Effects of cooking,germination and fermentation on the chemical composition of Nigerian Cowpea (Vigna unguiculata)

The effects of cooking, germination, and fermentation on the chemical composition of cowpea were studied. There were noticeable trends in the protein, carbohydrate and crude fiber as a result of the different treatments. Both the germinated and fermented samples contained more ether extractable lipids than the raw and cooked samples. Untreated raw cowpea contained 5.9 mg/g phytic acid, 1.66 mg/g phytate phosphorus, 3.3 mg/g total phosphorus, 56.8 mg/g total sugar, and no reducing sugar. Cooking the dry beans at 100°C for 1 1/2 hours had little effect on the phytic acid and phytate phosphorus. There were, however, significant decreases in total phosphorus and sugars of the cooked beans. After germination for 24 hours, 48 hours and 72 hours respectively, there was a significant decrease in phytic acid and total sugar and increase in total phosphorus and reducing sugar. Similar results were also obtained when the dry beans was fermented for 24 hours, 48 hours and 72 hours respectively.     

Compositional,functional and storage properties of flours from raw and heat processed African breadfruit (Treculia africana Decne) seeds

African breadfruit (Treculia africana Decne) seeds were either boiled or roasted and then milled into flour. Chemical composition, functional properties and storage characteristics of raw and treated flours and the effect of partial proteolysis on selected functional properties of the raw flour were determined. Raw flour contained 20.1% crude protein, 2.5% total ash and 13.7% fat. Heat processing significantly (p<0.05) improved in vitro protein digestibility, and water and fat absorption capacities but decreased bulk density, nitrogen solubility, emulsion and foaming properties, trypsin inhibitor, and phytic acid and polyphenol contents of the samples. Boiling proved more effective than roasting for improving protein digestibility, emulsion capacity and foam stability and reducing antinutritional factor levels. Partial proteolysis increased nitrogen solubility, bulk density and water and fat absorption capacities but decreased foam capacity at hydrolysis levels greater than 35%. Fatty acid and peroxide values of the samples increased during storage. Compared to raw samples, heat processed samples had significantly (p<0.05) lower and more acceptable peroxide values and free fatty acid contents and higher and more stable water (3.0 g/g sample) and fat (2.4 g/g sample) absorption capacities.     

Preparation and properties of flours and protein concentrates from raw, fermented and germinated fluted pumpkin (Telfairia occidentalis Hook) seeds

In vitro protein digestibility, chemical composition and selected functional properties of flours and protein concentrates prepared from raw, fermented and germinated fluted pumpkin (Telfairia occidentalis Hook) seeds were studied. Protein concentrates prepared by an alkaline extraction process had increased crude protein contents (61.5–70.8%) compared to flour samples (46.4–52.7%). The yields of protein concentrates ranged from 24.5% to 29.4% while values for protein recoveries varied between 64.8% and 65.2%. Protein concentrates also had increased foam volume and decreased foam stability (100% decrease over a 2 h period), compared to flour samples. Fermentation and germination were observed to significantly (p<0.05) lower polyphenol and phytic acid contents, but increased protein digestibility of fluted pumpkin seed flours and concentrates. Both raw flour and concentrate were significantly (p<0.05) higher in water absorption capacity than germinated or fermented flours and concentrates. Protein concentrates had comparatively better fat absorption properties than the flour samples. Hence protein concentrates may prove to have useful applications in ground meat formulations.     

Evaluation of selected food characteristics of three advanced lines of Nigerian soybean (Glycine max (L.) Merr.)

The seeds of three promising advanced lines of soybeans (TGx 923-2^EN, TGx 1019-2^EN and TGx 1497-1^D) which were part of a larger collection evaluated in agronomic field trials in Nigeria were selected for characterization of physicochemical properties, chemical composition, water absorption, cooking time and cooked texture as a function of soaking and cooking. Seed density, leached solids, swelling capacity and seed coat percentage were within a range of 1.15 to 1.26 g per ml, 1.00 to 1.26 g per 100 g, 80.25 to 84.35 g per 100 g and 6.6 to 10.1% w/w of dry beans, respectively. The total polyphenol content of the cream colored beans was similar (0.75 to 0.76 mg/g) but higher than the amount (0.60 mg/g) found in the white beans. Cooking times varied between 71 and 96 min without soaking and were reduced by about 32.0% following a presoaking treatment in water for 12 hours at room temperature (28±1°C). Small seeds absorbed higher amounts of water during soaking and required less cooking time than larger seeds. Unsoaked beans required 40 min of cooking to achieve the same degree of cooked texture as the soaked beans cooked for 20 min, suggesting that cooking times and cooked texture for all lines were improved through soaking.     

