Effect of Partial Proteolysis on the Functional Properties of Winged Bean (Psophocarpus tetragonolobus) Flour

The effect of partial proteolysis of winged bean flour with a protease from A. oryzae on its functional properties has been determined. At 45% hydrolysis, nitrogen solubility in water increased twofold and in 1M NaCl solution by 63%. Bulk density increased from 0.387 to 0.597 g/mL. Foam volume showed a maximum increase of 50% at 18% hydrolysis and then decreased. Emulsifying capacity did not show any change. Water absorption capacity decreased from 245g/100g to 135g/100g at 45% hydrolysis and oil absorption capacity from 190g/100g to 120g/100g.     

Effect of Acetylation and Succinylation on the Functional Properties of Winged Bean (Psophocarpus tetragonolobus) Flour

Winged bean flour was acylated to various degrees and changes in functional properties were monitored. Nitrogen solubility in water increased up to ?80% acylation and then decreased. Water absorption capacity increased continuously with the extent of acylation. The fat absorption capacity of the acetylated flour increased up to ?30% acetylation and then decreased while that of the succinylated flour remained unchanged. Emulsion capacity showed the same trend as nitrogen solubility in water. Foam capacity increased due to acylation but foam stability decreased. Bulk density of the acetylated flour increased up to ?80% acetylation and then decreased. Succinylated flour had higher bulk density at all levels of succinylation.     

Carbohydrate Composition of Winged Bean (Psophocarpus tetragonolobus)

The carbohydrate composition of winged bean has been studied. The seeds contain about 42.2% total carbohydrates of which starch alone accounts for 36.2%. The total monosaccharides constituted 2.7% and were identified as glucose (1.17%) and fructose (1.5%); oligosaccharides amounted to only 0.61% and were identified as sucrose, raffinose, stachyose, and verbascose, on a dry defatted basis. The cold water soluble gum of winged bean contains glucose and xylose as the major sugars together with a small amount of arabinose while hot water soluble gum was found to be a glucantype polymer. Hemicellulose A consisted of glucose, xylose, and arabinose (15.5:9:1) whereas hemicellulose B consisted exclusively of glucose indicating that it is also a glucan-type polymer.     

Functional Properties of Winged Bean [Psophocarpus tetragonolobus (L.) DC] Proteins

A protein concentrate (71.45% protein on a dry weight basis) was prepared from winged bean [Psophocarpus tetragonolobus (L.) DC] seeds. Solubility of the protein concentrate was minimal at a pH of 4.0. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the bean flour proteins and protein concentrate indicated 9 subunits each, with apparent molecular weight ranges of 27,000–380,000 and 14,200–143,000 daltons, respectively. Least gelation concentrations and water and oil absorption capacities of the seed flour and the protein concentrate were determined. Emulsion and foaming properties of the protein concentrate were investigated. Effect of moist heat on seed protein digestibility was assessed in vitro. Protein concentrate had lower tannins and trypsin, chymotrypsin, and α-amylase inhibitory activities compared to bean flour.     

Isolation and Physicochemical Properties of Starch from Winged Bean (Psophocarpus tetragonolobus)

Preparation and physicochemical properties of winged bean starch have been studied. Gelatinization temperature range was 60–70°C and it exhibited single stage swelling and low solubility. The extensive solubility in dimethylsulfoxide may be due to heterogeneous bonding forces within the granule. The amylolytic susceptibility of native and gelatinized starch with human salivary α-amylase and glucoamylase was studied. The starch was found to be non-ionic. The amylose content was 38.5%.     

Baking Studies with Winged Bean (Psophocarpus tetragonolobus L.DC) Flour-Wheat Flour Blends

Physical, rheological and baking properties of winged bean-wheat composite flours were studied and the acceptability of the bread was evaluated by sensory tests. The sponge-dough method (SPD) gave bread with significantly greater specific loaf volume (P<0.05) than the straight-dough method (STD). Incorporation of 1% sodium stearoyl 2-lactylate (SSL) significantly improved (P<0.05) the specific loaf volume at all concentrations of winged bean full-fat flour (WBFF) tested, except for 15 and 20% substitution, for both STD and SPD methods. Using the STD method, 5% to 8% substitution of WBFF without SSL and 10% substitution with SSL gave acceptable breads. Using the SPD method, WBFF substitution at 10% without SSL and 12% with SSL gave acceptable breads.     

Chemical Composition Studies on Winged Bean (Psophocarpus tetragonolobus) Tubers

To add data to the very limited information on winged bean tubers, samples from 26 varieties were analyzed for proximate analysis, tannin, trypsin inhibitor activity (TIA) and nonprotein nitrogen (NPN). The averages obtained were: crude fat, 0.96%, ash, 2.94%; acid detergent fiber, 16.56%; crude protein, 16.4%; carbohydrate, 57.72%; tannin, 5.32 mg/g tubers; trypsin inhibitor, 1033 TIU/g tubers. NPN constituted only a small percentage (16.2%) of the total nitrogen indicating that most of the nitrogen is protein. A significant proportion of NPN (76%) was ninhydrin positive, indicating free amino adds, peptides and possibly other amines. Tannin concentration was higher than those present in seeds. The presence of TIA necessitates heat processing before consumption.     

