Selected physico-chemical properties of succinylated legumin from pea (Pisum sativum L.)

Selected physico-chemical properties of pea legumin before and after succinylation have been investigated using isoelectric focusing, PAGE, SDS-PAGE, hydrophobicity measurements, SE-HPLC and RP-HPLC. Exhaustive succinylation shifted the I.P. of legumin from 4.75 to 3.5. The stepwise dissociation of legumin by increasing succinylation has been confirmed both by means of PAGE in a nondenaturing system, and by SE-HPLC. The results of SDS-PAGE provided evidence for the exposure of α-polypeptide chains in the native legumin. High succinylation resulted in a decrease of the surface hydrophobicity (S₀) measured by both fluorescence probes (cis-parinaric acid and anilino-naphtalene sulfonic acid). RP-HPLC gave a response both to conformational changes and the introduced succinyl residues.     

Relationship between proportion and composition of albumins,and in vitro protein digestibility of raw and cooked pea seeds (Pisum sativum L.)

BACKGROUND: Peas provide an excellent plant protein resource for human diets, but their proteins are less readily digestible than animal proteins. To identify the relationship between composition and in vitro digestibility of pea protein, eight pea varieties with a wide range of protein content (157.3–272.7 g kg^?1) were determined for the proportion of albumins and globulins, their compositions using sodium dodecyl sulfate–polyacrylamide gel electrophoresis, and in vitro protein digestibility (IVPD) before and after heat treatment using a multi‐enzyme (trypsin, chymotrypsin and peptidase) method. RESULTS: The proportion of albumins based on total seed protein content decreased from 229 to 147 g kg^?1 as seed protein content increased from 157.3 to 272.7 g kg^?1, while the proportion of globulins increased from 483 to 590 g kg^?1. The IVPDs of eight raw pea seeds were 79.9–83.5%, with significant varietal variations, and those were improved to 85.9–86.8% by cooking. Albumins, including (pea albumins 2) PA2, trypsin inhibitor, lectin and lipoxygenase, were identified as proteolytic resistant proteins. Globulins were mostly digested by protease treatment after heating. CONCLUSION: The quantitative ratio of albumins and globulins, and the quantitative variations of albumin protein components, including lipoxygenase, PA2, lectins and trypsin inhibitors, appear to influence the protein digestibility of both raw and cooked pea seeds. Copyright © 2010 Society of Chemical Industry     

Functional properties of protein hydrolysates from pea (Pisum sativum,L) seeds

The aim of this study was to investigate the effects of partial enzymatic hydrolysis on functional properties of two different pea protein isolates obtained from two pea genotypes, Maja and L1. Papain and commercial protease (Streptomyces griseus protease) were used for protein modification. Solubility, emulsifying and foaming properties were estimated at four different pH values (3.0, 5.0, 7.0 and 8.0). Papain increased solubility of L1 pea protein isolate at pH 3.0, 5.0 and 8.0, emulsifying properties and foaming capacity at all pH values. Otherwise, papain increased solubility of Maja pea protein isolate only at pH 8.0. This pea protein isolate modified with both enzymes formed emulsions with improved stability at lower pH (3.0, 5.0). The commercial protease‐prepared pea protein isolates showed generally low solubility and different emulsifying and foaming properties. Proper selection of enzyme, conditions of hydrolysis and genotypes could result in production of pea protein isolates with desirable functional properties.     

Lactic acid assisted wet fractionation of field pea (Pisum sativum L.) flour

The use of lactic acid (LA) in the isolation of starch from field pea (Pisum sativum L.) flour was investigated. The yield, purity, morphology, and the physicochemical properties (color, swelling, pasting and gelatinization characteristics, X‐ray diffraction pattern, and crystallinity) of the starches isolated with and without LA were determined. When compared to the control (0% LA), addition of LA at concentrations ranged from 0.5 to 7.0% v/v significantly increased the purity of the isolated starches up to 4% w/w and reduced the residual protein content by 6% w/w. The resistant starch and apparent amylose contents of the isolated starches using LA were significantly higher (up to 25 and 42.5%, w/w, respectively). Furthermore, the starches produced by LA assisted extraction showed significantly lower swelling factor and pasting viscosities, but generally insignificant changes were observed in the gelatinization parameters as compared to that of control. Marginal differences were observed in the X‐ray diffractograms between control and the LA processed starches. However, the relative crystallinity of LA processed starches was significantly higher than the control. The present study revealed that the use of LA in pea starch extraction show benefits in terms of starch purity, brightness, resistance to amylolysis, and apparent amylose content.     

