Decrease In Starch Content Research Articles

Genes expressed in grapevine leaves reveal latent wood infection by the fungal pathogen Neofusicoccum parvum.

Some pathogenic species of the Botryosphaeriaceae have a latent phase, colonizing woody tissues while perennial hosts show no apparent symptoms until conditions for disease development become favorable. Detection of these pathogens is often limited to the later pathogenic phase. The latent phase is poorly characterized, despite the need for non-destructive detection tools and effective quarantine strategies, which would benefit from identification of host-based markers in leaves. Neofusicoccum parvum infects the wood of grapevines and other horticultural crops, killing the fruit-bearing shoots. We used light microscopy and high-resolution computed tomography (HRCT) to examine the spatio-temporal relationship between pathogen colonization and anatomical changes in stem sections. To identify differentially-expressed grape genes, leaves from inoculated and non-inoculated plants were examined using RNA-Seq. The latent phase occurred between 0 and 1.5 months post-inoculation (MPI), during which time the pathogen did not spread significantly beyond the inoculation site nor were there differences in lesion lengths between inoculated and non-inoculated plants. The pathogenic phase occurred between 1.5 and 2 MPI, when recovery beyond the inoculation site increased and lesion lengths of inoculated plants tripled. By 2 MPI, inoculated plants also had decreased starch content in xylem fibers and rays, and increased levels of gel-occluded xylem vessels, the latter of which HRCT revealed at a higher frequency than microscopy. RNA-Seq and screening of 21 grape expression datasets identified 20 candidate genes that were transcriptionally-activated by infection during the latent phase, and confirmed that the four best candidates (galactinol synthase, abscisic acid-induced wheat plasma membrane polypeptide-19 ortholog, embryonic cell protein 63, BURP domain-containing protein) were not affected by a range of common foliar and wood pathogens or abiotic stresses. Assuming such host responses are consistent among cultivars, and do not cross react with other trunk/foliar pathogens, these grape genes may serve as host-based markers of the latent phase of N. parvum infection.

Comparative transcriptome analysis reveals carbohydrate and lipid metabolism blocks in Brassica napus L. male sterility induced by the chemical hybridization agent monosulfuron ester sodium.

BackgroundChemical hybridization agents (CHAs) are often used to induce male sterility for the production of hybrid seeds. We previously discovered that monosulfuron ester sodium (MES), an acetolactate synthase (ALS) inhibitor of the herbicide sulfonylurea family, can induce rapeseed (Brassica napus L.) male sterility at approximately 1% concentration required for its herbicidal activity. To find some clues to the mechanism of MES inducing male sterility, the ultrastructural cytology observations, comparative transcriptome analysis, and physiological analysis on carbohydrate content were carried out in leaves and anthers at different developmental stages between the MES-treated and mock-treated rapeseed plants.ResultsCytological analysis revealed that the plastid ultrastructure was abnormal in pollen mother cells and tapetal cells in male sterility anthers induced by MES treatment, with less material accumulation in it. However, starch granules were observed in chloroplastids of the epidermis cells in male sterility anthers. Comparative transcriptome analysis identified 1501 differentially expressed transcripts (DETs) in leaves and anthers at different developmental stages, most of these DETs being localized in plastid and mitochondrion. Transcripts involved in metabolism, especially in carbohydrate and lipid metabolism, and cellular transport were differentially expressed. Pathway visualization showed that the tightly regulated gene network for metabolism was reprogrammed to respond to MES treatment. The results of cytological observation and transcriptome analysis in the MES-treated rapeseed plants were mirrored by carbohydrate content analysis. MES treatment led to decrease in soluble sugars content in leaves and early stage buds, but increase in soluble sugars content and decrease in starch content in middle stage buds.ConclusionsOur integrative results suggested that carbohydrate and lipid metabolism were influenced by CHA-MES treatment during rapeseed anther development, which might responsible for low concentration MES specifically inducing male sterility. A simple action model of CHA-MES inducing male sterility in B. napus was proposed. These results will help us to understand the mechanism of MES inducing male sterility at low concentration, and might provide some potential targets for developing new male sterility inducing CHAs and for genetic manipulation in rapeseed breeding.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1388-5) contains supplementary material, which is available to authorized users.

