Dry Solids Basis Research Articles

Dewatering of pulp and paper mill biosludge and primary sludge

Dewatering and handling of pulp and paper mill sludge is challenging and often comprises more than half of the overall wastewater treatment costs at a mill. Primary sludge is usually more dewaterable than biosludge (waste activated sludge), and the ratio between both types of sludge largely determines the dewaterability of the sludge mix. This study has quantified the benefits of adding primary sludge to biosludge to enhance the dewaterability in terms of cake solids and filtrate/pressate solids content. Furthermore, the effects of the particle size distribution and the monovalent to divalent cation ratio of the various types of sludge were investigated. Biosludge and three types of primary sludge from a Canadian pulp and paper mill were mixed at various ratios and tested for dewaterability using a Crown Press®, a bench-scale device which simulates industrial belt press dewatering. Results show that after addition of primary sludge at up to 40% mass proportion (dry solids basis) the dewatered cake solids content increased substantially, from 10.4% to 18.7–19.9%, depending on the type of primary sludge added. Further addition of primary sludge led to comparably only small improvements. Primary sludge addition also resulted in decreased total suspended solids (TSS) concentrations in the combined gravity filtrate / Crown Press pressate. Primary sludge content of only 10% in the sludge mix was sufficient to decrease the TSS concentration from 1.8 g/L to 0.2 – 0.4 g/L. The study shows that only less than half of the sludge mix needs to consist of primary sludge, in order to achieve adequate dewaterability. This opens up the possibility of retaining more primary fiber within the pulping process, without compromising downstream sludge dewatering.

Separation Behaviour of Iron Ore Fines in Kelsey Centrifugal Jig

Kelsey Centrifugal Jig was found to be promising for the beneficiation of fine iron particles. The present study was carried out to have a better understanding of the separation process of Kelsey Jig through detailed experimentation. Beneficiation of fine iron ore fines was studied in Kelsey Jig. A constant pulp density (25% solids) of the feed slurry was maintained in the study. The feed rate was also kept constant at 60 kg/hr (dry solids basis). Magnetite of size -0.853+0.6 mmwas used as ragging material to avoid the pegging of internal screen having an opening of 425 μm. The rotational speed was found to have significant effect on the depth of the ragging bed and its porosity. Pulsation was identified as the key factor in stratifying the iron bed and defining the misplacement as well as ragging bed porosity, influencing the mass yield and quality of product.

Influence of water treatment residuals on dewaterability of wastewater biosolids

Co-dewatering of water treatment residuals (WTR) and wastewater biosolids can potentially benefit municipalities by reducing processing equipment and costs. This study investigated dewaterability (using capillary suction time, CST) of combined alum residuals (Al-WTR) and anaerobically digested biosolids at various blending ratios (BR), defined as the mass ratio of WTR to biosolids on a dry solids basis. Without polymer addition, the CST was 160 s for a BR of 0.75 compared with 355 s for the biosolids alone. The optimum polymer dose (OPD), defined as the polymer dose yielding CST of 20 s, was reduced from 20.6 g kg(-1) dry solids for the biosolids alone to 16.3 and 12.6 g kg(-1) when BR was 0.75 and 1.5, respectively. Precipitated Al hydrous oxides in the WTR likely caused flocculation of the biosolids particles through heterocoagulation or charge neutralization. The solids contents of the blended materials and biosolids at their respective OPDs were not statistically different (α = 0.05) following dewatering by a belt-filter press. We conclude addition of Al-WTR improved biosolids dewaterability and reduced polymer dosage. In practice, the extent of these benefits may be limited by the quantity of WTR produced relative to the amount of wastewater solids generated by a municipality.

Analysis of the Leaching Efficiency of Inhibited Water and Tank Simulant in Removing Residues on Thermowell Pipes

