Amino acid composition, available lysine content and in vitro protein digestibility of selected tropical crop seeds

As the search for alternative sources of food to alleviate hunger continues, this study was undertaken to determine nitrogen and amino acid content, chemical score, protein digestibility corrected amino acid score, available lysine and in vitro digestibility of 8 lesser known, wild tropical seeds, gathered in Nigeria. Results were contrasted with a tropical soybean variety (Glycine max, TGX 1660-15F). The investigated seeds wereMillettia thonningii, Gliricidia sepium, Lonchocarpus sericeus, Albizia zygia, Daneillia ogea andAfzelia bella from the family of Leguminosae,Diospyros mespiliformis (Ebenaceae) andEntandrophragma angolense (Meliaceae). The crude protein content, based on nitrogen determination, was found to be lower in the wild seeds compared to soybean, which was partly due to the relatively high content of non-protein nitrogen. With reference to amino acid requirement and digestibility in most seed samples, lysine, followed by sulphur amino acids and threonine, were the limiting amino acids. It was concluded, that these less familiar wild seed plants may be used as valuable food or feed complements. However, further investigation is necessary to elucidate potential toxic and antinutritional factors.     

Screening soybean (grain and vegetable) genotypes for nutrients and anti-nutritional factors

Fifty six genotypes of grain-type soybean and 17 genotypes of vegetable-type soybean collections were analyzed for protein and oil content, trypsin inhibitor, and lipoxygenase activities. The protein and oil content ranged from 36.9 to 47.9% and from 13.3 to 23.0% for different accessions in grain- and vegetable-type soybeans, respectively. Trypsin inhibitor and lipoxygenase activities ranged from 22.0 to 47.0 trypsin inhibitor units/mg meal and from 482 to 6265 lipoxygenase units/min/mg meal for grain- and vegetable-type soybeans, respectively. Significant correlations (r=–0.62 and –0.52,P<0.05) were found between protein and oil, and between protein and trypsin inhibitor. A significant positive correlation (r=0.42,P<0.05) was also calculated for oil and lipoxygenase activity. Several genotypes of soybean and vegetable soybean (plant introductions 423905, 417330, 417223, 171451, 200506, 200523, 417124, 227687, 203402, 445842, 203399, 423852, 416771, FC31927, Avoyelles, and Sooty) showed good nutritional potential and may be useful in a breeding program to improve the nutritional quality of soybean. Screening for essential amino acids, fatty acids, and trace minerals for selected genotypes is underway.     

Production of nixtamalized flour and tortillas from amarantin transgenic maize lime-cooked in a thermoplastic extruder

The potential use of quality protein transgenic maize (genetically modified maize with the cDNA of amarantin) for preparation of flour and tortillas through an extrusion lime cooking process was investigated. Tortillas from extruded transgenic maize flour had similar physicochemical and sensory properties than those from the commercial brand MASECA™; however, the former had the highest (P < 0.05) protein content (12.91 vs 8.93%, db), essential amino acids content, calculated protein efficiency ratio (C-PER; 2.27 vs 0.90) and protein digestibility corrected amino acid score (PDCAAS; 55.54 vs 30.18%) and therefore they were nutritionally better. The use of transgenic maize for flour and tortilla preparation through an extrusion lime cooking process may have a positive impact on the nutritional status of people from countries where maize is the basic staple food. It also represents an alternative process to nixtamalization that requires little energy and water, it does not generate wastewater, and all components of the maize kernel are retained.     

Seasonal changes in feed intake,diet digestibility and diet composition by lactating and non‐lactating goats browsing in a semi‐arid rangeland of Argentina

