Nutritional assessment of yam (Dioscorea alata) tubers

The nutrient and antinutrient components of tubers from seven cultivars ofDioscorea alata were determined. The average crude protein content ofD. alata tubers was 7.4%. Starch (75.6–84.3%) was the predominant fraction of the tuber dry matter. Significant differences in crude protein and starch contents were observed among cultivars. Vitamin C content of the yam tubers ranged from 13.0 to 24.7 mg/100 g fresh weight. The results showed yams to be reasonably good sources of minerals. Phytic acid contents of the yams were low, with values ranging from 58.6 to 198.0 mg/100 g dry matter. Total oxalate levels in yam tubers were found to be in the range of 486–781 mg/100 g dry matter, but may not constitute a nutritional concern since 50–75% of the oxalates were in the water-soluble form. The overall results are suggestive of the nutritional superiority of yams compared to other tropical root crops.     

Composition and variation in vitamin C,carotenoids, protein,nitrate and oxalate contents inCelosia leaves

Twenty two lines/accessions belonging to 5 species ofCelosia were analysed for their nutritional and antinutritional composition. The nutrient contents, vitamin C varied from 18.8 to 53.6 mg/100 g, carotenoids 9.1 to 15.1 mg/100g, protein 2.1 to 5.9%, while the antinutritional factors, nitrate 0.18 to 0.46% and oxalate 0.98 to 3.93%. Moisture ranged 81 to 89%. Variation of these parameters with leaf position and the amino acids profile of some promising lines was also evaluated.     

Effect of blanching on the content of antinutritional factors in selected vegetables

The effect of blanching on the antinutritional content was studied in cabbage, turnip, collard, sweetpotato and peanut leaves. All the vegetables contained various amounts of phytic acid, tannic acid and/or oxalic acid. Tannic acid was found in largest amounts ranging from 1266.00 mg/100 g in cabbage to 491.00 mg/100 g in sweetpotato. Phytic acid content ranged from 0.31 mg/100 g in sweetpotato to 3.97 mg/100 g in collard. Oxalic acid was in trace amounts in cabbage and turnip; but high concentrations were found in sweetpotato (469.67 mg/100 g) and peanut greens (407.00 mg/100 g). Levels of both tannic acid and phytic acid were significantly (p<0.05) reduced by conventional and microwave blanching methods while oxalic acid levels were not significantly (p<0.05) reduced in most of the treatments by either of the blanching methods. In general, blanching is recommended as an effective method for reducing the antinutritional factors in green vegetables, however, further investigation on the heating times for both conventional and microwave blanching methods has been suggested.     

Chemical analysis and nutritional assessment of Teramnus labialis (L.) Spreng. (Fabaceae)

Seeds of Teramnus labialis (L.) Spreng.(Fabaceae), used as food by Malayali tribals in theKollihills of Salem District, Tamil Nadu in SouthIndia, were investigated for their nutritional value. These seeds were analyzed for proximate composition,total (true) seed proteins, seed proteinfractions, amino acid composition, fatty acidcomposition, minerals and antinutritional factors. Crude protein, crude fat, ash, and nitrogen freeextracts constituted 22.86%, 6.10%, 4.62%, and,58.15%, respectively, of the seed weight. The caloricvalue of 100 g dry matter of seed material was 378.94kcal. The essential amino acids lysine, leucine +isoleucine, arginine, valine and histidine werepresent in relatively large quantities. Theunsaturated fatty acids constituted more than 60% ofthe crude fat. Concentrations of minerals such aspotassium, magnesium, calcium, and, phosphorus werehigh. Antinutritional factors such as total freephenols, tannins, L-DOPA, hydrogen cyanide andphytic acid were present in minute quantities. Theseantinutritional factors are potentially eliminated using the conventional method of soaking the seeds in water,boiling with water and decanting prior to consumption.     

