No description available.

Urban forests grow in stressful environments that can have negativerepercussions on tree energy reserves. The goal of this research was to evaluate theimpact of exogenously applied carbohydrates on growth and vitality of live oaks(Quercus virginiana P. Miller). An initial study focused on carbohydrate partitioningrevealed that annual mean glucose concentration in leaf tissues (49.55 mg·g-1 DW) wasalmost double that in twigs, trunks, or roots. Starch concentrations in roots and trunks(38.98 and 38.22 mg·g-1 DW of glucose, respectively) were higher during the dormantseason and approximately three times the concentrations found in other tissues. Aninvestigation of the effects of exogenous soil applications of glucose and starch on soilmicrobial activity revealed no significant differences using recoverable viable microbes.However, soil respiration was significantly increased (P<0.05) by glucose a week afterapplication, while higher starch concentrations (120 g·L-1) significantly increased(P<0.05) soil respiration after the fourth week. Although tree soil drenched withcarbohydrates in a different study showed significantly (P<0.05) greener leaf color, higher chlorophyll fluorescence, and increased soil respiration at higher concentrationsof starch (120 g·L-1), no significant differences were observed in photosynthesis or trunk,canopy, or root growth. Analysis of 13C signatures was unable to detect uptake ofexogenous carbohydrates. For trunk-injected trees with glucose and sucrose, trunkgrowth was significantly (P<0.05) increased by carbohydrate supplementation.Differences were also found in twig glucose content, root starch content, and chlorophyllfluorescence among overall concentration means. A study to compare field diagnostictools with carbohydrate laboratory analysis established that a portable blood glucosemeter can be used to measure glucose content in trees. However, ohmmeter,refractometer, chlorophyll fluorescence spectrometer, and iodine staining results did notcorrelate well with laboratory analysis of carbohydrate concentrations. Results fromthese studies reveal that soil applied carbohydrates can greatly increase soil microbialactivity, provide evidence that trunk-injected carbohydrates may improve growth andvitality of live oaks, and provide a new field diagnostic tool to increase the efficiency ofmeasuring carbohydrates in trees.

<p>Ethanol production at Lantmännen Agroetanol AB in Norrköping began in December 2000. The objective of this master's thesis is to find and optimize factors affecting the yield of the liquefaction, a part of the upstream process. To measure successfulness of liquefaction it is desired that amount of non-solubilized starch is quantified, and hence a method for determination of non-solubilized starch in mash has to be developed.</p><p>Starch is a carbon reserve in plants. Starch granules are polymers of amylose and amylopectin which are polysaccharides of glucose. When a starch/water solution is heated the starch granules start to absorb water and swell, a process termed gelatinization. The swelling makes the granules susceptible to hydrolysis by enzymes such as alpha-amylase, this is called liquefaction. Eventually the granular structure is broken and the slurry contains solubilized starch which can be saccharified to glucose by glucoamylase. In the bioethanol production process, the milled grain is mixed with water and enzymes. The slurry is heated, gelatinization and liquefaction occurs. Saccharification occurs simultaneously to fermentation. Ethanol is purified from the fermented mash during downstream processing.</p><p>Starch in the form of starch granules cannot be quantified. The adopted principle for determination of non-solubilized starch in liquefied mash is to wash away the solubilized starch, then quantitatively hydrolyze non-solubilized starch to glucose and quantify glucose.</p><p>To find and optimize factors significant for yield of liquefaction multiple factor experiments were conducted where eight factors were studied. pH, temperature in mixtank and temperature in liquefaction tank 1 were the most significant factors. The temperature in liquefaction tank 1 should be kept as is is at 74°C. A small rise in pH should shorten the mean length of dextrins which is preferable. An increase of pH from 5.2 to 5.4 is therefore proposed. The temperature in mixtank should also be increased by a few degrees. The yield of the process should be carefully evaluated during the modifications.</p> / <p>Etanolproduktionen på Lantmännen Agroetanol AB i Norrköping började i December 2000. Målet med examensarbetet är att hitta och optimera faktorer som påverkar utbytet av likvifieringen i etanolproduktionen. För att studera utfallet av likvifieringen är det önskvärt att mäta hur mycket stärkelse som inte har löst sig, och därför måste en metod för att mäta olöst stärkelse i mäsk utvecklas.</p><p>Stärkelse utgör en kolreserv i växter. Stärkelsegranuler är polymerer av amylos och amylopektin, vilka i sin tur är polysackarider av glukos. När en stärkelse/vatten-blandning värms upp börjar stärkelsegranulerna att absorbera vatten och svälla, en process som kallas gelatinisering. Svällningen gör granulerna känsliga mot hydrolys av till exempel enzymet alfa-amylas, vilket kallas för likvifiering. Efter tillräckligt mycket gelatinisering och likvifiering förstörs hela den granulära strukturen och stärkelsen övergår till löst form. Löst stärkelse kan försockras till glukos med enzymet glukoamylas. I produktionen av bioetanol blandas malet spannmål med vatten och enzymer. Slurryn värms upp och gelatinisering och likvifiering sker. Försockring sker simultant med fermenteringen. Etanol renas fram från den fermenterade mäsken i nedströmsprocessen.</p><p>Stärkelse i granulform kan inte kvantifieras. Den valda metoden för mätning av olöst stärkelse i likvifierad mäsk innebär att den lösta stärkelsen tvättas bort, sedan hydrolyseras den olösta stärkelsen kvantitativt till glukos, vilken kan kvantifieras.</p><p>Flerfaktorförsök gjordes för att hitta och optimera faktorer signifikanta för utbytet av likvifiering. Åtta olika faktorer studerades. pH, temperatur i mixtank och temperatur i likvifieringstank 1 visade sig vara de tre mest signifikanta faktorerna. Temperaturen i likvifieringstank 1 ska bibehålla samma temperatur som idag, 74°C. En liten höjning av pH borde förkorta medellängden av dextrinerna, vilket är fördelaktigt. En ökning av pH från 5,2 till 5,4 är föreslås därför. Temperaturen i mixtanken ska ökas några få grader. Utbytet av processen måste noggrant utvärderas under modifieringarna.</p>

