Field peas

Raw soybeans also maybe used as a supplemental protein source. Dry beans, ie, beans normally harvested in the green / imm a tiire state, fava beans, lupins, field peas, lentils, and other grain legumes are potential supplemental protein sources however, several of these may have deleterious effects, predominantly enzyme inhibition, on the animal. The supply of each is limited (5). 

Leaves and flower plants Cabbage, Chinese cabbage, Japanese radish (leaves), broccoli, komatuna, soybeans (immature), field pea, kidney beans (immature), onion, garlic, scaUion, hops... 

Sleugh B, Moore KJ, George JR, Brummer EC (2000) Binary legume-grass mixtures improve forage yield, quality, and seasonal distribution. Agron J 92 24-29 Smolinska U, Morra MJ, Knudsen GR, James RL (2003) Isothiocyanates produced by Brassicaceae species as inhibitors of Fusarium oxysporum. Plant Dis 87 407-412 Soon YK, Harker KN, Clayton GW (2004) Plant competition effects on the nitrogen economy of field pea and the subsequent crop. Soil Sci Soc Am J 68 552-557... 

Figure 3. Representative sugar cookies prepared from defatted peanut, soybean, and field pea flours at 0, 10, 20, and 30% wheat flour replacement levels. Reproduced with permission from Ref. 3. Copyright 1978, American Association of Cereal Chemists.

Flours made from field peas by wet or dry milling, or air classification, possess distinctive sensory, functional and nutritional characteristics. 

The composition of the field pea depends not only on the species, but also on the cultivar that is being processed (4,5). Variations exist among cultivars (e.g., Trapper, Century) in protein, fat, carbohydrate (crude fiber and starch), and ash contents, as shown in Table I. Tyler and Panchuk (6) noted that the composition of field peas at different stages of maturity also affected the composition of the products, and this could ultimately influence their functionality in foods. 

The reported protein content of field peas ranges from 13.3 to 39.7%... 

KLEIN AND RAIDL Field-Pea Flours as Protein Supplements... 

Environmental factors which affect protein content of field peas include nitrogen fertilizer (14), maturation (15), soil P and K content (16), and temperature (17). The protein corrEent of field peas is important since it ultimately affects the amount of protein in field pea concentrates or isolates (18). 

Protein content of dehulled Trapper field peas is negatively correlated with the amino acids threonine, cystine, glycine, alanine, methionine, and lysine and positively correlated with glutamic acid and arginine (8). Holt and Sosulski (19) obtained similar correlations with Century field peas for all amino acids except glutamic acid. Other investigators (20) also found that sulfur amino acids (cys, met) are negatively correlated with protein content. 

The main storage proteins in field peas are two globulins (Table II), vicilin and legumin, which are similar to the 7S and US... 

The protein efficiency ratio (PER) of field pea flours is considerably less than that of casein (1.46 vs. 2.50), and somewhat less than that of soy flour (1.81). However, composites of wheat flour and pea or rice and pea (50% of the protein from each source) had PER s of 2 or more (22). Thus, supplementation of cereals with pea flour results in improvement of protein quality. 

Starch content of field peas (Pisum sativum L., cv. Trapper) ranges from 43.7 to 48% and, after being subjected to pin milling and air classification, produces a flour containing 78% starch (9,12,13). 

The predominant polysaccharide in dehulled field pea flour is starch (49.7-59.8%) and the major soluble sugars are a-galactosides (4.78%) and sucrose (1.85-2.2%) (8,23,24). Verbascose is the major a-galactoside present in field pea flour (23,24). The a-galactosides are the main contributors to the flatulence caused by ingestion of legume flours. 

Pea starch granules are oval, sometimes fissured, with a diameter of 20-40 ym (13). Molecular and structural characteristics of the two main components of field pea starch—amylose and amylopectin—are important in determining functional properties (25,26). Smooth field pea starch concentrate contains 97.2% starch of which 30.3-37.8% is amylose (9,23,25-27), and wrinkled pea starch concentrate contains 94.8% starch, which is 64% amylose (26). The gelatinization temperature of smooth pea starch is between 64 to 69 C, and that of wrinkled pea starch is greater than 99 C to 115 C. Gelatinization temperature depends on maturity of field pea seed and amylose content (26,27). 