Chemical composition of purslane (Portulaca oleracea)

Purslane (Portulaca oleracea), grown under greenhouse conditions, was harvested at three growth stages and analyzed for total solids, total protein, ash, soluble carbohydrate, and fructose/fructane in whole plants, leaves, stems, and roots. Significant increases were observed in total solids and protein during plant maturation. Leaves had the highest amount of protein in the third growth stage (44.25g/100g dry matter). Roots showed a decline in protein level as the plant aged. Soluble carbohydrate was significantly higher in growth states 1 and 3. Significant variation among growth stages was found with regard to total phosphorous, calcium, potassium, iron, managanese, and copper. Total phosphorus (P) content in leaves was significantly higher than P found in stems and roots. Iron (Fe) content varied significantly among growth stages, and roots and leaves had the highest Fe content (121.47 and 33.21 mg, respectively). Significant accumulation of managanese (Mn) was found in different growth stages. Leaves and roots had significantly higher Mn content than stems.     

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.     

Effect of plant age and severity of defoliation on regrowth of sheep's burnet during substrate moisture depletion

Regrowth of 3- and 4-month old (‘young’ and ‘old’ respectively) sheep's burnet [Sanguisorba minor ssp. muricata (Spach) Briq.] was studied under limiting and non-limiting moisture conditions in a glasshouse. Moisture deficits were imposed by using a single cycle of withholding moisture until first wilting. Plants of each age were defoliated severely at three levels which represented approximately 80–100% canopy removal. These levels were based on the proportion retained of the eight most mature leaves on each plant and were referred to as complete [0% residual leaf area (rLA)] and partial [50% rLA (four leaves) and 100% rLA (eight leaves)] defoliation. Vegetative growth and total non-structural carbohydrate (TNC) levels were studied. Leaf number (0-8 leaves), area (0-115 cm²) and dry weight (0-1·0 g) differed (P < 0·05) between defoliation intensities at the start of regrowth, while stubble (1·2 g) and root (12.·6 g) dry weights were similar. Soluble sugars [< 6% dry matter (DM)] and starch (< 1% DM) occurred in leaf, stubble and root. Old plants were morphologically and physiologically more developed than young plants. For example, stubble (2·0 g) and root (21·5 g) dry weights of old plants were greater (P < 0·05) than those of young plants (04 and 3·7 g respectively). Defoliation intensity had a major effect on regrowth, with completely defoliated plants at the final harvest having leaf numbers (forty-nine leaves) and areas (235 cm²) almost twice those of partially defoliated plants. Stubble soluble sugar levels (38% DM) were lower than those of partially defoliated plants (5·5% DM), and it was suggested that these contributed to regrowth. Moisture regime had a negligible influence on plant growth. However, plants in the dry regime had soluble sugar levels 1·4 (stubble) -1·7 (roots) times higher than those watered adequately, which suggested that plants adjusted to the water depletion. The effects of plant age on regrowth were similar for most characters, but the larger and physiologically more mature old plants would probably be more tolerant of successive defoliations.     

Nutrient and antinutrient composition of Amaranthus muricatus

The chemical and nutritional composition of theaerial parts of Amaranthus muricatus wasassessed. This is a wild plant growing well in aridand poor soil, which are not suitable for cereals. Thematerial under study was boiled, dried and ground andthen evaluated for chemical, nutritional andantinutritional properties. Protein concentration ofthe amaranth flour was 15.74 g/100 g and total dietaryfiber content was high (53.81 g/100 g), with 79%coming from insoluble dietary fiber. The calciumcontent was 1533 mg/100 g and the Ca/P ratio (5.94)was markedly higher than the value suggested in the1989 Recommended Dietary Allowances. Fifty-ninepercent of the fatty acids present were unsaturatedwith linoleic acid accounting for 40% of the totalfatty acid content. Nitrate, hemagglutinin, trypsininhibitor and saponin contents were within thenon-critical values. Net protein utilization (NPU),true digestibility (tD) and biological value (BV)measurements indicated a nitrogen gain of 74% that ofcasein. The results of this study indicate a nutritivepotential for the A. muricatus leaves, therefore,domestication of this plant is suggested along withassessment of its chemical and nutritionalproperties.     

