Starchy Materials Research Articles

The analysis of plant remains from the fortress Ras - the 12th and the beginning of the 13th century

The analysis of plant remains from the fortress Ras - the 12th and the beginning of the 13th century

Exopolysaccharide production from Sclerotium glucanicum NRRL 3006 and Botryosphaeria rhodina DABAC-P82 on raw and hydrolysed starchy materials.

Evaluation of fermentative usage of raw starchy materials for exopolysaccharide (EPS) production by Sclerotium glucanicum NRRL 3006 and Botryosphaeria rhodina DABAC-P82. Non-hydrolysed corn starch, soft wheat flour, potato flour, cassava flour, sweet and industrial potato flours, and corn starch hydrolysed to different dextrose equivalent (DE) were tested in shaken culture for EPS production. Both fungal strains produced EPS on all tested materials but the production was maximum on hydrolysed corn starch (30.5 and 19.8 g l(-1) by B. rhodina and S. glucanicum on corn starch at 100 and 62 DE, respectively). Raw starchy materials as such and, in particular, partially or totally hydrolysed corn starch could be used profitably for EPS production by S. glucanicum and B. rhodina. The excellent EPS production, productivity and yield of B. rhodina DABAC-P82 when grown on 60 g l(-1) of totally hydrolysed corn starch.

Stone tool function at the paleolithic sites of Starosele and Buran Kaya III, Crimea: behavioral implications.

Stone tools are often the most abundant type of cultural remains at Paleolithic sites, yet their function is often poorly understood. Investigations of stone tool function, including microscopic use-wear and residue analyses, were performed on a sample of artifacts from the Paleolithic sites of Starosele (40,000-80,000 years BP) and Buran Kaya III (32,000-37,000 years BP). The Middle Paleolithic levels at Starosele exhibit a typical variant of the local Micoquian Industry. The artifacts from Buran Kaya III most closely resemble an Early Streletskayan Industry associated with the early Upper Paleolithic. The results of the functional analyses suggest that hominids at both sites were exploiting woody and starchy plant material as well as birds and mammals. Both sites show evidence of hafting of a wide variety of tools and the possible use of projectile or thrusting spears. These analyses were performed by using two different techniques conducted by independent researchers. Combined residue and use-wear analyses suggest that both the Upper Paleolithic and Middle Paleolithic hominids at these sites were broad-based foragers capable of exploiting a wide range of resources.

Degradation of starchy food material by thermal analysis

Raw starch has been used in recent years as a direct substrate for enzyme digestion in the production of fermentation products. The objective of this study was to examine the differences between the residual raw starch produced after partial hydrolysis with these enzymes and compare the enzyme treated and native material. In order to examine the porous starch granules produced due to partial hydrolysis, they were examined calorimetrically using DSC. A structural analysis was also made using SEM.

Measurement of glass transition in native wheat flour by dynamic mechanical thermal analysis (DMTA)

Summary This work describes a method to study glass transition on native starch powders, based on dynamical mechanical thermal analysis using compression tests, and was applied to wheat flour (13.5% water content). This method will allow the determination of Tg in native (unprocessed) starchy materials, with minimal disturbance of the natural structures. The influence of the test conditions (heating rate, frequency and strain) on the glass transition measurements was determined using factorial designs. The values of Tg determined as the maxima of the energy dissipation (peaks in E″) of native flour and of freeze‐dried pre‐gelatinized flour were not statistically different (around 64 °C). The heating rate did not affect the measurements in the range tested (0.25 to 1 °C min−1). An interactive effect of the strain amplitude and the frequency was detected. The significance of this interaction can be caused by differences in mechanical energy dissipation, which would indicate that not only temperature but also the total energy input may affect this transition. Slight effects of phase separation between gluten and starch were found on native flour.

