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.     

Composition and properties of seeds and pods of the tree legume Prosopis juliflora (DC)

Seeds and whole pods of Prosopis juliflora were analysed for proximate composition, fatty acids, minerals and soluble sugars. Crude protein constituted 35 % and 10 % of the seeds and whole pods, respectively. Nitrogen free extracts (NFE) comprised approximately 45 % of the seeds and whole pods. In the case of the pods, sucrose represented approximately 75 % of the soluble sugars. The lipid of both the seeds and whole pods contained a relatively large proportion of unsaturated fatty acids with linoleic acid as the predominant fatty acid. Levels of the macronutrients Ca, Mg, K and P were relatively low in comparison with cultivated legumes. Alkaline extraction of the seeds and whole pods showed that more than 70 % of the proteins were extractable. Maximum precipitation of the proteins was observed in the pH range 4.0-4.5. Amino acid analysis of the isolated proteins showed relatively high levels of lysine (312mg g^?l N for the seed and 438 mg g^?l N for the pod protein) and adequate levels of valine, leucine, tyrosine and phenylalanine. Methionine was the most limiting amino acid. The in vitro enzymic digestibility of the proteins of Prosopis seed was comparable to that of proteins of other legume seeds.     

α-Glucosidase inhibitors from Devil tree (Alstonia scholaris)

α-Glucosidase inhibitors are used in the treatment of non-insulin-dependent diabetes mellitus. We attempt to isolate α-glucosidase inhibitors from 24 traditional Thai medicinal plant samples. Potent α-glucosidase inhibitory activity was found in aqueous methanol extract of dried Devil tree (Alstonia scholaris) leaves. Active principles against α-glucosidase, prepared from rat small intestine acetone powder, were isolated and identified. The structures of these isolated compounds were found to be quercetin 3-O-β-d-xylopyranosyl (1? → 2″)-β-d-galactopyranoside and (−)-lyoniresinol 3-O-β-d-glucopyranoside on the basis of chemical and spectral evidence. The latter exhibited an inhibitory activity against both sucrase and maltase with IC₅₀ values of 1.95 and 1.43 mM, respectively, whereas the former inhibited only maltase with IC₅₀ values of 1.96 mM. This preliminary observation will provide the basis for further examination of the suitability of Alstonia scholaris as a medicinal supplement that contributes toward the treatment and prevention of diabetes.     

Isolation and characterization of galactomannan from Dimorphandra gardneriana Tul. seeds as a potential guar gum substitute

A galactomannan was obtained from mature seeds of Dimorphandra gardneriana Tul., the plant from which rutin is extracted. The galactomannan extraction was based on manual separation of the endosperm, water dissolution, centrifugation and precipitation with ethanol. The galactomannan yield obtained (31%) was similar to values reported for other Brazilian seeds and to that of guar gum. The polysaccharide from D. gardneriana seeds (GalDG) was characterized by gas–liquid chromatography (GLC), gel permeation chromatography (GPC), rheology and also by ¹³C and ¹H nuclear magnetic resonance (NMR). The monosaccharide composition in weight % was mannose 64.2, galactose 34.7 and glucose 1.1. Small amounts of protein and uronic acid were found, values being 1.75 and 2.8% (w/w), respectively. The mannose/galactose ratio of GalDG (1.84) is similar to values reported for galactomannans extracted from other Brazilian seeds, and is the M/G value closest to that of guar gum (1.6–1.8). The intrinsic viscosity of galactomannan from D. gardneriana (8.7 dL/g), in water at 25 °C, is lower than the [η] value of guar gum, but the absolute viscosity of the GalDG in aqueous solution at concentrations of 0.1 and 1% (w/v) is higher. The aqueous solution at 1% (w/v) behaves as a pseudoplastic fluid, but a Newtonian behavior was noted for the solution at 0.1%. The high average molar masses, M_w of 3.9 × 10⁷ g/mol and M_n of 1.9 × 10⁷ g/mol, determined by GPC are probably due to molecular aggregation. ¹³C and ¹H NMR spectra (DEPT 135 and HSQC) of GalDG solutions in D₂O were recorded. The patterns of mannose substitution in GalDG and guar gum are similar.     

