Identification of a Bitter Peptide Contributing to the Off-Flavor Attributes of Pea Protein Isolates

Abstract

The aversive bitter taste of pea protein ingredients limits product acceptability. Compounds contributing to the bitter perception of pea protein isolates were investigated. Off-line multi-dimensional sensory-guided preparative liquid chromatography fractionation of a 10% aqueous PPI solution revealed one main bitter compound that was identified by Fourier transform ion cyclotron resonance mass spectrometry and de novo tandem mass spectrometry (MS/MS) sequencing as the 37 amino acid peptide PA1b from pea albumin and further confirmed by synthesis. Quantitative MS/MS analysis reported that the concentration of the bitter peptide was 129.3 mg/L, which was above the determined bitter sensory threshold value of 3.8 mg/L and in agreement with the perceived bitter taste of the sample.

Plant protein flavor chemistry fundamentals and techniques to mitigate undesirable flavors

“…Taylor et al (2004) identified a PA1b peptide variant in isolated pea protein that had insecticidal activity. More recently, Ongkowijoyo et al (2023) supported the presences of the bitter peptide PA1b in a commercial pea protein isolate. This bitter peptide was 37 amino acids in length.…”

“…However, they did find that the DoT for astringency was exceeded and thus at the concentration measured (1 mmol/kg) was sufficient to impart astringency but not bitterness. Ongkowijoyo et al (2023) also reported soyasaponin I concentration in a 10% solution of a commercial pea protein isolate was below the bitterness threshold and suggested that the bitterness observed was not due to this saponin. However, the conversion of DDMP saponins to soyasaponin I likely occurred during the production of the commercial pea protein isolates and resulted in a less bitter product due to the lower bitterness intensity of soyasaponin I compared to DDMP saponins (Heng, Vincken, Hoppe, van Koningsveld, Legger, et al, 2006;Heng, Vincken, Hoppe, van Koningsveld, Decroos, et al, 2006).…”

“…However, the 9,10,11-trihydroxyoctadec-12-enoic and 11,12,13-trihydroxyoctadec-9-enoic acids were determined to be the hydroxy fatty acids that contributed most to the bitterness. Ongkowijoyo et al (2023) also reported the presence of hydroxy fatty acids in a commercial pea protein isolate but found that the concentrations were lower than the threshold values for bitterness. Furthermore, 1-linoleoyl glycerol had significant bitterness (Gläser et al, 2020(Gläser et al, , 2021.…”

“…This approach is effective in assessing VOC but not non-VOCs. Instead, use of HPLC-based approaches coupled with mass spectrometry and sensory analysis (Cosson, Meudec, et al, 2022;Ongkowijoyo et al, 2023) are better suited for assessing non-VOC compounds. The main drawback to these methods is the potential variability of the sensory panelists.…”

Aroma Comparison between Plant-based Hamburgers and Traditional Beef Hamburgers

“…These proteins are known to sometimes contribute negative taste aspects such as astringency and bitterness (Glaser et al, 2020). There have been negative taste attributes associated with these proteins as well, for instance saponins (Heng et al, 2006) and a recently discovered bitter peptide in pea protein (Ongkowijoyo et al, 2023). Indeed, the challenges to recreate animal meat aroma and flavor with plant-based proteins are numerous.…”