Improved Nutritional Value in Wheat Bread by Fortification with Full-Fat Winged Bean Flour (Psophocarpus tetragonolobus L.DC)

The nutrient composition of winged bean (Psophocarpus tetragonolobus L.DC) full-fat flour (WBFF), wheat flour (WF) and WBFF-fortified breads was studied. When WBFF fortification was increased from 0 to 20%, there was an increase of 63% in protein, 153% in fat, 130% in calcium, 97% in phosphorus, and 105% in iron contents. WBFF contained greater amounts (g/16g N) of histidine and lysine compared to WF. Except methionine which decreased, all other essential amino acids increased when WBFF was substituted for WF from 0 to 15%. The protein efficiency ratio for 10%-WBFF bread (1.62) was found to be significantly greater (P<0.05) than that of 5%-WBFF bread (1.40) and wheat bread (1.11).     

Functional Properties of Raw and Heat Processed Cowpea (Vigna unguiculata, Walp) Flour

The functional properties, gelation, water and oil absorption, emulsification, foaming and protein solubility of raw and heat processed cowpea flour were determined. The effects of pH and NaCl concentration on some of these functional properties were also investigated. Protein solubility vs pH profile showed minimal solubility at pH 4. Water and oil absorption capacities of raw flour were 2.4 g/g and 2.9 g/g, respectively, while heat processed flour gave 3.6 g/g and 3.2 g/g, respectively. Addition of NaCl up to 0.4% improved the emulsification capacity of raw flour while a decrease was observed in the heat processed flour after 0.2%. Least gelation concentration of raw flour was found to be 16% and heat processed flour, 18%.     

Total Plant Analyses of Sterols and Fatty Acids of the Winged Bean (Psophocarpus tetragonolobus)

Various parts of the winged bean plant, Psophocarpus tetragonolobus were analyzed for sterols and fatty acids. The major sterols were sitosterol, stigmasterol and campesterol. Sitosterol occurred in greatest amounts except in roots where stigmasterol was the predominant sterol. In seeds, behenic acid (22:0) comprised 13.5% of the total fatty acids, whereas, in the other plant parts it varied from 0.1–6.9%. Leaves contained the highest level of fatty acids, but only 22% of these fatty acids were saturated.     

Functional-Properties of Raw and Heat Processed Brown Bean (Canavalia rosea DC) Flour

The proximate composition and the functional properties of the flour of brown bean (Canalia rosea DC) were investigated. Brown bean flour had 27.1 g/100g dry weight (DW) crude protein and 7.6 g/100g DW ether extractives. The brown bean flour had good water and oil absorption but poor gelation properties. Solubility of the brown bean protein was minimal at pH 4.0 but increased at pH 10. Foaming capacity of the flour could be improved by increasing concentration as well as by adding NaCl and was influenced by pH. Emulsion capacity was dependent on pH and salt concentration. Heat processing generally reduced the foamability and emulsification capacity of the brown bean flour.     

Effect of Extraction Conditions on the Extractability of Winged Bean (Psophocarpus tetragonolobus (L) DC) Proteins

Protein extractability from defatted winged bean flour was studied under various conditions of pH (2, 4, 6, 8, 10, 12), temperature (15°, 30°, 45°C) and time (10, 20, 30 min). Results indicated that protein extractability was strongly pH dependent. Maximum protein extract-ability was attained at pH 12 while the minimum extractability occurred at pH 4. Protein extractability was not significantly affected at the various temperature and time combinations; however, when extraction time was extended (at 15 min increments) from 30 min to 120 min, significantly higher (15%) protein was extracted at 30°C after an additional 60 min. Increased solvent-to-flour ratios resulted in increased protein extractability, but increased salt (NaCl and CaCl₂) concentrations (1M) decreased extractability.     

Changes in Chemical Composition of Winged Bean (Psophocarpus tetragonolobus L.) during Seed Development

Three cultivars of winged bean were analyzed for total dry matter, crude fat, nitrogenous constituents, phosphorus, calcium, magnesium, zinc, iron, copper and cooking behavior at different stages of seed maturity. Accumulation of dry matter, crude fat and nitrogen occurred during seed development whereas nonprotein nitrogen and tryptophan contents decreased significantly. Reduction in poly-phenol content was observed at all the stages of seed development. There was a significant decrease in total phosphorus content with concomitant increase in the proportion of phytate phosphorus throughout the seed development. In matured seeds, phytate phosphorus accounted for 66—73% of total phosphorus. A reduction in zinc content was noticed in all the cultivars studied. In contrast, calcium, magnesium, iron and copper contents of seeds of different stages of maturity did not exhibit marked differences.     