A cleaning protocol was determined and modeled, using the shrinking core model, for the removal of a solid residue coating thermo well pipes contained in the riser of a Savannah River Site (SRS) waste tank (Tank 48H). The solid residues on two sets of thermo well pipe samples removed from the D2 riser in SRS Tank 48H were characterized by high performance liquid chromatography (HPLC), ion chromatography (IC) and gamma spectroscopy. The residue thickness was determined using the ASTM standard D 3483-05 and was found to be three orders of magnitudes below the 1 mm thickness estimated from an earlier video of the tank cooling coil inspection. The actual estimated thickness ranged from 4 to 20.4 microns. The mass per unit area ranged from 0.15 to 0.82 milligrams per square centimeter. The residues appear to consist primarily of potassium tetraphenylborate (39.8 wt% KTPB) and dried salt solution (33.5 wt% total of nitrates, nitrites, and oxalate salts), although ∼30% of the solid mass was not accounted for in the mass balance. No evidence of residue buildup was found inside the pipe, as expected. Two aqueous solutions representing waste processing streams were chosen for the cleaning trials. The residue leaching characteristics were measured by placing one pipe in inhibited water (0.01 M NaNO2 and 0.01 M NaOH) and one pipe in Defense Waste Processing Facility (DWPF) Recycle simulant (primarily 0.20 M NaNO2 and 0.18 M NaOH). After soaking for less than 4 weeks, the inhibited water was 95.4% effective at removing the residue and the DWPF Recycle simulant was 93.5% effective. The surface appearance of the pipes after leaching tests appeared close to the clean shiny appearance of a new pipe. Total gamma counts of leachates averaged 48.1 dpm/mL, or an equivalent of 2.35E-11 Ci/gm Cs-137 (dry solids basis), which is much lower than the 1.4 E-03 Ci/gm expected for Tank 48H dry slurry solids.

Pretreatment of wheat straw using steam, steam/acetic acid and steam/ethanol and its enzymatic hydrolysis for sugar production

Wheat straw is a suitable raw material for ethanol production, since it has a high cellulose content. In the bioconversion of lignocellulosic materials to ethanol, pretreatment of the material prior to enzymatic hydrolysis is essential to obtain high overall yields of sugar and ethanol. The objective here is to find additives which increase the efficiency of the sugar production. The pretreatment of wheat straw by steam explosion soaked with acetic acid or ethanol prior to the pretreatment was investigated by varying the temperature (180–225) °C and the retention time (3–60 min). The results showed that the pretreatment of wheat straw by steam explosion with soaked with acetic acid or ethanol was more effective than that by steam explosion alone. Additionally, the pretreatment of wheat straw by steam explosion at 210 °C and 10 min, by steam/acetic acid at 220 °C and 8 min and by steam/ethanol at 220 °C and 5 min resulted in the best overall yield of reducing sugar which was found to be 177.3 g kg −1 on dry solids (DS) basis, 244.1 g kg −1 DS, and 264.3 g kg −1 DS, respectively.

Comparison of the Mechanical Properties of Cellulose and Starch Films

Some effects of water at levels up to 25% (dry solids basis db) on regenerated cellulose films with a thickness of 100 mum were investigated by dynamic vapor sorption (DVS), X-ray diffraction, tensile testing, and proton-nuclear magnetic resonance (NMR). The sorption isotherm fitted by the D'Arcy and Watt model and the increase in NMR T(2) with water content suggest that a mobile water fraction appears at water contents above 10%db. Water absorption increased the crystallinity of cellulose films from 31% (dry) to 38% (25%db) and altered the dimensions of crystallites. Mechanical measurements on planar and notched samples at all the water contents used here showed ductile fracture behavior. Although the properties of water in these cellulose films are comparable to previously reported data on starch, cellulose films at low water content are much less brittle than starch. The reasons for this difference are explored.

Utilization of Oxidized and Cross‐Linked Corn Starches in Wheat Flour Batter

ABSTRACTStarch is often added to batters to improve the texture and appearance of fried food products. However, comparisons of commercially available starches in terms of batter characteristics are rare. In this study, various corn starches, native or modified, were mixed with wheat flour (20% dry solids basis), and the physical properties of the batters after deep‐fat frying were examined. Native corn starches of different amylose contents (high‐amylose, normal, and waxy) and chemically modified corn starches (oxidized and cross‐linked) were tested. The batter was prepared by adding water to the starch‐flour mixtures (42% solids) and deep‐fat frying at 180°C for 30 sec. The texture of the fried batter was analyzed using a texture analyzer (TA) with a Kramer shear cell. The pasting viscosity profile of the starch‐flour mixtures (7% solids in water) was also measured with a Rapid Visco Analyser. When the native corn starches of different amylose contents were compared, the crispness (peak number before breakage) and hardness (maximum peak force) measured using the instrument were positively correlated with the amylose content in starches but negatively correlated with the residual moisture content of the fried batters. The peak viscosity and breakdown in viscosity profiles of the starch‐flour mixtures were also negatively correlated with crispness. The use of high‐amylose corn starch was effective not only in increasing the crispness, but also in reducing the oil uptake. However, the fried batter containing high‐amylose starch was denser and harder than the batter containing normal starch. Among the modified starches tested, oxidized (0.4% active Cl2) and cross‐linked (4% 99:1 mixture of STMP and STPP) starches showed improvements in the overall properties of the fried batters. With excessive oxidizations (>0.4% Cl2), however, the crispness was reduced.