Composition and functional properties of unprocessed and locally processed seeds from three underutilized food sources in Nigeria

Chemical and functional properties of unprocessed (raw) and locally processed seeds ofBrachystegia eurycoma, Detarium microcarpum andMucuna sloanei that affect their utilization as sources of human food were investigated. The seeds, which are underutilized food sources in Nigeria, were subjected to local processing methods which included roasting, boiling, dehulling/shelling, soaking and the changes in composition and functional properties were estimated. Chemical analyses showed that the crude protein contents of the raw seeds ranged from 12.2 to 23.2%; fat varied from 4.9 to 12.0%. The level of phytic acid in the raw seeds (192.4–215 mg/100 g) was observed to be lower than the levels found in some commonly consumed pulses in Nigeria. There were no significant differences (p>0.05) between crude protein contents and the least gelation concentrations of the raw and processed samples, but processing (roasting, boiling, dehulling and soaking) significantly (p=0.011) improved in vitro protein digestibility, water and fat absorption capacity and decreased the bulk density, nitrogen solubility and the phytic acid and polyphenol contents of the samples. Processed samples had high water (3.4–3.8 g/g) and fat (1.8–2.1 g/g) absorption capacities and hence may be useful as functional agents in fabricated foods such as bakery products and ground meat formulations.     

Influence of different tillage methods and pre-emergence herbicides on weed control in cowpea (Vigna unguiculata (L.) Walp.)

In the early and late cropping seasons of 1983, three different methods of tillage (minimum tillage, conventional tillage, and tilled and ridged) were evaluated for their influence on the performance of some pre-emergence herbicides used during the production of cowpea. Four varieties of cowpea (Ife Brown, H 144-1, TVx 3236, and Black-eyed bean) were planted in the early season while five varieties (Ife Brown, H 144-1, TVx 3236, H64/3 and Vita-5) were planted in the late season. A single spray application of 3·0 kg/ha alachlor, 3·0 kg/ha metobromuron + metolachlor and 3·5 kg/ha metolachlor was carried out one day before planting. Cyanazine at 3·0 kg/ha was included in the late season trial. The plots were either minimally tilled, conventionally tilled or tilled and ridged at the Teaching and Research Farm of the University of Ife. Results showed that the performance of all three herbicides used in the early season, as measured by weed control and grain yields, was best on the conventionally tilled, while the performance of the four herbicides in the late season was best on tilled and ridged plots. Metobromuron + metolachlor performed consistently better than each of the other herbicides irrespective of the method of tillage during both seasons. Conventional tillage enhanced the performance of metobromuron + metolachlor over minimum tillage plots and tilled and ridged plots in the early season; however, in the late season, the performance of metobromuron + metolachlor was best on tilled and ridged plots. Alachlor did not effectively control competing weeds in both seasons but did not injure any cowpea line. On the other hand, cyanazine did not control weeds effectively but was phytotoxic to Ife Brown variety of cowpea. In both seasons, the control of the broad-leaved weeds Ageratum conyzoides, Amaranthus spp., Euphorbia heterophylla, Ipomoea spp., Spigelia anthelmia, Synedrella nodiflora and Talinum triangulare was not adequate. The control of the grassy weeds Brachiaria deflexa, Cynodon dactylon, Imperata cylindrica and Eleusine indica was, however, effective.     

