High-performance capillary electrophoresis with indirect UV detection for determination of alpha-galactosides in Leguminosae and Brassicaceae

A rapid, easy, and reproducible capillary electrophoresis method for determination of raffinose family oligosaccharides (alpha-galactosides) was developed. Sucrose, raffinose, stachyose, verbascose, and ajugose were determined with indirect UV detection at moderate alkaline pH 9.2, using pyridine-2,6-dicarboxylic acid as background electrolyte in a sodium tetraborate buffer with added cetyltrimethylammonium bromide. The separation efficiency measured by the number of theoretical plates (N) ranged from 1.4 x 10(5) to 2.3 x 10(5). The precision of the method, measured by the relative standard deviation (RSD), was less than 0.53% for the migration times and better than 3.4% for normalized areas (NA), considering all sugars except verbascose (RSD(NA) = 11.8%). Detection limits were about 110 microg/mL, corresponding to 150-320 microM. Relative response factors (RRF) were calculated on the basis of linearity studies and used for quantification of alpha-galactosides in a lupine sample (Lupinus angustifolius).     

Chromatographic fingerprinting of <Emphasis Type="Italic">Lupinus luteus</Emphasis> L. (Leguminosae) main secondary metabolites: a case of domestication affecting crop variability

Secondary metabolites (SMs), such as alkaloids and raffinose oligosaccharides (RFOs), play important roles in plant physiology. Although alkaloid and RFO phenotypic variation has been reported for yellow lupin (Lupinus luteus L.), most evaluations have used a reduced number of accessions; thus, limiting the understanding of accumulation patterns and variation ranges. The main goal of this research was to assess alkaloid and RFO content in a diverse L. luteus sample to understand possible SM accumulation patterns across this legume species. Eighteen yellow lupin accessions were analyzed using high performance thin layer chromatography to provide insights on seed and leaf RFO and alkaloid phenotypic variation. Co-dominant markers (170) were used to examine genetic relationships among L. luteus accessions and possible accumulation patterns across closely related genotypes. Significant differences were observed for seed and leaf RFOs. Total seed RFO accumulation ranged from 79.738 to 131.079 mg g^?1. Raffinose, stachyose, and verbascose were observed in all genotypes’ seeds, but at different RFO concentrations. Raffinose was the only RFO detected in leaves (2.793–0.4224 mg g^?1). Total alkaloid accumulation ranged from 0.22 to 15.12 and 0.00 to 8.007 mg g^?1 for seeds and leaves, respectively. Lupinine, sparteine, and gramine were observed in seeds and leaves, and showed a wide range of variation. Neighbor-Joining (NJ) analysis showed an apparent pattern of seed alkaloid accumulation, most likely due to domestication events. However, high RFO accumulating accessions were scattered across the NJ tree. Alkaloid and RFO significant phenotypic variation will not only help to understand the roles of these SMs in L. luteus, but also to uncover the genetic basis behind their accumulation.     

Raffinose family oligosaccharides in seeds of <Emphasis Type="Italic">Pisum</Emphasis> wild taxa,type lines for seed genes,domesticated and advanced breeding materials

The content of raffinose family oligosaccharides (RFOs) in pea seeds constrains their usage in feeding humans and animals. In our research, the content of soluble carbohydrates—particularly α-d-galactosides of sucrose (RFOs)—was analyzed. The materials were as follows: 248 accessions from the Polish Pisum Genebank including representatives of taxa (from species to convarietas), type lines for genes controlling seed characters, and breeding materials and cultivars. Accessions were divided into homogeneous groups considering content of total soluble carbohydrates, total RFOs and individual RFOs: raffinose, stachyose and verbascose. The highest content of total soluble carbohydrates and total RFOs were stated for accessions with wrinkled seeds (r and rb genes) and the lowest content for seeds of the wild species P. fulvum Sibth. et Sm. Accessions valuable for breeding (for further decreasing of anti-nutritional compounds) were found among domesticated taxa (P. sativum subsp. sativum convar. vulgare Alef. and speciosum (Dierb.) Alef.), breeding lines, and some wild taxa. Accessions with decreased content of a total RFOs and verbascose are particularly valuable. It was found that the content of total RFOs was the most highly, frequently, and positively correlated with a stachyose and verbascose content. However, in P. fulvum seeds with the lowest content of RFOs and verbascose, a high correlation between the content of total RFOs and stachyose was revealed. Contents of all oligosaccharides were substantially lower in lines with dominant alleles of main pea seed genes (R, A, and I). It can be assumed that wild, primitive peas were characterized by not-all-to-high (rather not high) content of oligosaccharides; then recessive mutations in mentioned genes resulted in an increased content of RFOs. It seems to be an interesting observation from an evolutionary point of view.     

