Identification of Bitter Peptides in Whey Protein Hydrolysate

Abstract

Bitterness of whey protein hydrolysates (WPH) can negatively affect product quality and limit utilization in food and pharmaceutical applications. Four main bitter peptides were identified in a commercial WPH by means of sensory-guided fractionation techniques that included ultrafiltration and offline two-dimensional reverse phase chromatography. LC-TOF-MS/MS analysis revealed the amino acid sequences of the bitter peptides were YGLF, IPAVF, LLF, and YPFPGPIPN that originated from α-lactalbumin, β-lactoglobulin, serum albumin, and β-casein, respectively. Quantitative LC-MS/MS analysis reported the concentrations of YGLF, IPAVF, LLF, and YPFPGPIPN to be 0.66, 0.58, 1.33, and 2.64 g/kg powder, respectively. Taste recombination analysis of an aqueous model consisting of all four peptides was reported to explain 88% of the bitterness intensity of the 10% WPH solution.

Emerging trends in nutraceutical applications of whey protein and its derivatives

“…Assorted enzymes are used to hydrolyze whey protein concentrate to reduce its antigenic fractions and increase the peptides content. Alcalase, flavourzyme, trypsin, chymotrypsin or papain are recruited to degrade major antigenic fractions (β-lactoglobulin) in the concentrate (Liu et al 2014b;Zhang et al 2012). Cutting-edge techniques such as laser diffraction spectroscopy, rheology, tribology, scanning electron microscopy have facilitated characterization of whey components.…”

“…In this regard, four bitter peptides were identified in the hydrolysate by sensory-guided fractionation techniques (combination of ultra-filtration and chromatography). LC-TOF-MS/ MS analysis identified the constituent amino acids in the peptides (Liu et al 2014b). Supplementing whey protein concentrates with spirulina (blue-green freshwater algae rich in protein) improved antioxidant, radical scavenging and metalchelating activities in dose-dependent manner, in both in vitro and in vivo studies.…”

“…Enzymatic hydrolysis also reduces the allergenicity. As mentioned in the technical advancement section, an array of enzymes are used to decimate the antigenic fragments by hydrolysis (Zhang et al 2012;Liu et al 2014b). In vitro enzymatic hydrolysis of whey protein concentrates was performed using trypsin.…”

“…However, the hydrolysis often produces bitter peptides and destroys the biological function of the protein. Ultrafiltration is used to remove the large residual peptides causing the bitterness (Liu et al 2014b). So, at present scenario, there is a trade-off between allergenity reduction and bitterness increment.…”

Functional food relevance of whey protein: A review of recent findings and scopes ahead

“…A study in this direction led to the finding that sucralose, fructose, sucrose, adenosine 5′ monophosphate (5′AMP), adenosine 5′ monophosphate disodium, sodium acetate, monosodium glutamate, sodium gluconate and sodium chloride can mask the off-flavour (Leksrisompong, Gerard, Lopetcharat, & Drake, 2012). LC-TOF-MS/MS analysis could characterize the bitterness-causing peptides to be tri-to nonapeptides (Liu, Jiang, & Peterson, 2014). Ultra-filtration can be used to remove the bitterness-causing peptides (Liu et al, 2014).…”