Effects of simulated digestion in vitro on cell wall polysaccharides from kiwifruit (Actinidia spp.)

Cell wall polysaccharides are resistant to digestion and absorption in the human small intestine and are considered to be delivered to the colon in a chemically unaltered state. In this paper, pulp from green and gold kiwifruit was subjected to in vitro upper-intestinal tract digestion and the chemical and physical changes to cell wall polysaccharides (dietary fibre) were investigated. Yields of insoluble fibre decreased slightly with simulated digestion while soluble fibre yields increased. Constituent sugar and glycosyl linkage analysis of the soluble and insoluble fibre fractions revealed that the chemical composition and structure of the non-starch polysaccharides remained largely unchanged. However, the degree of methylesterification of galacturonic acid residues present in the pectin-rich soluble fibre fractions of both fruit decreased with treatment; size-exclusion chromatography detected changes in the molecular weight profiles of these fractions. These changes may affect the physicochemical properties and fermentability of kiwifruit dietary fibre in the large intestine.     

Characterisation of lipoxygenase from pea seeds (Pisum sativum var. Telephone L.)

Lipoxygenase (LOX) from pea seeds (Pisum sativum var. Telephone L.) was extracted and studied of biochemical properties. The molecular mass of purified lipoxygenase was 93 kDa. The effects of substrate specificity, pH, and sensibility to various inhibitors: caffeic acid, ferulic acid, benzoic acid, catechin, quercetin and kaempferol of LOX were investigated. Lipoxygenase showed the highest activity toward linoleic acid and the lowest toward oleic acid as substrates. Kinetic studies indicated that V_max of the LOX activity was 151.5 U/min and corresponding K_m value of 0.44 × 10⁻³ M. Optimum pH of lipoxygenase was reported at 5.5. Caffeic acid was the most effective inhibitor and kaempferol was the least effective.     

Adsorption isotherms of pinhão (Araucaria angustifolia seeds) starch and thermodynamic analysis

The seeds of Araucaria angustifolia, commonly known as pinhão, are widely consumed in both Southern and Southeastern Brazil due to their high nutritious value comprised basically by starch. The literature on the technological aspects of this seed is still very scarce. Moisture adsorption isotherms of pinhão starch were determined at 10, 20, 30 and 40 °C using the gravimetric method. Results show that the Peleg model most appropriately represents the experimental data. Other models (Chung–Pfost, GAB, Henderson, BET and Chirife) also were found to adjust well. The isosteric heat of sorption (differential enthalpy) was calculated by using the moisture adsorption isotherm and decreased as moisture content increased. The enthalpy–entropy compensation theory was applied to adsorption isotherms and the isokinetic temperature for pinhão starch was calculated by plotting the differential enthalpy versus differential entropy. It was found that the adsorption process investigated was enthalpy-controlled and spontaneous.     

A new steroidal saponin from the seeds of Allium tuberosum

A steroidal saponin, named tuberoside A, together with six known compounds, were isolated from the seeds of Allium tuberosum Rottl. ex Spreng. On the basis of acid hydrolysis, comprehensive spectroscopic analyses and comparison with spectral data of known compounds, its structure was established as (24S, 25S)-5β-spirostan-2β,3β,24-triol 3-O-α-l-rhamnopyranoyl-(1→2)-O-[α-l-rhamnopyranosyl-(1→4)]-β-d-glucopyranoside. The six known compounds were thymidine, adenosine, 2-hydroxy purine, adenine, uracil, and thymine. 2-hydroxy purine, adenine, uracil and thymine are isolated from the seeds of A. tuberosum for the first time. This paper deals with the isolation and structural elucidation of the new saponin.     