We determined the seasonal nutrient and secondary compound intake, in vivo diet digestibility (DD) and diet species composition of goats in different physiological states in a desert rangeland of Argentina. During the wet and the dry seasons, 24 mature female Creole goats (six non‐lactating, non‐pregnant and six lactating in each season) were used in a 2 × 2 factorial design. Diet botanical composition, DD and dry‐matter intake (DMI) were estimated by the combined use of visual observation, microhistological analyses of faecal samples and n‐alkane technique. Browse species dominated the goats’ diets (>80%) in both seasons and physiological states, with a twofold increase in the proportion of forbs during the wet season (p < 0.10). Lactating goats showed greater DMI than non‐lactating animals, and they also displayed greater intakes of some tanniferous (Mimosa ephedroides) and high‐protein (Atriplex lampa) shrubs (p < 0.10). Lactating and non‐lactating goats selected diets with adequate crude protein (CP) and fibre content but insufficient energy, although lactating goats tended to increase energy and tannin content in their diets (p < 0.20). Physiological state did not influence DD, but digestibility was greater (p < 0.10) in the wet season, attributed to the greater protein content and lower tannin content of the diet. These results have important implications for managerial interventions on traditional goat production systems in the study area aiming at enhancing goat nutrition and welfare, as well as the sustainability of rangeland resources in the region.     

The nutritive value of amaranth grain (Amaranthus caudatus)

The nutritional value of three pale seeded and one dark seeded variety ofAmaranthus caudatus was studied by chemical analyses and in balance experiments with growing rats. Effects of processing: popping, toasting and flaking were also examined. The pale seeds contained about 14% protein, 10% fat, 2.5% ash, 64% starch and 8% of dietary fibre. The black seeds had a much higher content of fibre (16%). The concentration of essential amino acids were high. Lysine ranged from 5.2–6.0 g/16 g N in the grains, and the limiting amino acids were leucine followed by valine or threonine. The grains contained small amounts of tannin (0.3%) and heat-labile protease inhibitor activity, at levels typical of common cereal grains. Digestibility of protein in the pale seeds was high (87%) and quite unaffected by processing. Protein digestibility of the black seeds was lower, and the digestibility was further reduced by toasting. The biological value of the protein was similar in all products, and very high. The content of minerals varied among varieties and was also affected by processing. Phytate: zinc molar ratios were high in most products, and rats fed the amaranth samples with the lowest zinc contents were in negative zinc balance. In general, femur zinc concentrations were rather low. However, amaranth is an unconventional crop which deserves further attention.     

Protein Nutritional Quality of Infant Cereals during Processing

The most common food for weaning at the age of 4–6 months is cereal since is that it is a good source of high quality protein. However, processing may affect this quality. The aim of the present study was ascertain the changes that take place during four processing stages of infant cereals (in the raw materials, after roasting, after enzymatic treatment and drum drying, and in the commercial product), the following protein nutritional parameters: crude and true protein (CP and TP, respectively), in vitro protein digestibility (IVPD), free amino acids (FAA), calculated protein efficiency ratio (C-PER) and total amino acids profile. Of the infant cereals studied two contained gluten (‘Multicereal’ and ‘Wheat’) and two were gluten-free (‘Growth’ and ‘Rice and carrot’). All the parameters studied were affected by the different processing stages, but none showed a clear trend. The CP and TP content decreased after heat treatment (roasting) with a consequent increase in FAA content due to protein hydrolysis and the release of amino acids. IVPD remained stable during the processing stages in all the infant cereals, except in ‘Wheat’, while C-PER increased significantly. Infant cereals containing gluten showed higher CP and TP contents, and also higher IVPD than gluten free cereals, in which a digestibility value higher than 75% was reached. The overall content of essential amino acids, including sulphur amino acids, was acceptable (equal to or higher than FAO/WHO recommendations), although lysine (Lys) was the limiting amino acid in all the infant cereals.     

Comparative study of the chemical composition of wild and cultivated beans (Phaseolus vulgaris)

Five wildPhaseolus vulgaris beans were compared with five cultivatedPhaseolus vulgaris beans in proximate composition, total (true) protein, amino acid composition, and toxic and antinutritional factors. The wild beans contained more protein (25.5% vs. 21.7%), ash (5.15 vs. 4.15%), crude fiber (7.08% vs. 5.04%) compared to cultivated beans while the former contained less fat (0.56 vs. 0.89%) and carbohydrates (61.64 vs. 68.05%). Sulfur amino acids were found to be limiting in both groups of bean as expected; however, the cultivated beans had a higher content of the limiting amino acids. Therefore, the cultivated beans showed a better amino acid profile than the wild beans. Toxic factors were not found in either type of bean; the determinations included saponins, alkaloids, and cyanogenic glycosides. The antinutritional factors investigated were hemagglutinins (lectins) and trypsin inhibitors. The wild beans presented a higher content of trypsin inhibitors (28 TUI per mg) and lectins (9.6) than the cultivated beans did (21 TUI per mg and 7 respectively). From the chemical point of view, domestication seems to be positive; however, the better protein nutritive quality of the cultivated beans should be further confirmed by biological assays.     