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references. Also available in print.

The xerophytic gourds, Apodanthera undulata and Cucurbita digitata, hold promise as new sources of starch for industrial and domestic use as world population increases and food demands become greater. Thus, understanding of the chemical and physical properties of the starches from these arid land plants is required. Moisture content, ash, fiber and starch content of A. undulata and C. digitata roots were comparable to Solanum tuberosum (potato) and Manihot utilissima (tapioca). High lipid content was observed in A. undulata, but C. digitata was similar to tapioca in this respect. The composition of subject starches was comparable to standard starches. The lipid content of C. digitata starch was similar to that of corn starch, but A. undulata starch exhibited a higher content. A. undulata starch showed a higher iodine binding capacity, hence a higher amylose content, than C. digitata, potato and C. foetidissima starches. The number of terminal aldehyde groups and the average granule size of subject starches were comparable to tapioca starch. Interestingly, gelatinization temperature and percent sag test values were more similar to cereal starches such as corn, than to potato or tapioca. The swelling power of both starches was intermediate between corn and tapioca, while the solubility of A. undulata was similar to corn starch. The paste viscosity of A. undulata and C. digitata, when compared to corn, potato and C. foetidissima, proved to be most similar to corn. Viscosity maxima were intermediate between corn and potato. C. digitata starch was very stable, showing little change in paste viscosity after heating for one hour at 90°C. Increases in viscosity occurred during the cooling period for A. undulata, C. digitata and corn, but negligible changes occurred in C. foetidissima and potato. Starches isolated from A. undulata, C. digitata and potato were evaluated nutritionally by an in vivo study. Increases in digestibility of autoclaved starches (85% for A. undulata, 85% for C. digitata and 91% for potato) over raw starches (40% for A. undulata, 40% for C. digitata and 24% for potato) were confirmed by statistical analysis. Feed consumption and body weight gain were higher than for the potato starch diet. Autoclaving also improved net protein ratio and protein efficiency ratio. The fine structure of the macromolecular fractions amylose and amylopectin from starches of A. undulata and C. digitata were examined. The dimethyl sulfoxide method proved to be effective for fractionation of each starch. Purity of these components was confirmed by iodine binding capacity, and they were found to be similar to standard starches. Calculated values for degree of polymerization (DP) were similar to that of potato. Study of the fine structure of these components showed beta-amylolysis limits of approximately 90% for the amyloses and above 60% for the amylopectins. These values were similar to those of potato and intermediate between tapioca and cereal starches. The average chain length of the A. undulata amylopectin was found to be 25 with an outer chain length of 18 and an inner chain length of 6. The average chain length of 18 and an inner chain length of 6. The average chain length for C. digitata amylopectin was 26 with an outer chain length of 19 and an inner chain length of 6. These relatively long exterior layers with respect to the short interior layers show the amylopectins of these starches to be asymmetric molecules comparable to potato.