Effect of Regeneration Thermal Treatment of Cellulosic and Starchy Materials on their Capacity to Separate Water and Ethanol

Inverse gas chromatography was used to study the adsorption of water and ethanol on to a starchy (wheat flour) and a cellulosic (wheat straw) substrate, in the temperature range 50–90 °C, before and after their regeneration by thermal treatments at 140 and 170 °C, for 12 and 24 h each. From the chromatographic retention data it was possible to calculate the separation factor (s) of the two solutes and to obtain values for Gibb's free energy (ΔGs) and enthalpy (ΔHs) of adsorption. The results showed that water was adsorbed more strongly than ethanol by both substrates, at all temperatures, before and after their regeneration. In addition, it was found that, for both untreated and thermally treated materials, the adsorption of both solutes was stronger at lower temperatures. Thermal treatment had no effect on the adsorption of ethanol on either substrate. In contrast, the adsorption of water was weaker for both substrates regenerated at 140 °C and even weaker for the substrates treated at 170 °C, irrespective of the duration of the regeneration process. Furthermore, at both regeneration temperatures, the decrease in water sorption was approximately the same for both materials, irrespective of regeneration time. The separation factors followed, in general, the same trend observed for water sorption. They had lower values for materials regenerated at 170 °C for 24 h. Both materials were equally affected by the regeneration process.

Production and Characteristics of an Ancient Form of Sake Made with Shitogi

Efforts have been made to reproduce shitogi, a finely pounded rice powder and to make sake from shitogi of the type produced in ancient times in Japan. As the particle size of the shitogi became smaller, the rate of degradation of shitogi by glucoamylase increased. The pounding of shitogi enhanced the saccharification of starchy materials. The ancient Japanese alcoholic beverage known as shitogi sake was made with cooked rice, dry yeast and tap water, using mould-infected shitogi as the saccharifying agent. It contained 10.7–14.3% ethanol (v/v) and had a fine aroma but a sour taste. We believe that we have reproduced the alcoholic beverage, shitogi sake which might have been one of original Japanese alcoholic beverages.

Modification of structure and digestibility of chestnut starch upon cooking: a solid state (13)C CP MAS NMR and enzymatic degradation study.

The modification of starch, which is the major component of the polysaccharide fraction of chestnuts (Castanea sativa), has been studied from the point of view of structure and digestibility to understand the modifications induced by cooking and, specifically, by the Maillard reaction. The study was carried out by enzymatic degradation kinetics, monitoring the glucose released upon time, and by solid state (13)C CP MAS NMR, which has the potential of monitoring the solid state phase changes occurring upon chemical modification due to the cooking process. Results obtained reveal that large changes are induced in the macromolecular structure of starchy materials and that these changes are correlated with changes of digestibility in terms of enzymatic degradation resistance. In the system studied, the extension of the Maillard reaction is not such as to exert a significant influence on structure and/or digestibility of chestnut starch.

Itaconic acid production by Aspergillus terreus on raw starchy materials

Starchy materials such as corn starch, soft wheat flour, potato flour, cassava flour, sorghum starch, sweet potato and industrial potato flours, either acid or enzymatically hydrolysed, were used as substrates for itaconic acid production by Aspergillus terreus NRRL 1960. Both production and yield were highest on corn starch (18·4 g l−1 and 34·0%, respectively). The degree of hydrolysis had a great influence on acid production which was highest when corn starch was saccharified at 85 DE (dextrose equivalent). In a 3 litre benchtop fermenter, itaconic acid production and productivity were 19·8 g l−1 and 0·13 g l−1 h−1, respectively.

