Pea and lentil protein extraction and functionality

Abstract

These studies have demonstrated that peas and lentils can be used as protein sources for flours, concentrates and isolates. Less research attention has been devoted to lentil protein extraction, probably because of the greater cost of lentils as compared to peas. Pin-milling and air classification is well adapted to extracting pea flours to produce pea protein concentrates. Apparently, air-classification can be applied successfully to starch rich legumes, but will not give satisfactory results with lipid rich legumes.Wet processes, including alkaline and salt and acid solubilization, together with isoelectric precipitation or ultrafiltration, have been developed. The pea and lentil protein extracts of these processes exhibit comparable and complementary functionality to homologous soybean products. Air-classified pea protein concentrates are different from soy protein concentrates because of residual starch which can be useful for particular functional applications. Pea isolates appear to exhibit better foaming properties and more solubility than soy isolates, but pea isolates have to be more concentrated than soy isolates to produce viscous dispersions. The economic feasibility of pea and lentil protein extracts is related directly to protein content of the flour, unique functionality of the extracts, marketability of the by-products of extraction and the cost of peas or lentils.Dry peas (Pisum sativum} and lentils (Lens culinaris) contain 20-30% lysine-rich protein. Air-classification and alkaline solubilization with isolelectric precipitation separate legume storage globulins and albumins into concentrates and isolates. Lipoxygenase oxidation in the protein extracts results in decreased nutritive value, digestibility and solubility. Solubility, amino acid composition, conformation, surface hydrophobicity, susceptibility to denaturation and inter-and intra-molecular binding influence functionality of extracted legume proteins in food systems.

Functional properties of protein isolates from different pea cultivars

“…Surface characteristics All isolates, regardless of cultivar, had similar isoelectric points (zeta potential=0 mV) with values ranging between 4.6 and 4.9 mV, which were comparable to other reported values for pea protein isolates (1,7,26,(31)(32)(33)(34). In this study, the surface charge of each isolate was determined at pH 7.0 (Table 3) and ranged from −23.05 to −26.75 mV.…”

Physico-chemical and functional properties of cowpea protein isolate as affected by the dehydration technique

“…The functional attributes of proteins like gelation, foaming, emulsification, thickening also drive the incorporation of isolated proteins in various foods like mayonnaise, baked foods and beverages. However the manner of converting the isolated proteins into powders also determines their functional properties (Swanson, 1990). Understanding the composition of proteins, their processing methods and their effects on the functional properties shall provide better insights for promoting the application of cowpea protein isolates in new food formulations.…”

Influence of dietary inclusion of a wet processed faba bean protein isolate on post-smolt Atlantic salmon ( Salmo salar )

“…One candidate could be a residual artifact of the processing methodology. The wet process for producing protein isolates from legumes generally involves protein extraction with alkaline solution followed by acid precipitation (Gueguen, 1983;Swanson, 1990). At the latter stage the pH of the solubilized protein solution is reduced with sulphuric acid and the precipitated protein recovered by centrifugal decanter before being dried.…”

“…The BPI was produced using wet processing methodology involving aqueous alkaline solubilisation and acid precipitation adapted from methods used for the production of legume, including pea and lupin, protein isolates (Gueguen, 1983;Swanson et al, 1990;Jayasena et al, 2011). In the present study, we investigated the effects of BPI on growth and performance of Atlantic salmon in a trial using practical feed formulations and growing conditions in seawater to simulate commercial production.…”