The composition of protein and starch fractions produced from pin milling and air classification are related to a number of variables variability in composition of field pea cultivars, number of passes through pin mill and air classifier, vane settings and protein content of peas, and seed moisture (5,9,23,31). 

Protein content of field peas is negatively correlated with lipid, cell wall material (CWM), sugar, and ash content and positively correlated with starch separation efficiency and protein separation efficiency in air classification of pea flour. The lower separation efficiency of low protein peas may be due to their high lipid and CWM content which makes disintegration of seeds and separation into protein and starch particles by pin milling difficult. It is suggested that peas with a specific protein content should be used in order to control the protein and starch fraction contents (18). 

As seed moisture in field peas decreases, there is a decrease in starch fraction yield, protein content of starch fraction, protein content of protein fraction, and percent starch separation efficiency, and a concurrent increase in protein fraction yield, percent starch in starch fraction, percent starch in protein fraction, percent protein separation efficiency, and percent neutral detergent fiber in the protein fraction. Lower moisture content of field peas improves milling efficiency and results in more complete separation of protein and starch fractions, which could explain the increase in protein fraction yield and percent starch in starch fraction, improved protein separation efficiency and less protein in the starch fraction. The decrease in starch separation efficiency was probably due to the increased starch content of protein fraction and increased protein fraction yield with lower seed moisture. 

Amino Acid Content. Amino acid content of field pea products is related to protein level, method of processing, and fraction (starch or protein). The protein fraction contains fewer acidic (glu, asp) amino acids than the starch fraction and more basic (lys, his, arg) amino acids than the starch fraction. Also, there are more aromatic (tyr, phe) amino acids, leu, iso, ser, val, and pro in the protein fraction than in the starch fraction (5). An amino acid profile of pea protein concentrate shows relatively high lysine content (7.77 g aa/16 g N) but low sulfur amino acids (methionine and cystine) (1.08-2.4 g aa/16 g N). Therefore, it is recommended that air classification or ultrafiltration be used because acid precipitation results in a whey fraction which contains high levels of sulfur amino acids (12,23). Also, drum drying sodium proteinates decreases lysine content due to the Maillard reaction (33). 

Field Pea Flours in Pasta. Incorporation of non-wheat flours into noodles improves the protein content and quality, but may have an adverse effect on the flavor and texture of the pasta. Hannigan (38) reported that 10% substitution of wheat flour with pea or soy flour resulted in satisfactory quality of Japanese Udon noodles. 

Field Pea Flours in Bread Products. Legume flours, particularly soy, have long been incorporated into wheat-based products, both for their functional effects and for protein fortification. In general, increasing the levels of legume flours results in decreased loaf volume, lower crumb grain quality, and adverse flavor characteristics in the baked bread (Table III). 

Results have varied with respect to the amount of field pea flour that can be incorporated into a yeast bread before an unacceptable product is produced. Tripathi and Dat (40) made breads containing 3, 10 and 13% field pea flour and found breads made with more than 5% pea flour were not acceptable. Loaf volume decreased as the percent substitution increased. At the 5% level, color, flavor and taste of the breads were rated as excellent, but at the 10 and 15% levels, there was a bitter taste. 

Table III. Baked Products Made with Field Pea...

Field Pea Flour in Other Baked Products. When McWatters (44) substituted 8% field pea flour and 4.6% field pea concentrate for milk protein (6%) in baking powder biscuits, sensory attributes, crumb color, and density of the resulting biscuits were adversely affected. No modifications were made in recipe formulation when pea products were incorporated. The doughs were slightly less sticky than control biscuits that contained whole milk. This might be due to lack of lactose or to the different water absorption properties of pea protein or starch. Panelists described the aroma and flavor of these biscuits as harsh, beany and strong. Steam heating the field pea flour improved the sensory evaluation scores, but they were never equivalent to those for the controls. 

Raidl and Klein (43) substituted 5, 10, and 15% field pea flour in chemically leavened quick bread. The viscosity of the pea flour batters was significantly lower than either the wheat control or soy containing batters. The starch composition of the pea flour and lower water absorption properties of the protein could have affected the viscosity. Volumes of pea flour loaves were lower than the control and soy loaves. Most of the sensory characteristics of the field pea loaves were similar to those of the control quick breads. However, all flavor scores were significantly lower for pea flour products, since they had a recognizably beany or off-flavor. 

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