Oligosaccharide Content and Composition of Legumes and Their Reduction by Soaking,Cooking, Ultrasound,and High Hydrostatic Pressure

Oligosaccharides, including raffinose, stachyose, ciceritol, and verbascose, are commonly found in legumes and often result in flatulence in humans. Effects of soaking, soaking with ultrasound (47 MHz), soaking with high hydrostatic pressure (HHP, 621 MPa), and subsequent cooking on the oligosaccharide content of lentils, chickpeas, peas, and soybeans were investigated. Legumes were soaked for 3 or 12 hr in water, soaked for 1.5 or 3 hr with ultrasound, or soaked for 0.5 or 1 hr with HHP. Oligosaccharides of lentils and chickpeas were mainly composed of raffinose, ciceritol, and stachyose, while those of peas and soybeans were raffinose and stachyose. Verbascose was the minor oligosaccharide in lentils and peas and was absent in chickpeas and soybeans. Ciceritol was not detected in peas and soybeans. Total oligosaccharide content of raw legumes ranged from 70.7 mg/g in yellow peas to 144.9 mg/g in chickpeas. Soaking was effective for the reduction of oligosaccharides in the tested legumes. Compared with soaking for 3 hr, soaking legumes with ultrasound for 3 hr in all tested legumes or soaking legumes with HHP for 1 hr, with exception of soybeans, appeared to be more effective for the reduction of oligosaccharides. The effect of cooking on the reduction of oligosaccharide content of presoaked legumes was evident in lentils, while oligosaccharide content of chickpeas, peas, and soybeans was either unchanged or even increased by cooking after presoaking, with or without ultrasound, probably due to the leaching of other soluble components and the release of bound oligosaccharides during cooking. During soaking or cooking of legumes, raffinose leached out faster than other oligosaccharides.     

Investigations into genotypic variations of peanut carbohydrates

Carbohydrates are known to be important precursors in the development of roasted peanut quality. However, little is known about their genotypic variation. A better understanding of the role of carbohydrates in roasted peanut quality requires first an understanding of the genotypic variation in the soluble carbohydrate components. Ion exchange chromatography was used to isolate 20 different carbohydrate components in 52 genotypes grown in replicated trials at two locations. Inositol, glucose, fructose, sucrose, raffinose, and stachyose were quantitated, and 12 unknown peaks were evaluated on the basis of the peak height of the unknown relative to the cellobiose internal standard peak height. Peaks tentatively identified as verbascose and ajugose could not be properly integrated because of tailing. Of the 18 carbohydrates that were estimated, 9 exhibited significant variation between test environments, 5 among market types, 14 among genotypes within market types, and 11 exhibited some significant form of genotype x environment interaction. Genotypes accounted for 38-78% of the total variation for the known components, suggesting that broad-sense heritability for these components is high. The observed high genotypic variation in carbohydrate components is similar to the high genotypic variation observed for the sweetness attribute in roasted peanuts, which raises the question regarding possible interrelationships. The establishment of such interrelationships could be most beneficial to peanut breeding programs to ensure the maintenance of flavor quality in future peanut varieties.     