Effects of infestation on the nutrient content and physiocochemical properties of two cowpea ( Vigna unguiculata) varieties

Two cowpea varieties (Ife-brown and Kano-white varieties) were used for the study. The effects of insect infestation on the chemical composition and physicochemical properties of these cowpea seeds were studied. The proximate composition, mineral content, total starch, total soluble sugars, bulk density, fat and water absorption capacities, viscosity, gelation capacity and emulsion properties of infested cowpea varieties were compared with those of uninfested cowpeas. Effects of infestation on nitrogen solubulity and on the protein fractions were also determined. lnfestation depleted the protein, starch and soluble sugar contents of cowpeas. Oil and water absorption capacities were increased while emulsification, foam and viscosity properties were reduced. The nitrogen solubility pattern was altered. Uninfested Kano-white cowpeas (UKW) possessed better foam properties than uninfested Ife-brown cowpeas (UFB). On the other hand, UFB had better emulsification properties than UKW.     

Changes induced by infestation on some chemical properties of cowpea seeds

Three cowpea varieties were used in the present study,Insect susceptible popular variety, `Ife-brown' (IFB), an improved varietyfor insect resistance IT 81D-975 (1975) and a local black cowpea varietywith a white hilium adapted to diverse habitats, `Akidi' (AKD).Cowpea seeds were infested with Callosobruchus maculatus. Crudeprotein content of infested and uninfested whole cowpea flour and proteinconcentrate was determined. Prolamin contents of flour and proteinconcentrates were evaluated. Fat content, free fatty acid and peroxidevalues of cowpea seeds were also determined. All determinations werecarried out in infested and uninfested cowpea seeds in 3 replicates for eachdetermination. Emulsion properties of cowpea seeds stored in 3 containers,plastic cans (PC) and polyethylene bags (white and black WPB/BPB) weremonitored on a biweekly basis for 24 weeks.Varietal differences existed in the protein, fat and prolamin contents ofcowpeas. Infestation reduced the contents of these nutrients in all cases. Free fatty acid contents and peroxide values were increased by >100%. Infestation reduced the prolamin content by > 25% inall cases. Varietal differences also existed in emulsion capacities of cowpeaflours; IFB and 975 formed better and more stable emulsions than AKDflour. Storage in plastic cans led to better retention of the emulsionproperties of the cowpeas.     

Proximate Composition and Functional Properties of Fullfat and Defatted Beniseed (Sesamum Indicum L.) Flour

The proximate composition and functional properties of fullfat and defatted beniseed (Sesamum indicum L.) flour were evaluated. Functional properties studied were foam capacity and stability, water and oil absorption, bulk density, emulsion capacity and nitrogen solubility. Defatting increased the crude protein, ash, crude fiber, carbohydrate and mineral contents. Defatted flour showed comparatively better foam capacity and stability, water absorption and emulsion capacities but diminished bulk density and oil absorption capacity. Nitrogen solubility was pH dependent with a minimum at pH 4 and maximum at pH 8. Maximum nitrogen solubility (95%) was recorded for defatted flour while that for the fullfat flour was 60%. The proximate composition and functional properties of the samples suggest that beniseed flour would have useful application in fabricated foods.     

Antinutrients in amphidiploids (black gram × mung bean): varietal differences and effect of domestic processing and cooking

Phytic acid, saponin and polyphenol contents in grains of various varieties of black gram (Vigna mungo) Mung bean (Vigna radiata L.) amphidiploids ranged from 697 to 750, 2746 to 2972 and 702 to 783 mg/100 g, respectively. Domestic processing and cooking methods including soaking, ordinary and pressure cooking of soaked and unsoaked seeds, and sprouting significantly lowered phytic acid, saponin and polyphenol contents of the amphidiploid seeds. Soaking for 18 h removed 31 to 37% of the phytic acid; the extent of removal was higher with long periods of soaking. Saponins and polyphenols were relatively less affected. Loss of the antinutrients was greater when soaked instead of unsoaked seeds were cooked. Pressure cooking had a greater effect than ordinary cooking. Antinutrient concentrations declined following sprouting; the longer the period of germination the greater was the reduction.     

Quality attributes of three new improved lines of Nigerian lima beans (Phaseolus lunatus L. Walp.)