Gelcasting of alumina foams using agarose solutions

Aqueous gelcasting of dense or cellular ceramics by using biopolymers as gel-formers, instead of monomers, is a promising technology mainly in terms of environmental aspects. The main difficulty of using biopolymer solutions in processing of cellular ceramics by foaming method is their high viscosity, which prevents the foaming capacity of the ceramic suspension. In this work, the procedure for preparing concentrated agarose solutions (4 wt.%) by dissolving under overpressure conditions was evaluated for the gelcasting of alumina foams, and the rheological behaviour of alumina suspensions containing agarose was studied. The viscosity of the gelling solution obtained under overpressure conditions was lower than that prepared by simply heating at 90 °C, thus providing high foaming capacity of the alumina suspensions and consequently manufacturing of highly porous ceramics (86–90%). The microstructure of alumina foams was typically composed of approximately spherical cells interconnected by circular windows. The use of different agarose concentrations in alumina suspensions effected the rheological conditions, which resulted in changes in the pore and window sizes of the resulting ceramics. Depending on agarose concentration (0.50–1.0 wt.% on a dry solids basis) in the starting (35 vol.%) alumina slurry, the mean pore size ranged from 529 to 375 μm, while the mean window size varied from 113 to 77 μm.

The Retrogradation of Concentrated Wheat Starch Systems

The ageing of non-expanded wheat starch extrudates containing 37% and 51% water on a dry solids basis (d.s.b.) at 25°C was studied using Differential Scanning Calorimetry (DSC), Wide Angle X-ray Diffraction (XRD), proton Nuclear Magnetic Resonance (NMR) relaxometry and Dynamic Mechanical Thermal Analysis (DMTA). The retrogradation rate increased with water content (∼0.02 h−1 at 37% water (d.s.b.) compared to ∼0.06 h−1 at 51%). While a good correlation was found between the DSC, XRD and NMR data, the kinetics of retrogradation measured by DMTA was delayed. The findings were interpreted in terms of the different molecular processes probed by the different techniques. In addition to the kinetics, information on the physical structure of the partially crystalline retrograded materials were obtained. DSC suggested a broad bimodal melting behaviour, which was attributed to the melting of the crystalline structure followed by the dissociation of the double helices. XRD suggested that at both water contents, the recrystallisation of amylopectin led principally to the A-polymorph. DMTA suggested a significant interaction between the amorphous and crystalline phases, with a requirement of a minimum relative crystallinity index of ∼0.8 (e.g. ∼80% of the crystallinity index of the fully retrograded material), before any increase in the elastic modulus (at 25°C) was measured.

Wet Oxidation Treatment of Organic Household Waste Enriched with Wheat Straw for Simultaneous Saccharification and Fermentation into Ethanol

Organic municipal solid waste enriched with wheat straw was subjected to wet-oxidation as a pre-treatment for subsequent enzymatic conversion and fermentation into bio-ethanol. The effect of temperature (185-195 °C), oxygen pressure (3-12 bar) and sodium carbonate (0-2 g l-1) addition on enzymatic cellulose and hemicellulose convertibility was studied at a constant wet oxidation retention time of 10 minutes. An enzyme convertibility assay at high enzyme loading (25 filter paper unit (FPU) g-1 dry solids (DS) added) showed that up to 78% of the cellulose and up to 68% of the hemicellulose in the treated waste could be converted into respectively hexose and pentose sugars compared to 46% for cellulose and 36% for hemicellulose in the raw waste. For all wet oxidation conditions tested, total carbohydrate recoveries were high (> 89%) and 44-66% of the original lignin could be converted into non-toxic carboxylic acids mainly (2.2-4.5 % on DS basis). Simultaneous saccharification and fermentation (SSF) of the treated waste at 10% DS by Saccharomyces cerevisae yielded average ethanol concentrations of 16.5 to 22 g l-1 for enzyme loadings of 5 and 25 FPU g-1 DS, respectively. The cellulose to ethanol conversion efficiency during SSF was 50, 62, 65 and 70% for a total enzyme loading of 5, 10, 15 and 25 FPU g-1 DS, respectively. Hence, this study shows that wet oxidation is a suitable pre-treatment for the conversion of organic waste carbohydrates into ethanol and that compatible conversion yields (60-65%) can be achieved at moderate enzyme loadings.