Involvement of α-Amylase Genes in Starch Degradation in Rice Leaf Sheaths at the Post-Heading Stage

Identifying the mechanisms regulating starch remobilization after heading in rice leaf sheaths is essential to understand the capability of the source for grain filling. In the present study, the changes in starch content and expression levels of α-amylase genes in the third leaf sheaths of Takanari, a high-yielding indica cultivar, were compared with those of Nipponbare, a standard japonica cultivar, during the post-heading stage to examine the starch remobilization characteristics in the leaf sheath of a high-yielding cultivar. Starch content in Takanari tended to decrease at a faster rate than in Nipponbare starting 3 days after heading. The decrease in starch content during 12 days after heading was greater in Takanari than in Nipponbare. Of eight genes predicted to encode α-amylase in the rice genome, RAmy2A and RAmy3C were primarily expressed in the leaf sheaths after heading. Moreover, RAmy2A mRNA level peaked at 9 days after heading in both cultivars. Particularly in Takanari, the RAmy2A mRNA levels rapidly increased from 3 to 9 days after heading. In addition, α-amylase activity was significantly higher in Takanari than in Nipponbare at 9 days after heading. Our results suggest that the rapid degradation of starch in the leaf sheaths of Takanari at the post-heading stage may be attributed, at least in part, to the enhancement of α-amylase activity caused by an increase in RAmy2A transcription level.

硒肥对马铃薯硒素吸收、转化及产量、品质的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 硒肥对马铃薯硒素吸收、转化及产量、品质的影响 DOI: 10.5846/stxb201304130697 作者: 作者单位: 西北农林科技大学 资源环境学院,西北农林科技大学 资源环境学院,西北农林科技大学 资源环境学院,西北农林科技大学 资源环境学院 作者简介: 通讯作者: 中图分类号: 基金项目: 农业部"948"项目(2010-Z19);林业局"948"项目(2009-4-64);陕西省自然科学基础研究计划项目(2010JM5004);陕西省攻关项目(2010K02-12-1) Effects of three fertilizers on uptake, transformation, yield and quality of potatoes Author: Affiliation: College of Resources and Environment, Northwest A,College of Resources and Environment, Northwest A,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:通过设对照(CK)、保水缓释硒肥(W)、生物炭基硒肥(C)、硒酸钠硒肥(S)4个处理来研究不同硒肥对马铃薯(品种为早大白)硒素吸收、转化及产量、品质的影响。结果表明:各处理马铃薯各器官硒含量在生育期内总体上呈下降趋势,马铃薯各器官的硒含量呈现:苗期根 > 茎 > 叶片;成熟期叶片 > 茎 > 块茎的特点;随着硒肥用量的增加,W处理下的总硒、无机硒、有机硒含量呈增大趋势,产量、有机硒转化率、粗蛋白、还原糖和Vc呈先升高后降低的趋势;C处理和S处理下,马铃薯以上各指标均呈先升高后降低的趋势,在低施硒量(0.126 kg/hm2)时,3种硒肥显著降低了马铃薯块茎淀粉含量,之后随着施硒量的增加淀粉含量变化不显著;与对照相比,3种硒肥在适宜施硒量(0.379 kg/hm2)时,马铃薯产量提高了4.87%-5.44%,粗蛋白含量增加了12.18%-20.03%,还原糖提高了6.45%-12.90%,Vc含量提高-0.54%-3.11%,有机硒转化率增加13.00%-15.10%,淀粉含量增加了-0.73%-1.12%;综合考虑3种硒肥对马铃薯含硒量、产量、品质的影响,W处理最佳,C处理次之,S处理最差。 Abstract:A field experiment was conducted to study the uptake and transformation of different selenium fertilizers by potato (cv. Zao Dabai) and the effects of these fertilizers on potato yield and quality. The experiment included four fertilizer treatments: sodium selenate fertilizer (S), biological carbon selenium fertilizer (C), slow-release, water absorbent selenium fertilizer (W) and an unfertilized control (CK). Results indicated that plant selenium concentrations gradually decreased as potato plants matured. Selenium concentrations in different potato organs generally decreased in the order roots > stems > leaves. However, by maturity, selenium concentrations decreased in the order leaves > stems > tubers. W treatments initially increased selenium contents, inorganic Se and organic Se of potatoes, however, yield, the organic Se transformation rate, crude protein, the reducing sugar and Vc of potatoes initially increased and then decreased as soil selenium concentrations increased. These three kinds of selenium fertilizers decreased starch contents of potatoes at the low selenium concentration (0.126 kg/hm2), then it could not influence starch contents of potatoes. Compared with CK, When applied in proper amounts(0.379 kg/hm2), all three selenium fertilizers increased yield by 4.87%-5.44%, tuber crude protein by 12.18%-20.03%, the reducing sugar by 6.45%-12.90%, vitamin C by -0.54%-3.11%, organic Se transformation rate by 13.00%-15.10% and starch content by -0.73%-1.12% of potatoes. Considering selenium contents, the yield and qualities of potatoes, the effects of W treatments were better than B treatments and effects of S treatments were the worst. 参考文献 相似文献 引证文献

