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.     

Water uptake during cooking of dry beans (Phaseolus vulgaris L.)

Water uptake during cooking of ten dry bean (Phaseolus vulgaris L.) varieties was investigated. Water uptake during early stages of cooking was characteristic of the variety. Although the optimal cooking times varied widely (52–85 min), all the beans absorbed similar amounts of water when cooked for their optimal times. Cooking times were significantly correlated with W_{20 min} (r=–0.92) and hardness index (r=0.76) of beans. Most other physical characteristics excepting the surface area of beans were generally unrelated to theW _{20 min},W _opt, and cooking times. No significant correlation was observed between phytate content and cooking times of beans. On cooking for their respective optimal times, all varieties absorbed nearly 1.5 times their weight of water and attained a moisture content of about 65% (wet basis).     

Effect of processing on flatus producing oligosaccharides in cowpea (Vigna unguiculata) and the tropical African yam bean (Sphenostylis stenocarpa)

The effect of dehulling, soaking and soaking/cooking on sucrose, raffinose and stachyose in mature dry seeds of nine varieties of cowpea (Vigna unguiculata) and one variety of tropical African yam bean (Sphenostylis stenocarpa) were investigated. The results showed a progressive decrease in sucrose, raffinose, and stachyose contents. Soaking for 12 hours and cooking for 30 min eliminated most of the sucrose, raffinose and stachyose. The sugar contents in whole raw cowpea were sucrose 0.73–4.58%, raffinose 0.71–6.86% and stachyose 2.38–3.87%, and for tropical African yam bean sucrose 4.08%, raffinose 1.08% and stachyose 4.14% while the seeds soaked for 12 hours and cooked for 30 min had for cowpea sucrose 0.03–0.81%, raffinose 0.04–0.20% and stachyose 0.12–0.72%, and tropical African yam bean sucrose 0.70%, raffinose 0.40% and stachyose 0.41%.     

Effect of domestic processing,cooking and germination on the trypsin inhibitor activity and tannin content of faba bean (Vicia faba)

The effects of domestic processing methods like soaking for 12 h dehulling, ordinary cooking of whole as well as dehulled seeds at 151bs/inch² pressure for 15 and 25 min, and germination for 24, 36 and 48 h were observed on trypsin inhibitor (TIA) and tannin content of two varieties of faba bean viz. VH-131 and WF. A non-significant reduction in TIA was observed on soaking and dehulling, while tannins showed a reduction of 42 and 51% on soaking in VH 131 and WF, respectively. Dehulled seeds showed a decline in tannin content by 70 to 73% in two varieties. There was a significant reduction in TIA (75–76 per cent) and tannin (76–81%) on cooking, while autoclaving for 25 min almost completely eliminated both of these stress factors. Germination of seeds for 48 h led to a reduction of 64–65% in TIA and 90–91% in tannins, which was more than germination for 24 and 36 h. Soaked seeds gave positive results of both these antinutrients.     

Quick-cooking beans (Phaseolus vulgaris L.): I. Investigations on quality

Soaking three beans cultivars (Phaseolus vulgaris L.: Great Northern, kidney, and pinto) in mixed salt solution (sodium chloride 2.5% + sodium bicarbonate 1.5% + sodium tripolyphosphate 1.0% + sodium carbonate 0.5%) resulted in 80%–85% reduction in cooking time over corresponding controls. Irradiation (-rays) at 500 krads of soaked and dehydrated beans caused a reduction of nearly 50% in cooking time. Water uptake and leaching losses for each treatment during soaking at 22°, 37°, and 45°C were investigated. High temperature (37° and 45°C) and pH (9.0) caused greater water imbibition and total solid loss than at room temperature (22°C). Organoleptic evaluation revealed that quick-cooking Great Northern beans appear to be more acceptable than kidney and pinto beans. Quick-cooking cooked beans had better in vitro protein digestibility than conventionally cooked beans. Phenolic content was found to be inversely related to in vitro digestibility.Utah Agricultural Experiment Station Journal article no. 2481.     

Effect of Cooking Procedures and Storage on Starch Bioavailability in Common Beans (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> L.)