Ethanol production at Lantmännen Agroetanol AB in Norrköping began in December 2000. The objective of this master's thesis is to find and optimize factors affecting the yield of the liquefaction, a part of the upstream process. To measure successfulness of liquefaction it is desired that amount of non-solubilized starch is quantified, and hence a method for determination of non-solubilized starch in mash has to be developed. Starch is a carbon reserve in plants. Starch granules are polymers of amylose and amylopectin which are polysaccharides of glucose. When a starch/water solution is heated the starch granules start to absorb water and swell, a process termed gelatinization. The swelling makes the granules susceptible to hydrolysis by enzymes such as alpha-amylase, this is called liquefaction. Eventually the granular structure is broken and the slurry contains solubilized starch which can be saccharified to glucose by glucoamylase. In the bioethanol production process, the milled grain is mixed with water and enzymes. The slurry is heated, gelatinization and liquefaction occurs. Saccharification occurs simultaneously to fermentation. Ethanol is purified from the fermented mash during downstream processing. Starch in the form of starch granules cannot be quantified. The adopted principle for determination of non-solubilized starch in liquefied mash is to wash away the solubilized starch, then quantitatively hydrolyze non-solubilized starch to glucose and quantify glucose. To find and optimize factors significant for yield of liquefaction multiple factor experiments were conducted where eight factors were studied. pH, temperature in mixtank and temperature in liquefaction tank 1 were the most significant factors. The temperature in liquefaction tank 1 should be kept as is is at 74°C. A small rise in pH should shorten the mean length of dextrins which is preferable. An increase of pH from 5.2 to 5.4 is therefore proposed. The temperature in mixtank should also be increased by a few degrees. The yield of the process should be carefully evaluated during the modifications. / Etanolproduktionen på Lantmännen Agroetanol AB i Norrköping började i December 2000. Målet med examensarbetet är att hitta och optimera faktorer som påverkar utbytet av likvifieringen i etanolproduktionen. För att studera utfallet av likvifieringen är det önskvärt att mäta hur mycket stärkelse som inte har löst sig, och därför måste en metod för att mäta olöst stärkelse i mäsk utvecklas. Stärkelse utgör en kolreserv i växter. Stärkelsegranuler är polymerer av amylos och amylopektin, vilka i sin tur är polysackarider av glukos. När en stärkelse/vatten-blandning värms upp börjar stärkelsegranulerna att absorbera vatten och svälla, en process som kallas gelatinisering. Svällningen gör granulerna känsliga mot hydrolys av till exempel enzymet alfa-amylas, vilket kallas för likvifiering. Efter tillräckligt mycket gelatinisering och likvifiering förstörs hela den granulära strukturen och stärkelsen övergår till löst form. Löst stärkelse kan försockras till glukos med enzymet glukoamylas. I produktionen av bioetanol blandas malet spannmål med vatten och enzymer. Slurryn värms upp och gelatinisering och likvifiering sker. Försockring sker simultant med fermenteringen. Etanol renas fram från den fermenterade mäsken i nedströmsprocessen. Stärkelse i granulform kan inte kvantifieras. Den valda metoden för mätning av olöst stärkelse i likvifierad mäsk innebär att den lösta stärkelsen tvättas bort, sedan hydrolyseras den olösta stärkelsen kvantitativt till glukos, vilken kan kvantifieras. Flerfaktorförsök gjordes för att hitta och optimera faktorer signifikanta för utbytet av likvifiering. Åtta olika faktorer studerades. pH, temperatur i mixtank och temperatur i likvifieringstank 1 visade sig vara de tre mest signifikanta faktorerna. Temperaturen i likvifieringstank 1 ska bibehålla samma temperatur som idag, 74°C. En liten höjning av pH borde förkorta medellängden av dextrinerna, vilket är fördelaktigt. En ökning av pH från 5,2 till 5,4 är föreslås därför. Temperaturen i mixtanken ska ökas några få grader. Utbytet av processen måste noggrant utvärderas under modifieringarna.