Relationships between carbohydrates and reproductive development in chardonnay grapevine: impact of defoliation and fruit removal treatments during four successive growing seasons

<p style="text-align: justify;"><strong>Aim</strong>: The present study was conducted in grapevines to evaluate the influence of source/sink disturbance on reserve restoration in the entire plant (trunk, roots) and the consequences on reproduction, yield, sugar yield, potential alcohol content and total acidity over four successive years of treatment.</p><p style="text-align: justify;"><strong>Methods and results</strong>: At véraison, either total defoliation or total fruit removal was performed on Chardonnay plants grown in vineyards. The impact was measured each year on reproductive parameters and after four years on both plant weight and carbohydrate content. Defoliation induced an alteration in carbohydrate distribution in the entire plant, as revealed by decrease of starch content and parallel increase of soluble sugar content. These modifications affected the number of inflorescences/clusters per plant the year after. By contrast, fruit removal resulted in a significant increase of carbohydrate reserves in the whole plant, although the efficiency of sexual reproduction was not improved the year after.</p><p style="text-align: justify;"><strong>Conclusion</strong>: Results confirm the close correlation between carbohydrate reserves and the efficiency of sexual reproduction. Moreover, grapevine is able to adapt the number of both inflorescences and flowers according to the amount of available carbohydrate reserves in perennial organs.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The quality of the crop is affected by defoliation, as shown by the decrease in yield and sugar yield. However, the impact on potential alcohol content and total acidity was less pronounced.</p>

In vitro gas production and dry matter digestibility of malting barley grain sown with different seeding and nitrogen fertilization rates in Canada

Two malting barley varieties, AC Metcalfe and CDC Copeland, were grown at seven sites in Canada with varying seeding rates (SR; 200 and 400 seeds/m2) and nitrogen fertilization rates (NR; 0, 30, 60, 90, and 120kg/ha) and were assessed for variation in chemical composition, gas production (GP), and dry matter digestibility (DMD) after 24h of batch culture. The variety affected (P<0.01) the crude protein (CP) content of malting barley grain and interacted with SR or NR on DMD. The increase in NR quadratically increased (P<0.01) CP and fiber content but linearly (P<0.01) decreased starch content of malting barley grain. Variety, SR, and NR had limited impact on in vitro GP and DMD. This study showed substantial variation in CP content and DMD among samples and that the chemical composition of malting barley grain and its potential feed value could be altered by NR.

Differences in cold hardiness, carbohydrates, dehydrins and related gene expressions under an experimental deacclimation and reacclimation in Prunus persica.