Three promising new improved lines of lima beans (Tpl 1^B, Tpl 7^A and Tpl 175^A) were evaluated for physicochemical properties and cooking quality. The beans varied in seed dimensions and weights with Tpl 1^B and Tpl 7^A having smaller seed volume than Tpl 175^A. Seed coat percentages, leached solids and swelling capacities were within a range of 10.2–19.6% (w/w), 0.44–0.92 g/100 g and 94.0–121.0 g/100 g dry bean, respectively. Cooking times varied between 62 and 81 min without soaking and were reduced by about 34%following a presoaking treatment in water for 12 h at room temperature (28 ± 1 °C). Small seeds absorbed higher amounts of water during soaking and required more cooking time than larger seeds. No significant (p>0.05) difference in cooked texture was found between unsoaked beans cooked for 50 min and soaked beans cooked for 30 min,suggesting that cooking times and cooked texture for all lines were improved through soaking.     

Physical Properties of Extruded Products from Three Mexican Common Beans (Phaseolus vulgaris L.) Cultivars

The physical properties of extruded products from three Mexican common bean cultivars were investigated. Common bean cultivars Flor de Mayo, Pinto Villa and Bayo Victoria from the same harvesting season (2006) were used in this work. Beans were milled and the flour was hydrated to 24, 26 and 28 g of water/100 g of dry weight. Two temperatures, 130 degrees C and 165 degrees C at the end of the extruder barrel without die, were experimented. Common bean flour extrudates were evaluated for water absorption index (WAI), water absorption capacity (WAC), oil absorption capacity (OAC), and emulsifying capacity (EC). Flor de Mayo extrudates showed the highest WAC and WAI values. Thus starch from Flor de Mayo beans showed minor restricted water availability. In all cases, the OAC of extruded products was lower than the crude bean flour. The EC for Bayo Victoria flour increased as a consequence of the extrusion process. The EC for Flor de Mayo was higher at lower temperature and lower moisture content than Pinto Villa and Bayo Victoria beans. EC behavior of Pinto Villa was similar to Bayo cultivar. These results indicate that it is possible to produce new extruded products with good physical properties from these common bean cultivars.     

Effects of heat on the removal of polyphenols and in vitro protein digestibility of cowpea (Vigna unguiculata (L.) Walp.)

Simple wet heat treatments like simple boiling (atmospheric pressure, 100 °C) and pressurized boiling (higher than 100 °C) reduced the polyphenol content of mature dark red seeds of cowpea (Vigna unguiculata (L.) Walp.) cultivar UPL Cp 3 by 61 to 80% and improved in vitro protein digestibility (IVPD) by 6 to 26%. Pressurized steaming (higher than 100 °C) removed 48 to 83% of the polyphenols but increased IVPD by only 1.1 to 4.2%. Dry heat as exemplified by roasting and microwave treatment inactivated 58 to 71% of the tannins but increased IVPD by only 1%. All the heat treatments were effective in removing/inactivating polyphenols though different responses were observed with the resulting in vitro protein digestibilities.     

Effects of debittering methods on the proximate composition,organoleptic and functional properties of sesame (Sesamum indicum L.) seed flour

Sesame seeds were boiled and allowed to sprout under ambient condition (30±2 °C) with an objective to reduce or eliminate the bitter taste associated with them. The untreated seeds were used as a control. The proximate composition, functional and organoleptic properties of defatted sesame flour were assessed at room temperature. There was a slight increase (about 10%) in protein content of sprouted seeds. The foaming capacity of flours from untreated, sprouted and boiled seeds were 34.6, 38.5 and 11.5%, respectively. The flour from the boiled seeds had the highest foam stability. Flours from untreated or sprouted seeds, gelation started at the least concentration of 6% whereas that from boiled seed was 11%. The emulsion capacity of flours from the untreated or sprouted seeds was the same (27.6 g oil/g sample) while that from boiled seeds was 12.9 g oil/g sample. Emulsion stability with prolonged storage appeared to be more with flours from the sprouted or boiled seeds than that from the untreated ones. The water absorption properties of flours from the untreated, sprouted and boiled seeds were 8.0, 5.9 and 6.5 g H₂O/g sample, respectively whereas the oil absorption capacity same (5.9 g oil/g sample). The bitter taste in flours from the untreated or sprouted was high. The bitter taste was not detected in flour from boiled seeds and the functional properties of the flour were not deleteriously affected except foaming and emulsion capacity. Therefore, this boiling method of debittering sesame seed could be practised. The quality of sesame flour obtained with this boiling method could still serve its role in traditional dishes and in the formulation of some other conventional food products.     

