NMR study of galactomannans from the seeds of mesquite tree (Prosopis juliflora (Sw) DC)

The seed gum from Prosopis juliflora is a galactomannan polysaccharide, which is located in the endosperm. Regarding P. juliflora galactomannan structural studies, there are reports on galactose substitutional pattern, but supporting data by NMR correlation studies are scarce. In this work, a procedure to obtain P. juliflora gum without contamination was employed and the gum was studied by NMR spectroscopy. Overall, results show that mesquite seed has a 1.1:1 Man/Gal ratio.     

Comparison of post‐germination mobilization of cell wall polysaccharides and non‐cell wall carbohydrates in soybean (Glycine max L.) cotyledons

BACKGROUND: In previous research, we demonstrated that cell wall polysaccharide (CWP) levels of soybean (Glycine max L.) cotyledons are negatively correlated with the sum of seed oil and protein content. Although the results suggest that reducing cotyledon CWP levels would be desirable, it is not known whether CWP are mobilized during early seedling growth and, if so, to what extent mobilization contributes to seed reserves. RESULTS: Ungerminated (dry) seeds contained equivalent amounts [approximately 20 mg (cotyledon pair)^?1] of non‐cell wall carbohydrates (NCWC) and CWP. Galactose and arabinose accounted for 47% of total CWP in cotyledons of dry seeds. Measured 14 days after planting (DAP), the levels of NCWC and CWP were reduced 98% and 34%, respectively, in cotyledons of seedlings grown under a 16‐h photoperiod. Measured 14 DAP, greater than 85% of cotyledon cell wall galactose plus arabinose was mobilized. The transformation of the cotyledon to a photosynthetic organ was associated with restructuring of the cell wall involving increases in uronic acids, glucose and rhamnose. CONCLUSION: CWP of soybean cotyledons are modified during early seedling growth due to mobilization and cell wall restructuring triggered by light. The amount of carbon mobilized makes only a small contribution to total cotyledon reserves. Published 2009 by John Wiley & Sons, Ltd.     

Physicochemical characterization and functional properties of galactomannans from mesquite seeds (Prosopis spp.)

In the present study, the physicochemical and functional characteristics of galactomannans (GM) from mesquite seeds were investigated and compared with the characteristics of a commercial GM. The mesquite gum was extracted with water at room temperature, and its physicochemical parameters, thermal constants and functional properties were determined. The results showed that mesquite GM had contents of 2.56% moisture, 4.54% protein and 0.06% ash; trace levels of fat; 95.40% total carbohydrate; +63.48 optical rotation; an intrinsic viscosity of 12.36 dL/g and a molecular weight of 1.2 × 10⁶ g/mol. The sugars detected were mannose (Man) and galactose (Gal), with a Man:Gal ratio of 1.50. The curves obtained by calorimetry indicated a transition temperature (Tg), melting temperature (Tm) and heat capacity (Cp) very similar to those of the guar GM. The evaluation of the functional properties of the mesquite GM revealed a solubility of 92.10%, an emulsion capacity of 95% and an emulsion stability of 92.24%. The polysaccharide extracted from the mesquite seeds is a GM with physicochemical and functional properties similar to those reported for other legume seed gums, allowing us to conclude that mesquite GM has the potential for use in the food industry.     

莲子发芽对其功能及化学特性的影响

将莲子浸泡于水中,放置不同时间(24、36h和48h)和温度(25℃和35℃)促进其发芽,以未发芽莲子为空白对照,比较发芽种子化学和功能特性的变化。种子发芽导致胚乳中粗蛋白质和粗脂肪(P＜0.05)显著增加,而灰分和水分含量则没有可观测到的显著变化,其他成分除了植酸显著增加(P＜0.05)外,总酚、单宁和儿茶酚类物质的含量显著降低(P＜0.05)。发芽莲胚乳粉的吸水能力、吸油能力、乳化活性以及起泡性增加,而蛋白质溶解性下降(P＜0.05)。此外,发芽后莲心的总酚类化合物(P＜0.05)、总黄酮和酚类生物碱(甲基莲心碱、莲心碱、异莲心碱)含量都显著增加。因此,萌发可以增加莲子胚乳的营养质量和功能性质,而降低其抗营养性质,同样发芽能提高莲心酚类生物碱的含量。研究说明莲子发芽是改善莲子和莲心的营养质量好的方法。     

Preliminary studies of the germination behaviour of guinea corn (Sorghum vulgare)

Sorghum seeds (Sorghum vulgare, variety Sorghum bicolor L181) were germinated in the dark for 12, 18, 24, 36, 48, 54, 60 and 66 h respectively. Optimum moisture content for germination was between 35 and 40%. Active germination and growth were assessed in terms of soluble carbohydrate and total starch in the seedling. Germination occurred between 15 and 30°C with an optimum at 22°C.     