To boost our understanding of a recent outbreak of freezing injury, we sought to confirm distinctive features between the shoot tissues of the peach (Prunus persica) cultivars Daewol and Kiraranokiwami by mimicking unseasonable changes of temperatures that occur in the early spring through repeated deacclimation and reacclimation treatments. Patterns of cold hardiness declined dramatically during the deacclimation and rose during the reacclimation in both cultivars. Our results indicated that 'Daewol' possessed higher capacity in response to repeated deacclimation and reacclimation treatments than 'Kiraranokiwami'. 'Daewol' showed more sensitive changes in the carbohydrates in response to warm and low temperatures compared with 'Kiraranokiwami'. 'Daewol' indicated almost similar repeated down- and up-patterns in soluble sugar content in response to repeated deacclimation and reacclimation, whereas it indicated repeated up- and down-patterns in starch content. However, 'Kiraranokiwami' showed a progressive increase in the soluble sugar content and a progressive decrease in starch content. Notably, patterns of accumulation of a 60-kDa dehydrin protein encoded by the PpDhn1 gene were confirmed through western blotting and paralleled fluctuations of cold hardiness in both cultivars. Expression of this dehydrin was weak in both cultivars during deacclimation but its band intensity increased during reacclimation. Changes in related genes (β-amylase, PpDhn1, PpDhn2 and PpDhn3) were positively correlated with changes in cold hardiness throughout the experiment. Our results indicate that recent repeated warm periods may cause premature deacclimation in the early spring, and that more cold-tolerant cultivar may be more resilient to freezing injury caused by unstable temperature conditions.

Effect of nitrogen levels and leaf position on carbohydrate and nitrogen metabolism in FCV tobacco (Nicotiana tabacum L.)

Interplay of nitrogen and carbohydrate metabolism, which influenced by nitrogen nutrient management determines the quality and chemical composition of cured tobacco leaf. Tobacco variety Kanchan is grown in Northern light soils of Andhra Pradesh and is a high yielding variety showing response to higher levels of nitrogen. Effect of nitrogen (0, 40, 80, 120, 160 and 200 kg N ha−1) on nitrate reductase, nitrate accumulation and starch content in different leaf position of variety Kanchan was studied in pot (150 kg) culture with Northern light soil of Andhra Pradesh. The starch content decreased significantly with increase in application of nitrogen in three growth stages. But the maximum decrease in starch content was observed with increase in application of nitrogen from 120 to 160 kg N ha−1 in all leaf positions except in the top position. The in vivo nitrate reductase (NR) activity increased significantly with increase in leaf position from bottom to top and decreased with age of the plant from 50 to 70 days. Nitrate–N content increased from 0.14 mg g−1 dry wt. in the bottom leaves of control plants to 8.615 mg g−1 dry wt in the leaves of plants treated with 200 kg N ha−1. The nitrate content increased from bottom to top position in all treatments with increase in nitrogen application. Increased application of nitrogen increased the NR activity and accumulation of nitrate–N, thus a positive relationship was observed between NR activity and nitrate–N accumulation whereas starch content decreased with increased application of nitrogen. The negative relationship was observed between NR activity and starch accumulation and also between nitrate–N and starch. The recommendation of 120 kg N ha−1 for the variety Kanchan grown in northern light soils of Andhra Pradesh was found to be optimum as NR activity was at a par between 120 and 200 kg N ha−1 application at 60 and 70 days of growth. Thus NR activity may be taken as one of the indicators to the maturity of leaf and availability of nitrogen to the plants.

Effects of Different Coagulants on Sweet Sorghum Juice Clarification

Sweet sorghum is a potential complementary crop for ethanol production in Brazil, United States and India. Since, phenols are playing inhibitory role in the process of ethanol production from extracted juice from sweet sorghum stalks, it's removal from juice is necessary for better ethanol yield. The aim of this research was to evaluate the use of magnesium oxide and calcium hydroxide as coagulant agents in different pH levels in the juice treatment. The experiment was arranged in a split-plot statistical design. Main treatments corresponded to the different coagulants and secondary treatments were the pH levels (6.0 and 7.0). Analysis of coagulant volume, juice pH, settling rate and sludge volume were performed during the decantation process. Clarified juice was analyzed as Brix, pH, ashes, phenolic compounds and starch. The use of magnesium oxide resulted in lower sludge volume, phenolic compounds and ashes. The use of calcium hydroxide decreased starch content, whereas clarification at pH 7.0 promoted higher sludge volume. Treating juice with magnesium oxide improved decantation dynamics of the process and clarified juice quality.

