Anti diabetic and antihypertensive activities of two flaxseed protein hydrolysate fractions revealed following their simultaneous separation by electrodialysis with ultrafiltration membranes
Anti diabetic and antihypertensive activities of two flaxseed protein hydrolysate fractions revealed following their simultaneous separation by electrodialysis with ultrafiltration membranes
Year: 2014
Authors: Doyen, A. Udenigwe, C.C. Mitchell, P.L. Marette, A. Aluko, R.E. Bazinet, L.
Publication Name: Food Chem.
Publication Details: Volume 145; Pages 66 – 76
Abstract:
Flaxseed protein hydrolysate has been fractionated by electrodialysis with two ultrafiltration membranes (20 and 50 kDa) stacked in the system for the recovery of two specific cationic peptide fractions (KCl-F1 and KCl-F2). After 360 min of treatment, peptide migration increased as a function of time in KCl compartments. Moreover, the use of two different ultrafiltration membrane allowed concentration of the 300 to 400 and 400 to 500 Da molecular weight range peptides in the KCl to F1 and KCl to F2 fractions, respectively, compared to the initial hydrolysate. After mass spectrometry analysis, higher amounts of low molecular weight peptides were recovered in the KCl to F2 compartment while relatively higher molecular weight peptides were more detected in the KCl to F1 compartment. Amino acid analysis showed that His, Lys and Arg were especially concentrated in the KCl compartments. Finally, glucose transport assay demonstrated that the KCl to F2 fraction increased glucose uptake while oral administration of KCl to F1 and final FPH decreased systolic blood pressure. (Authors abstract)
New bioactive molecules originating from various food matrices are being investigated especially bioactive peptides obtained and isolated after enzymatic hydrolysis. These bioactive peptides exert physiological effects on the gastrointestinal, nervous, cardiovascular and immune system. Recently, peptide fractions recovered from flaxseed protein after hydrolysis have demonstrated interesting bioactive properties. As protein hydrolysates represent complex mixtures of similar molecular weight peptides, it is important to use an appropriate method of fractionation to obtain purified peptide fractions with higher functionality and bioactivity. The objectives of the present study were (1) to perform the fractionation of FPH by electrodialysis with two different MWCO UFMs, (2) to evaluate the impact of this double stacking on peptide migration and fractionation selectivity, (3) to characterise peptides present in the peptide fractions recovered and (4) to test the bioactivities of FPH and peptide fractions in terms of glucose capitation (anti diabetic activity) and ACE inhibitory activity (antihypertensive activity).
The results showed that the stacking of UFMs with two different MWCOs (20 and 50 kDa) in the EDUF cell for the fractionation of FPH at pH 3.0 allowed the recovery of two cationic peptide fractions, KCl F1 and KCl F2 with, respective peptide migration rates of 4.70 ± 0.35 and 1.04 ± 0.50 g/m2 h. Compared to the initial FPH, EDUF allowed the concentration of the 300 to 400 and 400 to 500 Da MW range peptides in the KCl F1 and F2 compartments. Moreover, the results obtained with the MS analysis demonstrated that peptide composition in the KCl F1 and KCl F2 compartment was different. EDUF allowed the specific migration of Arg, Lys, His and Ser-rich peptides. Amongst peptide recovered in the KCl F2 fraction, specific peptide sequence(s) increased glucose uptake in L6 cells. Moreover, the KCl F1 and final FPH fractions demonstrated antihypertensive activities on SHRs with comparable or higher effect than captopril. According to UFM and IEM membrane fouling evaluation, it appeared that the integrity of the membranes was not affected. The stacking of two UFMs with different MWCOs, in the EDUF system, represents an additional parameter for the separation of complex polypeptide mixture and may be a new avenue for the simultaneous production of peptide fractions with different biological activities and without membrane fouling phenomenon (versus pressure-driven filtration technologies). (Editors comments)