Common commercial beans were cooked using two procedures: under pressure (autoclaving) and traditional cooking. Total starch extraction was higher in beans cooked with the traditional procedure (41.69–42.81%) than in the autoclaved samples (37.04–38.16%) and did not change during storage at 4 °C. However, available and total resistant starch levels in vitro were not influenced by the cooking procedure or storage. Retrograded resistant starch content was higher in beans cooked with the traditional process (2.65–2.79%) than in autoclaved beans (1.62–1.94%). The initial in vitro -amylolysis rate in freshly cooked beans was higher in the autoclaved preparation than in the beans cooked by the traditional process, but final hydrolysis indices (90 min) were similar for both samples. None of the bean samples showed statistical differences in -amylolysis behavior (=0.05) after storage at 4 °C for 96 hour.     

Nutrient composition and biological evaluation of mesta (Hibiscus sabdariffa) seeds

Two varieties of mesta (Hibiscus sabdariffa) seeds were analysed for their proximate composition. Their protein (18.8–22.3%), fat (19.1–22.8%) and dietary fiber (39.5–42.6%) contents were found to be high. The seeds were found to be a good source of minerals like phosphorus, magnesium and calcium. Their lysine and tryptophan contents were also high. Sulphur containing amino acids were limiting in this seed protein and the chemical score of mesta seed protein was 40 and 57 for AMV-2 and Bhimili-1 varieties respectively. Mesta seed oil is rich in unsaturated fatty acids (70%), of which linoleic acid constituted 44%. Weanling rats were fed with 10% mesta seed protein before and after cooking for 4 weeks. Food intake of animals receiving raw mesta seed diets was significantly lower than those receiving cooked mesta seed diets as well as the casein control diet. Protein and dry matter digestibilities of raw and cooked mesta seed diets were lower than that of casein control diet. Cooking improved the food intake, gain in body weight, dry matter and protein digestibility of mesta seed diets. PER and NPU of cooked mesta seed diets were significantly higher than the corresponding raw diets. These results indicate that cooked mesta seed protein is of relatively good quality.     

Effects of various water or hydrothermal treatments on certain antinutritional compounds in the seeds of the tribal pulse,Dolichos lablab var.vulgaris L.

Effects of soaking, cooking and autoclaving on changes in polyphenols, phytohaemagglutinating activity, phytic acid, hydrogen cyanide (HCN), oligosaccharides and in vitro protein digestibility were investigated in seeds ofDolichos lablab var.vulgaris. Both distilled water and NaHCO₃ solution soaking and autoclaving significantly reduced the contents of total free phenolics (85–88%) compared to raw seeds. Autoclaving (45 min) reduced the content of tannins by upto 72%. Soaking seemed to have limited effect in eliminating phytohaemagglutinating activity, whereas autoclaving (45 min) seemed to eliminate the haemagglutinating activity completely. The reduction in content of phytic acid was found to be some what greater in distilled water soaking (28%) compared to NaHCO₃ solution soaking (22%). Only a limited loss in content of phytic acid was observed under cooking as well as autoclaving. Loss of HCN was greater under autoclaving (87%) compared to the other processes studied. Of the three sugars analysed, soaking reduced the level of verbascose more than that of stachyose and raffinose. Autoclaving reduced the content of oligosaccharides more efficiently (67–86%) than ordinary cooking (53–76%). Autoclaving improved the in vitro protein digestibility (IVPD) significantly (13%). Of all the different water and hydrothermal treatments studied autoclaving seemed to be the most efficient method in improving IVPD and eliminating the antinutrients investigated except phytic acid.     

Pretreatment of African Yam Bean (<Emphasis Type="Italic">Sphenostylis stenocarpa</Emphasis>): Effect of Soaking and Blanching on the Quality of African Yam Bean Seed

The effect of pretreatment (soaking in sodium salts and blanching) on hydration coefficient (HC), chemical composition, texture, and color of African yam bean (AYB) was investigated. Soaking in water and in salt solutions increased the HC and about 90% of final HC values were attained at 12 and 4 hr of soaking for whole and dehulled beans, respectively. Protein content was slightly increased by soaking and blanching while ash and fat contents were reduced. Generally, a combination of dehulling and wet-processing reduced firmness of the beans more than soaking or blanching of the whole beans. Antioxidant activity was lowest (3260 TE³100 g) in cream-colored beans and highest (16,600 TE/100 g) in brown-colored beans. The tannin contents of unprocessed cream-colored beans and dehulled wet-processed marble variety were not significantly different (p > 0.05). The levels of tannins in the marble variety were reduced by blanching for 40 min (19.2%), soaking for 12 hr (16.0%), dehulling (72.0%), dehulling and blanching (88.8%). The whiteness of bean flours was increased significantly by dehulling, slightly by wet-processing of marble variety, and reduced significantly by wet-processing of cream-colored beans. TE: micromole equivalents of Trolox (TE) per 100 g of a sample. L^∗ value value: determined by McBeth colorimeter (Minolta Co., Japan).     