Effect of harvest maturity on carbohydrates for ethanol production from sugar enhanced temperate × tropical maize hybrid

A northern adapted sugar maize (Zea mays L.) hybrid was bred by crossing temperate×tropical maize for bioethanol production. Temperate×tropical maize (TTM) has a prolonged vegetative growth and accumulates more sugar in the stalk compared to its respective tropical and temperature parents (White et al., 2012). In this study, the sugar concentration in the stalk was further increased by preventing pollination by shoot bagging (covering) ears. It was observed that starch content was eliminated and sugar content increased to 30.1% (w/w) in the stalks. The whole plant biomass (grain, sugars and stover) was evaluated for ethanol production. Ethanol produced from sugars and starch was comparable from milk (R3) to dent (R5) reproductive growth stages between pollinated and non-pollinated TTM, indicating that soluble sugar contents increased correspondingly with decreased starch contents. Temperate×tropical maize samples from both pollinated and non-pollinated treatments had high extractives. Glucan and xylan percentages were increased in non-pollinated extractive free samples. Ethanol produced from cellulosic material was similar for both treatments. The total ethanol yield (from starch, sugar and stover) was comparable from milk (R3) to dent (R5) stages and ranged from 0.20 to 0.22g/g biomass. The pollinated TTM produced higher biomass in the field and resulted in 624.7gal of ethanol per acre of land. Future research in TTM could be focused on increasing biomass yield of non-pollinated TTM.

Influência de formas de aplicação de boro na qualidade e no rendimento de maçãs (Malus domestica)

O boro (B) é aplicado na maioria dos pomares brasileiros de maçã, porém sem fundamentação experimental regional. Este trabalho teve por objetivo avaliar o efeito de formas, doses e épocas de aplicação de B no rendimento e na qualidade de maçãs. O experimento foi instalado em São Joaquim-SC, em 2002, com as cultivares Imperial Gala e Fuji Suprema conduzidas em áreas diferentes, cujas avaliações foram realizadas nas safras de 2009/2010 e 2010/2011. Os tratamentos consistiram em um fatorial envolvendo doses de B aplicadas ao solo, a cada dois anos, e épocas de pulverização na planta, feitas anualmente. Utilizou-se de delineamento experimental de blocos ao acaso, com três repetições, cujos tratamentos foram arranjados em parcelas subdividas: na parcela principal, foram alocadas as épocas de aplicação foliar de ácido bórico (sem pulverização, 0,3% pulverizado na fase de botão rosado e 0,6% em pós-colheita) e nas subparcelas, as doses de bórax no solo (0; 2,5 e 5,0 kg ha-1 de B). A aplicação de B no solo foi mais eficiente do que a pulverização foliar para aumentar o teor de B na polpa, na folha e no solo; no entanto, não afetou nenhum dos atributos relacionados com a qualidade dos frutos, nas duas cultivares. A pulverização com B diminuiu o teor de amido e a acidez titulável, e não afetou o teor de sólidos solúveis e a firmeza da polpa dos frutos. A pulverização na floração diminuiu a germinação de grãos de pólen na cultivar Imperial Gala e a frutificação efetiva na cultivar Fuji Suprema. O rendimento de frutos não foi afetado pela adição de B, independentemente da época, da forma de aplicação ou dose, nas duas cultivares. Assim, não há necessidade de aplicar B nessas cultivares em pomares cultivados em solos com altos teores de matéria orgânica, com o objetivo de incrementar a produção e a qualidade dos frutos.