Quantitative and qualitative variability of pea (Pisum sativum L.) protein composition

Smooth and wrinkled pea cultivars were studied to evaluate the protein content of the seeds, the proportion of albumins to globulins and the variability of the vicilin/legumin ratio. Principal components analysis showed a strong negative correlation between albumin and globulin contents. Stepwise discriminant analysis demonstrated that two variables, protein content and vicilin/legumin ratio, divided the samples into smooth and wrinkled cultivars with a percentage of success of 95%. In addition, the vicilin/legumin ratio tended to increase, the lower the protein content is.     

Soyasaponin I,a compound possessing undesirable taste characteristics isolated from the dried pea (Pisum sativum L.)

One of the compounds contributing to the undesirable sensory characteristics (bitterness and astringency) of some cultivars of dried pea and their products has been identified by chemical and spectroscopic techniques as soyasaponin I, a sapogenin trisaccharide previously reported in soya.     

Studies on the thermal behaviour of pea (Pisum sativum)vicilin

The effect of heat on pea (Pisum sativum L) vicilin has been studied using differential scanning calorimetry (DSC), gel filtrtion chromatography and turbidimetry. By adjusting the variables of pII, ionic strength and protein concentration, two processes could be identified from the DSC thermograms: protein denaturation and protein aggregation. The results are discussed in terms of electrostatic and hydrophobic interactions. A mechanism for the thermal aggregation of pea vicilin is proposed.     

The effect of pea (Pisum sativum L.)‐originated asparaginase on acrylamide formation in certain bread types

The aim of this study was to investigate the effect of pea (Pisum sativum L.)‐originated asparaginase on acrylamide formation in white wheat, wheat bran and whole‐grain wheat breads. Two‐day germinated pea flour was used at 0%, 1%, 3% and 5% levels for each bread type. Acrylamide analysis was performed with liquid chromatography–mass spectrometry. Besides, colour and sensory properties of the breads were evaluated to search out the effects of pea flour substitution on the consumer acceptance. Reduction of acrylamide in white wheat bread was not found significant and addition of pea flour decreased the acceptance. However, it was found that acrylamide level can be reduced by 57% and 68% with addition of 5% pea flour in wheat bran and whole‐grain breads, respectively, without any negative impact on colour and sensory properties.     

Pilot scale isolation of proteins from field peas (Pisum sativum L.) for use as food ingredients

Summary The protein and starch fractions of field pea ( Pisum sativum L.) are potentially a source of novel ingredients for food processing. As part of research to elucidate the functional properties of field pea proteins, the pilot scale extraction of proteins has been undertaken. Two different approaches have been used and the recoveries of protein compared. The first involved extraction with a salt solution followed by decanting and clarification to remove solids. The solution was then further concentrated and salt removed by ultrafiltration and diafiltration. The second procedure was based upon alkaline extraction followed by decanting and recovery by isoelectric precipitation and neutralisation. Both spray drying and freeze drying methods were employed. The protein isolates have been compared and characterised with respect to solubility, chemical composition and to electrophoretic patterns. Overall, the proteins extracted with salt exhibited better physical properties than proteins extracted with alkali, in terms of colour and particle size. The solubilities showed little variation and the electrophoretic patterns were similar. Freeze drying resulted in isolates with darker colour compared with spray drying.     

Assessment of nutritional compounds and antinutritional factors in pea (Pisum sativum) seeds

The nutrient and antinutritional factor content of 18 pea lines was studied. The following levels were found: non‐protein nitrogen 5.2–10.2 g kg^?1 DM, protein nitrogen 35.3–42.4 g kg^?1 DM, lysine 50.7–76.3 g kg^?1 protein DM, histidine 17.8–24.8 g kg^?1 protein DM, tyrosine 22.6–30.0 g kg^?1 protein DM, protein 25.9–31.9% DM, in vitro protein digestibility 89.3–95.6%, vitamin B₁ 5.9–10.3 mg kg^?1 DM, vitamin B₂ 1.1–3.7 mg kg^?1 DM, sucrose 11.6–25.4 g kg^?1 DM, raffinose 4.1–10.3 g kg^?1 DM, stachyose 10.7–26.7 g kg^?1 DM, verbascose 0.0–26.7 g kg^?1 DM, total α‐galactosides 22.6–63.4 g kg^?1 DM, trypsin inhibitor activity 0.8–8.4 TIU mg^?1 DM, inositol hexaphosphate 2.3–6.5 g kg^?1 DM, inositol pentaphosphate 0.1–1.8 g kg^?1 DM and total inositol phosphates 2.8–7.1 g kg^?1 DM. Peas with yellow cotyledons had the highest trypsin inhibitor activities, those with light green cotyledons had the highest lysine contents, and those with dark green cotyledons were the richest in vitamins B₁ and B₂. Peas with brown testae had the lowest verbascose and sucrose contents, while they were the richest in inositol hexaphosphate. Smaller peas were characterised by the highest protein nitrogen contents as well as the highest contents of vitamins B₁ and B₂, verbascose and inositol pentaphosphate. Peas of medium size showed the lowest verbascose, α‐galactoside and vitamin B₂ contents. Bigger peas showed the lowest inositol pentaphosphate contents. © 2003 Society of Chemical Industry     

Genotypic abundance of carotenoids and polyphenolics in the hull of field pea (Pisum sativum L.)