Quinolizidine alkaloids in seeds of lupin genotypes of different origins

The intake of lupin-based foods could imply the exposure of consumers to quinolizidine alkaloids. The objectives of this study were to assess the genetic variation among and within 11 geographic regions of Lupinus albus ecotypes, verify the quinolizidine alkaloids amount of alkaloid-poor L. albus and Lupinus angustifolius varieties, and assess the effect of two climatically contrasting Italian environments on the alkaloid content. The quantitation was performed by GC-MS, and in all samples lupanine was the most abundant quinolizidine alkaloid, followed by albine and 13alpha-hydroxylupanine for L. albus and by 13alpha-hydroxylupanine and angustifoline for L. angustifolius. Some regions tended to have a high (Azores) or low (Egypt, Near East, Maghreb) total alkaloids content, but the variation among ecotypes within regions was larger than that among regions following the estimation of variance components. Alkaloid-poor varieties tended to have higher total alkaloid contents when grown in the subcontinental climate site, exceeding in some cases the limit of 0.200 mg/g.     

Stability of sugar content in soybean strains

Abstract

Objectives in this study were to measure total sugar and individual sugar content in whole, mature, soybeans of certain strains and to determine the stability of these components in strains grown over a wide geographical area. Soybean seed of three selected strains from each Maturity Group in the 1970 Uniform Tests‐Northern States were analyzed for total sugar, sucrose, raffinose and stachyose content. For Maturity Groups 00, 0, I, II, III and IV there were 10, 12, 23, 33, 27 and 24 locations, respectively. The locations were in 17 states and 2 Canadian provinces.

The average content of total sugar, sucrose, raffinose and stachyose was 9.36, 5.96, 0.75 and 2.65 g per 100 g seed, respectively. Analysis of variance of total sugar content and individual sugars among the three strains within each Maturity Group revealed significant differences (P<.01) in total sugar among strains in Maturity Groups II and III but not in the other four Maturity Groups. Except for strains within Maturity Group IV, there were significant differences (P<.01 or P<.05) among the strains within each Maturity Group for sucrose, raffinose and stachyose. Few significant environmental index (linear) x strain interactions were observed for total sugar content or for any of the individual sugars.     

顽拗性板栗种子成熟前后褐变与可溶性糖的关系

试图揭示板栗种子褐变与脱水敏感性和可溶性糖含量之间的关系。板栗种子成熟脱落时，脱水敏感性相对较弱，子叶和胚轴中棉籽糖和水苏糖含量达最高峰，电导率和紫外吸收值最低，总酚含量与POD活性较低。种子脱落后，脱水敏感性上升，子叶和胚轴中棉籽糖和水苏糖含量下降，膜渗漏物质增多，总酚含量及POD活性急剧上升，从而导致褐变发生。胚轴中总酚含量与POD活性存在显著的正相关(r=0.999)，而棉籽糖含量分别与POD活性和总酚含量存在显著的负相关(r分别为－0.998和－0.995)。结果表明，可溶性糖的组分及其含量可能与板栗种子脱水敏感性大小有关，板栗种子脱落后还原性糖麦芽糖含量的上升与褐变的发生趋势一致，而非还原性糖特别是棉籽糖可能在抑制褐变方面具有一定作用。     

Characteristics and composition of watermelon, pumpkin, and paprika seed oils and flours

The nutritional quality and functional properties of paprika seed flour and seed kernel flours of pumpkin and watermelon were studied, as were the characteristics and structure of their seed oils. Paprika seed and seed kernels of pumpkin and watermelon were rich in oil and protein. All flour samples contained considerable amounts of P, K, Mg, Mn, and Ca. Paprika seed flour was superior to watermelon and pumpkin seed kernel flours in content of lysine and total essential amino acids. Oil samples had high amounts of unsaturated fatty acids with linoleic and oleic acids as the major acids. All oil samples fractionated into seven classes including triglycerides as a major lipid class. Data obtained for the oils' characteristics compare well with those of other edible oils. Antinutritional compounds such as stachyose, raffinose, verbascose, trypsin inhibitor, phytic acid, and tannins were detected in all flours. Pumpkin seed kernel flour had higher values of chemical score, essential amino acid index, and in vitro protein digestibility than the other flours examined. The first limiting amino acid was lysine for both watermelon and pumpkin seed kernel flours, but it was leucine in paprika seed flour. Protein solubility index, water and fat absorption capacities, emulsification properties, and foam stability were excellent in watermelon and pumpkin seed kernel flours and fairly good in paprika seed flour. Flour samples could be potentially added to food systems such as bakery products and ground meat formulations not only as a nutrient supplement but also as a functional agent in these formulations.     

