Soy Seeds Research Articles

Voltammetric Characterization and Amperometric Detection of β‐Carboline Alkaloids at Carbon Nanotube‐Modified Electrodes

AbstractThe voltammetric behavior of β‐carboline alkaloids at carbon nanotubes‐modified glassy carbon electrodes, as well as their quantification by amperometric monitoring of the oxidation responses, are reported. Cyclic voltammograms of harmane, harmine, harmaline and harmalol at the CNT‐GCE showed enhanced voltammetric responses with respect to those obtained at a bare GCE. The effect of pH on the oxidation ip and Ep values obtained by differential pulse voltammetry was discussed, as well as their mechanistic aspects. Hydrodynamic voltammogram of these compounds led us to select a potential value of +900 mV for their amperometric detection. Under these conditions, no fouling of the modified electrode surface is evidenced. The HPLC separation and determination of β‐carboline alkaloids were carried out using a mobile phase consisting of 20% (v/v) methanol‐20% (v/v) acetonitrile‐0.05 mol L−1 HPO solution of pH 9.0. Detection limits ranging between 28 nM (harmalol) and 88 nM (harmaline) were achieved. The usefulness of the chromatographic method with amperometric detection at the CNT‐GCE was demonstrated by analyzing soy seeds samples spiked with harmaline, harmane and harmine at a 0.25 μg/g level.

Teores de isoflavonas e capacidade antioxidante da soja e produtos derivados

ISOFLAVONE CONTENT AND PROFILE AND ANTIOXIDANT ACTIVITY OF SOY AND SOY PRODUCTS. The objective of this study was to determine the antioxidant activity and isoflavone content and type of soy seeds and soy products. The antioxidant activity was measured using β-carotene bleaching and 2.2-diphenyl-1-picryl-hydrazyl (DPPH•) free radical methods. The total isoflavone content of soy products varied from 95 to 711 mg/100 g DW (expressed as aglycones) and total phenolics content from 101 to 413 mg equivalents of catechin/100 g DW. Soybeans presented 110 and 200 mg/100 g DW of isoflavones and total phenolics, respectively. The β-glycosides and malonylglycosides were the main forms of the isoflavones found in the whole flour, defatted flour and commercial defatted flour, similar to the soy seeds. The soy germ (hypocotyl) and the defatted soy flours presented the highest antioxidant activities in both methods (5.0 μmoles equivalents of trolox/g DW and ~ 0.8 μmoles equivalents of BHT/g DW). Taking this into account, the results showed that total isoflavone and phenolic contents and isoflavone profile of soy products depend on processing conditions and that antioxidant activity varied significantly among products. Keywoards: soy, soy products, isoflavones, antioxidant activity.

Physicochemical and textural properties of heat-induced pea protein isolate gels

Chemical and thermal properties of pea protein isolates (laboratory prepared or native; PPIn and commercial; PPIc) and textural properties of heat-set gels obtained from pea protein isolates were compared with homologous soy protein isolates (laboratory prepared, or native; SPIn and commercial; SPIc). The protein banding pattern resulting from electrophoresis separation confirmed the presence of predominant storage proteins of pea and soy seeds in the respective protein products. PPIc and SPIc had lower nitrogen solubility than their native counterparts, likely due to their denaturated state which was further confirmed by the absence of distinct endotherms in these commercial materials compared to the laboratory prepared ones. Addition of NaCl at 1.0–2.0% (w/w) to PPIn and SPIn slurries increased thermal transition temperatures for both proteins. The optimal conditions for formation of strong heat-induced gels from PPIc were 19.6% (w/w) protein content, pH 7.1, 2.0% (w/w) NaCl, and heating at 93 °C. SPIc gels prepared under the same conditions were stronger and more elastic than PPIc gels as denoted by texture indictors.

Effects of the partial substitution of dietary fish meal by differently processed soybean meals on growth performance, nutrient digestibility and activity of intestinal brush border enzymes in the European sea bass ( Dicentrarchus labrax)

This study evaluated the effects of replacing fish meal (FM) in the diet of European sea bass ( Dicentrarchus labrax) with differently processed soybean meals on growth performance; apparent digestibility coefficients (ADCs); the activity of alkaline phosphatase and the brush border digestive enzymes: leucine amino peptidase, maltase and γ-glutamyl transpeptidase; and the fish morphometric and flesh quality. European sea bass with an initial average body weight of 187.8 ± 1.4 g, were fed either a FM based (control) diet or a soy replacement isoproteic, isolipidic and isocaloric diet. The treatments consisted replacing FM protein by: 25% toasted, dehulled and solvent-extracted soybean meal (SE25); 50% dehulled and toasted soy seeds subjected to dry extrusion and mechanical oil extraction (ME50); 50% enzyme-treated soybean meal (ET50) and an inclusion of 60% composed of 30% toasted, dehulled and solvent-extracted soybean meal and 30% enzyme-treated soybean meal (SE + ET/60). ADCs values of dry matter, crude protein, crude lipid and gross energy did not significantly differ between ME50 and SE + ET/60 but both of them were inferior to the other treatments ( P < 0.05). Compared with the control FM-based diet, only the group that consumed the ME50 diet had lower specific growth rate, feed conversion ratio and gross protein retention efficiency values ( P < 0.05). The protein efficiency ratio did not differ between the FM-based control group and all other soy derivate groups ( P > 0.05). In order to gain more insight on the effects of the diet on fish growth, activity of the brush border enzymes was measured. No significant differences were found in leucine amino peptidase and maltase activities, between the control group and the other soy derivate groups. The activity of γ-glutamyl transpeptidase was significantly higher in the upper section in fish that consumed the control diet compared with fish that consumed the soy derivate diets. Yet, the main activity of this enzyme was found in the lower intestinal section. In all the soy derivate diets except for the SE25 diet, the activity of alkaline phosphatase was significantly lower than its activity in the control diet. Feeding diets that include various types and levels of soybean derivatives did not affect the whole body composition and slaughter yield but significantly reduced liver weight. The results show that in methionine supplemented diets, FM can be replaced in terms of protein by 25% SE, 50% ET or 60% soy composed of 30% SE and 30% ET without hampering fish performance. The inclusion of 50% protein from ME resulted in significantly lower growth performance and feed utilization.

