possessed ACE inhibitory activity. Aiding RSM design the highest ACE inhibitory activity 56.3% was achieved under optimum hydrolysis conditions at the hydrolysis time, pH, hydrolysis temperature, and enzyme dosage were at 90.11 min, 8.88, 50°C and 3580.36 UgConclusion:Enzymatic hydrolysis and response surface methodology found good techniques in order to achieve hydrolysates with maximum ACE inhibitory activity. The findings of current research suggested that the hydrolysates obtained under optimized conditions could be utilized to formulate nutraceuticals and pharmaceuticals

Impact of Power Ultrasound on Antihypertensive Activity, Functional Properties, and Thermal Stability of Rapeseed Protein Hydrolysates

The effects of power ultrasound pretreatments on the degree of hydrolysis (DH), angiotensin-I-converting enzyme (ACE) inhibitory activity, amino acid composition, surface hydrophobicity, protein solubility, and thermal stability of ACE inhibition of rapeseed protein hydrolysates were evaluated. Ultrasonic pretreatments before enzymolysis in terms of power and exposure time increased the DH and ACE inhibitory activities over the control (without sonication). In this study, maximum DH 22.07% and ACE inhibitory activity 72.13% were achieved at 600 W and 12 min pretreatment. Compared to the hydrolysates obtained without sonication, the amino acid profile of ultrasound pretreated hydrolysates showed significant changes particularly in the proline content and hydrophobic amino acids with an increased rate of 2.47% and 6.31%, respectively. Ultrasound pretreatment (600 watts, 12 min) improved functional properties of protein hydrolysates over control by enhancing surface hydrophobicity and solubility index with an increased rate of 130.76% and 34.22%. Moreover, the stability test showed that the ACE inhibitory activity remains stable against heat treatments. However, extensive heat, prolonged heating time, and alkaline conditions were not in the favor of stability test, while under mild heat and acidic conditions their ACE inhibitory activities were not significantly different from unheated samples.