Effects of Hydroxypropylation on Themal Properties,Starch Digestibility and Freeze-Thaw Stability of Field Pea (Pisum sativum cv Trapper) Starch

Field pea starch with an amylose content of 34.2% was hydroxypropylated with propylene oxide and sodium hydroxide to give products with molar substitutions (MS) ranging from 0.04 to 0.12. Increasing the degree of MS resulted in progressive decreases in enthalpy of gelatinization. gelatinization temperatures, pasting temperatures and syneresis. and increases in paste viscosities at 95 and 50°C. The digestibility with a-amylase decreased with increases in MS only up to the level of 0.08 and further increases in MS caused an increase in digestibility which was higher than that observed for native starch. These results were confirmed by scanning electron microscopy on hydrolyzed starch.     

Heat Induced Gelation of Pea (Pisum sativum) Mixed Globulins, Vicilin and Legumin

Mixed globulins (MG) were extracted from ground dry peas (Pisum sativum, B-160) with 0.5M NaCl, 50 mM potassium phosphate, pH 7.2, and isolated by precipitation at pH 4.5. Crude vicilin and legumin were fractionated from the MG by dialysis against 0.2M NaCl, pH 4.8, and centrifugation, then further purified using DEAE-cellulose chromatography. Conditions for maximum gel hardness of heat induced MG gel, as determined with an Instron Universal Testing Machine, were heating for 20 min at pH 7.1 at 87°C. Purified vicilin, but not legumin, formed heat induced gels. The relationship was linear between protein (globulin) concentration and log gel hardness. At all protein concentrations studied, as proportion of legumin decreased, gel hardness increased.     

Antioxidant Activity of Pea (Pisum sativum L.) Seed Coat Acetone Extract

The contents of phenolic compounds in seed coat of pea and their antioxidative properties were examined. The pea seed coat was extracted with acetone-water (7:3 v/v) mixture and the extract was separated into five (?V) fractions using a Sephadex LH-20 column chromatography. Antioxidative activity of extract and fractions was measured by the oxidation of phosphatidylcholine to hydroxyperoxidephosphatidylcholine in liposome model and by scavenging effects of superoxide radical anion in xanthine-xanthine oxidase system. Phenolic compounds of extract and fractions were determined by spectrophotometric methods and characterized by HPLC analysis. Strong antioxidative properties were noted for extract and its five fractions measured by liposome method. The extract and fractions I, IV and V also showed scavenging effects of superoxide radical anion. A statistically significant correlation (P≤0.05) was found between the inhibition of PC oxidation in the system tested and contents of either total phenols or tannins. However no statistically significant correlation was found between O^•−₂ scavenging effect and contents of either total phenols or tannins. The HPLC analysis of phenolic compounds of extract and active fractions showed the presence of some phenolic acids (benzoic and cinnamic acids, and cinnamic acid derivatives), flavone and flavonol glycoside.     

The volatiles of off-flavoured unblanched green peas (Pisum sativum)

Volatile extracts of moderately off-flavoured frozen peas, prepared by vacuum sublimation followed by concentration of the sublimate by low temperature vacuum distillation, were examined by gas chromatography, silica gel chromatography and combined gas chromatography–mass spectrometry. The constituents identified included alcohols (29), carbonyls (31), esters (12), hydrocarbons (19), terpenes (6) and 3-alkyl-2-methoxypyrazines (3). Olfactory monitoring of the gas chromatographic column effluent indicated that most of the strong odours were associated with alkanals, alk-2-enals, alka-2,4- and 2,6-dienals, octa-3,5-dien-2-ones, 3-alkyl-2-methoxypyrazines and hexanol. However, no compound which, by itself, could account for the “hay-like” off-flavour of peas was evident. The off-flavour is considered to be complex and composed largely of the more odorous unsaturated carbonyls derived from the enzymic breakdown of the unsaturated pea lipids. The volatiles of pea shells similarly examined were found to contain many of the compounds present in peas.     

Functional properties of air-classified yellow pea (Pisum sativum)fractions

The objective of the present investigation was the characterisation of yellow pea (Pisum sativum L) fractions obtained on a commercial scale by air classification of the milled peas. Some analytical aspects of the process were investigated including particle size distribution of fractions and their functional properties.     

Water Absorption in Chickpea (C. arietinum) and Field Pea (P. sativum) Cultivars using the Peleg Model

Moisture absorption in seven chickpea cultivars and three field pea cultivars was investigated at 5, 15, 25 and/or 42°C using the Peleg model (M (t) = Mo + t/[K₁+ K₂t]). The Peleg constant K₁ varied with temperature. At a given temperature, the lower the K₁, the more water was absorbed. The Peleg constant K₂ was almost unaffected by temperature and could be used to predict the equilibrium water absorption. A constant K₃ expressing the temperature effect on water absorption (K₁= K₃T + K₄) was developed to distinguish two types of chickpea — Desi and Kabuli. All chickpeas had similar composition and initial moisture. The difference in water absorption rate was probably due to thickness and structure of the seed coat. The Peleg model could be used to predict water absorption in chickpea and field pea.     