Nutritional and Antinutritional Characteristics of Seven South Indian Wild Legumes

Seeds from seven species of wild legumes of the South India were analyzed for proximate composition, mineral profiles, amino acid profiles of total seed protein, in vitro protein digestibility, and certain antinutritional factors to assess their potential as alternative sources of protein crops. The major findings of the study were as follows: crude protein ranged from 20.3 to 35.0%, crude lipid 3.1–9.6%, crude fiber 5.9–12.1%, ash 2.7–5.1%, and carbohydrates 49.2–61.8%. Minerals viz., sodium, potassium, calcium, magnesium, phosphorus, iron, copper, zinc, and manganese occurred in the range 42.9–135.9, 556.2–1639.5, 304.5–572.2, 174.9–686.7, 98.4–947.8, 3.6–16.4, 0.2–1.2, 2.0–30.0, and 1.0–3.9 mg/100 g seed flour, respectively. Profiles of amino acids of total seed proteins detected in the present study revealed that levels of valine, phenylalanine, tyrosine, isoleucine, and histidine of all the seven wild legume seed samples, threonine of Canavalia ensiformis and C. gladiata, leucine of Mucuna pruriens var. pruriens, and lysine of Cassia floribunda and C. obtusifolia were found to be higher than FAO/WHO (1991) requirement pattern. The in vitro protein digestibility of the legumes under study ranged from 63.39 to 83.32%. Antinutritional factors such as total free phenolics ranged from 0.41 to 5.96%, tannins from 0.04 to 0.60%, L-DOPA from 1.34 to 8.37% and trypsin inhibitor activity from 13.48 to 65.43 TIU/mg protein. The detected antinutritional factors probably have little nutritional significance if the seeds are properly processed.     

Chemical composition, digestibility and antinutritional factors content of two wild legumes: Styphonolobium burseroides and Acacia bilimekii

The chemical composition, digestibility and toxin contents of two wild legumes: Styphnolobium burseroides and Acacia bilimekii, collected in a semi-arid zone of Mexico, were determined. Both legumes had a high fiber content. The seeds of Styphnolobium burseroides had a low protein content (14%), and the pod a high content of reducing sugars. However the seeds of Acacia bilimekii had a high protein concentration (35%). The seed proteins were low in sulphur amino acids and tryptophan in both legumes but were rich in lysine. Trypsin inhibitors and lectins were present in low concentrations; alkaloids and cyanogenic glucosides were not detected. The in vitro digestibility for monogastric animals was low but the same test with ruminal juice showed a high digestibility for both legumes. Based on their chemical composition and digestibility, these legumes could be a good alternative source in the feeding of ruminants.     

Effects of sourdough and dietary fibers on the nutritional quality of breads produced by bake-off technology

The aim was to evaluate the effect of sourdough and dietary fiber addition, as well as partially baked frozen (PBF) technology, on biological value of proteins, lipid profile, and some minerals content in selected tissues of rats.In all breads, the limited amino acid was lysine. Proteins of PBF conventional and PBF breads with an addition of dietary fiber (PBF DF breads) had significantly higher Chemical score and Essential amino acid index in comparison to proteins of Direct bread (P < 0.05). Protein digestibility corrected amino acids score was significantly lower in Direct DF and PBF improved breads (P < 0.05).Addition of fiber to Direct and PBF bread decreased significantly total digestibility of protein compared to all groups (P < 0.05).Concentration of calcium was significantly lower in liver of rats fed with Direct sourdough and PBF improved breads in comparison to rodents fed with Direct bread. The concentration of iron was significantly higher in liver of animals fed with Direct bread. The highest level of calcium in femoral bones of rats was shown in groups fed with PBF conventional bread. The lowest level of iron was measured in femoral bone of rats fed with PBF sourdough bread in comparison to the rest of the experimental groups.     