Amylolytic activities and starch reserve mobilization during the germination of quinoa

Quinoa (Chenopodium quinoa) is a dicotyledonous plant producing perispermic seeds that is increasingly popular in the Western world due to its nutritional value. Germination can be used in food processing to alter the sensory, nutritional and functional properties of grains, and the increased enzyme activities may have beneficial influences in food applications. Knowledge about the germination of perispermic seeds is scarce. In this study, the development of amylolytic activities and subsequent changes in sugar profiles and starch content were followed in quinoa over a period of 72 h. The seeds germinated rapidly with radicle protrusion occurring 8 h after imbibition, when the seeds had reached a moisture content of 44 %. A low level of α-amylase activity (determined at pH 5.2 using blocked ρ-nitrophenyl-maltoheptaoside as substrate) was present in the embryo of non-germinating seeds, but emerged in the perisperm only after 24 h, followed by a sharp increase in activity in both tissues. The accumulation of glucose and fructose (determined with high pressure liquid chromatography) and the decrease in starch content (determined with an enzymatic assay) were observed after 24 and 36 h, respectively, indicating the onset of starch reserve mobilization. Overall, the levels of amylolytic activities remained very low compared with traditional malting cereals, suggesting the unsuitability of quinoa as a source of amylases in food applications. Scanning electron microscopy, used to visualize changes in starch granule morphology, showed mainly exocorrosion, suggesting a homogenous structure of the outer layers of quinoa starch.

Ability to Acclimate to Sedimentation Gradually Decreases with Burial Time in Two Emergent Macrophytes from Dongting Lake Wetlands in China

Growth, below/above-ground mass ratio (BG:AG ratio), root morphology, carbohydrate content, and alcohol dehydrogenase (ADH) activity in the low-elevation species Phalaris arundinacea and the high-elevation species Miscanthus sacchariflorus buried under 0, 5, and 10 cm of sediment were investigated one, two, and three months after burial. Biomass accumulation, BG:AG ratio, and the starch content of both species generally decreased with increasing burial depth and burial time, except for higher biomass accumulation in P. arundinacea in the first month. In the first month, adventitious roots of both species, and first-order laterals of P. arundinacea, were shorter and thicker in the buried plants than in the controls. The ADH activity in both species and the soluble sugar content of P. arundinacea increased with increasing burial depth in the first month. Only the diameter of adventitious roots and the soluble sugar content of P. arundinacea were affected by burial depth after two or three months. It is concluded that P. arundinacea is more tolerant to sedimentation than M. sacchariflorus due to more efficient acclimation strategies in root morphology and soluble sugar content. However, the ability to acclimate becomes weaker over time due to consistently decreasing starch content and the trade-off between tolerance to sedimentation and plant growth.

Thermoplastic starch and poly(ε-caprolactone) blends: morphology and mechanical properties as a function of relative humidity

This paper describes the elaboration and characterization of biodegradable films from thermoplastic starch (TPS) and poly(e-caprolactone) (PCL) blends. The films were obtained by a single screw extrusion process. Two PCLs of different molecular weights (37,000 and 50,000 g.mol−1, referred as PCL37 and PCL50) have been tested. Phase distribution of PCL and thermoplastic starch (TPS) has been characterized by FTIR, DSC and SEM. For the blend with PCL37, material surface is enriched with PCL, whereas in the blend with PCL50, TPS and PCL phases are more homogeneously distributed. Evolution of crystalline structure of the different formulations has been studied by X-ray diffraction, and mechanical properties by tensile tests. Maximal deformation of TPS/PCL blends is smaller than that of TPS, attesting the lack of compatibility between both polymers. Blending with PCL modifies the crystalline structure of TPS. Water resistance of the blends has been characterized by water sorption and water contact angle measurements. The decrease in water absorption for the blends was attributed to the decrease of starch content. At the surface of the material, water resistance of TPS/PCL50 blends is improved.

The effect of gibberellic acid (GA3) on seed size and sprouting of potato tubers (Solanum tuberosum L.).