Effects of sugars and sugar alcohols on thermal transition and cold stability of corn starch gel

Various sugars and sugar alcohols (ribose, xylose, glucose, fructose, mannose, sucrose, maltose, isomaltose, trehalose, xylitol, mannitol, and sorbitol) were compared in their effects on thermal transitions and cold-storage stability of a corn starch–sugar gel (40% starch, starch:sugar=10:1 or 10:3 dry solids basis) using a differential scanning calorimetry. As the molar concentration of sugar increased, the onset temperature and enthalpy for starch melting were increased. Among the sugars, the samples with disaccharides exhibited higher onset temperature and enthalpy than those with monosaccharides at the same molar concentration. Under cold storage (4 or −20 °C), the sugars facilitated amylopectin recrystallization. Fructose and isomaltose produced higher degrees of amylopectin recrystallization than did other sugars. Sugar alcohols produced slightly greater recrystallization than did the corresponding sugars. Ice melting temperature and glass transition temperature ( T′ g) of the freeze-concentrated phase were decreased as the molar concentration of sugars increased, and there was no or little dependence on the chemical structure of sugars. Ice melting enthalpy for the gels showed no clear dependence on sugar concentration or structure. Sucrose addition lowered the ice melting enthalpy (ice formation by rapid freezing), whereas isomaltose or trehalose addition raised it. By cold storage, the T′ g of the starch gels was increased, whereas the ice melting enthalpy was decreased, as a result of water consumption for starch recrystallization. In the gel system (40% starch), sugar addition (10 or 30% based on starch) enhanced starch recrystallization, but decreased the ice melting and glass transition temperatures.

Moisture sorption isotherm characteristics of plantain ( Musa, AAB)

Moisture sorption isotherms of fresh, pre-treated and freeze-dried plantain, at 40°C, 50°C and 60°C, were constructed using the static gravimetric method. The pre-treatment involved blanching and infusion in 40° Brix sucrose at 4°C for 16 h. The isotherms of the fresh plantain were of BET type II, while those of the freeze-dried samples were BET type I. Hysteresis was observed between the adsorption isotherm of the freeze-dried plantain and the desorption isotherm of the fresh samples. At low values of a w, below 0.40, the moisture contents of the pre-treated samples were lower than that of the fresh plantain, at corresponding values of a w. However, above a w 0.50 the reverse applied. In both desorption and adsorption an increase in temperature resulted in lower equilibrium moisture contents at corresponding values of a w. The monolayer moisture contents of the moist-infused and freeze-dried samples were lower than those of the fresh material. Of the five models tested the Henderson, S. M. (1952, Agricultural Engineering 33, 29–32) and GAB (1981) versions fitted best to the isotherms of the fresh material. The Iglesias & Chirife model (1978) was the best fit to the isotherm of the infused material. The isosteric heat of sorption for the fresh plantain, ranged from 47.4 kJ/g mol at 18% moisture, dry solids basis, to 73.2 kJ/g mol at 2% moisture, dry solids basis. The comparable range for the freeze-dried material was 42.2–635 kJ /g. mol.

Bleu cheese flavor production by submerged fermentation with on-line monitoring by gas chromatography

Eight cultures ofPenicillium roqueforti and related species were compared in shake-flask cultures on the basis of aroma.P. decumbens IFO 7091 was chosen as having the aroma closest to real Bleu cheese, and was used for fermentation studies. Gas chromatography was employed to obtain a continuous record of 2-pentanone concentration in the fermentor. Methyl ketones are characteristic of Bleu cheese flavor, and a subjective correlation was observed between the aroma of the fermentor off-gas and the 2-pentanone concentration measured. Cell growth and milk fat utilization increased consistently with increasing agitation and aeration, but 2-pentanone production did not correlate with growth and was maximum at intermediate values of agitation and aeration. The maximum 2-pentanone concentration, 100 ppm, was approximately ten times the concentration in Bleu cheese on a dry solids basis. Production of Bleu cheese flavor by submerged fermentation offers the opportunity for a new commercial value-added product from butterfat.