Identification and quantification of epsilon-(gamma-glutamyl)lysine in digests of enzymatically cross-linked leguminous proteins by high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS)

A rapid and convenient method for the precise quantification of epsilon-(gamma-glutamyl)lysine isopeptide in lyophilized proteolytic digests of cross-linked plant protein samples was developed. The isopeptide was baseline-separated from three other isomers containing lysyl and glutamyl residues by reverse-phase high-performance liquid chromatography after exhaustive proteolytic digestion of the samples cross-linked by a microbial transglutaminase (MTG). Highly selective detection was performed by electrospray mass spectrometry in MS/MS mode. Demonstrating the applicability of the suggested analytical procedure, enzymatic cross-linking of protein isolates from soy [Glycine max (L.) Merr.], pea [Pisum sativum L.], and the sweet lupin species Lupinus albus L. and Lupinus angustifolius L. was investigated after incubation with 0.01 g of MTG/100 g of protein for 0-240 min at 40 degrees C. The liquid chromatography-mass spectrometry (LC-MS) method was successfully applied to monitor the kinetics of epsilon-(gamma-glutamyl)lysine isopeptide formation. Since the calculated initial levels of epsilon-(gamma-glutamyl)lysine in the genuine leguminous protein isolates were between 40 and 77 micromol/100 g, an isopeptide detection limit of 0.5 microg/mL, corresponding to approximately 50 micromol/100 g of protein, was shown to suffice for quantifying the cross-linking rate enzymatically induced by MTG. Concentrations of epsilon-(gamma-glutamyl)lysine in the texturized proteins ranged from 100 to 500 micromol/100 g of protein.     

Changes in the contents of sugars and organic acids during the ripening and storage of sufu, a traditional Oriental fermented product of soybean cubes

In the present study, sufu, an oriental fermented product of soybeans, was prepared by ripening the tofu cubes in Aspergillus oryzae fermented rice-soybean koji mash for 16 days at 37 °C. The sufu product was further kept at room temperature for another 30 days. Examining the changes in the sugar content revealed that stachyose, raffinose, and sucrose contents of tofu and rice-soybean koji granules decreased while levels of glucose and fructose increased during the ripening period and after storage. Glucose was the most abundant sugar detected. Four organic acids, including oxalic, lactic, acetic, and citric acid, were detected in the sufu product and koji granules after ripening. Generally, the contents of these organic acid increased as the ripening period was extended. Among them, acetic acid was the most highly detected.     

Chemical components with health implications in wild and cultivated Mexican common bean seeds (Phaseolus vulgaris L.)

Common bean effects on health have been related to its dietary fiber content and other active compounds. This study assessed the content of flavonoids, coumestrol, phenolic acids, galactooligosaccharides, and phytic acid in wild and cultivated Mexican common bean seeds (raw and cooked) and that of flavonoids, coumestrol, and phenolic acids in germinated bean seeds. The presence of isoflavones in raw bean seeds was not confirmed by the UV spectra. Quercetin, kaempferol, p-coumaric acid, ferulic acid, p-hydroxybenzoic acid, and vanillic acid mean contents were 10.9, 52.3, 10.1, 9.6, 5.4, and 18.2 microg/g, respectively; raffinose, stachyose, verbascose, and phytic acid mean contents were 8.5, 56.3, 5.5, and 11.5 mg/g, respectively, in raw seeds. All compounds were affected by autoclaving, and germination resulted in a de novo synthesis of flavonols, phytoestrogens, and phenolic acids. The impact on health of common bean seed is affected by dietary burden, specific compounds content, and processing. On the other hand, germinated bean seed or beans sprouts may be sources of antioxidants and phytoestrogens.     