Effect of blanching and ripening on functional properties of plantain (Musa aab) flour

Flours were prepared from raw and blanched samples of and ripe mature plantain Musa aab and examined for theirproximate composition, physical characteristics and functionalproperties. The plantain flours contained 3.5 g crude protein,2.5–3.5 g crude fat, 5.7–7.1 g moisture, 1.33–2.0 g crudefiber, 1.66–2.0 g ash, and 82.25–86.07 g carbohydrate per 100 gsample. The flours had bulk densities between 0.42–0.72 g/ml,emulsion capacities of 4.7–14.7%, water absorption capacitiesof 250–338%, oil absorption capacities of 214–371%,foaming capacities of 1.90–5.79%, least gelation concentrationsof 6–8%, and viscosities of 23.7–46.7 CP at 2% slurry concentration. Foaming capacity increased with increasing flourconcentration. Blanching considerably reduced the emulsion capacity and viscosity, while bulk density, water and oilabsorption capacities were increased by blanching. Ripening wasfound to have a negative effect on all the functional propertiesexamined except the bulk density, and gelation property. Unripe plantain could be used as an emulsifier and thickener in a foodsystem.     

An evaluation on intensity of infection of Pseudocercospora leaf spot disease of cowpea cultivars (Vigna unguiculata L. Walp), with respect to infector rows, dates of inoculation and cultivars, grown under field conditions in Northeast Thailand

This investigation was carried out at the Experimental Farm, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand to evaluate intensity of infection of Pseudocercospora Leaf Spot disease of cowpea cultivars, grown under field conditions with the use of Yasothon soil series (Oxic Paleustults). The experimental design used was a strip split plot design with four replications. The experiment consisted of three factors, i.e., with and without infector rows (Factor A), with and without inoculation and inoculated dates, i.e. none inoculation, inoculated at days 15 and 30 after sowing of seeds in main plots (Factor B) and three cowpea cultivars of KVC7, KKU25 and IT81D-1228-14-1 (Factor C). The results showed that the use of infector rows of cowpea plants (KKU25) being sown at 15 days before sowing seeds of cowpea cultivars in main plots gave a similar intensity of disease as those infector rows being sown at 30 days before sowing seeds of cowpea cultivars in main plots but significantly higher than without infector rows. Pathogenic disease being inoculated to the cowpea plants at 15 days after the sowing of seeds in main plots gave significantly higher intensity of disease than none inoculation. The establishment of infector rows at 15 days ahead of the sowing of seeds in main plots together with an inoculation of the disease at 15 days after the sowing of seeds in main plots gave the best results in evaluating amount of the infected disease. Thus infector rows surrounded the main plots are required whenever trials on disease evaluation are taken place.     

Effect of preparation and cooking on the nutritive value of broad beans

Nutritive value and protein quality of dried local broad beans (Giza 1) were studied before and after preparation and cooking, according to the methods commonly used in Egypt. Dried broad beans were: 1) germinated, 2) germinated and boiled, which is the method commonly used to make ‘Nabeet Soup’ and 3) Stewed, to make ‘Medammes’ the popular breakfast dish in Egypt and Middle East. Moisture, crude protein, fat, carbohydrate, ash, fiber, caloric value and some minerals including calcium, phosphorus and iron, were determined in both dried and prepared seeds. The methods used for evaluating proteins quality involved, the determination of both ‘protein efficiency ratio’ (P.E.R.) and ‘net protein ratio’ (N.P.R.) using weanling albino rats. Besides, analysis of serum of rats maintained on, diets containing both dried and prepared beans were done to study the effect of their proteins on some blood criteria. These, involved the determination of:

1. Total serum proteins.
2. Serum albumin/globulin ratio.
3. Free non essential/essential amino acids ratio.

The results showed that germination, boiling and stewing slightly improved the P.E.R. values of broad beans. The stewed beans had slightly higher value than either germinated or boiled germinated beans which have more or less the same P.E.R. value. It was also clear that using, in diets of rats, either germinated, boiled germinated or stewed beans instead of dried ones, it caused a slight increase in both total serum proteins and albumin/globulin ratios and a decrease in the non essential/essential amino acids ratios. The effect was more marked with boiled germinated beans than with other kinds of preparation.     

