Impact of Peptidase Activities on Plant Protein Hydrolysates Regarding Bitter and Umami Taste

Characteristics of meat flavoring prepared using hydrolyzed plant protein mix by three different heating processes

Meat flavoring was prepared using mainly enzymatic hydrolysate of plant protein mix, VB1, cysteine, and glucose by three heating processes, including A (80 °C-140 min), B (two-stage, 80 °C-30 min/120 °C-30 min), and C (120 °C-40 min). The A-, B-, and C-heated samples exhibited the strongest fatty and weakest meaty, the strongest meaty and kokumi, and the strongest roasted and bitterness characteristics, respectively. PLS-DA for free amino acids with TAVs and that for SPME/GC-MS results with GC-O and OAVs, suggested three amino acids and eight flavor compounds contributed significantly in differentiating taste or aroma attributes of the three heated samples. Molecular weight distribution and degree of amino substitution suggested 1-5 kDa peptides contributed to kokumi taste. Overall, C- and A-heating exhibited the highest rates in Maillard reaction and lipid oxidation, respectively, while those of B heating were between these two heating processes and responsible for better flavor of meat flavoring.

Synthesis of taste active γ-glutamyl peptides with pea protein hydrolysate and their taste mechanism via in silico study

Pea (Pisum sativum L.) protein hydrolysate (PPH) has a bitter taste, which has limited its use in food industry. γ-Glutamylation is used to debitter PPH. Results showed that the bitterness of PPH was decreased significantly due to the formation of γ-glutamyl peptides, including 16 γ-[Glu](n=1/2)-amino acids (AAs) and 8 newly discovered γ-glutamyl tripeptides (γ-Glu-Asn-Phe, γ-Glu-Leu-Val, γ-Glu-Leu-Tyr, γ-Glu-Gly-Leu, γ-Glu-Gly-Phe, γ-Glu-Gly-Tyr, γ-Glu-Val-Val, and γ-Glu-Gln-Tyr). Their total production concentrations were 27.25 μmol/L and 77.76 μmol/L, respectively. The γ-Glu-AA-AAs presented an umami-enhancing, salty-enhancing, and kokumi taste when their concentration reached 1.67 ± 0.20 ∼ 2.07 ± 0.20, 1.65 ± 0.25 ∼ 2.29 ± 0.45 and 0.68 ± 0.19 ∼ 1.03 ± 0.22 mmol/L, respectively. The γ-Glu-AA-AAs exhibited a kokumi taste by entering the Venus flytrap (VFT) of the calcium-sensing receptor and interacting with Ser147, Ala168, and Ser170. γ-Glu-AA-AAs can enhance the umaminess of Monosodium Glutamate (MSG) as they can enter the binding pocket of the taste receptor type 1 subunit 3 (T1R3)-MSG complex.

Identification of compounds contributing to umami taste of pea protein isolate

The umami taste of pea protein ingredients can be desirable or undesirable based on the food application. The compounds contributing to the umami perception of pea protein isolate (PPI) were investigated. Sensory-guided prep-liquid chromatography fractionation of a 10% aqueous PPI solution revealed one well-known compound, monosodium glutamate (MSG), however, it was reported at a subthreshold concentration. Two umami enhancing compounds 5'-adenosine monophosphate (AMP) and 5'-uridine monophosphate (UMP) were subsequently identified after the LC fractions were re-evaluated with MSG. Sensory recombination studies, utilizing the aqueous PPI solution as the base, confirmed AMP and UMP were umami enhancers of MSG and contributed approximately 81% of the perceived umami intensity. However UMP was only reported to enhance umami perception in combination with AMP (not individually) indicating synergistic interactions were observed between the two enhancer compounds. Therefore the presence of all three compounds are important for umami perception and provide an improved basis to tailor the flavor profile in PPI products.

Research Advances in Plant Protein-Based Products: Protein Sources, Processing Technology, and Food Applications

Plant proteins are high-quality dietary components of food products. With the growing interest in sustainable and healthy food alternatives, plant proteins have gained significant attention as viable substitutes for animal-based proteins. Understanding the diversity of protein sources derived from plants, novel processing technology, and multiple applications is crucial for developing nutritious and sustainable plant protein-based products. This Review summarizes the natural sources of traditional and emerging plant proteins. The classifications, processing technologies, and applications of plant protein-based products in the food industry are explicitly elucidated. Moreover, the advantages and disadvantages of plant protein-based food products are revealed. Strategies such as protein fortification and complementation to overcome these shortcomings are critically discussed. We also demonstrate several issues that need to be addressed in future development.

Enzymatic hydrolysis of lentil protein concentrate for modification of physicochemical and techno-functional properties

The effects of hydrolysis by commercial food-grade proteases on the physicochemical and techno-functional properties of lentil protein concentrate were investigated. Lentil protein concentrate was hydrolysed with Alcalase, Novozym 11028 or Flavourzyme, and a control was prepared without enzyme addition under the same conditions. Differences in specificity between the three proteases were evident in the electrophoretic protein profile, reversed-phase HPLC peptide profile, and free amino acid composition. Alcalase and Novozym were capable of extensively degrading all the major protein fractions. Alcalase or Novozym treatment resulted in considerably higher solubility under acidic conditions compared to the control. Flavourzyme treatment resulted in moderately improved solubility in the acidic range, but slightly lower solubility at pH 7. Alcalase treatment resulted in slightly larger particle size and slightly higher viscosity. The foaming properties of the protein concentrate were not significantly affected by hydrolysis. Increased solubility in acidic conditions with hydrolysis could broaden the range of food and beverage applications for lentil protein concentrate.

Enzymatic Hydrolysis of Pulse Proteins as a Tool to Improve Techno-Functional Properties

Pulse proteins are being increasingly investigated as nutritious and functional ingredients which could provide alternatives to animal proteins; however, pulse protein ingredients do not always meet the functionality requirements necessary for various applications. Consequently, enzymatic hydrolysis can be employed as a means of improving functional properties such as solubility, emulsifying, foaming, and gelling properties. This review aims to examine the current literature regarding modification of these properties with enzymatic hydrolysis. The effects of enzymatic hydrolysis on the functionality of pulse proteins generally varies considerably based on the enzyme, substrate, processing steps such as heat treatment, degree of hydrolysis, and pH. Differences in protease specificity as well as protein structure allow for a wide variety of peptide mixtures to be generated, with varying hydrophobic and electrostatic properties. Typically, the most significant improvements are seen when the original protein ingredient has poor initial functionality. Solubility is usually improved in the mildly acidic range, which may also correspond with improved foaming and emulsifying properties. More work should be carried out on the potential of enzymatic hydrolysis to modify gelation properties of pulse proteins, as the literature is currently lacking. Overall, careful selection of proteases and control of hydrolysis will be necessary to maximize the potential of enzymatic hydrolysis as a tool to improve pulse protein functionality and broaden the range of potential applications.