Inhibition of Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) development with essential oil extracted from Cymbopogon schoenanthus L. Spreng. (Poaceae), and the wasp Dinarmus basalis (Rondani) (Hymenoptera: Pteromalidae)

The control of the development of Callosobruchus maculatus was studied using a method that combined exposure to essential oil extracted from Cymbopogon schoenanthus and the introduction of a pteromalid natural enemy of the bruchid, Dinarmus basalis. The effect of the essential oil used was evaluated on all developmental stages of C. maculatus and on adults of D. basalis. At the highest concentration tested (33.3 μl/l) all adults of C. maculatus were killed within 24 h of exposure to the oil and the development of newly laid eggs and neonate larvae was also inhibited. However, the oil had variable efficacy against the bruchid instars developing inside the seeds: 5-day-old larvae (63% LI and 37% LII) of C. maculatus developing inside the seeds proving to be highly susceptible while 15-day-old insects (84% of pupae and 16% of larvae) were tolerant. Under the same conditions (33.3 μl/l), adults of D. basalis were very susceptible to oil vapours and to the residual activity of the oil after 3 or 6 days. However, the introduction of 10 pairs of adult D. basalis into a jar containing 100 hosts aged 10 days, 3 or 6 days before the oil application, gave respectively an emergence of 26 or 18 adults of the parasitoid compared to 28 in the control and there was no adult emergence of the host. The possibility of an integrated pest management strategy by using allelochemicals such as essential oils and indigenous natural enemies to control C. maculatus development in cowpea stocks is discussed.     

Phenylpropanoid glycosides from the seeds of Michelia hedyosperma

The seed of Michelia hedyosperma Law (Magnoliaceae) is a commonly used spice by the local people living in the south of Yunnan province, China. From which, six new phenylpropanoid glycosides, michehedyosides A–F (1–6) were obtained, in addition to six known compounds, eugenol, eugenol 4-O-β-d-glucopyranoside, martynoside, alaschanioside C, 3,4-methylenedioxycinnamyl alcohol, and (+)-pinoresinol 4-O-β-d-glucoside. Their structures were elucidated on the basis of detailed spectroscopic analyses and chemical methods.     

Caffeoylquinic acids from leaves of Etlingera species (Zingiberaceae)

3-O-caffeoylquinic acid, 5-O-caffeoylquinic acid (chlorogenic acid), and 5-O-caffeoylquinic acid methyl ester, as elucidated by ¹H and ¹³C NMR, were isolated from leaves of Etlingera elatior. This is the first report of caffeoylquinic acids (CQA) including chlorogenic acid (CGA) in Zingiberaceae. Leaves of Etlingera species were rich in total phenols and CQA, and non-cytotoxic to normal human liver and African green monkey kidney cells. Content of CQA of E. elatior, Etlingera fulgens, and Etlingera rubrostriata leaves was significantly higher than leaves of Ipomoea batatas, and comparable to flowers of Lonicera japonica. CGA found only in leaves of E. elatior and E. fulgens was significantly higher in content than flowers of L. japonica, the commercial source.     

A laboratory assessment of the potential of different strains of the entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metschnikoff) to control Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) in stored cowpea

Twelve indigenous and exotic isolates of Beauveria bassiana and Metarhizium anisopliae were evaluated for their virulence and their ability to suppress populations of Callosobruchus maculatus in stored cowpea. LT₅₀ values ranged from 3.11 to 6.12 days following immersion in aqueous suspensions containing 1×10⁸ conidia ml⁻¹. Indigenous isolates that had been recovered from C. maculatus were more virulent in laboratory bioassays than exotic isolates from other insects. The two isolates with the shortest LT₅₀ values were compared in dose-response assays by immersion and by exposure to cowpea grains treated with dry conidia. In both assays B. bassiana 0362 was consistently more virulent than M. anisopliae 0351. By immersion, LC₅₀ values on day 6 post-treatment were 9.10×10⁴ and 7.10×10⁵ conidia ml⁻¹ for B. bassiana 0362 and M. anisopliae 0351, respectively. Exposure to treated grains gave LC₅₀ values of 1.15×10⁷ and 4.44×10⁷ conidia g⁻¹ grain for B. bassiana 0362 and M. anisopliae 0351, respectively. In 1 kg batches of cowpea stocked with 50 adult C. maculatus, B. bassiana 0362 at both 1×10⁷ and 1×10⁸ conidia g⁻¹ grain led to significant adult mortality and reduced F₁ emergence relative to untreated populations. At 1×10⁸ conidia g⁻¹ the effect of the fungus persisted into the F₁ generation. The net reproductive rates, R₀, measured 26 days after insects were released were 5.16 and 7.32 for the high and low doses compared to 9.52 for the untreated control.     