Protein extraction from Atriplex lampa leaves: Potential use as forage for animals used for human diets

The purpose of this study was to evaluate the effectof pH on the extraction of protein nitrogen from Atriplex lampa leaves (Moquin) Dietrich. Thechemical characterization of the dry matter indicated thefollowing (g/100 g): protein, 26.93; ash, 21.80; etherextract, 4.65; dry matter, 37.30; sodium, 6.05; and calcium, 0.41.Non-critical values were obtained for saponins andnitrates. The high concentration of oxalic acid (8.52 g/100 g),together with elevated salt content accountfor the low palatability of the studied species.In order to determine the parameters needed to improvethe extraction in protein nitrogen from leaves, freshmaterial was macerated with 2% sodium metasulfite,followed by pulping with a hand-driven grinder.Extractions were performed at different pH values(2–12) adjusting the value with 5N HCL or NaOH, withagitation followed by centrifugation and pressing.Supernatants were collected and kept. The lastextraction was performed with Tween 20 in order toobtain maximum nitrogen recovery from the residuecake. Highest extraction (41.23%) was obtained at pH10 with a 1:5 ratio (leaf : deionized water, w/v). Itis proposed that this regional natural resource may beused to elaborate a protein concentrate, which can bemade more palatable by decreasing potassium and sodiumsalt content with the use of membrane technology.     

The biochemical composition and nutritional potential of the tribal pulse,Mucuna gigantea (Willd) DC

Seeds of the tribal pulse,Mucuna gigantea, were analysed for proximate composition, total (true) seed proteins, seed protein fractionation, amino acid composition, minerals and antinutritional factors. Crude proteins, crude lipids, ash and nitrogen free extractives constituted 30.62%, 9.03%, 5.99% and 42.79%, respectively. The calorific values of 100 g dry matter of seed material is 374.91 kCal. The essential amino acids, leucine +isoleucine, are present in relatively large quantities. The seeds are rich in minerals like K, Ca, Mg and Fe. Antinutritional substances like total free phenols and tannins, trypsin inhibitor activity and haemagglutinating activity also were investigated.     

Nutrient and antinutrient profiles of raw and fermented cocoa beans

Freshly harvested cocoa bean was subjected to natural fermentation for 3, 6, 9 or 12 days. The proximate, mineral, hydrocyanate (HCN), oxalate and theobromine levels in the products were determined and compared with those of raw (unfermented) cocoa. The latter sample had the following composition: protein (N×6.25), 17.5; lipid, 62.9; ash, 4.4; fibre, 5.9; and nitrogen-free extract (NFE), 9.3% dry matter. The effect of fermentation was variable, depending on duration and the nutrient under consideration. At day 3, protein content (17.6) was not different, but at day 6 (19.8) was higher (p<0.01), while days 9 and 12 (14.6 and 15.2, respectively) were lower (p<0.01) in comparison with the raw value. Inorganic P steadily decreased from 201.0 (raw) to 102.0 mg/100 g dry matter (day 12) but only the days 9 and 12 values were significantly different (p<0.05), whereas Ca increased from 29.2 (raw) up to 60.4 mg/100 g dry matter (day 3). The antinutrients, HCN, oxalate, and theobromine decreased with increasing duration of fermentation. The decreases for days 6, 9 and 12 were significant (p<0.05). The results are discussed with regard to optimization of the duration of cocoa fermentation for improved nutrient profile.     

Analysis of Flavonoids from Leaves of Cultivated <Emphasis Type="Italic">Lycium barbarum</Emphasis> L.

Leaves of Lycium barbarum are widely used as medicine vegetables and functional tea in China. The main flavonoids present in the leaves were separated and identified by high performance liquid chromatography (HPLC), liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-(APCI) MS) and ultraviolet-visible spectra with shift additives. The predominant flavonoid was identified as rutin. Leaves are the rutin-rich parts (16.03–16.33 mg/g). In the wild and cultivated L. barbarum fruits, contents of rutin were determined very low (0.09–1.38 mg/g). The contents of total flavonoids (21.25 mg/g) of cultivated L. barbarum leaves were much higher than those in the wild L. barbarum leaves (17.86 mg/g), so cultivated barbarum leaves are a suitable source for medicine vegetables and functional tea.     