Maturation profiles of cheddar-type cheese produced from high heat treatment milk to incorporate whey protein.

The whey proteins account for over 22% of the total milk protein and in the manufacture of cheese by traditional methodology, these nutritionally valuable proteins are lost in whey. It has been calculated (Banks et al. 1994) that if this protein could be incorporated into cheddar cheese, a yield increase of 11.5% on a dry solids basis would be expected.

Effects of freezing on toxicity of sediments contaminated with ddt and endrin

AbstractTwo freshwater sediments containing 3 and 11% total organic carbon (TOC) were spiked with DDT and endrin to compare the effects of cold (4°C) and frozen (−20°C) storage of the sediment on toxicity to the amphipod Hyalella azteca in 10‐d tests. Toxicity of the DDT‐spiked sediment was reduced when it was frozen for 14 d. LC50 values for cold‐stored and frozen‐stored sediments were 4.2 and 7.3 μg/g DDT (calculated on dry solids basis) at 3% sediment TOC and 11.1 and 23.2 μg/g DDT at 11% sediment TOC, respectively. Toxicity of the 3% TOC endrin‐spiked sediment was reduced by freezing; it exhibited LC50s of 5.1 and 7.7 μg/g endrin, respectively, for cold and frozen storage. Toxicity of endrin in two tests in the 11% TOC sediment remained essentially unchanged by freezing. LC50s were 19.6 and 21.7 μg/g endrin for cold and frozen sediments in one test and 10.3 and 9.8 μg/g endrin in the second test. Decreased toxicity was assumed to be related to the release of soluble organic carbon from the sediments during freezing and thawing. Relative differences in toxicity between DDT and endrin for cold and frozen sediments appear to be related to the different adsorptions of the chemicals onto the released carbon.

Enhanced ultrafiltration flux rates by enzymatic hydrolysis in protein recovery from wheat starch effluent

Wheat starch effluent contains several polysaccharide species which contribute to the formation of a viscous gel layer in the ultrafiltration of wheat starch effluent. Viscosity reduction tests with various hydrolytic enzymes on a wheat starch effluent concentrate revealed a commercial pentosanase, “Brew-N-Zyme Pentosanase” (Naarden), which was very effective at low doses (0.05 wt.% dry solids basis), was thermally stable at the ultrafiltration temperature of 70°C and had no proteolytic activity. Enzymatic hydrolysis considerably increased the permeate flux rate and the maximum achievable concentration in the ultrafiltration of wheat starch effluent from 9 to 18 wt.% solids. Flux-concentration profiles for wheat starch effluent and enzymatically hydrolyzed wheat starch effluent were closely fitted by modified mass transfer and pressure-driven models. The main resistance to permeate flux at the initial wheat starch effluent concentration was caused by adsorption of macromolecules on the surface of the membrane. This accounted for 57% of the total resistance for wheat starch effluent and 78% for enzymatically hydrolyzed wheat starch effluent. Enzymatic hydrolysis reduced the viscosity of the gel layer which was thus more easily removed by shear stress. Reduction of the thickness of the polysaccharide gel layer exposed the membrane to greater adsorption of macromolecules. At the final ultrafiltration concentration the reverse situation applied. The gel layer formed the most significant resistance accounting for 93% of the total resistance for wheat starch effluent and 80% for enzymatically hydrolyzed wheat starch effluent. In both systems, wall shear stress performed the important function of removing the mass flux of macromolecular material which impacted onto the surface of the gel layer.