An experiment was performed to evaluate the effect of gibberellic acid (GA3) on seed size and sprouting of potato (Solanum tuberosum L.). The experiment was laid done in factorial design (3 × 3) using Agria, Marfona and Draga cultivars and three concentrations of GA3 (0, 5 and 10 mg/lit). Results showed that application of gibberellic acid at low concentrations (5 and 10 mg/lit) was able to increase general performance and productivity of seed tubers of potatoes. Seed tuber production was increased by application of using gibberellic acid in all cultivars. Total weight of seed tubers produced by application of 5 mg/lit GA3 was statistically different compared to control (p ≤ 0.05). Also, results showed that after one week from application of GA3, starch content decreased and total content of sugar increased in potato tuber. The tubers treated with GA3sprouted earlier while in control sprouting was very late and slow. Furthermore, we indicated that sugar content is one of the important parameters determining the sprouting of seed potatoes. Thus the sequence of events can be summarized as: Application of GA3 → Starch hydrolysis → Decrease of starch content of tubers → Production and increase of total sugar content → Dormancy breaking → Tuber sprouting. Key words: Potato (Solanum tuberosum L.), gibberellic acid (GA3), tuber size, tuber sprouting.

Germination as a processing technique for soybeans in small-scale farming

Heat processing is an effective way of reducing antinutritional factors (ANFs) in legumes, but requires expensive facilities and equipment. Accurate control of temperature is critical to avoid under- or overheating. Therefore, heat treatment of soybeans is not a viable option for the average small-scale farmer in remote areas. Germination and other traditional methods, namely soaking and dehulling, were evaluated as alternative processing methods for soybeans. The effect of the processing treatment on the level of different ANFs, nutritional composition and in vitro protein digestibility (IVPD) of soybean seeds was determined. Soybeans were soaked for 24 hours and allowed to germinate for one to six days. Soaked soybeans were manually dehulled. Changes within seeds were noted for nutritional and ANFs during germination. Crude protein and fat content increased with increasing number of days germinated, but germination caused a decrease in starch content. Dehulling also increased the crude protein and fat content of the seeds. All treatments caused a significant decrease in condensed tannins of the soybeans. Trypsin inhibitor levels were numerically lower after germinating, soaking and dehulling of seeds, but not significantly so. There were no changes in IVPD after treatment of the soybeans. It was concluded that germination for a period of three days effectively improved the nutritional value of soybeans and can be considered an alternative treatment of soybeans for the small-scale farmer where heat treatment is impractical or impossible.

Voluntary Feed Intake in Rainbow Trout Is Regulated by Diet-Induced Differences in Oxygen Use

This study investigated the hypothesis that the voluntary feed intake in fish is regulated by diet-induced differences in oxygen use. Four diets were prepared with a similar digestible protein:digestible energy ratio (18 mg/kJ), but which differed in the composition of nonprotein energy source. This replacement of fat (F) by starch (S) was intended to create a diet-induced difference in oxygen use (per unit of feed): diets F30-S70, F50-S50, F65-S35, and F80-S20 with digestible fat providing 28, 49, 65, and 81% of the nonprotein digestible energy (NPDE), respectively. Each diet was fed to satiation to triplicate groups of 20 rainbow trout for 6 wk. As expected, diet-induced oxygen use decreased linearly (R2 = 0.89; P < 0.001) with increasing NPDE as fat. The digestible and metabolizable energy intakes of trout slightly increased with increasing NPDE as fat (i.e., decreasing starch content) (R2 = 0.30, P = 0.08; and R2 = 0.34, P = 0.05, respectively). Oxygen consumption of trout fed to satiation declined with increasing dietary NPDE as fat (R2 = 0.48; P = 0.01). The inverse relation between digestible energy intake of trout and the diet-induced oxygen use (R2 = 0.33; P = 0.05) suggests a possible role of diet-induced oxygen use in feed intake regulation as shown by the replacement of dietary fat by starch.