An evaluation of the effect of Bacillus cells and Bacillus spores in association with cowpea granules as starter cultures for the fermentation of African oil bean (Pentaclethra macrophylla Bentham) to `ugba'

Studies on the improvement of the traditional production of `ugba',a protein-rich fermented African oil bean seed product, were undertaken,by developing starter cultures of Bacillus subtilis cells andspores in association with cowpea granules. The viability of the cellsin association remained stable at 94.5% for 6 months at 30 <sup>°</sup>C and for up to 10 months at 4 <sup>°</sup>C while the viability of the sporesin association remained stable at ca. 96% for up to 10 months at both4 and 30 <sup>°</sup>C. The starter cultures resulted in high increases inprotease activity from ca 2.8 mg N/min to about 51.6 ± 0.4 mg N/minin 48 h and a corresponding increase in amino-nitrogen content of ca2.0 ± 0.2 mg N 100 g dry matter (DM) to ca 18.5 ± 0.3 mg N/100g (DM) during the same period. Changes in the protease activity of thenatural process were gradual and increased from 3.0 mg N/min to 38.0 ±0.8 mg N/min after 5 days of fermentation. The maximum amino nitrogencontent of `ugba' produced by the starter cultures (18.5 ± 0.3 mgN/100 g DM) after 2 days was significantly (p < 0.05) higher than themaximum amino nitrogen content (12.5 ± 0.8 mg N/100 g DM), of `ugba'obtained by the natural process. `Ugba' produced by the starter cultureswere well accepted and compared favorably with the natural product.     

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.     

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.     

Einfluss von Lagerung und Sorte auf die Verteilung der Glykoalkaloide in der Kartoffelknolle

Zusammenfassung Fünf Speisekartoffelsorten wurden w?hrend einer sechsmonatigen Lagerung fünfmal auf α-Solanin und α-Chaconin untersucht. Es wurden vier Gewebebereiche der Knolle getrennt überprüft. Der Gesamtglykoalkaloidgehalt betrug im Augenbereich 164, in der restlichen Schale 101 und in der Gef?ssbündelzone mit ?usserem Speichergewebe 8mg/100g. Trockensubstanz. Im restlichen Innenk?rper waren nur noch Spuren (0.164mg/100g TS) nachzuweisen. Zwischen den Sorten und diesen Gewebepartien traten statistisch gesicherte Wechselwirkungen auf, die im wesentlichen von einer Sorte verursacht wurden. W?hrend der Lagerung sind die Alkaloidgehalte leicht, aber statistisch nicht gesichert gesunken. α-Solanin und α-Chaconin kamen generell im Verh?ltnis von etwa 1∶1.5vor; die Korrelation zwischen beiden Formen ist sehr eng (r=0.865). Bezogen auf die gesamte Knolle lagen die Gesamtglykoalkaloide je nach Sorte zwischen 2.4 und 8mg/100g Frischsubstanz und damit im gesundheitlich unbedenklichen Bereich.

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Summary Five table potato cultivars (Erna, Granola, Gusto, Ulse, Margit) from the same source were examined for their content of α-solanine and α-chaconine during a sixmonths storage period. For the testing and subsequent analysis the tubers were dissected into four kinds of tissues: eye-zone, peel, vascular bundle region, medulla. The total glycoalkaloid content (TGA) in the total tuber mass varied between 2.4 and 8mg per 100g fresh matter depending on cultivar (Fig. 1). Despite significant differences between cultivars (Table 1), all potato cultivars remained within the safe range during the entire storage period. Remarkable differences in TGA per 100g dry matter could be noted in the tuber parts. For the eye-zones a TGA of 164mg was found; the peel region showed 101mg and the vascular bundle zone 8mg. The medulla of the tubers contained only traces of TGA (0.164mg/100g dry matter, Fig. 2). The statistical analysis only revealed significant interactions between cultivars and tuber parts (Table 1), mainly caused by the cultivar Gusto which showed higher contents of α-solanine and α-chaconine in its vascular bundle regions (Figs 3–5). The ratio between amounts of α-solanine and α-chaconine was approximately 1∶1.5, and after eliminating effects of cultivar, storage and tuber parts, the correlation coefficient between amounts was 0.865. This close correlation can be used for breeding. The non-significant, slightly negative effect of the six-months storage period on alkaloid content was noteworthy. It is assumed that only after long storage periods or through inappropriate storage (sprouting of tubers) a significantly higher glycoalkaloid content may be expected.