As part of a project to see whether potatoes with a low glycemic-index (GI) could be developed through plant breeding, the GI values of 4 new potato varieties differing in starch structure was determined in 3 studies over 2 years in human subjects. Since cooking and cooling affects starch structure the potatoes were studied both freshly cooked (boiled) and cooled. The first study showed that cooling reduced the GI of two varieties by 40-50% but had no effect in the others (treatment × variety interaction, p=0.024), an effect which was confirmed in study 2. Differences in GI were readily explained by differences in starch structure or in-vitro digestion rate. Carbohydrate malabsorption increased from 3 to 5% upon cooling, not enough to account for the reduced GI. It is concluded that the effect on GI of cooling cooked potatoes varies in different varieties. Further research is needed to understand the mechanism.

Starch is the major constituent of matured wheat grain. The details of subtle localized differences in the evolution of the structure of starch are important for an understanding of starch biosynthesis. However, the distinct stages involved in the formation and transformation of the molecular structure of starch during starch biosynthesis are still not fully understood. In this study, starches extracted from wheat grains harvested at 3, 7, 14, 28, and 49 days after anthesis (DAA) were used as a means of examining the molecular structure of starch from developing wheat grain. Gel-permeation chromatography and high-performance anion-exchange chromatography were employed for the analysis of the structure of both whole starch and its isolated amylopectin (AP) component. Scanning electron microscopy of 3 DAA wheat grain cross-sections revealed the absence of endosperm but the presence of spherical transitory-type small starch granules in the pericarp. Endosperm was present at 7 DAA and contained lenticular-shaped developing large granules. From 14 DAA onward, spherical-shaped small granules coexisted with large granules in the endosperm. The structure of transitory pericarp starch (PS) was compared with that of matured endosperm storage starch (ES). The composition of PS and ES differed: PS granules contained 14 % apparent amylose (AAM), whereas ES granules contained 33 % AAM. The AAM fractions of PS showed characteristics similar to those of intermediate-type materials with short branches, whereas ES contained both linear and branched amylose (AM). Differences in the amylopectin component of PS and ES were also apparent, especially in their internal structures. PS amylopectin had longer chains and fewer A-chains, resulting in a structure less branched than that of ES amylopectin. Starches isolated from 7 DAA to 49 DAA were studied with respect to endosperm development. The AAM of both large and small granules increased with increasing maturity. The AAM fraction of starch granules at early maturity (7 DAA and 14 DAA) consisted of intermediate-type materials in addition to linear AM, whereas starch at later maturity stages (28 and 49 DAA) contained linear and branched AM. During granule development, the fine structure of AP varied with the maturity level as well as with the size of the granule. During the post-physiological maturity stage, when the net accumulation of sugars ceases, the grain dries out; however, structural changes occurred in AP at this stage, possibly due to the action of starch branching and debranching enzymes. In both large and small granules, the external AP structure was more organized at post-physiological maturity (49 DAA) than at pre-physiological maturity (7 DAA to 28 DAA). Compared to their characteristics at post-physiological maturity, at the pre-physiological maturity stage, isolated clusters of AP were larger with more branches and building blocks. In addition to the time-dependent discrepancies in the AP structure of developing starch, differences were also evident between large and small granules with regard to glucan trimming and the type of new chains produced. The clusters isolated from small starch granules were more tightly branched than those isolated from large granules

Transformations in the properties of low-moisture dough products (cookies and crackers) during baking have been studied under idealized conditions in pilot facilities and laboratories. However, little research is published that describes dough development within the context of complex industrial baking processes. A process mapping approach was adopted, in which oven parameters were profiled and matched against changes in dough. In cookies, changes to starch A-granules, including loss of granule birefringence, disruption to granule borders and increased gel viscosity were observed. Development of acrylamide in cookies was seen to trail colour development, suggesting options for mediating acrylamide content. In crackers, the presence of additional water allowed significant changes to starch A-granules to occur, including: swelling similar to the early stages of gelatinization in bread, reduced pasting ability, a drop in enthalpy, and a loss of crystallinity. Emulation of low-moisture dough baking at the benchtop level, based upon internal product temperature data from industrial processes, was found to be limited in its ability to produce crackers having appropriate leavening and internal structure development. The determination of isosteric heat of desorption values for cookies and crackers, modeled on industrial processes at temperatures > 100°C, gave values of 44.3 and 42.7 kJ/mol, respectively. This data will be useful for establishing energy requirements in industrial baking processes / MITACS, OMAFRA

No description available.