澱粉質食品の調理科学的研究 澱粉の構造と糊化・老化性

Starchy materials such as cereals, legumes, tubers, and rhizomes are served as foods through the appropriate processing of cooking, which causes the gelatinization of starch. The gelatinized starch is thermodynamically unstable and tends to retrograde during storage. The retrogradation generally decreases the quality of foods known as the staling of bread and the hardening of cooked rice. Therefore, how to control gelatinization and retrogradation is of prime concern of cereal chemists and technologists. I have been involved in this study for nearly 40 years. As early as 1961 we found that microwave heating was very efficient for the rapid cooking of rice, but the cooked rice rapidly hardened by the retrogradation of starch. This was improved by the addition of a small amount of Takaamylase in cooking. Root vegetables are well known for being unable to become soft through cooking even by continued heating after heating has been suspended for a while halfway through cooking. By a detailed analysis of the gelatinization of starch during cooking, this phenomenon was found to be caused by the enhancement of retrogradation of the partially gelatinized starch by cooling. Furthermore, it was found that the heat-stable materials, including various minerals, enhanced the retrogradation. The relationship between structures and functions was investigated on various kinds of starch such as nagaimo (yam), lotus, arrowhead, taro, bracken, and tapioca used in confectioneries. It was found that starches having a high tendency to retrograde had amylopectin with long chain-length and smaller amylose molecules. For example, tapioca starch showed the lowest retrogradation tendency, and this appeared to be due to the short chain length of amylopectin and large amylose molecules, besides thee low amylose content. The relatively higher retrogradation tendency of potato starch seemed to be due to the long chain length of amylopectin. A clear-cut relationship was found between the phosphate content and the pasting viscosity in potato starch that the higher level of phosphorus gave the higher-pasting viscosities. Kuzu amylopectin showed a relatively low retrogradation tendency because of the medium chain length of amylopectin, but kuzu amylose had a high retrograding tendency because of small molecules. Bracken amylopectin with a similar chain length showed a similar retrograding tendency to that of kuzu. Some taro starches showed similar structures and properties to tapioca starch, and they also had low levels of amylose. The starches found in vegetables used in cuisine on New Year's Day have low retrograding tendencies. Therefore they are suitable for use as preservable foods. Amylose molecules are slightly branched molecules on average, and the branches are mostly short chains, but the function of side chains has not been investigated. We attempted to clarify this function by means of a model experiment on molecules that had incorporated small amounts of maltosyl side chains into linear chains by the reverse action of isoamylase. The results clearly showed that these small amounts of maltose side chains affected a decrease in retrograding tendency.

Effect of adsorbent particle size and temperature on water-ethanol separation by starchy and cellulosic substrates

Inverse gas chromatography was used to study the adsorption of water and ethanol on two starchy (cornmeal and wheatflour) and one cellulosic (wheat straw) substrate, in the temperature range 50–90 °C. Three particle size fractions of each substrate were investigated – 180–250 μm, 160–180 μm and 125–160 μm, denoted, respectively, by: 60–80 mesh, 80–100 mesh and 100-120 mesh. Values for the separation factor and for thermodynamic parameters, such as Gibbs free energy and enthalpy of adsorption, were calculated from the chromatographic retention data. The results showed that water was adsorbed more strongly than ethanol on all substrates, at all temperatures. In addition, it was found that lower temperatures were more favourable for the adsorption of both solutes. There was no significant difference between values of separation capacity of the three fractions of wheat straw. In contrast, the separation capacities of starchy materials with smaller particle sizes, i.e. 80–100 mesh and 100–120 mesh, were greater. The 100–120 mesh wheatflour fraction exhibited the highest separation at all temperatures.

Ethanol from babassu coconut starch

This study describes a pioneering industrial-scale experience by Tobasa in ethanol production from the amylaceous flour obtained by mechanical processing of the babassu mesocarp. Technical aspects related to enzymatic and fermentation processes, as well as overall economical aspects, are discussed. When produced in a small-size industrial plant (5000 L/d), babassu ethanol has a final cost of about $218/m3. The impact of raw materials, production, and processing (enzymes, steam, energy, and so on) on the final product cost is also presented. Babassu coconut ethanol can be produced at low cost, compared with traditional starchy raw materials or sugar cane. The net profitability of ethanol production is about 40% for babassu coconut and just 10% for sugar cane. If the estimated renewable babassu resources were entirely industrially used, 1 billion L/yr of ethanol could be produced, which would roughly correspond to 8% of the current Brazilian ethanol production.