Nitrogen fractions and mineral content in different lupin species (Lupinus albus, Lupinus angustifolius, and Lupinus luteus). Changes induced by the alpha-galactoside extraction process

The protein and mineral composition of different varieties of three different lupin species (Lupinus albus, Lupinus angustifolius, and Lupinus luteus) and the effect of alpha-galactoside removal by means of a hydroalcoholic extraction process on such composition were studied in relationship to nutrient distribution among the different anatomical parts of the seed (embryo, cotyledon, and seed coat). The extent of processing-derived protein insolubilization was assessed by both chemical and electrophoretic techniques and related to the amount of nitrogen soluble in H(2)O, NaCl, ethanol, NaOH, and sodium dodecyl sulfate/beta-mercaptoethanol (SDS/BME). The alpha-galactoside extraction process caused a significant increase in the amount of total and insoluble nitrogen and decreased the amount of soluble protein nitrogen, without affecting the content of soluble nonprotein nitrogen. alpha-Galactoside extraction was not effective at decreasing the levels of Mn present in lupins, and processing caused an increase in the content of this mineral in all of the species studied with the exception of L. albus var. multolupa. In general, the effect of processing on mineral content varied with the different lupin species, and mineral losses were lower in L. luteus.     

Antioxidants, low molecular weight carbohydrates, and total antioxidant capacity in strawberries (Fragaria x ananassa): effects of cultivar, ripening, and storage

Four cultivars of strawberries (Senga Sengana, BFr77111, Elsanta, and Honeoye) were studied for their content of antioxidants, total antioxidant capacity, and low molecular weight carbohydrates in relation to harvest year, ripening stage, and cold storage. For ascorbic acid, chlorogenic acid, ellagic acid, and total antioxidative capacity, measured in both water-soluble and water-insoluble extracts, there was a 2-5-fold variation among cultivars. Unripe berries contained lower concentrations of chlorogenic acid and p-coumaric acid and also quercetin and kaempferol compared with riper berries. During cold storage for up to 3 days, relatively few changes in the concentration of the different antioxidants occurred. The concentrations of several investigated parameters were interrelated, for example, for ascorbic acid and water-soluble antioxidant capacity and for ellagic acid and water-insoluble antioxidant capacity. The dominating sugars in strawberries were fructose and glucose, but considerable amounts of sucrose were also present, and their contents varied among cultivars, giving a predicted glycemic index of approximately 81. Verbascose, raffinose, and stachyose were found in only minor amounts. The study shows that the concentration of a number of bioactive compounds in strawberries varied according to cultivar, ripening stage, and storage. This information should make it possible to select strawberries with an optimal content of bioactive compounds.     

A simple and accurate method for determining wheat grain fructan content and average degree of polymerization

An improved method for the measurement of fructans in wheat grains is presented. A mild acid treatment is used for fructan hydrolysis, followed by analysis of the released glucose and fructose with high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Not only the amount of fructose set free from fructans but also the released glucose can be quantified accurately, allowing determination of the average degree of polymerization of fructans (DP(av)). Application of the mild acid treatment to different grain samples demonstrated that a correction should be made for the presence of sucrose and raffinose, but not for stachyose or higher raffinose oligosaccharides. The fructan content and DP(av) of spelt flour, wheat flour, and whole wheat flour were 0.6%, 1.2%, and 1.8% of the total weight and 4, 5, and 6, respectively. Validation experiments demonstrate that the proposed quantification method is accurate and repeatable and that also the DP(av) determination is precise.     