Efeitos alelopáticos sobre a germinação de sementes de soja (Glycine max L.Merrill)

This work had as objective to study the effect of natural substances found in root exsudates of other crops on the gemination of soybean seeds. Two experiments were accomplished. For the first experiment wheat seeds (Triticum aestivum), cale (Triticum sp.), corn (Zea mays), ervilhaca (Vicia sativa), and black oat (Avena strigosa), that were placed to germinate, in paper rolls, in BOD at 25°C. These seeds were discarded and the papers were reused for germination of soybean seeds, using as solution-test root exsudates, and as control distilled water to humidify the paper. For the second experiment, aqueous extract of above-ground part of black oat (Avena strigosa) was used to humidify the paper where the soy seeds were placed to germinate, in BOD at 25oC. Allelopatic effects alelopáticos of the root exsudates were verified on the percentage of germination of the soybean seeds, but it was not verified effect on the time and medium speed of germination. It was observed negative interference of black oat extract on the time and medium speed of soybean seeds germination.

Food allergy in atopic dogs.

The food sensitive dog provides a good animal model for food allergy, whose allergic reaction can be followed serially with repeated challenges both in skin and by oral challenges and by endoscopic direct visualization and serial biopsies. This model is proving useful in showing reduced allergenicity in food allergens-soy, wheat, cow's milk by thioredoxin treatment. Recently Dr. Buchanan has cloned the gene for the NADP-thioredoxin reductase (NTR) which he transferred into barley seeds with a bacterial vector. He is attempting to do the same with wheat and soy seeds to produce genetically hypoallergenic foods. The canine model for food allergy provides an excellent model in which to test such bio-engineered potentially hypoallergenic foods.

Simultaneous determination of oil and water contents in different oilseeds by pulsed nuclear magnetic resonance

AbstractRoutine analysis of oil and water contents in different oilseeds with the Bruker Minispec pulsed nuclear magnetic resonance (NMR) analyzer (Bruker Analytische Mestechnik, Rheinstetten, Germany) is rapid (16 s measurements), precise, accurate and nondestructive. In 1991, subcommittee SC2 (oil seeds) of the Technical Committee Number 34 [organized by the International Standards Organization (ISO), Geneva, Switzerland] organized an international collaborative study for pulsed NMR analysis of oil content in whole rapessed. An additional study was performed in 1993 to extend the method to sunflower, linseed and soy seeds. The Draft International Standard ISO DIS/10565 (Draft International Standards, International Standards Organization, Geneva, 1993) describes the procedure of the pulsed NMR method for determination of oil content in rapeseed and presents the interlaboratory comparison results based on the calculations described in the Normative ISO 5725 (Draft International Standards, International Standards Organization, Geneva, 1993). The standard was approved in 1992 and will be published in 1993. The interlaboratory collaborative studies showed that the analyses of oil and moisture by pulsed NMR were either comparable or more repeatable than measurements done by the traditional methods. No statistical differences between determinations by the traditional and pulsed NMR methods were found. Simultaneous determination of percent moisture and percent oil content in whole seeds is possible with pulsed NMR by the spin‐echo method. In addition, multiple components of the oil can be detected and quantitated by T2 analysis from the Carr‐Purcell‐Meiboom‐Gill pulse sequence. The instrument is easy to calibrate with whole oilseeds, and the calibration can be checked periodically with the same seeds because the measurement is nondestructive. Pulsed NMR provides a rapid alternative to the long, laborious, traditional methods of analysis and offers substantial long‐term savings of both time and money. Minimal operator training is required once the technique has been established for routine use.

Effect of Roasting Raw Soybeans at Three Temperatures on In Situ Dry Matter and Nitrogen Disappearance in Dairy Cows

Solvent-extracted soybean meal, raw soybeans, and roasted raw soybeans were compared for chemical composition and in situ DM and N rumen disappearance. Soybeans were drum-roasted to attain seed temperatures of 125, 150, and 165°C; rolled; and cooled rapidly. In situ disappearance was measured by nylon bags (41-μm pore size) in three ruminally cannulated lactating Holstein cows. Raw soybeans were affected chemically and physically by roasting. Roasting and rolling of raw soybeans diminished soluble N by over 50%, visibly scorched the seeds, lowered the NDF content, and had no effect on ruminal DM and N disappearance rates, but significantly decreased the rapidly soluble “a” fraction and effective degradability of N. Soyhull loss probably occurred during flame roasting and rolling, hence the lower NDF in roasted beans. However, soybean meal was lowest in effective degradability of DM and N. Effective degradability of DM and N were not affected by temperature of roasting. Inadequate heat penetration of soy seeds from roasting probably occurred from the initial use of whole versus broken seeds and the short (45 to 60s) roasting time and rapid cooling thereafter. Methods to physically rupture raw beans before roasting and maintain bean temperature after roasting should be explored.

Nutritive Value of Cotton, Peanut, and Soy Seeds

Nutritive Value of Cotton, Peanut, and Soy Seeds