Effects of feeding dried distillers grains with supplemental starch on fecal shedding of Escherichia coli O157:H7 in experimentally inoculated steers1

Distillers grains (DG), a co-product of ethanol production used as protein and energy supplements in cattle diets, have been shown to increase fecal shedding of Escherichia coli O157:H7, a major foodborne pathogen. The reason for the positive association is not known. Because DG often replaces grain in the diet, decreased starch content and flow to the hindgut may create a favorable environment for E. coli O157:H7. Our objective was to determine whether the addition of starch to a corn DG-supplemented diet negates the effects of DG on fecal shedding of E. coli O157:H7. We conducted a study with 21 steers fed 1 of 3 diets: a corn grain-based basal diet (CON), basal diet supplemented with 25% corn dried DG (DDG), and basal diet supplemented with 25% DDG with corn starch (DDG+S) added at a level intended to increase starch concentration to that of the CON diet. Steers, housed individually in a biosafety level 2 animal facility, were randomly allocated to treatment diets and orally inoculated with a 5-strain mixture (10(9) cfu per steer) of nalidixic acid-resistant (Nal(R)) E. coli O157:H7. Fecal samples were collected for 5 wk, and on d 35, steers were euthanized and necropsied to collect gut content samples. Fecal or gut samples were cultured to determine prevalence and concentrations of Nal(R) E. coli O157:H7. Dietary starch concentrations, based on feed analysis, were 46.3% in the CON compared with 43.3 and 41.3% in the DDG and DDG+S diets, respectively. Steers fed DDG or DDG+S diets shed Nal(R) E. coli O157:H7 more often (P = 0.0027 and 0.0003, respectively) and at greater concentrations (1.9 or 2.0 cfu/g; P = 0.0025 and 0.0006) than those fed CON diet (1.4 cfu/g), but no difference was observed between DDG and DDG+S diets. Cumulative prevalence and concentrations of Nal(R) E. coli O157:H7 were greater in gut samples collected at necropsy in steers fed DDG and DDG+S diets compared with those fed CON diet, but no difference was observed between DDG and DDG+S diets. The lack of effect of starch addition to the DDG diet on fecal shedding of E. coli O157:H7 may be because either the decreased starch content in the DG-supplemented diet is not a factor in the increased shedding of E. coli O157:H7 or inclusion of pure starch in the diet may not have achieved our intended goal to have starch flow into the hindgut similar to that of corn grain. The study confirms our previous finding of the positive association between feeding DG and fecal shedding of E. coli O157:H7.

Effects of Heat Stress During Grain Filling on the Functional Properties of Flour from Fresh Waxy Maize

ABSTRACTThe effects of temperature during grain filling on the quality of fresh waxy maize grain were investigated using three varieties. Plants of the selected varieties were subjected to two temperature treatments, namely, control (mean daily air temperature, 30°C) and heat stress (35°C), after artificial pollination (1–23 days after pollination). Heat stress decreased starch content and crystallinity and increased the contents of protein and protein fractions (albumin, globulin, zein, and glutenin), but it did not affect soluble sugar content in general. The effects of heat stress on grain textural characteristics were variety dependent, except for springiness, which was similar between treatments. Pasting and thermal properties were also affected by heat stress. The results suggest that heat stress during grain filling changes the composition of flour and crystalline structure of starch, thereby decreasing viscosities and enthalpies of gelatinization as well as increasing the pasting and gelatinization temperature of fresh waxy maize.

Accumulation and degradation of starch in carrot roots

Carrot (Daucus carota L.) roots are traditionally considered as containing negligible amounts of starch. Depending on the type of extraction medium used to remove interfering sugars from root tissue however, the yield of starch content varies. To re-examine the role of starch in carrots, high-starch cultivars were identified and their starch and sugar content monitored during root development in the field and during storage. Starch up to 150 or even 180mgg−1 dry weight accumulated in some of these cultivars. Low-temperature storage (2°C) decreased the starch content dramatically and concomitantly increased the sucrose content. Sensory triangle tests and ranking tests of sweetness performed with juices produced from carrot roots revealed significant differences between freshly harvested and stored roots, indicating a gain in sweetness achieved by starch mobilization. Post-harvest sweetening of carrots was accompanied by a transient increase in total amylase activity and malto-oligosaccharides (MOS) content. In contrast, if roots were stored at room temperature (19°C), there was also a decrease in starch content and an increase in sucrose content, but total amylase activity and MOS content declined, suggesting different metabolic pathways at the two temperatures. The possible role of starch in sugar accumulation and in stress adaptation of carrot is discussed. It is concluded that starch is a key reserve carbohydrate in carrot.