闽南9种人工栽培的野菜营养成分分析

对闽南地区9种人工栽培的野菜的基本营养成分和氨基酸组成作较全面系统的分析,结果表明：9种野菜营养成分差异较大,其可食部分都含有较丰富的粗蛋白、粗脂肪、Vc、钾、钙、钠等成分;氨基酸含量丰富,配比合理;羽衣甘蓝、马兰、九层塔、薄荷4种野菜在氨基酸总量、必需氨基酸和鲜味氨基酸含量都明显高于其它野菜品种。     

Protein,calcium, iron,and amino acid content of selected wild and domesticated cultivars of finger millet

Two wild and eight domesticated cultivars of finger millet were analyzed to determine their proximate composition and calcium, iron, and amino acid content. Wide variations were observed in the protein (mean values ranged from 7.5 to 11.7%), calcium (376 to 515 mg/100 g), and iron (3.7 to 6.8 mg/100 g) content of the wild and domesticated cultivars. A wild progenitor of finger millet, Ecoracana subsp.africana was significantly higher in protein than four of the six domesticated accessions analyzed. The calcium and iron content of the wild progenitor was also significantly greater than that of two domesticated cultivars. The wild species was also found to be higher in lysine and five other essential amino acids. These results indicate that the nutritional value of finger millet may be significantly improved by selective crossbreeding of the cereal's wild and domesticated cultivars.     

Relationship between total sulphur and sulphur amino acids in chickpea (Cicer arietinum L.) and pigeonpea (Cajanus cajan [L.] Millsp.)

Total sulphur was determined in seed meal of 30 chickpea and 24 pigeonpea cultivars by the wet digestion procedure and by using the Leco sulphur analyser. Methionine and cystine were determined after performic acid oxidation in an amino acid analyser. The two methods used for total sulphur determinations were highly correlated (r=0.943). Percent meal protein was significantly correlated (r=0.476) with total sulphur in chickpea but not in the case of pigeonpea. Total sulphur content exhibited a significant positive correlation (r=0.651) with sulphur amino acids of pigeonpea when expressed as percent of protein but not in the case of chickpea. Correlation coefficients between total sulphur and sulphur amino acids when the results were expressed as percent of sample were positive for both chickpea (r=0.494) and pigeonpea (r=0.534). The amount of sulphur in methionine and cystine accounted for 54.8% of the total sulphur in chickpea and for 75.5% in pigeonpea. In both chickpea and pigeonpea, methionine was positively and significantly correlated with cystine when they were expressed either as percent of sample or as percent of protein.Submitted as J.A. no. 159 by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).     

Nutritional and antinutritional components of Canavalia spp. seeds from the west coast sand dunes of India

Seeds of two coastal sand dune wild legumes, Canavalia cathartica and Canavalia maritima from the west coast of India were analyzed for their nutritional and antinutritional properties. The seeds contained 35.5 and 34.1% crude protein, 52.8 and 50.5% crude carbohydrates, 1.3 and 1.7% crude lipids and 3.1 and 3.5% ash content, respectively. Among the minerals, potassium was the highest followed by phosphorus. Globulins and albumins constituted the major seed proteins of both plants. Most of the essential amino acids were at adequate levels. Although the crude lipids were below 2%, the unsaturated fatty acids were high. Seeds did not contain tannins and trypsin inhibitors. The levels of total phenolics were low, but showed high hemagglutination activity. The nutritional properties of these seeds have been compared with other Canavalia spp. and wild unconventional or tribal legumes. Overall, the study results suggest that the seeds of C. cathartica and C. maritima possess potential nutritive value particularly higher protein, essential amino acids and low levels of antinutritional factors. These wild legumes are adapted to low nutrient, high saline and drought conditions of the coastal sand dunes; their conservation and domestication are warranted as potential alternative sources of protein.     