Effects of Maturity at Harvest and Fermentation Conditions on Bioactive Compounds of Cocoa Beans

Cocoa beans and cocoa products contain considerable amounts of bioactive compounds. Harvesting cocoa fruit too early or too late may have effects on the phenolic and alkaloid concentrations of the cocoa powder. Fermentation, a primary processing used to transform cocoa beans to cocoa powder, may also influence the contents of bioactive compounds. In this study, proanthocyanidins, the major compounds in cocoa polyphenols, caffeine and theobromine of cocoa beans, were evaluated at different maturities at harvest, and with different fermentation durations, with and without the addition of a commercial enzyme, Pectinex® Ultra SP-L. The amounts of proanthocyanidins, caffeine and theobromine, and the antioxidant capacities of the unfermented cocoa beans increased as the fruits matured. The values ranged from 16.12–27.28 g catechin equivalents (CE)/100 g dry weight (DW); 99.66–173.61 mg/100 g DW; 556.39–948.84 mg/100 g DW; 23.23–26.32 mol Trolox equivalents (TE)/100 g DW, respectively. Prolonged fermentation with or without the addition of pectinase, from three to seven days, significantly reduced the amounts of these compounds present. Fermentation using the enzyme significantly reduced the proanthocyanidin content and antioxidant capacity of the cocoa powder, with the overall means decreasing from 8.93–4.93 g CE/100 g DW and from 15.81–12.95 g mol TE/100 g DW, respectively. Two-way ANOVA analyses showed that the proanthocyanidins, caffeine, theobromine contents and the antioxidant capacity of cocoa beans were strongly dependet to their stages of maturity, fermentation methods and fermentation duration.

     

Anti-nutrient analysis of 30 Bambara groundnut (Vigna subterranea) accessions in South Africa

Bambara groundnut is a leguminous crop that originated in West Africa. It is a drought-tolerant crop and has the potential to provide improved food and nutritional security in the dry areas of Africa. However, the plant contains anti-nutritional factors that affect its food value chain. The objective of this study was to assess the content of four major anti-nutritional factors in 30 bambara groundnut accessions in South Africa. The seeds of the bambara groundnut landraces were ground to make a fine powder and assessed for condensed tannins (CTs), phytic acid phosphate (PAP), polyphenol, and trypsin inhibitor content. Each assay was done in triplicate. The content of the four anti-nutritional compounds varied widely among the bambara groundnut accessions. The mean values for CTs ranged between 0.2 and 6.2 mg/g of prodephinidin equivalent, whereas that of the PAP was between 1.4 and 4.9 mg/g. A low mean polyphenol content of 0.4 mg/g of GA (gallic acid) equivalent was observed among the accessions. The level of trypsin inhibitor ranged from 5.3 to 73.4 TI/mg. With the exception of CTs and trypsin inhibitor, no significant correlation was observed among the four anti-nutritional factors assessed in this study. Generally, higher levels of anti-nutrients were observed in this study compared with certain studies reported earlier.     

Effect of soaking,cooking and germination on the oligosaccharide content of selected Nigerian legume seeds

The identity and quantity of and effect ofprocessing on raffinose oligosaccharides in raw,mature seeds of lima beans (Phaseolus lunatus),pigeon peas (Cajanus cajan), African yam beans(Sphenostylis sternocarpa) and jackbeans (Canavalia ensiformis) were investigated. Sucrose,raffinose, stachyose and verbascose were identified byHPLC in all the legume seeds. The total-galactoside contents of the seeds in decreasing order were African yam beans3.84 mg/100 mg; white lima beans 3.62 mg/100 mg; creampigeon peas 3.51 mg/100 mg; red lima beans3.37 mg/100 mg; jackbeans 2.83 mg/100 mg and brownpigeon peas 2.34 mg/100 mg. The predominantoligosaccharide was verbascose in pigeon peas andstachyose in the other three legumes. Cooking unsoakedseeds brought about a greater reduction in the total-galactoside content than soaking for ninehours. The removal of oligosaccharides was higher inlegumes cooked in alkaline solution than in water.Germination quantitatively reduced raffinose,stachyose and verbascose while sucrose was increasedin all seeds except red lima beans and jackbeans.