Palm kernel cake protein was hydrolyzed using seven different proteases namely alcalase, chymotrypsin, papain, pepsin, trypsin, flavourzyme, and bromelain. The antioxidative activity of the proteolysates was evaluated using DPPH. radical scavenging activity assay. Out of seven proteolytic enzyme-generated proteolysates, papain - generated proteolysate showed the highest antioxidative activity (73.5 ± 0.25%). Papain generated hydrolyzate was further fractionated using RP-HPLC. In this step, 31 fractions were collected and their DPPH. radical scavenging activities were measured. Fraction numbers 16, 18, 19 and 20 showed relatively high DPPH. radical scavenging activities. These fractions were used for further purification and characterization based on their peptide contents and isoelectric points by using an IEF system. Peptides were analyzed using an Ultra-High Performance Liquid Chromatography system coupled to a high-resolution, accurate mass hybrid quadrupole-time of flight (Q-TOF) mass spectrometer. Nine novel peptides with antioxidant and ACE inhibitory were identified from palm kernel cake (PKC) proteolysate.
Palm kernel cake (PKC), the main by-product of the palm oil extraction process, has poor utility. Its protein content (15-19%), low cost and more availability (2.4 million tons per year) has made it as an attractive source of plant proteins in Malaysia (202,000 tons per year). This amount can be a valuable source for many applications. Generation of bioactive peptides from PKC protein increases exponentially the value of this raw material. Therefore, nine novel bifunctional bioactive peptides were generated and purified from the PKC protein. antihypensive and antioxidative activities. Cardiovascular diseases (CVDs) are the number one cause of death globally. An estimated 17.3 million people died from CVDs in 2008, representing 30% of all global deaths. Around 80% of CVD deaths take place in low- and middle-income countries and occur almost equally in men and women. Since hypertension and oxidative stress play a crucial role in cardiac and vascular abnormalities in different types of cardiovascular diseases, the antioxidant therapy may prove beneficial in combating these problems. PKC produced bioactive peptides revealed potent antihypertensive and antioxidative effects to reduce the oxidative stress and modulate the blood pressure. All PKC generated novel bioactive peptides were more preferable due to their low cost, safety, nutritional and functional value, consumer's preference and concern over the safety of synthetic products.
This is the first project on the palm kernel cake protein and proteolysate to derive novel and multifunctional bioactive peptides from by-product of the palm oil extraction process (PKC). In addition this is the first study that tried to increase the added value of PKC by using its protein. Malaysia has an excellent potential to produce protein hydrolysate and multifunctional peptides with low price because PKC as a protein source is very cheap and available. All nine bioactive peptides derived in this study showed a potent multifunctionality such as ACE inhibitory activity, a strong radical scavenging activity, good chelating and antibacterial activity.