Chemical composition and nutrient digestibility of pearl millet (Pennisetum glaucum) fed to growing pigs

Pearl millet grown at two different locations in the U.S.A., pearl millet A (PMA) and pearl millet B (PMB), were analyzed for chemical composition and nutrient content and compared to corn. The two samples of pearl millet and corn were incorporated into diets and fed to 24 growing pigs in a metabolism trial to determine nitrogen and mineral balance and digestibilities of energy, fat and amino acids. Pearl millet (PMA and PMB) was found to be richer in crude protein, gross energy, ether extract, acid detergent fiber, amino acid profile and mineral content than corn. However, digestibilities of dry matter (corn, 86·8%; PMA, 80·5%; PMB, 82·0%) and energy (corn, 85·3%; PMA, 78·8%; PMB, 80·5%) were higher (P<0·05) for corn than either of the pearl millet samples. Fat digestibility was much higher in pearl millet than corn. Although nitrogen intake and absorption were higher (P<0·05) for pearl millet, the digestibility of nitrogen was similar for pearl millet and corn. Net protein utilization was lower (P<0·05) in pearl millet when compared to corn (corn, 44·8%; PMA, 34·6%; PMB, 39·9%). Digestibilities of the essential amino acids, arginine, threonine, valine, isoleucine and lysine were higher in pearl millet than corn. Phosphorus retention, expressed as a percentage of intake and absorption, was higher in corn than pearl millet. Calcium intake and absorption were similar for pearl millet and corn. Intake and absorption of magnesium and managanese were also similar in pearl millet and corn. Zinc and copper retention, when expressed as a percentage of intake, were higher in corn, but absorption for both minerals was similar in corn and pearl millet. Pearl millet was found to supersede corn in nutrient content and amino acid digestibility.     

Chemical composition and protein quality of buckwheat (Fagopyrum esculentum Moench)

The chemical composition and protein quality of two varieties of buckwheat were measured and compared with the values of wheat. The protein quality was based on amino acid composition and true protein digestibility, biological value, net protein utilization, and utilizable protein obtained in N-balance experiments with rats. The protein content in buckwheat was approximately 12% and thus very much the same as in wheat. The fat content in buckwheat was close to 3% whereas the crude fiber concentration was very high (12.7 and 17.8%, respectively, for two varieties). The high fiber content caused a low concentration of soluble carbohydrates with the lowest value of 48.7%. Both buckwheat varieties had a high tannin content (1.76 and 1.54%, respectively). The protein quality was very high, with biological values above 90%. This can be explained by a high concentration of most essential amino acids, especially lysine, threonine, tryptophan, and the sulphur-containing amino acids. However, due to the high contents of crude fiber and tannin, the true protein digestibility was slightly below 80%.     

Proximate Analysis and Some Antinutritional Factor Constituents in Selected Varieties of Jamaican Yams (<Emphasis Type="Italic">Dioscorea</Emphasis> and <Emphasis Type="Italic">Rajana</Emphasis> spp.)

Two wild (Dioscorea polygonoides and Rajana cordata) and seven cultivated varieties of Jamaican yams (Dioscorea spp.) were analyzed for their proximate composition and the levels of antinutritional factors. The protein level range was 47.8 ± 2.6 to 88.0 ± 2.5 g/kg dry weight. The lowest level was seen in D. cayenensis. The range for the dietary fiber content in the tubers was 16.3 ± 0.7 to 63.5 ± 0.4 g/kg dry weight. The wild yam varieties recorded higher levels. Saponins level was < 600 mg/kg dry weight in all the tubers analyzed except for bitter yam (2962.5 ± 60.5 mg/kg dry weight). Total phenol content ranged from 1.3 ± 0.1 to 79.3 ± 6.1 g/kg while total condensed tannin content ranged from 0.1 ± 0.0 to 26.7 ± 3.8 g/kg dry weight. Samples that showed high levels of phenols also had high levels of condensed tannins. All the samples analyzed contained low levels of lectins and no alkaloids were detected. The levels of antinutritional factors did not clearly delineate the wild varieties from the edible varieties.     