BACKGROUND: Consumption of pulse crops, including field pea, is considered effective for a healthy diet. Hulls (seed coats) play an important role for protection of the cotyledon and embryo, but also as mediating positive effects on health outcomes. The biochemical attributes of field pea hulls were thus assessed to determine the occurrence of specific phytochemicals and their genotypic variability. RESULTS: Sequestered bioproducts in mature hulls predominantly consisted of trans‐lutein and chlorophylls a and b. Trace amounts of other carotenoid and pheophytin metabolites were identified. In developing hulls, violaxanthin, neoxanthin, lutein, zeaxanthin, chlorophylls a and b and β‐carotene were detected. Genotypic differences in the accumulation of lutein and chlorophylls a and b were observed over years and locations. Polyphenolics and hydroxybenzoic acids were detected in the ‘dun’ and ‘maple’ field pea types—the only genotypes to have pigmented hulls. Unextractable patches of condensed tannin influenced the visual uniformity of the maple and dun genotypes, CDC Rocket and CDC Dundurn. CONCLUSIONS: Within the yellow and green market classes, carotenoid and chlorophyll accumulation was consistent. Green cotyledon varieties sequestered higher concentrations of lutein than the yellow cotyledon varieties. Maple and dun types were more variable, reflective of different selection criteria. The occurrence of flavonoid‐related compounds was correlated only with pigmented seed coat genotypes. The dietary potential of the chlorophylls and carotenoids that accumulated in the hulls split from the green and yellow field pea types is discussed as a value‐added prospect in food supplements. © 2012 Society of Chemical Industry     

The health benefits,functional properties,modifications, and applications of pea (Pisum sativum L.) protein: Current status,challenges, and perspectives

In recent years, the development and application of plant proteins have drawn increasing scientific and industrial interests. Pea (Pisum sativum L.) is an important source of high‐quality vegetable protein in the human diet. Its protein components are generally considered hypoallergenic, and many studies have highlighted the health benefits associated with the consumption of pea protein. Pea protein and its hydrolysates (pea protein hydrolysates [PPH]) possess health benefits such as antioxidant, antihypertensive, and modulating intestinal bacteria activities, as well as various functional properties, including solubility, water‐ and oil‐holding capacities, and emulsifying, foaming, and gelling properties. However, the application of pea protein in the food system is limited due to its poor functional performances. Several frequently applied modification methods, including physical, chemical, enzymatic, and combined treatments, have been used for pea protein to improve its functional properties and expand its food applications. To date, different applications of pea protein in the food system have been extensively studied, for example, encapsulation for bioactive ingredients, edible films, extruded products and substitution for cereal flours, fats, and animal proteins. This article reviews the current status of the knowledge regarding pea protein, focusing on its health benefits, functional properties, and structural modifications, and comprehensively summarizes its potential applications in the food industry.     

Effect of the stage of growth,wilting and inoculation in field pea (Pisum sativum L.) silages. I. Herbage composition and silage fermentation

The stage of growth, field wilting and inoculation with lactic acid bacteria (LAB) effects were studied by ensiling herbage of field pea (Pisum sativum L.) at four consecutive stages. Stands of semi‐leafless field pea, sown in spring, were harvested at four progressive morphological stages (end of flowering, I; beginning of pod filling, II; advanced pod filling, III; beginning of ripening, IV). For each stage of growth, the herbage was field wilted to a dry matter (DM) content of 318, 300, 348 and 360 g kg^?1 for stages I, II, III and IV, respectively. The unwilted and wilted herbages were ensiled in 5‐L silos, with (I) and without (C) a LAB inoculant (Lactobacillus plantarum). High levels of ethanol, lactic acid and volatile fatty acids (VFA) were observed in all silages, facilitated by the high levels of water‐soluble carbohydrates (WSC) at ensiling (from 111 to 198 g kg^?1 DM). Despite the low pH values (4.3 and 4.1 for C and I silages, respectively), all the silages showed detectable levels of butyric acid. Field peas can be successfully ensiled after a short wilting period with reduced field curing and reduce DM losses onward from advanced pod filling stage, with the aid of LAB inoculum. Copyright © 2006 Society of Chemical Industry     

Distribution of fatty acids in triacylglycerols and phospholipids from peas (Pisum sativum L.)