Veal Calf Waste Production and Composition

Volume and composition of fresh waste were deter-mined from 12 newborn male Holstein veal calves during a 14-week trial. Total waste (feces and urine) was collected daily from beneath the slatted floors of each individual wooden calf pen, weighed, and a subsample obtained for analysis. Daily composite aliquots of fresh waste from all calves were placed in triplicate simulated anaerobic pits. Average total daily waste production over the trial was 3470 g (7.64 lb) per day or 3.96% of the calf s live weight. Average daily total solids (dry solids basis) production over the trial was 120 g (0.26 lb) per calf per day or 0.132% of the calf s live weight. As a percentage of live weight, total waste production decreased with increased calf size. Fresh manure (wet basis) contained a relatively small amount of total solids (3.4%), but high total nitrogen (0.41%) ammonium nitrogen (0.22%), phosphorus (0.13%), potassium (0.56%), and sodium (0.24%), as well as high pH (8.08). After 17 weeks of anaerobic storage, total solids content decreased 12%, and total nitrogen loss was 23%. The percentage of total nitrogen in the ammonium nitrogen form was 52.8% in fresh waste compared with 93.4% after storage in anaerobic pits.

Extrusion behaviour of different soya isolates and the effect of particle size

Eleven different commerically produced soya isolates, and one defatted soya flour, were extruded at temperatures of 120 and 180 °C at a moisture content of 35% on a dry solids basis (dsb), using a Brabender laboratory extruder. The pressure, torque and flow rate during extrusion, and product expansion and texture of the final extrudate following rehydration varied considerably between different soya isolate preparations. Analysis by multiple regression yielded about twenty significant (P < 0.05) correlations between the three extrusion variables (pressure, torque and flow rate), the four feed variables (bulk density, solubility in water, particle size distribution and angle of slope) and the three extrudate characteristics (resistance to shear, solubility in water and product diameter) measured. It was concluded that the best extrusion behaviour was obtained with feed containing insoluble but native protein. Fine powders containing insoluble protein were less prone to agglomeration, and, hence, were easier to feed than powders containing high levels of soluble protein. In addition, higher shear force values after retorting were obtained with extruded products prepared from feed containing insoluble, but native protein. This was interpreted in terms of the formation during extrusion of covalent disulphide linkage between initially insoluble regions of protein. The wide variation in extrusion behaviour of chemically similar materials prepared in different ways suggests that extrusion studies on single materials should be interpreted with caution.

Effect of Sludge Application on Physical Properties of a Silty Clay Loam Soil

AbstractThis study was conducted to elucidate the long‐term effect of dewatered sludge application on a silty clay loam soil, which possesses poor permeability and other undesirable physical properties. A Zimpro®‐processed dewatered sludge was applied in early 1977 at treatment rates of 0, 11.2, 22.4, 44.8, and 112.0 Mg ha−1 (dry solids basis) to a Kewaunee silty clay loam soil (Typic Hapludalf). A sixth treatment was an annual application of 22.4 Mg ha−1 from 1977 to 1982, resulting in a total input of 134.4 Mg ha−1.Bulk density, infiltration, hydraulic conductivity, and aggregate stability were measured $ yr after application (note: fifth year of annual sludge application at 22.4 Mg ha−1). The bulk density decreased by 0, 0.7, 3.5, 8.3, and 6.3% over the control for the 11.2, 22.4, 44.8, 112.0, and 134.4 Mg ha−1 of sludge treatment, respectively. The hydraulic conductivities of saturated soil cores were 0, 4.2, 45.4, 70.2, and 70.6% higher for the 11.2, 22.4, 44.8, 112.0, and 134.4 Mg ha−1 sludge treatment, respectively, over the control. The improved soil permeability was due to the enhancement of aggregate stability, which increased relative to the control by 3.3, 9.4, and 11.9% with the 44.8, 112.0, and 134.4 Mg ha−1 treatment, respectively. The in situ volumetric moisture content of the sludge‐treated soils was always higher than the control, especially after a prolonged period of evaporation. At 33.3 kPa or less, more water was released from soils treated with high rates of sludges. This indicated an increase in the volume of larger pores, which resulted in the higher hydraulic conductivities.Lower rates of sludge treatments (11.2 and 22.4 Mg ha−1) had no effects on the soil physical properties after 5 yr. Small yearly applications improved the soil physical properties equally as well as a single large application.

Reinvestigation of potato starch volume during the sorption process

A thorough reinvestigation of the dependence of the specific volume of potato starch on water ad- and desorption is described. Measurements by toluene pycnometry show that hysteresis only occurs between 0 and 13% H 2O (dry solids basis). The results are interpreted in terms of a progressive filling of intergranular voids by water molecules of equivalent constant density. Other results give information on bulk starch density, thermal expansion coefficients, the influence of different immersion liquids and the effect of the different physical states of starchy products (dry gels and acid hydrolysed fractions).