Influence of hardening procedure and soaking solution on cooking quality of common beans

Two common bean (Phaseolus vulgaris) varieties were seeded in the same location, harvested and cleaned. Three hardening procedures were used (soaking in acetate buffer, pH 4.1 at 37°C for 5 h; storage at 37°C, 100% RH for 28 days; and storage at 31–33°C, 76% RH for 120 days) to have seeds in a hard-to-cook (HTC) state. The adverse effects of HTC condition, in terms of cooking time as assessed by a Mattson bean cooker, were practically eliminated by soaking seeds in salt solutions (1% NaCl+0.75% NaHCO₃; and 0.75% NaHCO₃) instead of only water. Ultrastructural changes of cotyledon cells from fresh, HTC and softened seeds were observed. Results of this study may be used for the development of a technological procedure to utilize properly HTC beans generated by unefficient storage systems.     

Effect of cooking on cowpea protein fractions

Nine cowpea cultivars obtained from Wad Medani Research Station were used in this study. The variation in protein fraction was: albumins 4.0–12.0, globulins 65.6–79.7, prolamins 1.4–2.2, G₁-glutelins 0.9–3.0, G₂-glutelins 1.4–2.9. G₃-glutenins 9.1–14.0 and insoluble protein 0.5–3.0%. Two cowpea cultivars, H8-14 and CB-46, selected for their high albumin content, were cooked in 150 ml of boiling distilled water under reflux for 45 minutes. The protein fractions in the cooked seeds were determined. Results indicated that albumin and globulin fractions decreased significantly (p0.05) for both cultivars after cooking. This decrease was accompanied by a significant increase in G₃-glutelin fractions.     

Effect of domestic processing on the cooking time,nutrients, antinutrients andin vitro Protein digestibility of the African yambean (Sphenostylis stenocarpa)

The effects of processing (soaking, dehulling, fermentation and heat treatment) on the cooking time, protien, mineral, tannin, phytate and in vitro protein digestibility (IVPD) of the african yambean (AYB) were examined. The cooking time ranged from 90–155 minutes. Soaking reduced cooking time by about 50 percent. Soaking for 12 hours was the most appropriate to reduce cooking time, tannin and phytate levels. It improved in vitro protein digestibility (IVPD). Prolonged soaking (24 hours) decreased calcium (Ca) and iron (Fe) values by 19 percent and 35 percent, respectively. Dehulling showed that Ca, Fe, magnesium (Mg) and zinc (Zn) were concentrated in the seed coat of the AYB. The seeds soaked and dehulled retained Mg and Zn. Dehulling reduced tannin but had no significant effect on phytate and the IVPD of the AYB except for seeds soaked for 12 hours before dehulling. Soaking for 24 hours before dehulling significantly increased crude protein content by 16 percent (p<0.05). Blanching and roasting increased the IVPD by 8–11 percent. Fermentation had no effect on the crude protein, Ca, Fe, Mg and Zn but significantly reduced phytate content of the AYB. Fermentation had no advantage over heat treatment with respect to improving the in vitro protein digestibility of the AYB.     

Interrelationships between certain physical and chemical properties of dry bean (Phaseolus vulgaris L.)

The interrelationships among certain physical and chemical properties of ten cultivars of dry beans (Phaseolus vulgaris L.) were investigated. The length/breadth ratio was similar (1.51–1.65) except for kidney beans (>2.0) and sanilac (1.37) cultivars. The breadth/thickness ratio ranged from 1.17–1.65. The 100-bean weight indicated a wide variation of 15.03–50.33 g. The density, bulk density, and porosity characteristics were within a narrow range of 1.18–1.36 g/cc, 68–75 g/100 cc, and 40.7–48.5%, respectively. Water uptake rates during the first 6 h of soaking at room temperature (21 °C) were characteristic of the cultivar. At the end of 24-h soaking, however, all cultivars had absorbed similar amounts of water (approximately 1 g/g bean). Leaching losses (g solids leached/100 g beans) had characteristic trends and ranged from 0.54 for cranberry to 3.46 for sanilac cultivars after 24-h soaking. Most correlations between selected chemical constituents and physical characteristics of the dry bean were relatively low.Journal Paper No. 2751 of Utah Agricultural Experiment Station and a contribution of Western Regional Project W-150.     