Protein Digestibility using Corrected Amino Acid Score method (PDCAAS) of four types of mushrooms grown in Jordan

This study was conducted to evaluate the protein quality of four types ofedible mushrooms common in Jordan in terms of protein digestibility –corrected amino acid score (PDCAAS), which is a combination of thechemical score of the limiting amino acid multiplied by true digestibility ofthe protein. True protein digestibility values were low (61.4, 73.4, 52.6and 80.5 for Terfezia claveryi, Pleurotus ostreatus, Tricholoma terrum and Agaricus macrosporus, respectively). Based onthe essential amino acids pattern requirements for children, the limitingamino acids in P. ostreatus and A. macrosporus protein weresulphur-containing amino acids with chemical scores of 0.61 and 0.50,respectively. However, lysine was the limiting amino acid in the protein ofT. claveryi and T. terreum with chemical scores of 0.71 and 0.67,respectively, and the PDCAAS was 0.43, 0.45, 0.35 and 0.40 for themushrooms types, respectively. Considering the pattern of essential amino acid requirements of laboratory rats, thesulphur containing amino acids were the limiting amino acids in the proteinof T. claveryi, P. ostreatus, T. terreum and A.macrosporus with chemical scores of 0.56, 0.30, 0.34 and 0.25,respectively. The PDCAAS were 0.34, 0.22, 0.17 and 0.20,respectively. It is concluded that the four mushroom types studied are of lowprotein quality.     

Relationship between amino acid scores and protein quality indices based on rat growth

Protein efficiency ratio (PER), relative PER (RPER), net protein ratio (NPR) and relative NPR (RNPR) values, and amino acid scores were calculated for 20 food products (casein, casein + Met, beef salami, skim milk, tuna, chicken frankfurters, sausage, heated skim milk, peanut butter, rolled oats, soy isolate, chick peas, pea concentrate, kidney beans, wheat cereal, pinto bean, lentils, rice-wheat gluten cereal, macaroni-cheese, and beef stew). In most cases, PER, RPER, NPR or RNPR ranked the products in the same order and positive correlations among the protein quality methods were highly significant (r=0.98–0.99). Amino acid scores (based on the first limiting amino acid, Lys-Met-Cys, Lys-Met-Cys-Trp or lys-Met-Cys-Trp-Thr) were positively correlated to the PER, RPER, NPR or RNPR data (r=0.61–0.75). Inclusion of the correction for true digestibility of protein improved the correlations between amino acid scores and the indices based on rat growth. The correlations were especially high between Lys-Met-Cys scores (corrected for true digestibility of protein) and PER, RPER, NPR or RNPR (r=0.86–0.91). Inclusion of the correction for true digestibility of individual amino acids did not result in further improvements of the correlations in most cases. It is concluded that adjusting amino acid scores for true digestibility of protein would be sufficient and further correction for digestibility of amino acids would be unnecessary in mixed diets.This paper was presented in part at the 71st annual FASAB meeting, Washington, DC, March 29–April 2, 1987.     

Nutrient content of young cassava leaves and assessment of their acceptance as a green vegetable in Nigeria

Cassava (Manihot esculenta Crantz) leaves contained a high level of crude protein (29.3–32.4% dry weight) compared to a conventional vegetable,Amaranthus (19.6%). Ash was 4.6–6.4% in cassava leaf samples but 13.1% dry weight inAmaranthus. Dietary fibre was very high in all samples (26.9–39% dry weight) while HCN-potential was low (5.1–12.6 mg/100 g dry weight). Tannin was the highest in IITA red cassava leaves (29.7 mg/g) and the lowest inAmaranthus vegetable. In vitro digestibility was very low in oven dried samples (15.6–22.7%). Blanching increased protein content (exceptAmaranthus) and in vitro protein digestibility but decreased ash, minerals, dietary fibre and tannin, while HCN-potential was unchanged. Grinding reduced both HCN-potential and tannin by 84 and 71% respectively while oven drying only reduced the HCN content marginally. Preference studies showed that the highest percentage of respondents (25.3%) preferredAmaranthus vegetable, followed by Celosia (17.5%), Talinum (12.4%), garden egg (11.5%), with cassava leaves as the least (0.5%). Organoleptic evaluation rated cassava leaf soup inferior toAmaranthus in terms of appearance, colour and texture but equal in terms of taste and flavour and overall acceptability.