Structure-function properties of pea-protein derived peptides with inhibitory activities against gastrointestinal enzymes

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Date
2018
Authors
Awosika, Temitola
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Abstract

Obesity and Type 2 diabetes mellitus (T2DM) are chronic disease conditions of public health significance. An approach to combating these conditions is the inhibition of digestive enzymes. Synthetic compounds, such as Acarbose and Orlistat, have been developed for enzyme inhibition; however, they tend to possess negative side effects ranging from diarrhea to hepatotoxicity. With the global prevalence of both conditions, identification of alternative enzyme inhibitors becomes imperative. Compounds of natural sources (such as dietary components) are more desirable as they are thought to possess a lower risk of negative side effects when compared to the synthetic inhibitors. Therefore, the overall aim of this study was to produce yellow field pea protein-derived peptides that can inhibit activities of α-amylase, α-glucosidase, pancreatic lipase, trypsin and chymotrypsin, the main enzymes responsible for carbohydrate, protein and lipid digestion within the human gastrointestinal tract. Protein hydrolysates were produced via enzymatic hydrolysis of pea protein isolate using four different enzymes: alcalase, pepsin, trypsin, and chymotrypsin. Each hydrolysate was then fractionated into different peptide sizes (<1, 1-3, 3-5 and 5-10 kDa) by membrane ultrafiltration. The unfractionated hydrolysates and peptide fractions were analyzed for their ability to inhibit in vitro activities of the gastrointestinal enzymes. The mode and kinetics of enzyme inhibition were then determined using the most active peptide fractions. Results indicate that the fractionated peptides were better inhibitors of the digestive enzymes (except for pancreatic lipase) compared to the unfractionated hydrolysates. The mode of inhibition was identified to be non-competitive for α-glucosidase and competitive for α-amylase, trypsin, and chymotrypsin. Findings from this study suggest that pea-protein derived peptides have the potential to be developed into functional foods and/or nutraceuticals for management of caloric intake with respect to obesity and T2DM.

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Keywords
Peptides, Obesity, Type 2 diabetes melltius, Inhibition, Gastrointestinal enzymes, Kinetics, Bioactive peptides, Mode of inhibition
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