Water uptake and its impact on the texture of lentils (Lens culinaris)

Water uptake behavior of three cultivars of lentils (Boomer, French-green and Nugget) was studied at three different hydration temperature regimes (room temperature, 50 °C and 85 °C). Boomer had the highest amount of water uptake capacity (74.60 g water/100 g of seeds) at room temperature (20 °C) which can be linked with its pore properties. French-green lentils imbibed the largest amount of water at elevated soaking temperatures (50 °C and 85 °C) and can be attributed to its higher seed surface area to volume ratio, high protein content and relatively thinner seed coat. Water uptake at elevated temperatures (50 °C and 85 °C) were predicted by a two parameter Mitscherlich model (R² > 0.99, χ² < 0.5) within 1.36–3.07% average absolute error. At room temperature, only the water uptake of Boomer was reasonably predicted by this model. The texture (hardness) of the soaked lentils was found to be related the amount of water uptake and soaking temperature used rather than seed size or seed mass alone. The hardness values of Boomer, French-green and Nugget at 85 °C after 75 min soaking were reduced to 5.66%, 3.53% and 6.77%, respectively compared to their respective initial seed hardness values. The water uptake capacity of the aged Boomer was found to be significantly reduced compared to the fresh seeds (p < 0.01) while French-green and Nugget do not exhibit significant change (p < 0.05). During 72 h of germination, hardness of all lentil cultivars showed a typical pattern which decreased in the first 24 h followed by an increase compared to the hydrated seeds. A peak hardness value was obtained within 36–48 h before finally declining in all types of lentils. Structural changes within the cotyledon, such as depletion of starch granules, new nuclei formation and development of tissues in vascular bundles and rupture of the seed coat were observed during germination.     

Characterisation of Chilean hazelnut (Gevuina avellana) tissues: light microscopy and cell wall polysaccharides

By applying several differential staining techniques and light microscopy, the structure and composition of Chilean hazelnut (Gevuina avellana) seeds were analysed. The structure of the G avellana seed is very simple, with a thin, heavily lignified seed coat and two voluminous cotyledons. The embryo food reserves are uniformly distributed over the cotyledon cells. The cell wall polysaccharides were recovered from the alcohol‐insoluble residue by mild treatment with warm chlorite solution and sequential extraction with alkali solutions of increasing concentration. FT‐IR spectra in the 1200–850 cm^?1 region were used together with chemometric techniques to distinguish the hemicellulosic and pectic polysaccharides in the extracts. The most abundant extracts were fractionated by graded precipitation in ethanol. A xyloglucan was identified by ¹H and ¹³C NMR as the major hemicellulosic polysaccharide, with a sugar composition of 4Glc:3.5Xyl:1Gal:0.5Fuc. The hazelnut cell walls are composed of equivalent amounts of pectic polysaccharides, xyloglucans and cellulose. © 2003 Society of Chemical Industry     

Effect of seed treatments on the chemical composition and properties of two amaranth species: starch and protein

The seeds of two Amaranth species were studied. The starch contents were 543 and 623 g kg^?1 while crude protein contents were 154 and 169 g kg^?1 for Amaranthus caudatus and Amaranthus cruentus seeds, respectively. The effect of several treatments, including cooking, popping and germination and flour air classification on the protein and starch properties were studied. Air classification decreased the starch content and increased the protein content, while heating increased the protein but did not affect the starch content. Germination decreased both starch and protein contents. Amylose content was increased by air classification and heating, but was not affected by germination. It was found that all treatments increased the starch swelling power and reduced the falling number. The resistant starch content was increased in the high protein flour (HPF) fraction and germinated flour compared with the raw flour, while its content decreased in the heat treated seed flours. These processes also affected the starch gelatinization temperature and peak viscosity. The thermal properties of the starch flour were not affected by air classification while gelatinization energy was decreased significantly (by 52.0 and 90.0% and by 70.0 and 95.0%) in cooked and popped A caudatus and A cruentus seed flours, respectively. The gelatinization energy was highest in germinated seeds dried at 90 °C with values of 2.67 and 3.87 J g^?1. Air classification reduced the level of all protein fractions. Thermal treatment decreased the water‐soluble fraction (albumins + globulins) and alcohol‐soluble fraction (prolamins) in both species. The levels of all fractions except the water‐soluble fraction (albumins + globulins) were reduced significantly in both species by germination, which mainly increased the amount of aspartic acid, serine and alanine, while the amounts of threonine, arginine and tyrosine decreased in both species. The polypeptide bands of the HPF in both species were unchanged compared with the raw seed flours, but more intensive coloured bands were observed. Thermal treatments eliminated major and minor bands above 35.0 KDa in both species. Copyright © 2004 Society of Chemical Industry     