Effects of Germination on the Proximate Composition and Nutritional Quality of Winged Bean (Psophocarpus tetragonolobus) Seeds

Winged beans were germinated using the between paper technique. The nonprotein nitrogen was found to increase gradually and the protein nitrogen content to decrease. A slight decrease in the lipid content was also observed. Trypsin inhibitor activity was uneffected by germination. However, lipoxygenase activity was found to decrease; 77% of the original activity was lost after 120 hr. These changes are compared to the changes in proximate composition of other legumes during germination. Following a decrease in the amino acid composition of the seeds after 48 hr of germination, significant increases in the concentrations of cysteine, aspartic acid, and histidine were found after 72 hr incubation.     

Investigations on Winged Bean [Psophocarpus tetragonolobus (L.) DC] Proteins and Antinutritional Factors

Two cultivars of winged bean (Chimbu and HF-10) were investigated. The molecular weight distribution profiles of two cultivars differed significantly. Major protein subunits of Chimbu had estimated molecular weights of 51,000, 18,000, 15,400, and 12,300 daltons while subunits with estimated molecular weights of 145,000; 55,000; 29,000; 14,700; and 14,000 daltons characterized HF-10 proteins. Sequential extraction with distilled water and 2% NaCl recovered 91.08 and 87.7% (respectively for Chimbu and HF-10) of the total proteins. Soaking the beans in alkali resulted in elimination of hemagglutinating activity, significant reduction in tannins and trypsln inhibitory activity, and improvement in in vitro protein digestibility.     

Free Amino Acids and Related Compounds in Seeds and Sprouts of Winged Bean Psophocarpus tetragonolobus (L.) DC)

Free amino acids and related compounds in the nonprotein nitrogen (NPN) fraction of winged bean seeds and sprouts were quantitatively determined. The proportion of NPN to total nitrogen was low in the seeds (9%) and in the cotyledons of the sprouts (11%), and relatively high in the epicotyls of the sprouts (54%). About 6% and 40% NPN were attributable to free amino acid nitrogen in the seeds and the sprouts, respectively. The free amino acid profile of seeds was characterized by the presence of sizable amounts of γ-L-glutamyl-L-tyrosine and γ-L-glutamyl-L-phenylalanine, indicating similarities to that of soybean seeds. Accumulation of free amino acids, particularly nonprotein amino acids such as α-aminoadipic acid and γ-aminobutyric acid, were demonstrated in the sprouts. No canavanine was detected in either seeds or sprouts.     

Physicochemical and Functional Properties of Winged Bean Flour and Isolate Compared with Soy Isolate

The proximate composition, amino acid profile and functional properties of isolated winged bean proteins were determined and compared with soy protein isolate. Winged bean protein extracted at pH 10 and pH 12 had protein contents of about 90% and 80%, respectively. Alkali extraction of winged bean proteins at pH 10 and pH 12 did not affect the amino acid distribution of the isolated proteins. Oil and water absorption, emulsion, and foaming properties of winged bean isolated compared favorably with soy isolate. Least gelation concentration for winged bean isolate was 18% compared to 14% for soy isolate. Thus, winged bean protein isolate with its high protein content, high lysine and other essential amino acid content and good functionality has a good potential as an ingredient in food products.     

四棱豆奶的研制

以四棱豆为主要原料,辅以一定的甜味剂、乳化剂、稳定剂等,配制出营养丰富、风味独特的四棱豆奶.经单因素试验和正交试验确定最佳工艺参数为豆水比1:6(g/mL),脱脂奶粉2.5:100(g/mL),白砂糖5.0:100(g/mL),复合乳化剂0.15:100(g/mL)(其中单硬脂酸甘油酯32%,蔗糖脂肪酸酯68%),CMC-Na 0.08:100(g/mL),海藻酸钠0.05:100(g/mL),黄原胶0.08:100(g/mL).最后所得产品营养丰富,口感细腻圆润,并具有一种特殊风味.     

Changes in Sugars, Starch and Trypsin Inhibitor Activity in Winged Bean (Psophocarpus tetragonolobus L.DC) During Seed Development

Three cultivars of winged bean were analyzed for starch, sugars and trypsin inhibitor activity at different stages of seed maturity. The starch content ranged from 5.66-6.22% whereas sugar content varied from 4.40-6.53% in the matured seeds. The starch content increased as the seed maturation progressed from stage I (40 days after flowering) to stage II (50 days after flowering) followed by a decrease up to complete maturity. The total sugar content increased up to stage III (60 days after flowering) of maturity followed by a decrease during subsequent stages of maturation. The trypsin inhibitor activity increased as the seed maturation advanced from stage I to complete maturity.     

Soaking Studies on Winged Bean (Psophocarpus tefragonolobus L.DC) to Process Full-Fat Flour and Determine It's Shelf-Life Stability

Suitable methods to process full-fat flour from dried winged bean seeds, their effect on trypsin-inhibitor activity and keeping qualities of the flour were studied. Soaking in 0.5% or 1% sodium bicarbonate solution and boiling for 30 – 45 min was found to be suitable process for hull removal. Dry dehulling methods resulted in only 14 – 22% hull separation, while wet processing treatments were not effective. Soaking the winged bean seeds (12 hr) in 0.5% sodium bicarbonate, sodium carbonate and sodium chloride solutions reduced 30 – 40% of the trypsin inhibitor activity. Winged bean full-fat flour could be stored for 4 wk under ambient conditions.