Purification and Characterization of Peroxidase Isoenzymes from Green Peas (Pisum sativum)

Peroxidase isoenzymes were purified from green peas with ion-exchange chromatography on DEAE- and S-Sepharose. Three isoenzymes were identified, one neutral (N) and two cationic (C1, C2). N was extremely heat labile, with 50% original activity lost after heating 1.5 min at 25°C. N had Km values (pH 5.0) of 10.2 mM and 2.6 mM for guaiacol and H₂O₂, respectively. C1 and C2 retained activity on heating at 30–70°C. C1 was able to reactivate after thermal inactivation. Km values for guaiacol/H₂O₂ were 10.8 mM/7.2 mM (pH 5.0) and 10.8 mM/4.3 mM (pH 6.0) for C1 and C2, respectively. The three isoenzymes exhibited different peroxidase activities with different H-donors, different sensitivities to cyanide and different abilities to catalyze oxidation of indoleacetic acid.     

Enhancement of Resistant Starch (RS3) in Amylomaize,Barley, Field Pea and Lentil Starches

Native starches isolated from amylomaize. Glacier high amylose barley, field peas and lentils contained 3–5% (w/w) resistant starch (RS3). Retrograded gels that were prepared from these starches had higher RS3 (6–9%) contents. The effects of gel concentration (% starch), storage temperature and time on the RS3 content of the retrograded gels were investigated; the optimum RS3 content was determined in gels prepared at = 10% (w/v) starch concentration and stored under = 20°C for = 5 days. Annealing of the retrograded starch gels by heating and cooling cycles, further enhanced RS3 content to 9–19%; the effect of annealing temperature and number of heat-cool cycles on the RS3 content of the annealed gel were studied. The hydrolysis of retrograded starch gels by pulanase enzyme or acid (2.2 N HCl), prior to annealing, enhanced the RS3 formation during annealing; the enzyme or acid treatment increased RS3 content of the annealed gel to 15–24% or 17–24%, respectively. The potential molecular mechanism that is responsible for the RS3 increase is discussed.     

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.     

Proximate Composition of Triangular Pea,White Pea,Spotted Colored Pea,and Small White Kidney Bean and Their Starch Properties

Physicochemical properties of beans and starches extracted from triangular pea, white pea, spotted colored pea, and small white kidney bean grown in China were investigated. Results pointed out that each of the different legumes might be a good resource of starch and protein, which could be utilized for specific applications in food processing. Starches separated from different legumes differed significantly with respect to their protein content, amylose/amylopectin ratio, lipid content, ash content, swelling power, and solubility. The scanning electron micrographs revealed the presence of kidney or elliptical- to irregular-shaped granules and with a diameter ranging from 5 to 40 μm. All starches exhibited a C-type X-ray diffraction pattern. The pasting properties were tested in a Rapid Visco Analyser and thermal properties with a differential scanning calorimeter. Small white kidney bean had the highest peak, trough, breakdown, and final viscosity among various starches. Triangular pea starch showed the highest gelatinization transition temperatures (T _o, T _p, and T _c) and enthalpy of gelatinization, while white pea starch showed the lowest transition temperatures and gelatinization enthalpy. The results obtained provide a technical basis for processing these legumes and starches.     

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     

Air Classification of Peas (Pisum sativum) Varying Widely in Protein Content

Four samples of field peas, ranging in protein content from 14.5–28.5% (dry, dehulled seed basis), were pin milled and air classified yielding protein concentrates and starch concentrates containing 33.6–60.2 and 3.8–11.3% protein, respectively. The protein content of the dehulled peas were negatively correlated with their starch content (49.7–59.8%), lipid content (3.0–4.1%) and cell wall material (CWM) content (7.1–9.6%). The % protein in all air classified fractions was positively correlated to % protein in the dehulled peas, whereas, lipid and CWM content was negatively correlated. Air classification at lower air flows (smaller cut sizes) resulted in protein and starch fractions containing higher levels of protein. Starch separation efficiency and protein separation efficiency generally increased with increasing protein content.     

Phytate content and phytate degradation by endogenous phytase in pea (Pisum sativum)

In order to rapidly reduce the content of inositol tri–hexaphosphates in pea flour by action of the endogenous phytase, raw materials as well as incubation conditions have been evaluated. The phytate (inositol hexaphosphate) content was analysed in 27 pea varieties; the influence of storage time and the difference in phytate content between the germ and the cotyledon were determined. Furthermore, degradation of inositol phosphates by the endogenous phytase enzyme was studied in pea flour, germ and cotyledon. To find the maximum phytate degradation, the effects of temperature and pH during pea flour incubation were investigated. The most efficient phytate degradation in pea flour incubation was achieved at pH 7.5 and 45 °C. At this condition an almost complete degradation of phytate and a 66% reduction in the sum of inositol hexa‐, penta‐, tetra‐ and triphosphates were reached in 10 h. The storage time of pea seeds or removal of the germ did not have a major effect on the phytate content. Since several inositol pentaphosphate isomers were produced during phytate degradation, it can be concluded that peas contain several phytate‐degrading enzymes, or one phytate‐degrading enzyme with unspecific initial hydrolysation pattern. © 2001 Society of Chemical Industry.     

Pea Starch: Composition,Structure and Properties — A Review

Recently, pea has developed into a major protein crop in Western Canada. In the search for new food protein resources, small commercial facilities in Canada have engaged in manufacturing protein concentrates from pea by air classification or wet milling techniques. However, the major products from these processes are either crude or refined pea starches. Pea starch has been utilized almost exclusively for industrial application. A major factor, which has an adverse effect on the widespread utilization of pea starch in food industry, it its high extent of retrogradation. This review summarizes the present knowledge on composition, structure and physiochemical properties of smooth and wrinkled seeded pea starches with a view to providing suggestions for needed research to improve the utilization of pea starches in the food industry.