Comparative effect of boiling and solid substrate fermentation using the tempeh fungus (Rhizopus oligosporus) on the flatulence potential of African yambean (Sphenostylis stenocarpa L.) seeds

The tropical African yambean (AYB, Sphenostylis stenocarpa L.) is a protein-rich underutilized African legume. The presence of the flatulence- and diarrhoea-causing raffinose family oligosaccharides (RFO: raffinose, stachyose and verbascose) or α-galactosides has limited the food use of African yambean seeds. To reduce this limitation, non-traditional processing methods are required. Seeds of three varieties were (i) examined for the flatulence- and diarrhoea-causing RFO and (ii) fermented with Rhizopus oligosporus for tempeh production. The traditional tempeh production process involved dehulling, soaking in water for 24 h, boiling in water for 30 min, inoculation and fermentation. In addition, the traditional tempeh procedure was modified by using 1% citric acid solution instead of water for soaking and cooking. Comparisons with traditionally cooked beans, which involved boiling in water for 4 h, were made. Boiling seeds for 4 h resulted in 8–30% reduction of total α-galactosides in the three varieties, while the traditional tempeh procedure resulted in an almost complete loss (98%) of the same (P < 0.05). The modified procedure resulted in a bacteria-free tempeh but α-galactoside reduction was 22–39%. Both tempeh production processes were clearly more effective than was traditional cooking in reducing the flatulence potential of the AYB seeds.     

Distribution of the Medea factor M in populations of Tribolium castaneum (Herbst) in the United States

The distribution of the maternally acting, selfish gene Medea⁴ (M⁴) was determined in populations of the red flour beetle, Tribolium castaneum (Herbst), collected in the southern and midwestern United States. We found clear evidence for the existence of two major regional subpopulations, with a boundary that roughly corresponds to 33°N latitude. All 26 strains collected in 10 states north of this latitude were homozygous for the M⁴ allele, while only two of 29 strains collected in six states south of this latitude were homozygous for the allele. Of the remaining 27 southern strains, 21 lacked the M⁴ allele entirely, while six contained a mixture of M⁴ and non-M⁴ alleles. This is the first evidence of either the existence of biotypes or the presence of major barriers to gene flow in wild populations of this ubiquitous insect species.     

Insecticidal effect of Steinernema feltiae (Filipjev) (Nematoda: Steinernematidae) against Tribolium confusum du Val (Coleoptera: Tenebrionidae) and Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) in stored wheat

The confused flour beetle, Tribolium confusum, and the Mediterranean flour moth, Ephestia kuehniella, are important pests of stored grain products. The insecticidal effect of three strains (UK 76 [=Nemasys], USA/SC, and Hawaii) of the entomopathogenic nematode Steinernema feltiae was determined in the laboratory, in wheat, against these pests. The nematodes were applied at three dose rates: 100, 300 and 900 nematodes/insect individual. The Hawaii strain was most virulent against T. confusum adults and larvae, with a significant dose effect in the case of the larvae. Larval mortality of this species reached 79% and 100% after 7 and 14 d of exposure to the nematodes, respectively, at the highest dose applied. On the other hand, adult mortality of T. confusum did not exceed 66%. In the case of E. kuehniella larvae, USA/SC performed best causing 52% and 69% mortality after 7 and 14 d exposure, respectively, at the highest dose tested. Since very few data are available on the effect of entomopathogenic nematodes against these pests, it is concluded that the Hawaii and USA/SC strains of S. feltiae should be further investigated as promising biological control agents for T. confusum and E. kuehniella.     