Effects of altitude above sea level on the cooking time and nutritional value of common beans

The present study was conducted with the objective to determine the effects of altitude above sea level, on the cooking time and nutritional value of common black beans (Phaseolus vulgaris). Three 100 g samples of theOstua variety were cooked at 8 individual locations, ranging in altitude from 0 to 2256 meters, in Guatemala, to establish water uptake and cooking time. The cooked samples were separated into cooked beans and cooking broth for chemical analysis. This included moisture, protein, lysine, tannins, total and enzyme susceptible starch, and fiber fractionation. The cooking liquor was analyzed for total solids, moisture, protein, ash and K. A 1200 g sample was cooked for the cooking time established previously, for biological testing of nutritional value,which included Net Protein Ratio (NPR), Protein Effciency Ratio (PER), and protein digestibility. Altitude influenced cooking time which increased from 78 min at 0 m, to 264 min at 2256 m. Final moisture content in the cooked bean was similar at all altitudes and there was a tendency to yield smaller amounts of solids in the cooking broth at higher altitudes. The increase in cooking time was significant. Bean water uptake at all times was significantly slower and smaller at ambient T, as compared to water uptake at boiling T, at all altitudes. Protein and lysine content were not affected by altitude, however, tannin and catechin were lower in cooked samples, as compared to the raw material. Altitude did not affect the content of these substances. Total starch and total sugars were higher in the raw sample, as compared to the cooked samples, but there was no effect of altitude. Enzyme susceptible starch (ESS) was lower in the raw sample as compared to the cooked samples, which contained similar amounts with respect to altitude. No change was observed in fiber fractions of the cooked beans. Likewise, the composition of the cooking broth was very similar between cooking locations. There was a small tendency to a lower protein quality, with respect to altitude, the effect of which was more obvious in the apparent protein digestibility values. Undercooking or overcooking at one location influenced protein quality values. The extended cooking time of beans at high altitudes, has important economic and environmental implications, since significant amounts of wood have to be used.     

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.     

Soaking and cooking parameters of tepary beans: effects of cooking time and cooking temperature on hardness and activity of nutritional antagonists

Tepary samples were examined for patterns of hydration, dry matter losses during the processes of soaking and cooking, residual hardness in partially cooked samples and heat lability of endogenous proteinaceous antinutritional factors. At 24 °C, teparies imbibed water equivalent to their weight (100% hydration) in 4 h and continued to absorb water rapidly for an additional 4 h before reaching an equilibrium hydration. During the processes of soaking and cooking, materials leached from raw beans represented 7.3 and 13.5% of their dry weight, 4.3 and 12.4% of their protein content, 7.1 and 12.2% of their stored carbohydrate and 22.4 and 33.4% of their mineral levels, respectively. In samples prepared at different cooking times (60, 90, 120, 150, 180 min) and cooking temperatures (80, 85, 90, 95°C), longer times and higher temperatures resulted in greater reductions in residual bean hardness; interactive effects of time and temperature treatments were significant. Residual activity of trypsin and chymotrypsin inhibitors in partially-cooked samples appeared to be negligible. In addition, at least 80% of the original hemaglutinating activity of lectins in raw beans was lost during partial-cooking of samples under all cooking regimes.     