Protein and Starch Digestibility and Flatulence Potential of Germinated Cowpeas (Vigna unguiculata)

In vivo and in vitro methods with experimental rats and commercial digestive enzymes, respectively, were used in assessing the protein and starch digestibility and flatulence potential of germinated cow-peas. Germination (24 hr at 25° or 30°C) reduced the flatulence potential of seeds (52 to 77%). In vivo digestibility of starch and protein was also significantly increase by germination. Germination did not affect in vitro protein digestibility, but reduced in vitro digestibility of freeze-dried and 70°C-dried starch. Cooking in boiling water significantly increased in vitro protein and starch digestibility of both ungerminated and germinated seed.     

Immunological investigation of lipases in germinating oilseed rape,Brassica napus

An anti-lipase antibody has been used to investigate the lipases of cotyledons from germinating seedlings of oilseed rape, Brassica napusL, var Mikado. Immunological and enzymic assays revealed that lipases were confined to germinating seeds and were absent from other tissues, such as developing seeds, leaves, roots and flowers. The antibody totally inhibited microsomal lipase activity at a ratio of 12 μg IgG protein: 10 μg microsomal protein. It was shown by immunoblotting of microsomal, oil-body and total cotyledon proteins separated by gel electrophoresis that, in each case, the antibody specifically bound to a single polypeptide. This polypeptide had an electrophoretic mobility consistent with a molecular weight of 56 kDa. The appearance and subsequent decline of the 56 kDa polypeptide during the first 10 days of germination closely followed that of the lipase activity, both in microsomal protein and total cotyledon protein fractions. An ELISA for the lipase demonstrated that the amount of immunoreactive microsomal lipase present at each stage of germination was proportional to its enzymic activity. The enzymic and immunological activities of the microsomal lipase each exhibited buoyant densities of 1.087 g ml^?1 on sucrose density gradients. Lipases were present in only very small amounts in dry seeds and were synthesised de novo after 2–3 days of germination.     

Chemical changes and diastatic activity in grains of sorghum (Sorghum bicolor) cultivars during germination

Grain samples from nine sorghum (Sorghum bicolor (L) Moench) cultivars were germinated for 16, 48, 96 and 144 h, and changes in their diastatic activity, protein, starch, soluble sugars, tannin and total phenols contents were studied. The diastatic activity increased up to 96 h of germination and decreased at 144 h. Diastatic activity showed significant variation among cultivars, which ranged from 10.0 to 88.3 units at 48 h and from 20.0 to 150.4 units at 96 h germination. In general, starch content decreased while soluble sugars increased during germination. Variation in protein content during germination was appreciable among the cultivars.     

Soluble Carbohydrates Oligosaccharides and Starch in Lima Bean Seeds

Seven genotypes of lima bean seeds at three maturity stages were analyzed by HPLC for the monosaccharide, fructose; the disaccharide, sucrose; the oligosaccharides, raffinose, stachyose, and verbascose; and the polysaccharide, starch. As maturity and size of the seeds increased, the concentrations of fructose and sucrose decreased while raffinose, stachyose and verbascose increased. No significant differences were found in the starch concentration. The concentration of the carbohydrates did not correlate with cotyledon color, seed color or growth habit. Sufficient variability existed in the oligosaccharide concentration in the investigated genotypes that reduction of the flatulence promoters (raffinose, stachyose and verbascose) might be possible by breeding.     

Proximal composition and in vitro digestibility of starch in lima bean (Phaseolus lunatus) varieties

BACKGROUND: Beans are rich and inexpensive sources of proteins and carbohydrates around the world, but particularly in developing countries. However, many legume varieties are still underutilized. In this study, physical characteristics of the seeds of three Phaseolus lunatus cultivars were characterized. Also, the chemical composition and starch digestibility in the cooked beans were assessed. RESULTS: ‘Comba floja’ variety exhibited the highest thousand‐kernel weight whereas the lowest was found in ‘comba violenta’. This agrees with seed dimensions: ‘comba floja’ had the Longest seeds (16.36 mm) and ‘comba violenta’ the shortest ones (13.98 mm). All samples exhibited high protein content, but levels in ‘comba blanca’ variety (216 g kg^?1) were lower than the in other two cultivars. Total starch (370–380 g kg^?1) and potentially available starch content (330–340 g kg^?1) were similar in the three varieties. Resistant starch level in the cooked seeds ranged between 38 and 45 g kg^?1. Low enzymatic hydrolysis indices (HI) were recorded (30.2–35%), indicating a low digestion rate for Phaseolus lunatus starch. HI‐based predicted glycemic indices ranged between 34% and 39%, which suggests a ‘slow carbohydrate’ feature for this legume. CONCLUSION: Phaseolus lunatus beans appear to be a good source of protein and slow‐release carbohydrates with potential benefits for human health. Copyright © 2007 Society of Chemical Industry     