Effect of osmotic dehydration on Actinidia deliciosa kiwifruit: A combined NMR and ultrastructural study

The effects of individual osmotic dehydration processes (OD) on kiwifruit outer pericarp tissue were studied as reliant on treatment temperature (25, 35 and 45 °C) and extent (0–300 min). Macro (Low Frequency Nuclear Magnetic Resonance, LF-NMR), micro (Light Microscopy, LM) and ultrastructural (Transmission Electron Microscopy, TEM) measurements were performed to evaluate modifications of three cellular compartments, namely vacuole, cytoplasm – extracellular space and cell wall.     

Effectiveness of products from four locally grown plants for the management of Acanthoscelides obtectus (Say) and Zabrotes subfasciatus (Boheman) (both Coleoptera: Bruchidae) in stored beans under laboratory and farm conditions in Northern Tanzania

The effectiveness of whole or powdered leaves (botanicals) from four locally grown plant species applied at a rate of 1.5 kg per 100 kg beans (Phaseolus vulgaris) against Acanthoscelides obtectus and Zabrotes subfasciatus was compared under laboratory and farm conditions. In the laboratory, Chenopodium ambrosioides, applied as powder or as whole leaves, was the most effective, with 100% mortality of adult insects in less than three days and no progeny. Less C. ambrosioides (about 200 g per 100 kg beans) still resulted in 100% mortality within 24 h. Tagetes minuta applied as powder also increased mortality and reduced oviposition and progeny production significantly. The other treatments - T. minuta applied as leaves, and Azadirachta indica or Cupressus lusitanica applied as powder or as whole leaves - had no significant effects upon mortalities, oviposition rate, or progeny production compared with control treatments. When the rate of application was increased to about 8.3 kg per 100 kg beans, there was a slight increase in mortality using T. minuta and A. indica, but not with C. lusitanica. An additional trial with C. ambrosioides from different collections and with plants at different stages of development revealed considerable variations in the efficacy of the treatment.In the on-farm trials, A. indica-seed powder was the most effective treatment, followed respectively by leaf powders of C. ambrosioides, C. lusitanica and T. minuta. All treatments were significantly more effective than the control in reducing the numbers of live insects; they also reduced numbers of damaged beans and maintained germination rates after 5 months of storage. The results of evaluations of the treatments made by farmers just after the trials and five years later are reported.     

Comparative study of field and laboratory evaluations of the ethnobotanical Cassia sophera L. (Leguminosae) for bioactivity against the storage pests Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) and Sitophilus oryzae (L.) (Coleoptera: Curculionidae)

The powdered leaves of Cassia sophera along with hot- and cold-water leaf extracts of this plant were tested in laboratory experiments in the UK and in field trials in Tamale, Northern Ghana, using traditional storage containers, to determine their inhibitory and toxic effects against Sitophilus oryzae and Callosobruchus maculatus infestation of stored rice and cowpea, respectively. Laboratory and field experiments with cowpea showed that the use of C. sophera hot-water extracts was more effective at reducing C. maculatus infestation and adult emergence on cowpea than the traditional leaf-powder application (1% and 5% w/w) or the use of a cold-water extract of C. sophera. Hot-water extracts of C. sophera might be a more effective technique of applying the plant material on to stored cowpea than using powdered C. sophera leaves, the currently used application by small-scale farmers. In contrast, experiments with S. oryzae on rice showed that C. sophera leaf powder (5% w/w) effectively reduced adult emergence in the laboratory, but this could not be confirmed under field conditions. The hot and dry climatic conditions in the field might impart a natural protection against rice infestation by S. oryzae, making the use of protectants and pesticides less necessary for farmers. This was supported by the negligible rice grain damage after 6 months of field storage and by the failure of the S. oryzae population to establish itself under field conditions. The implications of using botanicals in pest control are discussed.