An In Vitro Method, Based on Chewing, To Predict Resistant Starch Content in Foods Allows Parallel Determination of Potentially Available Starch and Dietary Fiber

The purpose of this work was to develop a method for measurement of the major forms of resistant starch (RS) in foods. The analytical procedure was chosen to mimic physiologic conditions, and included chewing as a prestep before incubation with pepsin, pancreatin and amyloglucosidase. The undigestible polysaccharides, including RS, were recovered by ethanol precipitation and subsequent filtration. RS was analyzed as total starch in the filter residue. The residues were also used for gravimetric determination of dietary fiber after correcting for remaining protein, ash and RS. The potentially available starch fraction was determined from analysis of glucose in the filtrate. The foods included were prepared to resemble products for which RS figures were available from in vivo measurements, and/or from analysis with other current in vitro methods. For six of these foods, and for three additional starchy materials, RS figures were compared with in vivo and/or in vitro data for identical products. The pooled standard deviation for the suggested RS method was 2.9%. A high correlation was obtained with in vivo figures from the literature for 19 realistic foods (r = 0.97; y = 0.77x + 0.45). After correction for RS, dietary fiber figures corresponded well with conventional gravimetric dietary fiber analysis for 14 starchy foods (r = 0.97). It is concluded that the procedure described here provides a convenient way to estimate RS content of realistic foods, allowing parallel determination of the potentially available starch fraction and dietary fiber.

Structural Modification and Bioavailability of Starch Components As Related to the Extent of Maillard Reaction: An Enzymatic Degradation and a Solid-State (13)C CPMAS NMR Study.

Starch and starch components, amylose and amylopectin, from potato, have been studied in order to understand the modifications, induced by different levels of the Maillard reaction occurring in the presence of amino acids (L-lysine in this study), in the macromolecular structure and digestibility. Structural characterization was performed by (13)C CPMAS NMR, and differences in the bioavailability of these polymers were studied by enzymatic degradation kinetics. Results obtained reveal that changes are induced by the Maillard reaction, whose occurrence has been verified and measured by the furosine (epsilon-N-2-furoylmethyl-L-lysine) evaluation, on the macromolecular structure of starchy materials and on their enzymatic susceptibility. Lysine seems to act as a disordering agent; a loss of crystallinity is evident for starch and amylopectin and, in particular, for amylose. Finally, within the same sample, as the lysine concentration increases, the polymer digestibility decreases, confirming that structural organization is not the only determinant of starch digestibility.

Evaluation of the function of arming yeast displaying glucoamylase on its cell surface by direct fermentation of corn to ethanol

We have constructed a Saccharomyces cerevisiae strain displaying glucoamylase from Rhizopus oryzae on its cell surface, which could grow on soluble starch as the sole source of carbon and energy (Murai et al., Appl. Environ. Microbiol., 63, 1362–1366, 1997). This system was introduced into a yeast strain, G-1315, with a high fermentation ability, and the direct production of ethanol from corn was examined. When a transformant of strain G-1315 displaying glucoamylase on the cell surface was cultivated statically at 27°C for 7 d using ground raw corn as starchy material, ethanol was produced at a concentration of 2.34% (w/w). Addition of an α-amylase reagent (Termamil) to liquefy the ground corn prior to fermentation improved the ethanol production to 5.32% (w/w), which was comparable to that of transformants secreting glucoamylase. These results demonstrate that the “arming yeast” developed by a cell surface engineering technique and its further improvement is applicable to direct fermentation of starchy materials.

Compaction and flow of potato starch and potato granules Compactación y flujo de almidón de patata y gránulos de patata

Potato starch and potato granules are materials that are often used in extrusion processes. It is important to quantify their rheology for modelling and prediction of process performance. The compaction behaviour of potato starch was examined at water contents of 4-18% wwb (wet weight basis) for pressures between 1 and 85 MPa. The Heckel deformation stress decreased as the water content increased up to 12% but became inaccurate at 18%. This decrease agreed qualitatively with other observations of the decrease in stiffness of starchy materials over this water content range. Potato granules were examined at water contents of 25-45% wwb and aspects of their rheo logical behaviour characterized using different approaches. A first approximation used the shear viscosity-shear rate power law which produced a law exponent for the resulting pastes (0.1-0.2). The classical Benbow equation was used to estimate yield and wall shear stresses in capillary flow. The latter indicates the presence of slip which was examined more fully as a function of wall shear stress. The Mooney technique was used together with a variation of the method where the shear rate for each die was subtracted from that for a non-slip flow, which was approximated using rough dies. A critical wall shear stress for slip was found to be 0.05-0.1 MPa, making it consistent with published results for other materials.