Method for analysis of fatty acid distribution and oil content on a single Lesquerella fendleri seed

Lesquerella fendleri is a developing oilseed crop suitable for temperate growing regions in the US. The seed oil is rich in lesquerolic acid (57%) and could serve as a domestic source of hydroxy fatty acids. A method for the analysis of fatty acids and total oil content of a half or single lesquerella seed was developed. Lesquerella seeds are small with 1000 seed weights around 0.6 g (half seed mass of 200–500 μg). Conventional analytical balances provide mass accuracy to ±40 μg which fails to provide sufficient accuracy/precession (4–40% mass error) for the initial seed mass. A microbalance which measures to ±2 μg provided good reproducibility in initial seed weights but was not suitable for mass balance of the extracted oil. A normal phase HPLC coupled to an evaporative light scattering detector gave good response for oil in the mass range of 22 μg to 110 μg/mL. Therefore, micelle concentrations from single or half seed extractions could be determined with good reproducibility. This method was then evaluated on bulk seed that had been fractionated on a gravity table. Gravity table fractionation of L. fendleri seeds obtained from a large field plot provided seven fractions with increasing bulk density. These fractions were then analyzed in sets of 30 individual seeds and as an aggregate of 50 seeds. Oil content for individual seeds varied widely (15.6–44.2%) as did lesquerolic acid content (42.2–63.7%). The mean oil content increased (27–33%) with increasing bulk density (684–745 g/L). The mean lesquerolic acid content did not correlate with bulk density.     

Effects of cooking and screw-pressing on functional properties of protein in milkweed (Asclepias spp.) seed meals and press cakes

This study determined the effects of oil processing conditions on functional properties of milkweed seed proteins to evaluate their potential for value-added uses. Flaked milkweed seeds were cooked at 82 °C (180 °F) for 30, 60 or 90 min in the seed conditioner, and then screw-pressed to extract the oil. Proximate composition and protein functional properties of cooked flakes and press cakes were determined and compared with those of unprocessed ground, defatted milkweed seeds. Milkweed seed protein was most soluble at the pH range of 7–10, had excellent emulsifying properties, and produced substantial but highly unstable foams. Heat applied during seed cooking and screw-pressing did not reduce protein solubility and improved emulsifying, foaming, and water-holding capacities. Emulsifying capacity was much higher at pH 10 than at pH 7. These results showed that the protein in both the milkweed seed and its press cake from oil processing has useful functional properties that could be utilized in applications such as paint emulsifier and adhesive extender.     

Influence of phytate on in vitro digestibility of casein under physiological conditions

The phytic acid content of four different varieties of beans under different processing conditions was estimated. It was highest in red kidney (1.86–2.13%) slightly lower in pigeon (1.86–2.03%), white (1.80–1.96%) and black eyed beans (1.15–1.64%). There was no significant change in phytic acid content of beans after soaking at 25°C for 22 hours. However, both soaking and cooking revealed 26–37% loss of phytic acid in all four varieties of beans.The rate of in vitro casein digestibility with and without phytic acid at concentrations found in legumes was determined at pH 8 and 37°C using multienzyme technique. Addition of 5 mg Na-phytate reduced the casein digestibility up to 20% compared to the control. However, only 25% reduction of casein digestibility was observed in the presence of 25 mg of Na-phytate. Higher concentration of Na-phytate had no significant effect on the rate of casein digestibility. Data strongly suggest the formation of protein phytate complex at alkaline pH of small intestine.Part of this work was presented at the XIII International Congress of Nutrition in Brighton, UK in August 1985.     

Evaluation of selected food attributes of four advanced lines of ungerminated and germinated Nigerian cowpea (Vigna unguiculata (L.) Walp.)

The chemical composition and functional properties of ungerminated and germinated seeds of four advanced lines of cowpeas (IT81D-699, IT82E-18, IT84S-2246-4 and TVx 3236) were investigated. Ungerminated seeds contained 20.1 to 25.8% crude protein, 2.0 to 2.2% lipid, 115.1 to 210.0 mg phyticacid/100 g and 8.9 to 9.6 mg iron/100 g. The polyphenol contents of the brown- and cream-colored beans were similar (192.0 to 196.0 mg/100 g) but were significantly (p<0.05) higher than the amount (99.8 mg/100 g) found in the white beans. Germination increased the crude protein content, total phosphorus content, nitrogen solubility, fat absorption capacity and foam capacity but decreased ether extract, polyphenol and phytic acid contents, water absorption capacity, bulk density and foam stability of all cowpea lines. Incorporation of up to 0.2 M NaCI improved foam volume. Ungerminated seeds had high water (2.3–3.2 g/g) absorption capacities, while germinated seeds had high fat (3.1–3.6 g/g) absorption capacities. TVx 3236 and IT81D-699 might be selected for combining such characteristics as high crude protein, low phytic acid content and good foaming properties into a single cowpea line through breeding.