Hydrothermal treatments of two cowpea (Vigna unguiculata L. Walp) varieties: effect of micronisation on physicochemical and structural characteristics

The effects of a hydrothermal treatment consisting of tempering (to 41% moisture) and heating to 153 °C (micronisation) on the structural and physicochemical characteristics of two cowpea varieties were studied. The untreated varieties had similar cooking times, although cooked Bechuana white cowpeas were significantly (P ≤ 0.05) softer and had a higher incidence of splitting than Var. 462 cowpeas. This may be due in part to differences in cotyledon structure affecting water uptake during cooking. The hydrothermal treatment changed the physical structure and chemical properties of the cowpea seeds. This led to significant (P ≤ 0.05) reductions in the cooking time of micronised Bechuana white and Var. 462 cowpeas, by 47 and 36% respectively, as compared with control samples. Micronisation caused physical fissuring of the seed coat and cotyledon and significantly (P ≤ 0.05) reduced the bulk density of treated seeds. These changes in the physical structure significantly (P ≤ 0.05) improved the initial water uptake during soaking and cooking, increased the enzyme‐susceptible starch and reduced the protein solubility and hydration capacity of the cowpea seeds. Cooked (60 min) micronised cowpeas also had significantly (P ≤ 0.05) more splits and a significantly (P ≤ 0.05) softer texture than control samples. Copyright © 2005 Society of Chemical Industry     

Gamma irradiation of cowpea (Vigna unguiculata L. Walp) seeds: effect on colour,cooking quality and pasting characteristics

Cowpea seeds were treated to various gamma irradiation doses, and their colour, cooking quality and pasting properties studied. Irradiation at 50 kGy resulted in significant browning (indicated by decreases in L colour value) of cowpea seeds. At 2 and 10 (but not at 50) kGy, irradiation led to significant reduction in cooking time of cowpea seeds possibly through irradiation‐induced degradation of starch and pectic substances (indicated by decreases in peak and final viscosities) leading possibly to enhanced heat and mass transfer within the seed cotyledon and cell wall, respectively. At 50 kGy, the cooking time of cowpea seeds was prolonged significantly owing possibly to extensive polymer cross‐linking occurring within the seeds at this high dose. Splitting of cowpea cotyledons during cooking decreased significantly at 50 kGy, but was unaffected at 2 and 10 kGy. Irradiation resulted in significant leaching of nutrients from cowpea seeds during cooking in a dose‐dependent manner.     

Changes in carbohydrates and the activity of α-galactosidase,pentosanase and lipase during germination of groundnuts (Arachis hypogea)

The quantitative changes in carbohydrates of two varieties (i.e., red netal and HG-4) of groundnuts during germination have been investigated. On germination, raffinose, stachyose and verbascose decreased gradually up to 48 h and almost disappeared completely in later stages of germination (140 h). Glucose and fructose levels increased 4–6 fold; while sucrose content increased considerably throughout germination in both the varieties of groundnuts. The starch content increased about four fold during germination in both the varieties. The pentosan content was almost constant up to 36 h but decreased in later stages of germination. The oil content decreased significantly from 52 to 8.0%. The fairly high initial α-galactosidase and lipase activity in resting seeds, increased considerably during germination in both the varieties studied. On the other hand the pentosanase activity was not detected up to 36 h of germination but it appears to increase abruptly afterwards.     