Water and ethanol adsorption on starchy and cellulosic substrates as biomass separation systems

Adsorption of water and ethanol on to one cellulosic and five starchy materials of constant particle size has been studied in the temperature range of 50 – 90°C using inverse gas chromatography (IGC). The results showed that all substrates adsorbed water to a greater extent than ethanol, at all temperatures. On the other hand, the type of adsorber affected the adsorption of water more significantly than that of ethanol. Starchy materials showed a greater separation capacity compared to the cellulosic material. From the chromatographic retention data it was possible to calculate the separation factors for the two solutes and to obtain values for thermodynamic parameters such as Gibb’s free energy (ΔGs) and the enthalpy (ΔHs) of adsorption of water and ethanol on to the substrates. Calculated ΔGs values revealed that the adsorption of both solutes was more spontaneous at lower temperatures, as expected. The ΔHs values obtained for water were significantly higher than those for ethanol, indicating stronger water/substrate interactions. Wheatflour of 70% rate extraction proved to be the substrate with the highest separation factor at all temperatures.

A fractal isotherm for multilayer adsorption in foods

The effect of the fractal surface on physical adsorption has been analysed and a new three-parametric isotherm equation was derived. The model describes the multilayer adsorption on fractal surfaces within the framework of BET theory. It predicts lower buildup of the multilayer coverage on a fractal surface than on a flat surface. The results of the simulation show that increasing the fractal dimension of the surface affects the adsorption isotherms; namely, the upward curvature of the isotherms at high relative pressures is decreased as D increases. For the submonolayer region, the curves become independent of the fractal nature of the absorbent. The isothermal data for water vapor sorption on grains and other starchy materials were used to evaluate the new isotherm equation. The parameters of the isotherms were calculated using computational regression techniques. Fractal dimension ranged from 2.6 to 2.9, approximately, indicating the contribution of the pore structure to the sorption capacity of the products investigated. Results show that the model allows an accurate and simple description of the sorption data for the whole range of water activity.

Mathematical models of non-steady states in a continuous culture system

In order to develop a methodology of analysis, mathematical modelling (simulation) and calculation of non-steady states in continuous mixing flow apparatus (CMFA), well-known dynamic differential equations are considered, extended and solved for practical problems. Two types of non-steady states have been studied: (1) the filling process in CMFA before continuous cultivation; (2) transient responses for continuous flow cultivation in CMFA prompted changes in process conditions (dilution rate and feed concentration). The theoretical analysis of these process dynamics shows the possibility of analytical solutions and satisfactory numerical calculation. Such methodology enables us to design the required filling process, to provide the optimal steady state for continuous cultivation and achieve the maximum biomass productivity for non-steady states. The methodology is illustrated by experimental data and numerical examples for ethanol production from starchy raw material.

A Rapid Method for the Determination of Amylose Content by Using Differential‐Scanning Calorimetry

AbstractA calorimetric procedure to measure amylose content of various starchy raw materials has been developed. It is based on the measurement by Differential Scanning Calorimetry (DSC) of the enthalpy change of the formation of complexes between amylose and add phospholipid (L‐α‐lysophosphatidylcholine from egg yolk) observed during cooling. Contrasting to the colorimetric determination of amylose, the DSC procedure is not influenced by the presence of amylopectin or indigenous lipids. For rice and maize flours, the amylose content determinations are very similar for both colorimetric and DSC methodologies whether the starchy material was raw or pre‐cooked. But the DSC methodology is more repeatable and time saving; in particular, the defatting and starch determination steps can be omitted.