BACKGROUND: The fatty acid distribution of triacylglycerols (TAG) and major phospholipids (PL) obtained from four varieties of peas (Pisum sativum) was investigated. The total lipids extracted from the peas were separated by thin layer chromatography into seven fractions. RESULTS: The major lipid components were PL (52.2–61.3%) and TAG (31.2–40.3%), while hydrocarbons, steryl esters, free fatty acids and diacylglycerols (sn‐1,3 and sn‐1,2) were also present in minor proportions (5.6–9.2%). The main PL components isolated from the four varieties were phosphatidylcholine (42.3–49.2%), phosphatidylinositol (23.3–25.2%) and phosphatidylethanolamine (17.7–20.5%). Significant differences (P < 0.05) in fatty acid distribution were found for different pea varieties. Phosphatidylinositol was unique in that it had the highest saturated fatty acid content among the three PL. However, the principal characteristics of the fatty acid distribution in the TAG and three PL were evident among the four varieties: unsaturated fatty acids were predominantly located in the sn‐2 position while saturated fatty acids primarily occupied the sn‐1 or sn‐3 position in the oils of the peas. CONCLUSION: These results should be useful to both producers and consumers for the manufacture of pea foods in Japan. Copyright © 2007 Society of Chemical Industry     

Effect of the stage of growth,wilting and inoculation in field pea (Pisum sativum L.) silages,III. Changes in the herbage and silage protein profiles

BACKGROUND: The effects of stage of growth, field wilting and inoculation with lactic acid bacteria (LAB) on the protein profile of herbage and silage were studied on field peas (Pisum sativum L.) harvested at four progressive morphological stages (end of flowering, I; beginning of pod filling, II; advanced pod filling, III; beginning of ripening, IV). The herbage was field wilted to a dry matter (DM) content around 330 g kg^?1, for each stage of growth. The unwilted and wilted herbages were ensiled with (I) and without (C) a LAB inoculant. RESULTS: As a result of the advancing maturity of the crop, the main protein component was Rubisco in the early stages and seed storage proteins in the more advanced stages, due to the redistribution of organic nitrogen during seed filling. Extensive degradation of Rubisco occurred in all the silages, without any effect of inoculation or wilting. A good preservation of the proteins was observed in stage IV for both unwilted and wilted silages, without further protein preservation due to LAB inoculation. CONCLUSION: Protein protection observed in the more mature pea silage was due to the protein type and its localization and not to the level of DM at ensiling or to the inoculation. Copyright © 2007 Society of Chemical Industry     

Studies on the biological responses of rats to seed trypsin inhibitors using near-isogenic lines of Pisum sativum L (pea)

In order to determine the true antinutritional status of pea seed trypsin inhibitor (TI) proteins, pea lines are being produced that are near-isogenic except for the genetic locus, Tri, containing the TI structural genes. These lines are based on selection from the progeny of a cross between lines showing quantitative variation in TI content, as well as TI isoform and gene polymorphisms that serve as markers. Chemical analyses revealed that the composition of seeds from lines of each near-isogenic pair was extremely similar, except for a more than five-fold difference in TI content. Such lines provide material that is superior to the diverse lines previously used for nutritional assessment of pea TI. The specific biological effects of pea TI were studied by including the near-isogenic lines in standardised rat diets. The results indicated that TI content was correlated with a significant negative effect on protein digestibility and biological value. The difference in TI content of the pea seeds was reflected in the relative activity of pancreatic chymotrypsin whereas the activities of trypsin, lipase and amylase were less clearly affected. © 1999 Society of Chemical Industry     

The effects of blackcurrant powder (Ribes nigrum) supplementation on pasting properties,physicochemical properties,and nutritive values of starch derived from mung bean (Vigna radiata L.) and pea (Pisum sativum L.)

Incorporation of bioactive-containing fruits and/or vegetables into the carbohydrate-rich food matrix are effective strategies to develop food products with functional health benefits. In this study, blackcurrant powder was added into pea starch and mung bean starch to form pastes to investigate the effects of blackcurrant powder on physicochemical and nutritional properties of the starch pastes. The predictive in vitro glycaemic response of the pastes was highlighted by in vitro glycaemic glucose equivalent assay and alpha-amylase inhibitory activity assay. Both assays showed that blackcurrant powder attenuated (P < 0.05) reducing sugar released, through the inhibition of α-amylase. The colour profiles and textural properties of the pastes were modified by the additions of blackcurrant berry powder at different levels. Nutritional characteristics of the pastes, including total phenolic content and antioxidant activity, were significantly changed (P < 0.05) with the addition of blackcurrant powder.