Nutritional Enhancement of Soy Meal via Aspergillus oryzae Solid‐State Fermentation

Antinutritional factors in soy meal (SM) include trypsin inhibitor, galactooligosaccharides (GOSs), structural polysaccharides, and large‐molecular‐weight protein. These antinutritional factors limit the usage of SM for young monogastric animals. Aspergillus oryzae solid‐state fermentation was applied to eliminate these factors, and changes in physical and chemical characteristics of SM were investigated. A. oryzae–treated SM was more nutrient dependent than oxygen dependent, which was illustrated by scanning electron microscopy. After 36 h of fermentation, the concentration of GOSs (raffinose, stachyose, and verbascose) and trypsin inhibitor decreased from an initial value of 9.48 mmol/100 g to a nondetectable level. Structural polysaccharides decreased by 59% (w/w), and the degree of hydrolysis of SM protein increased from an initial value of 0.9 to 7% (w/w) through the seven‐day fermentation. Fermentation also modified nutritional factors. Protein content increased from 50.47 to 58.93% (w/w) after 36 h of fermentation. Amino acid contents were significantly enhanced. The research thoroughly studied the A. oryzae solid‐state fermentation of SM, and the resulting premium product could provide a better protein source for monogastric animals.     

Amino acid, carbohydrate, and fat composition of soybean meals prepared at 55 commercial U.S. soybean processing plants

To quantify variation in U.S. soybean meals (SBM), samples were collected from 55 U.S. soybean (SB) processing plants located in seven of the geographic SB maturity zones at three time points. These samples were analyzed for crude and acid-hydrolyzed fat, oligosaccharide, and amino acid concentrations. Acid-hydrolyzed fat concentrations were poorly correlated (r = 0.28) to crude fat concentrations and were higher for SBM prepared in the southern zones (V-VII) as compared with the northern zones (I and II). Raffinose and verbascose concentrations were lowest (P < 0.05) for SBM prepared in northern maturity zones, while stachyose concentrations were highest for SBM prepared in central maturity zones (III and IV). Total essential, total nonessential, and total amino acid concentrations were lowest for SBM prepared in northern zones. There was variation in oligosaccharide and amino acid concentrations over time, probably due to variation in composition of SB arriving at the plants within maturity zone.     

NMR characterization of saccharides in Italian honeys of different floral sources

The saccharide profiles of 5 different botanical species in 86 Italian honey samples were investigated by 1H and 1H-13C NMR spectroscopy. Nineteen saccharides were identified in the aqueous extracts, namely, fructose, glucose, gentiobiose, isomaltose, kojibiose, maltose, maltulose, melibiose, nigerose, palatinose, sucrose, turanose, erlose, isomaltotriose, kestose, maltotriose, melezitose, raffinose, and maltotetraose. PCA performed on NMR spectral regions, in particular between 4.400 and 5.700 ppm and the fructose signal at 4.050 ppm, revealed a partial sample grouping. The score contribution plots derived from PCA performed using the mean values for the buckets of the anomeric region for each floral source allowed the identification of saccharides characterizing different honeys. OPLS-DA models were further evaluated to confirm the previous findings. OPLS-DA models were also built to highlight differences between polyfloral and high mountain polyfloral honeys and between high mountain polyfloral and rhododendron honeys, both collected at high altitude; S-plots highlighted the characteristic saccharides.     

Establishment of selenium uptake and species distribution in lupine, Indian mustard, and sunflower plants

Selenium has been recognized as essential for all mammals; therefore, its concentration level and speciation are of great concern. Plants are one of the main sources of selenium in the diet. Thus, inorganic selenium uptake and its transformation in different species were evaluated in Indian mustard (Brassica juncea), sunflower (Helianthus annus), and white lupine (Lupinus albus). More than 1.2 g x kg(-)(1) (dry matter) of Se was found in the aerial part of Indian mustard when growing on 1 mg x L(-)(1) of Se as Na(2)SeO(4), and approximately half this amount was determined in the leaves of the lupine, which is still quite high. Selenomethionine was the main selenium-containing amino acid identified in most of the extracts by HPLC-ICP-MS. The higher values were 6.8 and 14.5 mg x kg(-)(1) (expressed as Se in dry matter) in the leaves of lupine and sunflower, respectively. This is of great importance because some authors have considered the combination of this enriched material with non-enriched food as a source of selenium supplementation.