     

氮钾配比对寒地玉米干物质积累、产量及品质的影响

通过田间小区试验,研究不同氮钾配比对玉米不同生育期和不同器官的干物质积累、分配、运转和产量及对品质的影响。结果表明,施氮量为150 kg/hm2、施钾量为100 kg/hm2的处理在成熟期茎、叶、穗干物质量、阶段子粒干物质积累量、茎部转运量、转运率、贡献率以及玉米子粒产量、子粒蛋白质与淀粉含量均高于其他处理。因此,氮、钾肥施用量为150 kg/hm2和100 kg/hm2有利于寒地玉米的干物质积累、产量及其品质的提高。     

Influence of growth conditions on the value of crisphead lettuce

The marketable and nutritional quality of crisphead lettuce as affected by nitrogen supply, cultivar, and plant age at harvest was investigated in six plantings during 1989 and 1990. The optimum yield of marketable heads was obtained at a total nitrogen supply of 150 kg N per ha although only small differences were observed to the yield at 100 and 200 kg total N per ha. The total nitrogen supply included the amount of mineral nitrogen within the rhizosphere. The incidence of dry tipburn in older leaves was clearly decreased by an increased nitrogen supply, especially at late planting. The content of nitrate was increased and the content of dry matter and vitamin C decreased with increased nitrogen supply. The vitamin C content was higher for the cultivar Marius than for Saladin. As plants got older, the nutritional quality of crisphead lettuce decreased because the content of nutrients, especially vitamin C, decreased with increased plant age at harvest.     

Chemical composition of the underutilized legume Cassia hirsuta L.

Seven accessions of the underutilized legume, Cassia hirsuta L., seeds collected from seven different agroclimatic regions of Tamil Nadu, India, were analyzed for proximate composition, total proteins, protein fractions, mineral profiles and selected antinutritional factors. Crude protein ranged from 15.52 to 20.74%, crude lipid 3.77–7.04%, crude fiber4.68–6.92%, ash 3.98–6.42% and carbohydrates 62.45–70.16%. Energyvalues of the seeds were 1549–1634 kJ/100 g (DM), which are comparable to those of other legumes. Data on seed protein fractions revealed thatglobulins constituted the bulk of the seed protein as in most legumes. Mineralcontents of the seeds showed greater variation. Potassium was the mostabundant mineral (1029–1786 mg/100 g), whereas manganese was low (2.1–2.2 mg/100 g). Antinutritional factors such as total free phenolics,tannins, L-DOPA and lectins were analyzed. The results of the studydemonstrated that the accessions of C. hirsuta seeds collectedfrom Tamil Nadu, India, could be good sources of some important nutrientsfor humans.     

Agrobotanical traits and chemical composition of Cassia obtusifolia L.: A lesser-known legume of the Western Ghats region of South India

Four accessions of the lesser-known legume, Cassia obtusifolia L. (Sickle pod), collected from four different agroclimatic regions of Western Ghats, were evaluated for agrobotanical traits and chemical composition. Amongthe four accessions, the Keriparai accession had the highest values for plant height (cm), number of flowers per cluster, number of pods per cluster, pod length (cm), seeds per pod, seed weight (g) per pod and seed recovery percentage. Crude protein ranged from 18.56–22.93%, crude lipid was between 5.35–7.40%, crude fiber ranged from 6.83–9.45%, ash content ranged from 5.14–5.83% and carbohydrate varied from 57.00–60.69%. Globulins constituted the bulk of the seed protein as in most legumes. Mineral profiles, viz., sodium, potassium, calcium, magnesium, phosphorus, iron, copper, zinc and manganese ranged from 42.92–84.83, 758.05–1555.79, 559.92–791.72, 456.36–709.47, 629.13–947.79, 8.42–12.35, 0.93–2.06, 10.60–30.04 and 2.12–4.12 Mg/100 g seeds flour, respectively. Seed proteins of all accessions exhibited relatively high levels of non-essential and essential amino acids, with the exception of threonine. The in vitro protein digestibility of the legume ranged from 74.66 to 81.44%. Antinutritional substances such as total free phenolics ranged from 0.34–0.66%; tannins were between 0.47–0.60%, L-DOPA content ranged from 0.98–1.34%; trypsin inhibitor activity varied from 11.4–13.5 TIU/mg protein and chymotrypsin inhibitor activity ranged from 10.8–12.3 CIU/mg protein. Phytohemagglutinating activity also was assayed. Inconclusion, the accessions of C. obtusifolia, collected from Western Ghats, South India, could serve as a low-cost source of some important nutrients for humans. The antinutritional factors might have little nutritional significance, if the seeds are processed properly.