Nutritional quality of storage proteins during germination of Indian bean (Dolichos lablab. var. lignosus) seeds

The dry Indian bean seed composed of starch is the major component (33%) and protein accounted for 25% of dry weight. The ability of germination to increase the nutritional quality of storage proteins was studied by germinating the Indian bean seeds for 0, 8, 16, 24 and 32 h and evaluated the nutritional quality through an in vitro protein digestibility (IVPD), protein efficiency ratio (PER), apparent and true digestibility. The IVPD of raw Indian bean seeds by pepsin alone was 60.12% and the digestibility by pepsin and trypsin together improved to 64.24%. The in vitro digestibility by both processes increased appreciably with germination and marked increase was noticed in the early stage of germination. The PER values followed the same pattern as the value of weight gain of rats fed with diets containing raw and germinated Indian bean. The lowest PER values were observed with raw bean diet. However, the value increased in rats fed with diets of Indian bean germinated for different intervals of time, reaching comparable PER values with the group maintained on casein diet. The true and apparent nitrogen digestibility of raw bean low being only 82 and 72%, respectively observed with casein diet. Diets with germinated bean protein showed a marked increase in both parameters, although the values were still less than that displayed by the casein fed rats. Germination is a simple biochemical enrichment tool and significantly improves palatability, digestibility and the nutritive utilisation of proteins in Indian bean seeds.     

藜麦发芽过程中蛋白质与皂苷及淀粉消化特性的变化规律

发芽是改善谷物质构及其营养价值的一种高效的加工方式。本文研究了藜麦发芽过程中蛋白质与皂苷及淀粉消化特性的变化规律。结果显示,发芽显著地提高了藜麦中粗蛋白和可溶性蛋白含量,分别增加了5.38%和17.55%。随着发芽时间不断增加,藜麦总淀粉、直链淀粉及支链淀粉含量分别减少25.95%、4.86%和29.53%,而还原糖含量增加了26.60%。发芽处理显著改善了藜麦种子的淀粉消化性能。发芽前藜麦种子中快消化淀粉、慢消化淀粉及抗性淀粉的百分含量分别为38.45%、43.64%和17.90%。发芽48h后,快消化淀粉的百分含量显著地增加至53.46%,而慢消化淀粉及抗性淀粉的百分含量分别下降至40.42%和6.11%。此外,发芽后藜麦种子中总皂苷含量显著增加了16.46%。研究表明,发芽的藜麦种子含有更好的营养价值和消化性能,可以用于加工功能性食品,促进人体健康。     

Occurrence of phenolic compounds in the seed coat and the cotyledon of peas (Pisum sativum L.)

This work determined the phenolic composition of the seed coat and the cotyledon of two varieties of dark peas (Pisum sativum L), Fidelia and ZP-840, by HPLC-PAD and HPLC-MS. High concentrations of glycosides of quercetin, luteolin and apigenin were found in the seed coat of both varieties of peas. Minor concentrations of monomers and dimers of proanthocyanidins were identified. The cotyledon mainly contains hydroxybenzoic and hydroxycinnamic compounds and some of the flavone and flavonol glycosides found in the seed coat. Two conjugated compounds with malic acid, trans p-coumaroyl-malic acid and p-hydroxybenzoyl-malic acid were identified in the cotyledon and in the seed coat, and the stilbene trans-resveratrol-3-glucoside, only in the seed coat. These compounds had not been previously reported in peas. The results obtained allow an overview of the distribution of the phenolic compounds in the seeds of these varieties of peas, and contribute to the knowledge of the implications of these compounds in the dietary intake.     

Distribution of fatty acids in edible organs and seed fractions of borage (Borago officinalis L.)

BACKGROUND: Borage (Borago officinalis L.) is currently used as a vegetable in the north of Spain. The edible parts of the plant are the petioles, leaves and stems. The objective of this study was to determine the oil and fatty acids content in the edible tissues (leaves, petioles and stems) and seed fractions (endosperm + cotyledon, seed coat and elaiosome) of white‐ and blue‐flowered borage accessions. RESULTS: Leaves showed higher mean values of oil content (2.7%) than petioles and stems (1.1% and 1.4%, respectively) in both, blue‐ and white‐flowered material. The most abundant fatty acids in leaves were palmitic, linoleic, α‐linolenic and stearidonic acids (about 75% of the total fatty acids), while in petioles and stems myristic and linoleic acids were most abundant (about 60% of the total fatty acids). Palmitic, oleic, linoleic and γ‐linolenic (GLA) acids were the major fatty acids of seed coat and endosperm + cotyledon in borage seeds (85% of the total fatty acids), while palmitic, stearic, oleic and linoleic acids were the most abundant fatty acids of elaisome in borage seeds (80% of the total fatty acids). CONCLUSION: This paper shows that green parts of borage contain substantial amounts of omega‐3 and omega‐6 fatty acids, which are essential fatty acids for animal and human nutrition. Thus, borage could be a ‘power food’ of the future because of its content of unsaturated fatty acids, particularly the essential fatty acids, which have great potential to prevent cardiovascular disease, cancer and infectious diseases. Copyright © 2007 Society of Chemical Industry