Discovery of Salt Taste Enhancing Arginyl Dipeptides in Protein Digests and Fermented Fish Sauces by Means of a Sensomics Approach

Abstract

As enzymatic digests of fish proteins were recently reported to enhance salt taste, the fish protein protamine was digested by chymotrypsin and trypsin and subsequently screened for candidate salt taste modulating (STM) peptides. To achieve this, first, a two-step sensory assay was developed and demonstrated to be a rather suitable tool for the detection of salt taste enhancers and the "quantitation" of their salt taste enhancing activity on the basis of isointensities with reference solutions. By means of activity-guided fractionation using ultrafiltration, gel permeation chromatography, and hydrophilic liquid interaction chromatography in combination with the sensory assay for STM activity assessment, a series of arginyl dipeptides, with RP, RA, AR, RG, RS, RV, VR, and RM being the most active, as well as l-arginine were found as salt taste enhancing molecules in fish protamine digests. For the first time, HPLC-MS/MS analysis on a PFP and a HILIC stationary phase, respectively, enabled the quantitative analysis of the arginyl peptides in a series of commercial and laboratory-made protein hydrolysates as well as fermented fish sauces.

Potential of Szechuan pepper as a saltiness enhancer

“…Determination of saltiness enhancement level A 2-step rating test [19] was performed to assess the level of saltiness enhancement in fried potato sticks. First, 11 trained panelists (3 males and 8 females, between 22 and 34 years old) worked on four randomly coded samples of seasoned potato sticks of different salt concentrations (0.5%, 1.0%, 1.5%, and 2.0%).…”

“…This number was similar to that of arginyl dipeptides having a 26.8% impact in saltiness modulating activity. [19] Moreover, the addition of Szechuan pepper reduced the need of salt by 22.32%. In terms of public health, the average sodium intake of an American adult was 3,440 mg/day while the recommendation was 2,300 mg/day.…”

“…[22,23] It is also applied in several studies concerning sweet, [47] kokumi, [48] and saltiness enhancers. [19] Subfraction 14, the highest potency enhancing part, was further analyzed by HPLC-DAD. Chromatography data showed several major compounds observed at λ max 254 and 300 nm.…”

Biologically Active Peptides Released From Food Proteins

“…Przykładami peptydów o smaku słonym są dipeptydy arginylowe zidentyfikowane w chymotrypsynowych i trypsynowych hydrolizatach białek ryb. Za najbardziej aktywne uznano następujące sekwencje aminokwasowe: RP, RA, AR, RG, RS, RV, VR oraz RM, a obecność L-argininy decydowała o aktywności wymienionych peptydów [89]. Z kolei aminokwasami decydującymi o kwaśnym smaku peptydów są reszty kwasu glutaminowego i/lub asparaginowego [44].…”

High-Throughput Proteomics: A New Tool for Quality and Safety in Fishery Products

“…Specific peptides obtained after enzymatic digestion of fish proteins can be utilized to enhance salt taste in food, namely a series of arginyl dipeptides, with RP, RA, AR, RG, RS, RV, VR, and RM having been found to be the most active, as well as L-arginine as salt taste enhancing molecules in fish protamine digests and fermented fish sauces [66]. In this recent study, the authors applied chromatography techniques coupled to LC-MS/MS analysis utilizing "sensomics", a new research area which aims to characterize the most intense taste-active metabolites in fresh and processed foods.…”